BMC Medical Informatics and Decision Making Utilization of the PICO framework to improve searching PubMed for clinical questions

Connie Schardt email@example.com
Medical Center Library
Duke University
DUMCBox 370227710DurhamNorth CarolinaUSA

Martha B Adams
Department of Medicine
Duke University Medical Center
Box 322827710DurhamNorth CarolinaUSA

Thomas Owens email@example.com
Department of Medicine
Duke University Medical Center
Box 367527710DurhamNorth CarolinaUSA

Sheri Keitz firstname.lastname@example.com
Department of Medicine (111)
VAMC
1201 NW 16th St33125MiamiMiami, FloridaUSA

Paul Fontelo firstname.lastname@example.com*correspondingauthor†equalcontributors
National Library of Medicine
8600, 20894Rockville Pike, BethesdaMarylandUSA

BMC Medical Informatics and Decision Making Utilization of the PICO framework to improve searching PubMed for clinical questions
10.1186/1472-6947-7-16BioMed Central Page 1 of 6 (page number not for citation purposes) Research article
Background: Supporting 21 st century health care and the practice of evidence-based medicine (EBM) requires ubiquitous access to clinical information and to knowledge-based resources to answer clinical questions. Many questions go unanswered, however, due to lack of skills in formulating questions, crafting effective search strategies, and accessing databases to identify best levels of evidence.Methods: This randomized trial was designed as a pilot study to measure the relevancy of search results using three different interfaces for the PubMed search system. Two of the search interfaces utilized a specific framework called PICO, which was designed to focus clinical questions and to prompt for publication type or type of question asked. The third interface was the standard PubMed interface readily available on the Web. Study subjects were recruited from interns and residents on an inpatient general medicine rotation at an academic medical center in the US. Thirty-one subjects were randomized to one of the three interfaces, given 3 clinical questions, and asked to search PubMed for a set of relevant articles that would provide an answer for each question. The success of the search results was determined by a precision score, which compared the number of relevant or gold standard articles retrieved in a result set to the total number of articles retrieved in that set.Results: Participants using the PICO templates (Protocol A or Protocol B) had higher precision scores for each question than the participants who used Protocol C, the standard PubMed Web interface. (Question 1: A = 35%, B = 28%, C = 20%; Question 2: A = 5%, B = 6%, C = 4%; Question 3: A = 1%, B = 0%, C = 0%) 95% confidence intervals were calculated for the precision for each question using a lower boundary of zero. However, the 95% confidence limits were overlapping, suggesting no statistical difference between the groups.Conclusion:Due to the small number of searches for each arm, this pilot study could not demonstrate a statistically significant difference between the search protocols. However there was a trend towards higher precision that needs to be investigated in a larger study to determine if PICO can improve the relevancy of search results.

Background

Practicing evidence-based medicine (EBM) requires integration of clinical experience, the best available research evidence, and the values and preferences of the patient into the clinical decision-making process [1]. The steps in practicing EBM are centered on the patient and involve asking well-focused questions, searching for the best available evidence, appraising that evidence for validity, and then applying the results to the care of the patient. Supporting 21 st century health care and the practice of EBM requires ubiquitous access to clinical information and to knowledge-based resources. Clinicians and educators currently utilize a variety of resources and interfaces to search the biomedical literature to answer clinical questions. PubMed is a service of the U.S. National Library of Medicine (NLM) that provides access to over 16 million citations from MEDLINE and other life science journals dating back to the 1950s [2]. Since 1997, PubMed has been freely available to physicians, researchers, and the public. The information obtained from literature searches in PubMed can have a significant impact on patient care and clinical outcomes. Crowley et al reported on a study of 625 clinical questions asked by residents during an inhospital general medicine rotation. Seventy-seven percent of the answers to these questions came from MEDLINE and the information from the articles changed patient management 47% of the time [3]. Klein et al. showed that conducting a MEDLINE search early in the hospitalization of a patient could significantly lower costs, charges, and lengths of stay [4]. Westbrook et al reported that the use of an online information retrieval system improved the quality of clinicians' answers to clinical questions by 21% [5]. The literature also reports that many clinical questions go unanswered due to difficulties formulating a relevant question [6], forgetting the question [7], lack of access to information resources, and lack of skills in searching [8].

Formulating a well-focused question is the first and arguably the most important step in the EBM process. Without a well-focused question, it can be very difficult and time consuming to identify appropriate resources and search for relevant evidence. Practitioners of EBM often use a specialized framework, called PICO, to form the question and facilitate the literature search. PICO stands for Patient problem, Intervention, Comparison, and Outcome. [9] The PICO framework can be expanded to PICOTT, adding information about the Type of question being asked (therapy, diagnosis, prognosis, harm, etc.) and the best Type of study design for that particular question. Using this framework helps the clinician articulate the important parts of the clinical question most applicable to the patient and facilitates the searching process by identifying the key concepts for an effective search strategy. [10,11] PubMed includes a feature called Clinical Queries, which helps identify citations with appropriate study design by linking the type of question (therapy, diagnosis, etiology and prognosis) to a stored search strategy that retrieves the appropriate research methodology. The Clinical Queries are based on extensive research by the Hedges Study Team at McMaster University [12] and have been shown to improve searching results. Combining the PICO framework with the PubMed Clinical Queries has the potential to improve the efficiency of literature searching. Bergus et al reported that questions with at least a defined intervention (I) and outcome (O) were more likely to be answered than questions with one or none of these parameters [13]. The objectives of this pilot study were to measure the relevancy or precision of PubMed search results when using a PICO search framework, to test feasibility of the study design and to identify possible trends.

Methods

This randomized trial was designed as a pilot study to measure the relevancy of search results using three different interfaces for the PubMed search system. Each participant was randomly assigned to one of 3 interfaces for searching PubMed (Figure 1). Protocol A, [14] used a PubMed/PICO template designed for use on a wireless handheld device. The PubMed/PICO template prompted the searcher for the PICO elements of the question (patient problem, intervention, comparison and outcome), as well as patient age group and gender. There was also an option to select a publication type. The publication types listed were clinical trial, randomized controlled trial, meta-analysis, review or practice guideline. If no publication type was selected, the search default was to include all five study designs. The PubMed/PICO template with these publication options was designed to favor questions of therapy, the most common type of question asked by clinicians [3]. Protocol B, [15] used a PubMed/ PICO/Clinical Queries template that prompted for the PICO and allowed the search to be filtered by type of question and scope of strategy (narrow or broad) or by systematic review. Protocol B incorporated the Clinical Queries filters and allowed the searcher to consider a broader range of question types. Because templates for Protocols A and B were designed for handheld devices, participants assigned to these two protocols were given a handheld device of their choice (either a Palm™ Tungsten C or a HP iPAC Pocket PC™) to use during the study. The Web browser home page for the wireless handheld study devices was preconfigured to connect to the appropriate study interface. Protocol C, PubMed, [2] used the standard web-based PubMed system on a PC workstation. Protocol C did not include a PICO template for formulating the search strategy, but the participants had access to Clinical Queries if they chose to use them.

Study subjects were recruited from interns and residents on an inpatient general medicine rotation at an academic medical center in the US. Thirty-one subjects were each given three clinical questions and asked to search PubMed for a set of relevant articles that would provide an answer to the questions. The three study questions were taken from a database of actual clinical questions formulated by residents during general medicine rotations between 2001 and 2002 [3]. Two of the questions (Q2 and Q3) were related to treatment or therapy, the most common type of question asked and one question (Q1) was related to prognosis. (Table 2.) While the PICO framework was developed specifically for therapy questions [16], the prognosis question was included because PICO is being Three interfaces used in searching PubMed taught for all types of questions. Protocol assignments and the 3 clinical questions were placed in a concealed envelope, and participants were asked to select one envelope from a group of identical envelopes. Participants were instructed to search each clinical question, as many times as needed, in order to retrieve a final set of articles that would provide the relevant information needed to make a clinical decision in each case.

The success of the search was measured by comparing the number of relevant citations retrieved to the total number of article retrieved in the final set. The research team identified the relevant articles for each clinical question. The criteria for an article being included as relevant was that it addressed the specific clinical question, including patient, intervention and outcome, and that it was of the best study methodology based on the type of question. For example, a therapy question needed to be answered by a randomized controlled trial, systematic review, or metaanalysis, while a prognosis question required a prospective cohort study. Two researchers conducted PubMed searches for each question. These two and a third researcher selected the relevant articles from the pooled results of the searches. A fourth researcher also reviewed the results and reconciled any disagreement among the other reviewers.

Participants using the handheld devices wrote down their IP address, the time, and the number of citations in the set that best addressed the clinical question. This information was matched with data collected by the project server at NLM and was used to verify the final result set. Participants using the PC workstation were asked to save their final set results to the study account in MyNCBI. Screen captures, a means of saving the image of the search, were made of their complete search history to back up their saved strategies. For all participants, the search terms, date and time of the search, and the Unique Identifiers for the citations retrieved were collected by the system transactions logs and stored on the NLM project server or in MyNCBI. There were no time constraints on any of the participants. The DUMC Institutional Review Board approved the study method and all participants signed an informed consent form.

Results

The primary outcome measurement was the precision of the final result set selected to answer the clinical question. Precision was defined as the ratio of relevant citations retrieved to the total number of citations retrieved in the set. The higher the precision the more efficient the search, as more of what is retrieved is also relevant. The measurement of precision is appropriate in the clinical setting, where it is often desirable to find a few good articles, as opposed to a research setting, where the measurement of recall, finding all possible relevant articles, is more important. We also examined the number of terms and filters used in the search strategy and user satisfaction with the search interface.

Thirty-one residents completed the study. Ten residents were randomized to Protocol A; 10 residents were randomized to Protocol B; and 11 residents were randomized to Protocol C. The results from one participant in Protocol C were discarded because the saved search strategies were corrupted and not useable. All three groups had similar clinical experience and searching experience, although the participants in Protocol A had less training in EBM (Table  1). Participants using the PICO templates (Protocol A or Protocol B) had higher precision scores for each question than the participants who used the standard PubMed system in Protocol C. (Question 1: A = 35%, B = 28%, C = 20%; Question 2: A = 5%, B = 6%, C = 4%; Question 3: A = 1%, B = 0%, C = 0%) 95% confidence intervals were calculated for the precision for each question using a lower  boundary of zero. The 95% confidence limits were overlapping, suggesting no statistical difference between the groups. Although there were no statistical differences between the groups, there may be a trend toward improved precision with the PICO search screens. (Table  2) In addition to quantitative comparisons, this pilot study provided an opportunity for more open-ended insight into how practitioners search. Some searches within each question (Question 1 = 3/30, Question 2 = 9/30, and Question 3 = 27/30) did not retrieve any relevant citations. A qualitative assessment of search strategies that produced no acceptable results revealed three common types of errors: ambiguous mapping of subject headings (MeSH); selecting the wrong publication type; and limiting search queries to just words in the title. The error that accounted for the largest number of non-productive searches was related to the MEDLINE indexing structure or MeSH (Medical Subject Headings). In question three, most searchers used the phrase "African Americans", which maps to the MeSH "African Americans" and retrieves 29077 citations [searched 4/18/07]. However, the common word "blacks" maps to the broader MeSH term "African continental ancestry group" and retrieves 48195 citations [searched 4/18/07]. Most of the relevant citations used either the word "blacks" or were indexed to the broader MeSH term "African continental ancestry group."

The second most common error was related to selecting the wrong study design or Clinical Query for the type of question being searched. This was a common problem for Protocol A, which only listed therapy study designs. The third error affected Protocol C and involved limiting search terms to the title field. While searchers often select their articles based on relevant words in the title, a problem arises when more than one word or phrase is appropriate to the topic. For example, a "peg" is also called a "percutaneous endoscopic gastrostomy tube" or "feeding tube." Limiting the search to the word "peg" in the title eliminates mapping to appropriate subject headings (MeSH) such as intubation, gastrointestinal and therefore may exclude relevant articles on the topic that use alternative terminology. Understanding these errors can help in teaching effective searching and in developing better search systems.

Perceptions of ease of use and time spent searching were approximately the same across all three protocols, as were the numbers of terms used in each search, regardless of protocol used. However, of the 30 searches performed using Protocol B (PubMed/PICO/Clinical Queries), 25 (83%) actually incorporated the Clinical Queries into the strategy, as opposed to only 2 (7%) of the searches using Protocol C (PubMed/Web). Both Protocol A and B facilitated the use of publication types and the Clinical Queries by prompting the searcher to consider these elements in the strategy. While these elements were also available in Protocol C, they are either behind the Limits tab or listed in the PubMed Services menu.

Discussion

Effective searching requires a series of steps to lead the practitioner from the clinical question or bedside to informed decision making. In March of 2005, over 68,000,000 searches were conducted in PubMed, from seven million unique IP addresses. [17] This study attempted to show that targeted interfaces structured to help clinicians search PubMed using the PICO format could affect the relevancy of the results, which ultimately could improve patient care. While this study was intended to look only at the actual search process using the intermediate measure of precision, examining the impact this can have on clinical care requires further research. Even though the standard PubMed search screen provides access to the Clinical Queries function, searchers in Protocol C used it infrequently. Placing the Clinical Queries option directly on the search screen, as in Protocol B, increased the likelihood of their use. This study has several limitations. First, as this study was designed as a pilot for a larger study, the sample size was small and may not have been adequately powered to show a significant difference. Second, we provided the subjects with wellfocused questions, which might have been unrealistic in their simplicity and transfer to the PICO template. In the clinical setting the work of generating questions from clinical situations and translating them into the PICO format may be much more difficult. The success of the search may be much more dependent on asking a good question than on the search framework. Third, we recruited our subjects from a busy general medicine rotation, where EBM is taught and residents are expected to search the literature to address clinical questions. These residents may be more skilled in database searching than at other institutions and therefore generalizing the results to a less experienced population may not be appropriate. Finally, searching PubMed from a handheld may have resulted in some frustration with the searching process, especially if participants were not familiar with the specific devices. Although all residents within the Internal Medicine Residency Program had been given PDAs, none had previously used the device to search PubMed. While this study was not designed to address the technical issues of using handheld devices for searching PubMed, we did test the effectiveness of the search template, which NLM had designed specifically for use on the PDA. Using a handheld device and a PICO template to search the biomedical literature can address some of the barriers of time and access to resources for answering clinical questions.

Conclusion

Searches performed on a PICO-formatted screen retrieved a higher percentage of relevant citations than searches performed on the standard PubMed search interface. However, due to the small number of searches for each arm, this pilot study could not demonstrate a statistically significant difference between the search protocols. There was a suggestion of a trend towards higher precision that needs to be investigated in a larger study to determine if PICO can improve the relevancy of search results.

Figure 1
1Three interfaces used in searching PubMed.

Table 2 :
2Precision of search resultsPICO A
95% CI
PICO B
95% CI
PubMed
95% CI

Q1
35%
16.40% -53.60%
28%
15.84% -40.16%
20%
10.70% -29.30%
Q2
5%
1.42% -8.58%
6%
2.42% -9.58%-
4%
1.50% -6.50%
Q3
1%
-0.43% -2.43%
1%
-0.14% -2.14%
0%
0.00%

Q1: Does BMI affect mortality in obese patients undergoing a CABG?
Q2: Is survival prolonged if I place a PEG or feeding tube in my patient with dementia?
Q3: Is an ACE inhibitor alone better than a diuretic alone for reducing hypertension in African American patients?

Table 1 :
1Baseline characteristics of study participantsProtocol A
N = 10

Protocol B
N = 10

Protocol C
N = 10

Interns
5
5
4
Residents
5
4
5
Other
0
0
1
Previous EBM training
5
9
8
Previous searching
training

10
9
9

How often do you
search MEDLINE?
Daily
3
3
3
Weekly
6
3
5
Monthly or less
1
3
2

(page number not for citation purposes)
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Competing interestsThe author(s) declare that they have no competing interests.Authors' contributionsCS and TO participated in the study design, carried out the study, analyzed the results, and contributed to the writing of the manuscript. MA participated in the study design, carried out the study, and contributed to the writing of the manuscript. SK participated in the study design, analyzed the results, and contributed to the writing of the manuscript. All authors read and approved the final manuscript. FP conceived of the study, participated in the study design, developed the PICO templates, and contributed to the writing of the manuscript. All authors read and approved the final manuscript.Pre-publication historyThe pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-6947/7/16/prepub
Evidence-based medicine: how to practice and teach EBM. S E Straus, London: United Kingdom ElsevierStraus SE: Evidence-based medicine: how to practice and teach EBM. 3rd edition. London: United Kingdom Elsevier; 2005. 2. PubMed [http://www.pubmed.gov]

A Web-based compendium of clinical questions and medical evidence to educate internal medicine residents. S D Crowley, T A Owens, C M Schardt, S I Wardell, J Peterson, S Garrison, S A Keitz, Acad Med. 78Crowley SD, Owens TA, Schardt CM, Wardell SI, Peterson J, Garri- son S, Keitz SA: A Web-based compendium of clinical ques- tions and medical evidence to educate internal medicine residents. Acad Med 2003, 78:270-274.

Effect of online literature searching on length of stay and patient care costs. M S Klein, F V Ross, D L Adams, C M Gilbert, Acad Med. 69Klein MS, Ross FV, Adams DL, Gilbert CM: Effect of online litera- ture searching on length of stay and patient care costs. Acad Med 1994, 69:489-95.

Do online information retrieval systems help experienced clinicians answer clinical questions?. J I Westbrook, E W Coiera, A S Gosling, J Am Med Inform Assoc. 123Westbrook JI, Coiera EW, Gosling AS: Do online information retrieval systems help experienced clinicians answer clinical questions? J Am Med Inform Assoc 2005, 12(3):315-21.

Obstacles to answering doctors' questions aboutpatient care with evidence: qualitative study. J W Ely, J A Osheroff, M H Ebell, M L Chambliss, D C Vinson, J J Stevermer, E Pifer, BMJ. 324710Ely JW, Osheroff JA, Ebell MH, Chambliss ML, Vinson DC, Stevermer JJ, Pifer E: Obstacles to answering doctors' questions aboutpa- tient care with evidence: qualitative study. BMJ 2002, 324:710.

Residents' medical information needs in clinic: are they being met?. M L Green, M A Ciampi, P J Ellis, Am J Med. 109Green ML, Ciampi MA, Ellis PJ: Residents' medical information needs in clinic: are they being met? Am J Med 2000, 109:218-23.

Why do residents fail to answer their clinical questions? A qualitative study of barriers to practicing evidence-based medicine. M L Green, T R Ruff, Acad Med. 80Green ML, Ruff TR: Why do residents fail to answer their clin- ical questions? A qualitative study of barriers to practicing evidence-based medicine. Acad Med 2005, 80:176-82.

The wellbuilt clinical question: a key to evidence-based decisions. W S Richardson, M C Wilson, J Nishikawa, R S Hayward, ACP J Club. 123Richardson WS, Wilson MC, Nishikawa J, Hayward RS: The well- built clinical question: a key to evidence-based decisions. ACP J Club 1995, 123:A12-3.

Improving question formulation for use in evidence appraisalin a tertiary care setting: a randomised controlled trial. E V Villanueva, E A Burrows, P A Fennessy, M Rajendran, J N Anderson, BMC Med Inform Decis Mak. 1:4. EpubVillanueva EV, Burrows EA, Fennessy PA, Rajendran M, Anderson JN: Improving question formulation for use in evidence apprais- alin a tertiary care setting: a randomised controlled trial. BMC Med Inform Decis Mak 2001, 1:4. Epub 2001 Nov 8.

Using the clinical question to teach search strategy: fostering transferable conceptual skills in user education by active learning. R Snowball, Health Libr Rev. 14Snowball R: Using the clinical question to teach search strat- egy: fostering transferable conceptual skills in user education by active learning. Health Libr Rev 1997, 14:167-173.

Hedges Team: Robustness of empirical search strategies for clinical content in MEDLINE. N L Wilczynski, R B Haynes, Proc AMIA Annu Symp. Wilczynski NL, Haynes RB, Hedges Team: Robustness of empiri- cal search strategies for clinical content in MEDLINE. Proc AMIA Annu Symp 2002:904-8.

Family medicine residents do not ask better-formulated clinical questions as they advance in their training. G R Bergus, C S Randall, S D Sinift, D M Rosenthal, Fam Med. 377Bergus GR, Randall CS, Sinift SD, Rosenthal DM: Family medicine residents do not ask better-formulated clinical questions as they advance in their training. Fam Med 2005, 37(7):486-90.

. Pico B, PICO B [http://pubmedhh.nlm.nih.gov/nlm/picostudy/pico2.html]

Evaluation of PICO as a Knowledge Representation for Clinical Questiosns. X Huang, J Lin, D Demner-Fushman, AMIA Annu Symp Proc. Huang X, Lin J, Demner-Fushman D: Evaluation of PICO as a Knowledge Representation for Clinical Questiosns. AMIA Annu Symp Proc 2006:359-63.

. NLM Technical Bulletin. NLM Technical Bulletin 2005 [http://www.nlm.nih.gov/pubs/tech bull/mj05/mj05_mla_dg.html].


Human Activities on the Deep Seafloor in the North East Atlantic: An Assessment of Spatial Extent

Angela R Benn
Ocean Biogeochemistry and Ecosystems Group
National Oceanography Centre Southampton
SouthamptonUnited Kingdom

Philip P Weaver
Geology and Geophysics Group
National Oceanography Centre Southampton
3 MedianSouthampton, ValldoreixUnited Kingdom, Spain

David S M Billet
Ocean Biogeochemistry and Ecosystems Group
National Oceanography Centre Southampton
SouthamptonUnited Kingdom

Sybille Van Den Hove
Institut de Ciència i Tecnologia Ambientals
Universtitat Autò noma de Barcelona
BarcelonaSpain

Andrew P Murdock
GeoData Institute
University of Southampton
SouthamptonUnited Kingdom

Gemma B Doneghan
GeoData Institute
University of Southampton
SouthamptonUnited Kingdom

Tim Le Bas
Geology and Geophysics Group
National Oceanography Centre Southampton
3 MedianSouthampton, ValldoreixUnited Kingdom, Spain

Human Activities on the Deep Seafloor in the North East Atlantic: An Assessment of Spatial Extent

Background: Environmental impacts of human activities on the deep seafloor are of increasing concern. While activities within waters shallower than 200 m have been the focus of previous assessments of anthropogenic impacts, no study has quantified the extent of individual activities or determined the relative severity of each type of impact in the deep sea.Methodology: The OSPAR maritime area of the North East Atlantic was chosen for the study because it is considered to be one of the most heavily impacted by human activities. In addition, it was assumed data would be accessible and comprehensive. Using the available data we map and estimate the spatial extent of five major human activities in the North East Atlantic that impact the deep seafloor: submarine communication cables, marine scientific research, oil and gas industry, bottom trawling and the historical dumping of radioactive waste, munitions and chemical weapons. It was not possible to map military activities. The extent of each activity has been quantified for a single year, 2005.Principal Findings: Human activities on the deep seafloor of the OSPAR area of the North Atlantic are significant but their footprints vary. Some activities have an immediate impact after which seafloor communities could re-establish, while others can continue to make an impact for many years and the impact could extend far beyond the physical disturbance. The spatial extent of waste disposal, telecommunication cables, the hydrocarbon industry and marine research activities is relatively small. The extent of bottom trawling is very significant and, even on the lowest possible estimates, is an order of magnitude greater than the total extent of all the other activities.Conclusions/Significance: To meet future ecosystem-based management and governance objectives for the deep sea significant improvements are required in data collection and availability as well as a greater awareness of the relative impact of each human activity.

Introduction

Environmentally sustainable governance and management requires the availability of reliable and comprehensive information on the natural environment as well as information on the social, economic, legal and political systems. However, even though the deep seafloor covers approximately 60% of Earth's surface [1] only about 0.0001% of it has been the focus of biological scientific investigation [2]. Whilst remoteness and inaccessibility restrict research, they have not protected these depths from human impacts. Increasing demand for living and non-living resources and diminishing or exhausted reserves on land and in shallow water are pushing human activities ever deeper into the world's oceans. At the same time advances in technology now allow access to resources of economic value that were previously inaccessible. This has resulted in an increasing number of direct and indirect anthropogenic pressures on deep-sea ecosystems [1][2][3][4][5][6].

Governance and management of the deep sea is of increasing international concern. The United Nations, the Regional Seas conventions and organisations, including the European Union, are developing marine environment policies as well as monitoring and reporting procedures. Rules and codes of conduct are being established to regulate activities impacting on the deep ocean. For example, the OSPAR Commission has recognised the scientific case for establishing Marine Protected Areas in areas beyond national jurisdiction in the deep North East Atlantic e.g. [7]. It has developed a code of conduct for Responsible Marine Research in the Deep Seas and High Seas of the OSPAR Maritime Area [8] ( Figure 1). The North East Atlantic Fisheries Commission (NEAFC) (Figure 1) has adopted procedures and rules for existing and new bottom-fishing areas aimed at the protection of vulnerable marine habitats [9][10][11][12]. NEAFC and the OSPAR Commission have initiated the first efforts towards multi-sectoral management in the High Seas in the North East Atlantic. Under a new memorandum of understanding, adopted by the two organisations in 2008, an attempt is being made to combine fisheries and conservation management [7].

The requirement for environmental and socio-economic data is recognised in many political forums. The 1995 United Nations (UN) Fish Stocks Agreement calls for the sharing of ''complete and accurate data concerning fishing activities'' [13]. The Convention on Biological Diversity [14] promotes the ecosystem approach as its primary framework for action. The ecosystem approach is a strategy for the integrated management of land, water and living resources that promotes conservation and sustainable use in an equitable way, recognizing that humans and their activities are integral to ecosystems. At the European level, the Marine Strategy Framework Directive (MSFD) [15] and the OSPAR Biological Diversity and Ecosystems Strategy [16] both require assessments of human activities within the marine environment, some of which will be in the deep sea and beyond national jurisdictions. To fulfill these assessments and to implement the ecosystem approach, comprehensive and consistent information on human activities is necessary.

Data on human activities are collected and held i) by public institutions and private companies to fulfill regulatory requirements, ii) for commercial and operational purposes and iii) or for scientific research. In addition, the European Union Directive on Public Access to Environmental Information [17] defines environmental information to include ''measures (including administrative measures), such as policies, legislation, plans, programmes, environmental agreements, and activities affecting or likely to affect the elements and factors …''. These include ''… water, soil, land, landscape and natural sites, … marine areas, biological diversity and its components, … and the interaction among these elements''.

This study assesses, for the first time, the relative spatial extent of major human activities in the deep North East Atlantic, within and beyond Exclusive Economic Zones (EEZs) in the OSPAR maritime area of the North Atlantic (Figure 1), of which 8,517,010 km 2 is deeper than 200 m, during the single year, 2005. The marine ecosystems here are some of the most heavily impacted by human activities [18]. The availability and suitability of data relating to these activities are assessed and the spatial extent of the direct physical impact on the seafloor is quantified. However, the extent of collateral physical impacts, for example smothering caused by sediment plumes and chemical effects on the benthos, for example those related to oil industry cuttings piles, are not assessed. In addition, we do not estimate the wider chemical and biological impacts caused by pollution. In the current study, ''human activities'', identified by reference to literature [1][2][3][4][5], are defined as intentional human activities occurring directly on the sea floor as well as structures and artefacts present on the seafloor resulting from past activities. Previous studies in shallower waters have examined much smaller areas in detail [19,20] , or have looked at single activity impacts [21], whilst some studies such as Halpern et al. [18] have taken a broad global view.

Methods

Data for activities were requested from sources listed in Tables 1, 2 and 3. They were rarely in a format immediately suitable for assessing the spatial extent of each activity. Typically, data were provided as text files or MS Excel sheets with XY point locations of features; for example marine scientific research sample sites or radioactive dumpsites. In the case of vessel tracks or pipelines data were either strings of coordinate points (in text files or MS Excel) or actual GIS datasets (polyline features). As such, these have no areal definition but merely describe the route a vessel took based on its GPS track or location of a point on the seabed.

To define a realistic areal footprint for features, the data were processed in ArcGIS v. 9.3 (Environmental Systems Research Institute) for processing. This industry standard GIS package has tools for 'buffering' spatial features by a specified width (or range of widths). The output of this processing is a polygon shape which is a proxy for the actual spatial location and extent of the features on the seabed (the footprint). The tools operate on point or polyline features and can be used in a variety of coordinate systems. ArcGIS's implementation of the North Pole Lambert Azimuthal Equal Area Conic projection was chosen as appropriate for use within the OSPAR regional extent and is designed to minimise area distortions.

Some of the datasets contained the necessary information to create the areal footprint, for example, known diameters of oil industry pipelines. Where this information was unavailable, values were sought from owners of the assets, industry experts or from published literature values.

Depth zones were identified by reference to the GEBCO dataset (General Bathymetric Chart of the Oceans) [22]. GEBCO is a world bathymetry dataset on a 1 arc minute grid and is the most extensive freely available bathymetric dataset.

Buffer polygons were created for each feature and the area values (automatically created by the GIS) were extracted and totalled to estimate the spatial extent of each activity (Table 4). A confidence rating relating to the quality of data was applied, based on the method described by Eastwood et al. [19]. A score of 1 denotes an estimated location and extent; 2 denotes a known location but estimated extent and 3, a known location and extent. Figure 2 shows the geographical distribution of activities. Where the data used to calculate the estimates did not represent the total extent of an activity in the OSPAR deep water area, (marine research, submarine cables and bottom trawling) a further estimate, extrapolated to represent the total of each activity, was calculated ( Table 5).

The datasets were drawn from a variety of sources. They were collected for a variety of purposes. Some data were only indicative. Some were derived from GPS tracking. Others were surveyed precisely. Therefore, positional accuracies varied. This is a broad scale strategic study and while it is important to obtain as accurate information as possible, the study is considering the relative spatial extent of these activities in the context of the OSPAR region, and small errors are not likely to be significant to the final values. The study quantifies the physical footprint but does not quantify how significant (detrimental or beneficial) these impacts might be on the surrounding ecosystems. This study does not tackle contamination that may be spread away from the specific impact e.g. leakage of radioactivity.

Marine Scientific Research

Marine scientific research is carried out by academic institutions or fisheries research laboratories. Research by academic institutions involves a range of equipment on the seafloor to sample the marine environment including moorings, grabs, corers, dredges and trawls. Much of this equipment has only a single impact of a few square meters. While fisheries research also involves the  deployment of sampling equipment, such as grabs and moorings, it involves a higher proportion of bottom impact trawling. Data were obtained from the seven online sources listed in Table 1 and individual scientists. Twenty four cruises, which took place in water deeper than 200 m and carried out activities on the seafloor, were identified from cruise reports and station lists. A further 29 cruises which may have impacted on the seafloor in water deeper than 200 m were accessed on the ROSCOP website but searches in PANGAEA, BODC and European project databases (e.g. HERMES) did not locate station lists or cruise reports. Cruises for which data were available represent approximately 45% of the total number of cruises identified during 2005 which may have impacted on the seafloor within the OSPAR area listed on the ROSCOP cruise summary. Where cruise reports and station lists were available activities on the seafloor were mapped. According to the footprint size of each piece of equipment buffers were applied to estimate the spatial extent on the seafloor. Where the footprint area of each activity was not included in the cruise report (size of equipment deployed, length and width of trawl) it was estimated based on published literature and advice from individual institutions.

Submarine Communication Cables

Greater than 95% of international communications are routed via submarine fibre-optic cables. In areas where cables are vulnerable to damage from fishing or anchoring (200-1,500 m water depth) they often have one or more layers of armour and can be up to 50 mm in diameter. In waters deeper than 1,500 m, currently beyond the reach of fishing, cables are nonarmoured and are between 17 mm and 20 mm in diameter [23]. An alternative protective measure is the burial of cables in water depths shallower than 1,500 m [23]. During the burial operation a plough opens a furrow in the seafloor into which the cable is laid and the sediment replaced. Skids supporting the plough can leave a footprint on the seabed, particularly in zones of soft sediment, potentially increasing sediment compaction and leading to the disturbance of the marine fauna. The overall width of the disturbance strip produced by the plough-share and skids in direct contact with the seabed ranges from 2 to 8 m width [23]. The spatial extent calculated here represents the width of either the unburied cables on the seafloor or, for buried cables, the footprint of the plough based on the minimum and maximum width of disturbance strips (2 m and 8 m) [23], although it is unlikely that the disturbance strip is 8 m everywhere. Geospatial data for submarine cables were obtained from the two sources listed in Table 1. Kingfisher Information Service -Cable Awareness data were available in Microsoft Excel format to an accuracy of 10 m and France Telecom's SigCables, available as ESRI shape files. These websites, for users of the seabed and, in particular, for skippers of fishing vessels, give cable locations to approximately 25uW, beyond which the water is too deep for the cables to be in danger. As no data were available beyond ,25uW, the cable lines were extrapolated from the final data point provided for each cable to a landfall in the United States or Canada, identified from ICPC, 2008 [24]. The distance to the western boundary of the OSPAR maritime area, 42uW was calculated. Forty five cables were identified with an approximate total length of 75,055 km, which included all of the current in- service systems as at 2005. However, this does not take into account all systems dating back to the start of telegraphic communications. The total approximate length of all cables (including coaxial, fibre optic and telegraph cables but not including military) on the seafloor within the OSPAR area during 2010 is estimated at 184,200 km (Steve Bennett, Global Marine Systems Limited, personal communication). This is the nearest total value obtainable by the study. The spatial extent of cables calculated within this study is estimated to represent approximately 41% of the total area of cables.

Neither dataset reported whether the cables were buried, armoured or non-armoured. Therefore, 4 scenarios have been considered based on the following assumptions:

1. No cable burial at any water depth. Cable diameter 50 mm in water depths 200 m-1,500 m and 20 mm diameter in water depths greater than 1,500 m. 2. No cable burial at any water depth. Cable diameter of 50 mm at all water depths (the maximum diameter of modern, double armoured fibre optic cables [23]). 3. In water depths between 200 m-1,500 m cables buried by a plough with an overall disturbance footprint of 2 m widththe minimum width reported [23]. In water depths greater than 1,500 non-buried cable, 20 mm diameter. 4. In waters depths between 200 m-1,500 m cables buried by a plough with an overall disturbance footprint of 8 m width -the maximum width reported [23]. In water depths greater than 1,500 non-buried cable, 20 mm diameter.

The data were input into ArcGIS. Cables whose entire length was in water ,200 m depth were removed from the dataset. The lines depicting the cables were segmented to account for the different depth zones (200-1,500 m and .1,500 m). The relevant depth zones were extracted from the GEBCO dataset. The linear features were intersected with the depth zones, splitting the line at the boundaries of the zones and the sections were attributed with the required width values (50 mm, 20 mm, 2 m and 8 m). This allowed variable buffers to be created for different sections of each line. The depth contours were simplified in areas of complex geomorphology to avoid adding spurious detail to the calculations. Cables crossing areas of Mid-Atlantic Ridge at depths ,1,500 m were assumed to be 20 mm diameter as there is no cable burial or armouring in this area.

Waste Disposal

This study focused on chemical and conventional munitions and low level radioactive waste dumped prior to the 1996 London Protocol [25]. This protocol came into force on 24 March 2006 and recognised seven categories of waste; i) dredged material; ii) sewage sludge; iii) fish waste (or material resulting from industrial fish processing operations); iv) vessels and platforms or other man-made structures at sea; v) inert, inorganic geological material; vi) organic material of natural origin. The seventh category includes ''bulky items primarily comprising iron, steel, concrete and similar unharmful materials for which the concern is physical impact and limited to those circumstances, where such wastes are generated at locations, such as small islands with isolated communities, having no practicable access to disposal options other than dumping'' [25].

Radioactive waste. Between 1949 and1982 radioactive waste was dumped routinely at sites in the North East Atlantic. It included i)'low level' wastes from nuclear power plant operations; ii) other nuclear fuel cycle operations, including fuel fabrication and reprocessing; iii) radionuclide use in medicine, research and industry and iv) decontamination and dismantling of redundant plant and equipment [26].

In 1983 increasing concern over the continued sea disposal of radioactive waste led the Contracting Parties to the London Convention [27] to adopt a voluntary moratorium on the sea dumping of all types of radioactive waste. Amendments to the Convention, adopted in 1993 , which came into force on 20 February 1994, eventually banned sea dumping of all types of radioactive waste [25]. Twenty five years from this date, contracting parties are required to complete a scientific study relating to all radioactive wastes and other radioactive matter  other than high level wastes, followed by further studies at 25 year intervals [27]. Information relating to dumping sites for radioactive waste was obtained from a single source [26], (Table 1). An estimate of the total area designated for dumping of radioactive waste was 26,323 km 2 , based on the aggregated areas with overlapping boundaries dissolved for each of the four designated sites (Table 6). However, this does not represent the area of seafloor covered by drums of waste so a second estimate of the extent of this activity was based on the tonnage and estimated number of drums (Table 6). Thiel [5] estimates that, in total, between 1949 and 1982, 222,732 drums containing 114,726 tonnes (t) of radioactive waste were dumped at sites in the deep North East Atlantic. This is a mean of ,0.5 t of waste per drum. Of the 42 dumping events listed in [26], 24 events totalling 112,793 t ( Table 6) of waste were deposited in the OSPAR area in waters deeper than 200 m. A second estimate was calculated based on a mean of 0.5 t of waste per drum. It was estimated that there were 225,586 drums within the OSPAR area in waters deeper than 200 m with an approximate area of 1 m 2 per drum [26].

Munitions and chemical weapons. The locations of dumpsites for conventional and chemical munitions were identified by reference to [28] (Table 1). Of the 148 dumpsites recorded, 24 are in waters deeper than 200 m (Table 7). While the locations of dumpsites were reported, there was no indication of the area of each. However, twelve sites are described as a ''scuttled ship''. Based upon this information a nominal square 100 m6100 m was assigned for each site.

Military Activities

It was not possible to estimate the spatial extent of this activity. Requests for information relating to military activities on the seafloor during 2005 were made to sources listed in Table 2. Only the Irish Defence Forces responded, reporting no activities on the seafloor deeper than 200 m during 2005. The UK Ministry of Defence redirected the request to the UK Hydrographic Office for locations of practice and exercise areas, but these provided no specific details of activities. The request to NATO was directed to the NATO Science Department which was unable to help.

Oil and Gas Industry

Geospatial data for oil and gas industry subsurface installations, pipelines and exploration and development wells were obtained from the UK Digital Energy & Atlas Library (UKDEAL) [29] and the Norwegian Petroleum Directorate (NPD) [30] ( Table 1).

The locations of pipelines were reported in the UK and Norwegian datasets but the diameter was recorded only in the UKDEAL data. Diameters for Norwegian pipelines were extracted individually from NPD Facts [31]. These data were imported into ArcGIS. Sections of pipeline in waters 200 m or deeper were identified and buffered to represent their respective diameters.

Neither the UKDEAL nor NPD datasets contained dimensions of other types of installations. Eastwood et al. [19] proposed two categories of installation, 'platform' and 'well' and assigned nominal areas of ,180 m 2 and a diameter of 50 m respectively. The UKDEAL datasets listed one platform and eleven wellheads in waters deeper than 200 m. Circular buffers of 180 m 2 and 50 m diameter were applied to estimate the spatial extent of these features.

Most Norwegian deep water installations are floating platforms with wells drilled through templates on the seafloor. The original downloaded NPD dataset did not include the type of installation but, on request, a dataset was provided which included date installed and type of installation. In waters deeper than 200 m three platforms sited on the seafloor and 230 templates were listed. Four legs sit on the seabed supporting the template which typically covers 416 m 2 of seafloor (Tore Indreiten, Statoil, personal communication). A square buffer of 416 m 2 was applied to estimate the spatial extent of these installations and circular buffers of 180 m 2 were applied to estimate the spatial extent of platforms.

In addition to structures on the seafloor, drill cuttings piles are a part of the footprint of oil and gas operations. A variety of oilbased, synthetic and water-based drilling fluids have been used, each with different technical and environmental properties [32]. Typically, cuttings piles are a mixture of man-made and natural substances containing higher concentrations of metals and hydrocarbons than background sediments. They consist of fragments of rock, mixed with drilling muds [33]. Discharge to the seafloor of oil-based drilling muds and associated cuttings ceased in 1993 and 1996 in Norway and the UK respectively. While water based drilling fluids and cuttings can, with permission, be discharged, used oil-based drilling fluids and cuttings are now either transported to land for processing or injected into the seafloor [34]. Recent photographic surveys carried out by the SERPENT Project (www.serpentproject.com) at exploration drilling sites in the Faroe-Shetland Channel and the Norwegian Sea indicate a mean area of 21,744 m 2 is covered by drill cuttings in the deep sea (SERPENT Project, unpublished data). To estimate the spatial extent of oil and gas industry activities, including the presence of cuttings piles, a circular buffer of 21,744 m 2 (radius of ,83 m) was applied to wells, platforms and templates. This area represents the physical presence of cuttings rather than the extent of biological impacts.

A further component of oil and gas industry activities is the drilling of exploration, development and appraisal wells. In the period up to and including 2005 the UKDEAL and NPD datasets report a total of 1,608 of these in waters deeper than 200 m. Buffers of 21,744 m 2 (radius ,83 m) with overlapping boundaries merged and dissolved were also applied to these wells to estimate the spatial extent of drill cuttings. Of the wells listed, coordinates for 114 UK wells were not readily available. The buffered area for these was estimated from the mean area of the other UK wells.

Bottom Trawling

From 1 January 2005 all vessels i) exceeding 15 m overall length operating in European waters and ii) belonging to contracting parties to the North East Atlantic Fisheries Commission (NEAFC) Vessel

Monitoring System Programme over 24 m overall length operating within the NEAFC Regulatory Area (Figure 1), were required to install and operate satellite-based tracking devices [35,36]. Vessels were required to transmit data at intervals of 2 hours or less to Fishing Monitoring Centres (FMCs) located in the States in which they were registered. (In November 2009 an amendment to the NEAFC convention required data to be transmitted at least once every hour in the NEAFC Regulatory Area [37]). Data relating to vessels operating beyond EEZs (in the NEAFC Regulatory Area) are transmitted from the flag State to NEAFC.

There was no definitive source identifying i) bottom trawling vessels, ii) where trawls started and ended and iii) the size of the gear deployed. Therefore the spatial extent of bottom trawling had to be estimated from VMS datasets. VMS data for 2005 were requested from the sources listed in Table 3. Only France, the UK and NEAFC provided data. These data comprised a reporting code, position, time, date and occasionally details of the catch. No dataset gave any indication of whether the vessel was engaged in fishing at the time the position was reported. Data supplied by the UK, covering UK waters, included information about the type of vessel (e.g. demersal trawler, purse seiner) but this was not reported for all vessels. The French dataset, covering French waters, did not include speed. This had to be calculated by reference to time and distance covered between successive reported positions.

Bottom trawling activity was inferred by examining the course of each vessel in relation to seabed contours and speed. Unlike pelagic trawlers, bottom trawlers, while fishing, are likely to follow the contours of the seafloor [38]. Additionally, deep water bottom trawlers can fish only within a limited range of speeds: 1.5-5.0 knots [3,38] (Tables 8 and 9). The size of the fishing gear was not reported. The possible distance between trawl doors, 22 m, 80 m and 125 m was identified by reference to published literature [39] and personal communication (Dick Ferro, Fisheries Research Services, Aberdeen, UK).

The NEAFC data allowed a detailed study of just one fishery in the OSPAR area in the vicinity of Hatton and Rockall. These data were used to estimate the spatial extent of bottom trawling because it was possible to determine the relationship between vessel movements and seafloor contours. This relationship was less clear for other areas within the NEAFC Regulatory Area and within French and UK waters, consequently these areas were not included in this study. Speed frequency profiles, produced for each vessel in the NEAFC dataset using GeoCrust2.0 software [40], were provided by ICES. These profiles identified vessels with peaks of activity the 1.5-5.0 knot range. As a further check the entire 2005 NEAFC dataset comprising 797 vessels was imported into ArcGIS and patterns of vessel activity, following seafloor contours were studied. Twenty eight vessels were identified as engaged in bottom trawling in the Hatton -Rockall area. All vessels not considered to be bottom trawling were removed from the dataset. Data for the remaining 28 vessels were filtered to remove points with speeds outside the 1.5-5.0 knots range. Data points, within the speed range but lying outside the fishing grounds, in waters too deep to bottom trawl, were also removed. Sequences of consecutive data points were considered to indicate trawling periods. It was decided that each sequence was considered to have ended when the time difference between data points exceeded 2.5 hours. This time difference was chosen because occasionally the time between consecutive signals was greater than 2 hours. The resulting dataset encompassed the full range of speeds identified for bottom trawling (1.5-5.0 knots). Three further datasets were produced for the speed ranges: 3.5-5.0 knots [3], 1.5-4.5 knots [3] and 2.0-3.0 knots [38]. Each spreadsheet was imported into ArcGIS and a point to polyline conversion used to map vessel tracks.

A limitation of this method is that although vessel activity relates to seafloor contours and speeds fall within the range of bottom trawling speeds, is it not certain when fishing gear is in contact with the seafloor. Further limitations are i) the two-hourly signal frequency gives a limited indication of the true speed and activity of vessels, ii) the distances between data points are represented by straight lines so represent the minimum distance covered, iii) the absence of information about gear type and size makes further assumptions necessary.

The estimates of spatial extent of bottom trawling represent a proportion of the true extent of this activity in the OSPAR area as they are based on an analysis of vessels operating only within the Hatton -Rockall area from the NEAFC dataset. Deep water bottom trawling also takes place on the Reykjanes Ridge, the Mid-Atlantic Ridge and the continental slope [41] but these areas were not included in this study.

Results

Marine Scientific Research

There was no single source for marine scientific research cruise data. The quality of station lists and cruise reports ranged from purely narrative, lacking description of equipment and latitude and longitude of sampling sites, to comprehensive, including station number, cast number, type of gear, event, date and time, decimal latitude and longitude, depth, remarks, core length where applicable and institute responsible for sample. Table 4 shows that approximately 22 km 2 of marine research comprised activities carried out by fisheries research vessels and approximately 4 km 2 were attributable to non-fisheries marine research. This includes the tracks of trawls, dredges and sleds and the 'footprint' of individual pieces of static equipment on the seafloor such as corers and grabs, which are removed immediately and the anchor weights of moorings (,1 m 2 ) which remain on the seafloor.

The cruises mapped in this study were estimated to represent approximately 45% of all scientific cruises reported on the ROSCOP website which carried out sampling on the seafloor during 2005 in water depths greater than 200 m in the OSPAR area. Table 5 shows figures extrapolated to include the cruises for which no data were available. Extrapolating these figures gives a total spatial extent of approximately 49 km 2 and 9 km 2 respectively for fisheries and non-fisheries research.

For those data that were available confidence ratings of 2 and 3 denote that the location of activities were, in most instances, available but the extent of individual activities (e.g. size of equipment deployed, length of trawls) were occasionally unreported.

Submarine Communication Cables

The data for this activity were from the two sources listed in Table 1. However, these data do not include all cables present on the seafloor. The complete dataset is only available commercially.

The results for the 4 scenarios (Table 4) considered for submarine communication cables demonstrate that this activity covers a relatively small spatial extent in all cases. The first scenario, giving an estimated 2 km 2 , represents the spatial extent of the physical presence of submarine cables for the study area. The second scenario, giving an estimated area of 4 km 2 , is independent of cable type and burial and uses a single value for cable width. The third scenario, giving an estimated area of 15 km 2 introduces the concept of plough burial and is based on the most conservative estimate of the width of the disturbance strip, 2 m, reported in [23]. The fourth scenario, giving an estimated area of 61 km 2 , is based on the maximum estimated width of disturbance strip of 8 m [23].

The values for scenarios 1 and 2, representing an estimated 41% of all submarine communications cables, can be extrapolated to give an estimate of the total extent of this activity because they Table 9. Spatial extent of seafloor trawled in the Hatton -Rockall area during 2005: overlapping tracks merged. represent the physical presence of cables on or in the seabed ( Table 5). The extrapolated values are 5 km 2 and 10 km 2 respectively. It is not appropriate to extrapolate scenarios 3 and 4 because plough burial was not introduced until the 1980s, all cables laid before that date were laid on the seabed surface. The confidence rating of 1 and 2 denotes that while data relating to the location of submarine cables for areas to ,25uW were available there was no specific indication of the cable diameter or whether it was buried. There was no freely available information for areas beyond 25uW.

Waste Disposal

Radioactive waste. Information relating to dumping sites for radioactive waste was obtained from a single source [26], (Table 1). While the total area designated for dumping of radioactive waste was estimated to be 26,323 km 2 , based on the aggregated areas with overlapping boundaries dissolved for each of the four designated sites (Table 6) this does not represent the area of seafloor covered by drums of waste. A second estimate of ,0.2 km 2 was calculated based on the tonnage, estimated number of drums (Table 6) and the area of each.

The confidence rating of 2 relating to the spatial extent of this activity denotes that while the location is reported the spatial extent is based on an estimated number of drums and drum size.

Munitions and chemical weapons. Inadequate documentation at the time of dumping of chemical weapons and munitions and the subsequent loss or destruction of documentation means that the full extent of this activity is unknown [28]. Accurate information on the quantities, present condition and current location of these materials is lacking [5,28,42]. While the location and type of some conventional and chemical munitions are known, other material is reported to have been dumped outside official dumping areas [43]. Furthermore, movement across the seabed or burial through natural processes or anthropogenic activity, have complicated establishing the locations of dumped munitions [43]. The disposal of redundant munitions has continued intermittently [4]. The most recent known event occurred during 1994 when Portugal, under Sovereign Immunity, scuttled a redundant vessel loaded with .2000 t of surplus munitions 346 km from the Portuguese coast at the edge of their EEZ in .4000 m of water [44].

The total spatial extent for this activity was estimated to be 1.4 km 2 .

While information relating to munitions dumpsites was available openly online [28], lack of knowledge about the precise current location and extent of dumped material is reflected in a confidence rating of 1.

Oil and Gas Industry

The datasets and GIS shapefiles for this activity were downloaded free of charge in February 2008. However UKDEAL shapefiles are now available only on payment of a subscription. Norwegian data remain available without charge.

The estimated spatial extent of oil and gas industry pipelines in water deeper than 200 m was 4 km 2 , while the footprint for structures on the seafloor (platforms, templates and wellheads) totalled 0.2 km 2 . This figure is likely to be an underestimate as it includes only templates, wellheads and platforms. Other equipment and activities such as anchors and rock dumps were not included. The addition of the associated cuttings piles to the latter estimate resulted in a total estimated spatial extent of 3 km 2 . The estimated spatial extent of exploration, development and appraisal wells drilled between 1960 and December 2005 together with the associated cuttings piles totalled approximately 15 km 2 while that for the single year, 2005, totalled 1 km 2 . The total spatial extent of pipelines, structures and associated cuttings piles together with all exploration, appraisal and development wells drilled between 1960 and December 2005 and their associated cuttings piles in water deeper than 200 m was 23.2 km 2 .

Oil and gas industry installations are complex. A wide variety of equipment is used each with its own type of disturbance (e.g. rock dumps, anchors). It has not been possible to evaluate these impacts in this study because data are not readily available. Confidence ratings of 2 and 3 reflect the variations in the quality of data. The UKDEAL dataset reported both location and diameter of pipelines resulting in a confidence rating of 3. Although diameters of Norwegian pipelines were not recorded in the NPD dataset this information was available by searching for each pipeline individually in NPD Facts [31] also giving a confidence rating of 3. Neither dataset indicated the size of individual installations on the seafloor, although the location of each is reported, giving a confidence rating of 2. Similarly, the location of development, appraisal and exploration wells are reported but no indication of the extent of these activities was recorded. It was unclear what type of installation was being referred to in the NPD dataset without following a hyperlink for each individual facility. Although a description of the individual installations was given in the UKDEAL dataset (e.g. clump weight, pipe crossing, wellhead) no indication of dimensions was included.

Bottom Trawling

As there was no definitive source identifying i) bottom trawling vessels, ii) where trawls started and ended and iii) the size of the gear deployed the spatial extent of bottom trawling had to be estimated from analysis of VMS datasets. Willingness to provide VMS datasets varied between States. Only two States out of the nine to which requests for data were made provided VMS datasets. Table 8 shows the total area of seafloor trawled for each speed range, calculated by applying buffering to the vessel tracks of 22 m  (Tables 4 and  8). The greatest possible area trawled, 37,160 km 2 relates to the widest speed range of 1.5-5.0 knots and gear width of 125 m (Tables 4 and 8). Table 9 shows the spatial extent of bottom trawling when overlapping tracks were merged. Even if multiple trawls pass over a section of seafloor during the year only a single area is recorded. The least possible area trawled, 548 km 2 , relates to the narrowest speed range of 2.0-3.0 knots and gear width of 22 m (Tables 4 and  9). The greatest possible area trawled, 13,920 km 2 relates to the widest speed range of 1.5-5.0 knots and gear width of 125 m (Tables 4 and 9). Figure 3 shows the distribution of this activity in the Hatton -Rockall area.

The spatial extent of bottom trawling during 2005 in the Hatton -Rockall area is greater than that of any other activity in the OSPAR region. The most conservative estimate of 548 km 2 is one order of magnitude greater than the largest estimate for impacts by the oil and gas industry, while the estimate of 13,920 km 2 , based on the widest gear (125 m) and widest speed range (1.5-5.0 knots) with overlapping tracks merged is three orders of magnitude greater. The spatial extent for the two scenarios above without merging overlapping tracks is 741 km 2 and 37,160 km 2 respectively. This suggests that much of the seafloor was trawled more than once during the year.

Calculations for the spatial extent of bottom trawling were based on data from only one part of the OSPAR area -Hatton -Rockall. Extrapolations have been made based on the estimate that the Hatton -Rockall area comprises ,50% of the deep sea trawling grounds in the OSPAR area ( Table 5) The confidence rating of 1-2 (Table 4) reflects that while VMS data indicate the position of vessels and fishing can be inferred from speed and course, neither the location nor extent of the bottom impact i.e. actual trawling were reported.

Discussion

The results in Tables 4 and 5 are a first attempt to quantify the extent of human activities in the deep North East Atlantic together with an evaluation of confidence in the data. It is not practicable to present a definitive, unequivocal value for each activity as each encompasses a range of alternatives. Variables include the size of fishing gear, speed ranges within which vessels can operate, width of submarine cables, buried or non-buried cables, the size of individual oil and gas industry installations and extent of cuttings piles. Nevertheless, the figures presented represent the best estimates available and we have provided estimates based on both high and low extremes e.g. for the fishing data. This study has highlighted how complex it is to determine impacts in the deep-sea and how difficult it is to establish a comprehensive baseline for management.

Although the principal scope of this study is to establish the spatial extent of each activity it is worth noting that while some activities have an immediate impact after which seafloor communities may be re-established (albeit on perhaps long timescales), other activities, such as waste disposal, may have an effect for many years and the impact is likely to extend far beyond the physical disturbance.

The results demonstrate that the extent of human activities on the deep-sea floor in the OSPAR area of the North East Atlantic varies widely. Of the activities assessed dumping of waste was found to have the lowest spatial extent. The combined total of radioactive waste, munitions and chemical weapons dumpsites was found to be 1.6 km 2 . The strategy of sea disposal of low level radioactive waste was one of dispersal and dilution rather than containment [45]. The lifetime of the iron drums containing the waste was estimated to be between 15-150 years while bitumen or concrete blocks encasing waste were estimated to last 1000 years [26]. So, although the dumping has ceased, such material may still leak from containers into the environment [26]. The main source of artificial radionuclides in the deep North East Atlantic is from atomic weapons testing carried out during 1960s. However, 233 Pu/ 239+240 Pu isotopic ratios in some samples of the fish Coryphaenoides armatus suggest an influence from the dumped material [46]. Similarly, while the spatial extent of munitions and chemical weapons dumpsites, estimated to be 1.4 km 2 , is a relatively small area, the presence of this material poses a significant risk, particularly when disturbed [28].

Non-fisheries marine scientific research has a relatively small footprint. It is usually carried out by academic institutions using a range of equipment on the seafloor to sample the marine environment including moorings, grabs, corers, dredges and trawls. Much of this equipment has only a single impact of a few square meters. Considerably more research is carried out by academic institutions or fisheries research laboratories to determine fish population size and distribution. The spatial extent of fisheries marine scientific research is moderate. While fisheries research also involves the deployment of sampling equipment, such as grabs and moorings, it involves a higher proportion of bottom impact trawling.

The spatial extent of telecommunication cables is low to moderate depending on the whether cable burial is included in the calculation. The maximum extent of this activity (61 km 2 ), based on an 8 m wide disturbance strip in water depths between 200-1,500 m is likely to be an overestimate. This is because about 20% of cables in 200-1,500 m water depth are not buried and an 8 m wide disturbance strip may be an overestimate in many cases.

The spatial extent of oil and gas industry activities is moderate. While structures such as templates, wellheads, platforms and cuttings piles have been included in the estimates it is likely that this is an underestimate as other equipment and activities, for example, weights, anchors, rock dumps are not included.

A major finding of this study is that the spatial extent of bottom trawling is orders of magnitude greater than that for the other activities assessed. Even on the lowest possible estimates it is an order of magnitude greater than the sum of all the other activities. Despite the extent of this activity the total global catch from bottom fisheries -longliners, gillnetters and bottom trawlerscontributed only 0.31% to the total marine capture during 2006 [47].

The maximum total area impacted by the various activities discussed here is 27,932 km 2 ( Table 5, based on the merged trawler tracks and 50 mm cable diameter data). This is a very small percentage of the total OSPAR area (11,032,175 km 2 ), but such a calculation does not provide useful information. An analogy would be the area of annual destruction of Amazon rainforest as a percentage of the landmass of South America, which would mean far less than destruction as a percentage of the total area of the rainforest. Human activities are concentrated in certain areas and particularly in shallower depths. The OSPAR area also comprises many different habitats each with different and diverse ecosystems. The percentage impact in each of these habitats would provide important information but unfortunately there is virtually no detailed seabed mapping to provide this information.

Conclusions

To meet future ecosystem-based management and governance objectives for the deep sea significant improvements are required in data collection and availability as well as a greater awareness of the relative impact of each human activity. In this paper we have shown the relative physical impacts of different activities with nonfisheries scientific research, submarine communication cables and waste disposal having low physical impacts whilst oil and gas activities and fisheries scientific research have moderate impacts. The impact of bottom trawling is at least an order of magnitude greater than all the other activities combined.

Figure 1 .
1North East Atlantic Fisheries Commission Regulatory Area and OSPAR Maritime Area. OSPAR Regions I: Arctic Waters, II: Greater North Sea, III: Celtic Seas, IV: Bay of Biscay and Iberian Coast, V: Wider Atlantic. doi:10.1371/journal.pone.0012730.g001

Figure 2 .
2Human activities on the seafloor, including structures and artefacts present on the seafloor resulting from past activities, within the OSPAR Maritime Area, .200 m water depth, during 2005. doi:10.1371/journal.pone.0012730.g002

F-I-NL-S-CH-UK a square of side 50 nautical miles centred on 48.5, 217.08333 Total 112 793 Location of dumping area, quantities and sources of radioactive waste (based on NEA, 1985) [26]. B = Belgium; CH = Switzerland; D = Germany; F = France; I = Italy; NL = Netherlands; S = Sweden; UK = United Kingdom. doi:10.1371/journal.pone.0012730.t006

on 28 vessels engaged in bottom trawling, identified from speed profiles and pattern of activity. Overlapping tracks merged to give single area. encompasses the range of bottom trawling speeds referred to byDavies et al., 2007 [3]  and ICES, 2007[38]. doi:10.1371/journal.pone.0012730.t009

[39] , 80 m and 125 m, the possible spreads of the trawl doors. The least possible area trawled, 741 km 2 , relates to the narrowest speed range of 2.0-3.0 knots and gear width of 22 m

. The estimate for the most conservative speed range and gear width (2.0-3.0 knots, 22 m) with overlapping tracks not merged is an extrapolated value of 1,482 km 2 . The widest speed range and gear width (1.5-5.0 knots, 125 m) with overlapping tracks not merged gives an extrapolated value of 74,320 km 2 . The extrapolated estimate for the most conservative speed range and gear width (2.0-3.0 knots, 22 m) with overlapping tracks merged is an extrapolated value of 1,096 km 2 . The widest speed range and gear width (1.5-5.0 knots, 125 m) with overlapping tracks merged gives an extrapolated value of 27,840 km 2 .

Figure 3 .
3Bottom trawling. Tracks of vessels operating between 1.5 and 5.0 knots in the Hatton -Rockall area during 2005. doi:10.1371/journal.pone.0012730.g003

Table 1 .
1Data sources. Report of Observations/Samples collected by Oceanographic Programmes (ROSCOP) Cruise Summary Reports http://www.ices.dk/Ocean/roscop/index.aspSource

Table 2 .
2Military activities.Source

Table 3 .
3Sources to which requests for VMS data were addressed.State
Source

Table 4 .
4Spatial extent and confidence rating of activities. Estimates of the spatial extent of six major human activities occurring directly on the sea floor, including structures and artefacts present on the seafloor resulting from past activities, within the OSPAR maritime area of the North East Atlantic in waters .200 m during 2005. Estimates for bottom trawling and marine scientific research are based on 2005 data only. wd: water depth;Confidence ratings indicate whether the spatial extent of each activity is based on data or estimates of location and extent(Eastwood et al.Activity

Table 5 .
5Comparison of extrapolated spatial extent of human activities in the OSPAR area in 2005. Bottom trawling in Hatton and Rockall during 2005 estimated as ,50% of all deep sea bottom trawling area in the OSPAR area Estimates and extrapolations of the spatial extent of six major human activities occurring directly on the sea floor, including structures and artefacts present on the seafloor resulting from past activities, within the OSPAR maritime area of the North East Atlantic in waters .200 m during 2005. Estimates for bottom trawling and marine scientific research are based on 2005 data only. wd: water depth; *Carter et al., 2009] [23].Information from NPD and Statoil datasets andEastwood et al., 2007 [19].Activity

Table 6 .
6Radioactive waste dumpsites in water deeper than 200 m in the OSPAR region of the North East Atlantic between 1949 and 1984.Longitude
Latitude
Year
Tonnes
Country of Origin
Description of Dumpsite

216.75
46.00
1977
5 605
NL-CH-UK
a rectangle 45.8333 to 46.1666 and 216.00 to 217.50

1978
8 046
B-NL-CH-UK

1979
5 416
B-NL-CH-UK

1980
8 391
B-NL-CH-UK

1981
9 434
B-NL-CH-UK

1982
11 693
B-NL-CH-UK

217.42
46.25
1971
3 968
B-NL-CH-UK
a circle of radius 35 nautical miles centred on 46.25, 217.41666

1972
4 131
B-NL-CH-UK

1973
4 350
B-NL-UK

1974
2 265
NL-CH-UK

1975
4 454
B-NL-CH-UK

1976
6 772
B-NL-CH-UK

213.25
48.25
1965
1 760
UK
not described

1966
1 044
UK

213.27
48.33
1970
1 674
UK
not described

1968
3 164
UK

213.00
48.50
1949
9
UK
not described

211.33
55.43
1951
33
UK
not described

212.17
55.13
1953
57
UK
not described

26.17
46.45
1962
253
UK
not described

26.27
45.45
1963
5 809
B-UK
not described

26.60
45.45
1964
4 392
UK
not described

Table 7 .
7Conventional and chemical munitions dumpsites in waters .200 m in the OSPAR region (OSPAR, 2005) [28].Site number
Longitude
Latitude
Type of munitions
Details

42
213.66
48.33
Conventional
Only remaining UK dumpsite by 1993

43
29.02
43.73
Conventional

45
1.46
62.97
Chemical
4,500 tons scuttled vessels

46
27.67
59
Chemical

49
211
58
Chemical

51
212.08
56.52
Chemical

52
212
56.5
Chemical

53
29.45
56.37
Chemical

54
210
56
Chemical

55
211
55.5
Chemical

56
29.37
48.67
Chemical
Scuttled ship, Dora Oldendorf -February 1947.

57
28.15
48.05
Chemical
Scuttled ship, Empire Nutfield -September 1946.

58
28.35
48
Chemical
Scuttled ship, Lanark -November 1946.

59
28.56
47.95
Chemical
Scuttled ship, Empire Peacock -August 1946.

60
28.97
47.92
Chemical
Scuttled ship, Harm Freitzen -March 1948.

61
28.26
47.92
Chemical
Scuttled ship, Empire Lark -July 1947.

62
28.35
47.9
Chemical
Scuttled ship, Kindersley -October 1946.

63
28.85
47.87
Chemical
Scuttled ship, Empire Connyngham -June 1949.

64
28.31
47.79
Chemical
Scuttled ship, Thorpe Bay -September 1947.

65
210.5
47.63
Chemical
CW (Approx 70 Tonnes) encased in concrete. Dumped in 1980.

66
29.52
47.6
Chemical
Scuttled ship, Margo -November 1947.

67
29.4
47.38
Chemical
Scuttled ship, Miervaldis -September 1948.

68
29.4
47.28
Chemical
Scuttled ship, Empire Success -August 1948.

70
21.6
64.7
Chem. -Tabun
462 shells recovered in Wolgast Harbour dumped, set in concrete.

doi:10.1371/journal.pone.0012730.t007

Table 8 .
8Spatial extent of seafloor trawled in the Hatton -Rockall area during 2005: overlapping tracks not merged.Speeds (knots)

Area trawled based on *125 m
gear width (km 2 )

Area trawled based on *80 m
gear width (km 2 )

Area trawled based on **22 m
gear width (km 2 )

1

3.0-5.0
21,346
13,631
3,738

1

1.5-4.5
27,487
17,619
4,855

2

2.0-3.0
4,255
2,711
741

3

1.5-5.0
37,160
23,855
6,585

Estimates based on 28 vessels engaged in bottom trawling, identified from speed profiles and pattern of activity. All overlapping tracks included in estimate.
*Dick Ferro, Fisheries Research Services, Aberdeen, personal communication.
**Hall-Spencer et al., 2002 [39].

1

Davies et al., 2007 [3].

2

ICES, 2007 [38].

3

1.5-5.0 knots encompasses the range of bottom trawling speeds referred to by Davies et al., 2007 [3] and ICES, 2007 [38].
doi:10.1371/journal.pone.0012730.t008

PLoS ONE | www.plosone.org
September 2010 | Volume 5 | Issue 9 | e12730
AcknowledgmentsWe are grateful to Professor Robert Carney of Louisiana State University for his support and interest; Carlos Pinto of ICES for advice on the analysis of the NEAFC VMS dataset; Tore Indreiten of Statoil and Jan-Allan Ede of the Norwegian Petroleum Directorate for additional oil industry data and assistance in its interpretation; Andrew Gates, SERPENT Project, for advice on recent research into cuttings piles; Richard Hill, Chairman of the United Kingdom Cable Protection and Steven Bennett of Global Marine Systems Limited for advice on submarine cables; Dick Ferro, Fisheries Research Services, Aberdeen, UK for advice on deep sea trawling and Brian Bett and Ben Boorman, National Oceanography Centre, Southampton, UK for advice on marine research equipment.Author ContributionsConceived and designed the experiments: AB PW DB SvdH. Performed the experiments: AB. Analyzed the data: AB AM GD TLB. Contributed reagents/materials/analysis tools: AM GD TLB. Wrote the paper: AB. Commented on manuscript: PW DB SvdH AM GD.
The deep-sea floor ecosystems: current status and prospects of anthropogenic change by the year 2025. A G Glover, C R Smith, Environmental Conservation. 30Glover AG, Smith CR (2003) The deep-sea floor ecosystems: current status and prospects of anthropogenic change by the year 2025. Environmental Conservation 30: 219-241.

Ecosystems and Biodiversity in Deep Waters and High Seas: A scoping report on their socio-economy, management and governance. S Van Den Hove, V Moreau, UNEP-WCMC84Switzerlandvan den Hove S, Moreau V (2007) Ecosystems and Biodiversity in Deep Waters and High Seas: A scoping report on their socio-economy, management and governance. , Switzerland: UNEP-WCMC. 84 p.

Preserving deep-sea natural heritage: Emerging issues in offshore conservation and management. A J Davies, J M Roberts, J Hall-Spencer, Biological Conservation. 138Davies AJ, Roberts JM, Hall-Spencer J (2007) Preserving deep-sea natural heritage: Emerging issues in offshore conservation and management. Biological Conservation 138: 299-312.

. Ospar, OSPAR Quality Status ReportOSPAR (2000) OSPAR Quality Status Report 2000, Chapter 3. Human Activities. Available: http://www.ospar.org/eng/doc/pdfs/qec3.pdf. Accessed 2 January 2008.

Anthropogenic impacts on the deep sea. H Thiel, Tyler PAElsevierAmsterdam, NetherlandsEcosystems of the World: The Deep SeaThiel H (2003) Anthropogenic impacts on the deep sea. In: Tyler PA, ed. Ecosystems of the World: The Deep Sea. Amsterdam, Netherlands: Elsevier. pp 427-471.

Deep-Sea Biology: A Natural History of Organisms at the Deep-Sea Floor. J D Gage, P A Tyler, Cambridge University Press504CambridgeGage JD, Tyler PA (1991) Deep-Sea Biology: A Natural History of Organisms at the Deep-Sea Floor. Cambridge: Cambridge University Press. 504 p.

Ospar, Summary Record of the Meeting of the OSPAR Commission. Brest (FranceOSPAR 08/24/1-E. AvailableOSPAR (2008) Summary Record of the Meeting of the OSPAR Commission, Brest (France), 23-27 June 2008, OSPAR 08/24/1-E. Available: http://www. ospar.org. Accessed 19 August 2009.

Code of Conduct for Responsible Marine Research in the Deep Seas and High Seas of the OSPAR Maritime Area. Ospar, ?menu = 00820431000000_000000_000000&v0 = Code+of+Conduct+for+Responsible+Marine+Research+in+the+Deep+Seas+ and+High+Seas+of+the+OSPAR+Maritime&v1 = Agreements. OSPAR (2008) Code of Conduct for Responsible Marine Research in the Deep Seas and High Seas of the OSPAR Maritime Area. Available: http://www.ospar.org/ v_measures_spider/browse.asp?menu = 00820431000000_000000_000000&v0 = Code+of+Conduct+for+Responsible+Marine+Research+in+the+Deep+Seas+ and+High+Seas+of+the+OSPAR+Maritime&v1 = Agreements. Accessed 19 August 2009.

North East Atlantic Fisheries Commission. NEAFC. Recommendation XVINEAFC (2008) Recommendation XVI: 2008. North East Atlantic Fisheries Commission. Available: http://www.neafc.org/system/files/16-rec_bottom_ fishing_em_2008.pdf. Accessed 9 September 2009.

Recommendation XIII: 2009 North East Atlantic Fisheries Commission. NEAFC. NEAFC (2009) Recommendation XIII: 2009 North East Atlantic Fisheries Commission. Available: http://www.neafc.org/system/files/%252Fhome/ neafc/drupal2_files/rec13_bottom_fishing2009.pdf Accessed 9 September 2009.

NEAFC (2010) Recommendation VIII: 2010. North East Atlantic Fisheries Commission. NEAFC (2010) Recommendation VIII: 2010. North East Atlantic Fisheries Commission. Available: http://www.neafc.org/system/files/rec-viiil++-+ Hatton+extension+corrected+rev4.pdf. Accessed 14 March 2010.

NEAFC (2010) Recommendation XI: 2010. North East Atlantic Fisheries Commission. NEAFC (2010) Recommendation XI: 2010. North East Atlantic Fisheries Commission. Available: http://www.neafc.org/system/files/%252Fhome/ neafc/drupal2_files/rec11_threshholds_plus_new_and_existing_fishingarea- s_and_maps.pdf. Accessed 14 March 2010.

Agreement for the implementation of the provisions of the United Nations Convention on the Law of the Sea of 10 December 1982 relating to the conservation and management of straddling fish stocks and highly migratory fish stocks. United Nations Available. UNUN (1995) Agreement for the implementation of the provisions of the United Nations Convention on the Law of the Sea of 10 December 1982 relating to the conservation and management of straddling fish stocks and highly migratory fish stocks.: United Nations Available: http://daccess-dds-ny.un.org/doc/UNDOC/ GEN/N95/274/67/PDF/N9527467.pdf?OpenElement. Accessed 21 August 2009.

UN (1992) Convention on Biological Diversity. United Nations Environment ProgrammeUN (1992) Convention on Biological Diversity. United Nations Environment Programme. Available: http://www.cbd.int/convention/convention.shtml. Ac- cessed 21 August 2009.

establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive). Official Journal of the European Union L. 164ECEC (2008) Directive 2008/56/EC of the European Parliament and of the Council of 17th June 2008 establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive). Official Journal of the European Union L 164: 19-36.

Strategies of the OSPAR Commission for the Protection of the Marine Environment of the North-East Atlantic. Ospar, Biodiversity and Ecosystem StrategyOSPAR (2003) Biodiversity and Ecosystem Strategy, 2003 Strategies of the OSPAR Commission for the Protection of the Marine Environment of the North-East Atlantic. Available: http://www.ospar.org/html_documents/ospar/ html/Revised_OSPAR_Strategies_2003.pdf#nameddest = biodiversity. Ac- cessed 7 August 2009.

on public access to environmental information and repealing Council Directive 90/313/EEC. (The Environmental Information Directive). Official Journal of the European Union. 41ECEC (2003) Directive 2003/4/EC of the European Parliament and of the Council of 28th January 2003 on public access to environmental information and repealing Council Directive 90/313/EEC. (The Environmental Information Directive). Official Journal of the European Union L41/26: 26-32.

A Global Map of Human Impact on Marine Ecosystems. B S Halpern, S Walbridge, K A Selkoe, C V Kappel, F Micheli, Science. 319Halpern BS, Walbridge S, Selkoe KA, Kappel CV, Micheli F, et al. (2008) A Global Map of Human Impact on Marine Ecosystems. Science 319: 948-952.

Human activities in UK offshore waters: an assessment of direct, physical pressure on the seabed. P D Eastwood, C M Mills, J N Aldridge, C A Houghton, S I , ICES Journal of Marine Science. 64Eastwood PD, Mills CM, Aldridge JN, Houghton CA, S.I. R (2007) Human activities in UK offshore waters: an assessment of direct, physical pressure on the seabed. ICES Journal of Marine Science 64: 453-463.

The Irish Sea Pilot: Report on collation and mapping of data. Peterborough: Joint Nature Conservation Committee. C M Lumb, M Webster, N Golding, S Atkins, M A Vincent, 88Lumb CM, Webster M, Golding N, Atkins S, Vincent MA (2004) The Irish Sea Pilot: Report on collation and mapping of data. Peterborough: Joint Nature Conservation Committee. 88 p.

Quantitative assessment of the development of the offshore oil and gas industry in the North Sea. S J De Groot, ICES Journal of Marine Science. 53de Groot SJ (1996) Quantitative assessment of the development of the offshore oil and gas industry in the North Sea. ICES Journal of Marine Science 53: 1045-1050.

Ioc, Iho, Bodc, Centenary Edition of the GEBCO Digital Atlas: British Oceanographic Data Centre. LiverpoolIOC, IHO, BODC (2003) Centenary Edition of the GEBCO Digital Atlas: British Oceanographic Data Centre, Liverpool.

Submarine Cables and the Oceans -Connecting the World. L Carter, D Burnett, S Drew, G Marle, L Hagadorn, UNEP-WCMC Biodiversity Series No. ICPC/UNEP/UNEP-WCMC31Carter L, Burnett D, Drew S, Marle G, Hagadorn L, et al. (2009) Submarine Cables and the Oceans -Connecting the World. In:, , ICPC/UNEP/UNEP-WCMC, editor (2009) UNEP-WCMC Biodiversity Series No 31. Available: http://www.unep- wcmc.org/resources/publications/UNEP_WCMC_bio_series/31.aspx. Accessed 12 February 2010.

International Cable Protection Committee. Atlantic Region Available. ICPCICPC (2008) International Cable Protection Committee. Atlantic Region Available: http://www.iscpc.org. Accessed 29 January 2009.

Protocol to the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter. Imo, ?topic_id = 258&doc_id = 681#7. IMO (1996) 1996 Protocol to the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, 1972. Available: http:// www.imo.org/Conventions/contents.asp?topic_id = 258&doc_id = 681#7. Ac- cessed 19 November 2009.

Review of the continued suitability of the dumping site for radioactive waste in the North-East Atlantic. Paris: Nuclear Energy Agency, Organisation for Economic Cooperation and Development. 448NEANEA (1985) Review of the continued suitability of the dumping site for radioactive waste in the North-East Atlantic. Paris: Nuclear Energy Agency, Organisation for Economic Cooperation and Development. 448 p.

Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter. Imo, IMO (1972) Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, 1972. Available: http://www.imo.org/Conventions/ contents.asp?topic_id = 258&doc_id = 681. Accessed 24 November 2009.

Overview of Past Dumping at Sea of Chemical Weapons and Munitions in the OSPAR Maritime Area. OSPAR Commission. Ospar, OSPAR (2005) Overview of Past Dumping at Sea of Chemical Weapons and Munitions in the OSPAR Maritime Area. OSPAR Commission. Available: http://www.ospar.org/documents%5Cdbase%5Cpublications%5C- p00222_2005%20Revised%20Dumping%20at%20Sea%20of%20chem- ical%20weapons.pdf. Accessed 17 November 2008.

UKDEAL (2006) UK Digital Energy Atlas and Library Common Data Access Limited. UKDEAL (2006) UK Digital Energy Atlas and Library Common Data Access Limited. Available: http://www.ukdeal.co.uk. Accessed 28 February 2008.

The NPD's Fact-pages. Npd, NPD (2009) The NPD's Fact-pages. Available: http://www.npd.no/engelsk/ cwi/pbl/en/index.htm. Accessed 20 January 2009.

Npd, FACTS 2005 Norwegian Petroleum Directorate. NPD (2005) FACTS 2005 Norwegian Petroleum Directorate. Available: http:// www.npd.no/en/Publications/Facts/Facts-2005/. Accessed 10 November 2008.

Annual Environmental Report 2006, the Norwegian Oil Industry Association. Olf, Norwegian Oil Industry Association Available. OLF (2006) Annual Environmental Report 2006, the Norwegian Oil Industry Association. Norwegian Oil Industry Association Available: http://www.olf.no/ miljoerapporter/environmental-report-2006-article1954-247.html. Accessed 24 November 2009.

Drill cutting accumulations in the northern and central North Sea: a review of environmental interactions and chemical fate. E Breuer, A G Stevenson, J A Howe, J Carroll, G B Shimmield, Marine Pollution Bulletin. 48Breuer E, Stevenson AG, Howe JA, Carroll J, Shimmield GB (2004) Drill cutting accumulations in the northern and central North Sea: a review of environmental interactions and chemical fate. Marine Pollution Bulletin 48: 12-25.

. Olf, Annual Environmental ReportOLF (2009) Annual Environmental Report 2009. Available: http://www.olf.no/ getfile.php/Bilder/Publikasjoner/OLF%202009%20Environmental%20Re- port-webres.pdf. Accessed 24 November 2009.

laying down detailed provisions regarding satellite-based Vessel Monitoring Systems. do?uri = OJ:L:2003:333:0017:0027:EN:PDF. AccessedOfficial Journal of the European Union L. 333ECEC (2003) Commission Regulation (EC) No. 2244/2003 of 18 December 2003 laying down detailed provisions regarding satellite-based Vessel Monitoring Systems. Official Journal of the European Union L 333: 17-27. Available: http://eur-lex.europa.eu/ LexUriServ/LexUriServ.do?uri = OJ:L:2003:333:0017:0027:EN:PDF. Accessed 19 February 2008.

Scheme of Control and Enforcement, Article 11. NEAFC. North East Atlantic Fisheries CommissionNEAFC (2010) Scheme of Control and Enforcement, Article 11. North East Atlantic Fisheries Commission. Available: http://www.neafc.org/system/files/ scheme_2010.pdf. Accessed 17 May 2010.

NEAFC (2010) Recommendation XVII: 2010. Available. NEAFC (2010) Recommendation XVII: 2010. Available: http://www.neafc. org/system/files/%252Fhome/neafc/drupal2_files/rec17_vms.pdf. Accessed 15 March 2010.

. ICES. 9ICES (2007) ICES Advice 2007, Book 9. Available: http://www.ices.dk/ committe/acom/comwork/report/2008/Special%20Requests/NEAFC%20re- quest%20on%20VMS%20data.pdf. Accessed 13 August 2009.

Trawling damage to Northeast Atlantic ancient coral reefs. J Hall-Spencer, V Allain, J H Fosså, Proceedings of the Royal Society of London Series B -Biological Sciences. the Royal Society of London Series B -Biological Sciences269Hall-Spencer J, Allain V, Fosså JH (2002) Trawling damage to Northeast Atlantic ancient coral reefs. Proceedings of the Royal Society of London Series B -Biological Sciences 269: 507-511.

A dedicated GIS to estimate and map fishing effort and landings for the Portuguese crustacean trawl fleet. M Afonso-Dias, J Simões, C Pinto, Afonso-Dias M, Simões J, Pinto C (2004) A dedicated GIS to estimate and map fishing effort and landings for the Portuguese crustacean trawl fleet;

T Nishida, P J Kailola, C E Hollinworth, Saitama, Japan: Fishery-Aquatic GIS Research Group. Nishida T, Kailola PJ, Hollinworth CE, editors. Saitama, Japan: Fishery-Aquatic GIS Research Group. pp 323-340.

High Seas Bottom Trawl Fisheries and their Impacts on the Biodiversity of Vulnerable Deep-Sea Ecosystems: Options for International Action. M Gianni, IUCNGland, SwitzerlandGianni M (2004) High Seas Bottom Trawl Fisheries and their Impacts on the Biodiversity of Vulnerable Deep-Sea Ecosystems: Options for International Action. Gland, Switzerland: IUCN, Available: http://www.iucn.org/themes/ marine/pubs/pubs.htm. Accessed 26 June 2009.

Assessment of the impact of dumped conventional and chemical munitions (update. Ospar, OSPAR Commission. OSPAR (2009) Assessment of the impact of dumped conventional and chemical munitions (update 2009). OSPAR Commission. Available: http://www.ospar.org/ documents%5Cdbase%5Cpublications%5Cp00365_Munitions%20assessment.pdf. Accessed 18 November 2009.

Munitions dumped at sea: A literature review London: Imperial College Available. J Beddington, A J Kinloch, Beddington J, Kinloch AJ Munitions dumped at sea: A literature review London: Imperial College Available: http://www.mod.uk/NR/rdonlyres/77CEDBCA- 813A-4A6C-8E59-16B9E260E27A/0/ic_munitions_seabed_rep.pdf. Accessed 19 September 2009.

Oslo and Paris Conventions for the prevention of marine pollution: Working group on sea-bed activities (SEABA). Ospar, Summary Record SEBA 95/8/1-EOSPAR (1995) Oslo and Paris Conventions for the prevention of marine pollution: Working group on sea-bed activities (SEABA). Summary Record SEBA 95/8/1-E.

Ocean disposal of radioactive waste: Status report. C Calmet, International Atomic Energy Agency Bulletin. 4Calmet C (1989) Ocean disposal of radioactive waste: Status report. International Atomic Energy Agency Bulletin 4. Available: http://www.iaea. org/Publications/Magazines/Bulletin/Bull314/31404684750.pdf. Accessed 9 July 2009.

Cycle du combustible nucléaire et milieu marin. Devenir des effluents Rhodaniens en Méditerranée et des déchets immergéés en Atlantique Nord-Est. Commissariat à l'Energie Atomique. S Charmasson, 363Charmasson S (1998) Cycle du combustible nucléaire et milieu marin. Devenir des effluents Rhodaniens en Méditerranée et des déchets immergéés en Atlantique Nord-Est. Commissariat à l'Energie Atomique. 363 p.

Worldwide review of bottom fisheries in the high seas. FAO Fisheries and Aquaculture Technical Paper Rome. A Bensch, M Gianni, D Gréboval, J Sanders, A Hjort, Bensch A, Gianni M, Gréboval D, Sanders J, Hjort A (2008) Worldwide review of bottom fisheries in the high seas. FAO Fisheries and Aquaculture Technical Paper Rome. Available: ftp://ftp.fao.org/docrep/fao/011/i0540e/i0540e.zip. Accessed 19 October 2009.