number of centers and institutes with a separate governing board, but that organisationally belong to a department. Courses and programmes Stockholm University offers courses at both undergraduate and advanced level. There are 190 study programmes in total, including 75 master's programmes taught in English, and 1,700 courses to choose from within human science and science. Students can choose between studying one or more free-standing courses, that each may last between five weeks and one semester, or apply for a full study programme. Research The university's researchers engage in governmental investigations, are active in the media, provide responses to proposed legislation and are included in several Nobel committees and international expert bodies. Field stations Askö Laboratory Stockholm University Marine Research center (SMF) provides "Askö Laboratory", where Research on ecosystems, ecology and the impact of human interference is carried out. The field station was built in 1961 by Professor Lars Silén, Head of the Department of Zoology, and is now established as a renowned marine research center. Tarfala Tarfala research station belongs to the Department of Physical Geography. The station is located 1135 meters above sea level in Tarfaladalen, on the east side of Kebnekaise in arctic / alpine surroundings and conducts glaciological, hydrological, meteorological and climatological research. The station has the capacity to accommodate groups of up to 25 people and the staff consists of 2–5 people. Tovetorp Tovetorp Zoological Research Station belongs to the Department of Zoology, and is located about 95 km southwest of Stockholm. It conducts research and training activities in ecology and ethology. Every year Tovetorp is visited by up to 600 students who live and study between 2–10 days on the station. On the research side, over 20 people work today with different research projects. The number of employees are currently 6 people. Student unions Prior to 2008, Stockholm University had only one student union called Stockholm University Student Union (Stockholm universitets studentkår, SUS). However, since 2008 the computer and system science students and the teacher students have their own, independent, student unions called DISK and "The Teacher's College's Student Union" (Lärarhögskolans studentkår). The law students also have their own student union, as do journalism students (Studentkåren vid JMK). The future of the Teacher's College's Student Union is however not entirely safe, as Stockholm University's Student Union has declared it will begin talks with the Teacher's College's Student Union on transferring its members to it, as