Climate Change, Climate Change-Kyoto Protocol, Desertification, Law of the Sea, Ozone Layer Protection, Ship Pollution, Whaling signed, but not ratified: none Tuvalu ratified the Convention on Biological Diversity in 1993. Tuvalu signed the Pacific Islands Cetaceans Memorandum of Understanding on 9 September 2010. Funafuti atoll Structure of Funafuti atoll Funafuti atoll consists of a narrow sweep of land between wide, encircling a large lagoon (Te Namo) of about long and wide. The average depth in the Funafuti lagoon is about 20 fathoms (36.5 metres or 120 feet). With a surface of , it is by far the largest lagoon in Tuvalu. The northern part of the lagoon has a deep basin (maximum depth recorded of 54.7 m) basin, and the southern part of the lagoon has very narrow shallow basin. The land area of the 33 islets aggregates to , less than one percent of the total area of the atoll. The boreholes on Fongafale islet at the site now called Darwin's Drill, are the result of drilling conducted by the Royal Society of London for the purpose of investigating the formation of coral reefs to determine whether traces of shallow water organisms could be found at depth in the coral of Pacific atolls. This investigation followed the work on The Structure and Distribution of Coral Reefs conducted by Charles Darwin in the Pacific. Drilling occurred in 1896, 1897 and 1898. Professor Edgeworth David of the University of Sydney was a member of the 1896 "Funafuti Coral Reef Boring Expedition of the Royal Society", under Professor William Sollas and lead the expedition in 1897. However, the geologic history of atolls is more complex than Darwin (1842) and Davis (1928) envisioned. The survey of the atoll published in 1970 described its structure as being: Aquifer salinization of Fongafale Islet, Funafuti The investigation of groundwater dynamics of Fongafale Islet, Funafuti, show that tidal forcing results in salt water contamination of the surficial aquifer during spring tides. The degree of aquifer salinization depends on the specific topographic characteristics and the hydrologic controls in the sub-surface of the atoll. About half of Fongafale islet is reclaimed swamp that contains porous, highly permeable coral blocks that allow the tidal forcing of salt water. There was extensive swamp reclamation during World War II to create the air field that is now the Funafuti International Airport. As a consequence of the specific topographic characteristics of Fongafale, unlike