Arctic Biology Field Course Qeqertarsuaq, 2002 University of Copenhagen Title: Arctic Biology Field Course, Qeqertarsuaq, 2002 Editor: Jesper Guldberg HANSEN Publisher: Zoological Museum, University of Copenhagen. Universitetsparken 15 2100 København Ø Tlf: 35 32 10 00 Fax: 35 32 10 10 Printed by: H.C.Ø. TRYK Universitetsparken 5 2100 København Ø ISBN: 87-87519-58-5 Cover photo: Angelica archangelica at the warm spring Anguujaartuutit, Disko Fjord. The research vessel Porsild is seen in the background. Photo by J. G. HANSEN. 1 Foreword Reinhardt Møbjerg KRISTENSEN1 & Poul Møller PEDERSEN 2 1 Department of Invertebrate Zoology, Zoological Museum, University of Copenhagen. 2 Department of Phycology, Botanical Institute, University of Copenhagen. Introduction The arctic field courses from the University of Copenhagen have been held regularly since 1973 at Arctic Station, Qeqertarsuaq. The Arctic Station is located near the town Qeqertarsuaq (Godhavn) on the south coast of Disko Island, West Greenland. It was founded in 1906 by the Danish botanist Morten Porsild, and the station is thus the oldest research institution north of the Polar Circle. The research vessel ”Porsild”, named after the founder, was donated by Mærsk McKinney Møller in 1994. Today the station is owned by the Faculty of Science and it is open for international and national scientists as well as graduate students. For a more comprehensive introduction to the Arctic Station, please consult the homepage: http://www.nat.ku.dk/as/. Arctic Station - Photo by M. Smith 2 This report summarises the results from the biological field course organised at the Arctic Station, Qeqertarsuaq and Kangerlussuaq from 3 July to 27 July 2002. Twelve students from the University of Copenhagen participated in the field course. Field activities were supervised by senior researchers from three institutes. The botanical teachers were Niels Daugbjerg and Poul Møller Pedersen both from Botanical Institute, the zoological teacher was Reinhardt Møbjerg Kristensen from Zoological Museum, and a special guest teacher in geology was Bjørn Buchhardt from Geological Institute. Furthermore, Martin V. Sørensen (postdoc) and Katrine Worsaae (Ph. D. student), both from Zoological Museum also participated in the field activities and supervision of the students. The station was overbooked during the field course. Several other activities were going on with special emphasis on terrestrial botany supervised by Marianne Philipp, University of Copenhagen (six persons), a French team of four persons working with cormorants in Disko Fjord headed by David Gremillet, a Belgian team of three persons working with soil biology leaded by Louis Beyens and finally a joint team of geologists and geographers working with the surging glacier in Kuannersuit - leading Niels Tvis, Siri Hansen and David Roberts (five persons). In fact, all these scientists were not a disadvantage for the field course, because they all gave lectures in the evenings for the students, so they really felt that Arctic Station is a very dynamic and international place. The terrestrial botanical team jointed us on several excursions and we learned a lot about the unique flora in the neighbourhood of Arctic Station, and finally the Belgian team joined us during the field trip to the glacier of Lyngmarksfjeldet. The scientific leader Bente Graae Jessen borrowed us her laboratory with the new microscopes with digital camera and video-recorder. Without this great gesture we could not have taken all the digital photos shown in this report, and the unique video recording of the new phylum, Micrognathozoa (Limnognathia maerski), now under display at the Zoological Museum in Copenhagen. She also introduced us to her work on dispersal and germination of arctic seeds. The field course projects addressed terrestrial, limnic and marine issues, but the main effort was clearly marine biology. During the course we visited Diskofjord/Kangerluk, Mellemfjord/Akuliit and Mudderbugten/Aqajarua on board the research vessel “Porsild”. A field trip to Isunngua spring and the Lymnaea-Lake in Kvandalen/Sullorsuaq was made the 11 July to 12 July. The course deviated from standard procedures by not using campsites for longer periods of time, as the students needed the laboratory facilities such as microscopes, refrigerators and cooling room more than to stay out in camps. One project, the bird project was based on bird songs recorded in the vicinity of Arctic Station, but all students were allowed to joint several cruises to more remote localities at Disko Island. The two days in Kangerlussuaq were used for a visit to the margin of the ice cap and sampling in the salt lakes. Our stay on Disko Island was generally successful from a scientific point of view. Some of the results in this report are outstanding and three contributions are currently being prepared for publication in international journals. These are: • HANSEN, J. G. & KATHOLM, A. K. (in prep): A study of the genus Amphibolus from Disko Island with special attention on the life cycle of Amphibolus nebulosus (Eutardigrada: Eohypsibiidae) 3 • KIRKEGAARD, M. & KNUDSEN, S. (in prep): First report on a new tantulocaridan (Crustacea: Maxillopoda) parasitic on harpacticoid copepods found off the coast of West Greenland. • JENSEN, K. G., DAUGBJERG, N. & THOMSEN, H. A. 200X. Diversity and succession of planktonic and sea ice diatoms from the Disko Bugt, West Greenland. Submitted to MoG, Bioscience. All the contributions published in this report are also available as PDF-files at the homepage of the Arctic Station: http://www.nat.ku.dk/as/. Following the diversity studies of marine protists in July 2002 Niels Daugbjerg established a homepage for his DATMAP-D project (DAtabase of MArine Protists from Disko Bugt, West Greenland). This homepage can be visited at http://www.bot.ku.dk/disko/index.asp and it lists all records of protists from the area and attempts to include micrographs of all species and previous records. Acknowledgements. First we want to thank the entire staff at the Arctic Station for providing logistic support, especially the crew onboard “Porsild”, who also learned us that there is nothing as “Greenlandic time” at the sea. Thanks are also given to a number of colleagues at the University of Copenhagen for assisting the students to process field data and samples etc.: Torben Dabelsten (Zoological Institute), Bjarne Bisballe (Zoological Museum), furthermore Rony Huys (British Museum) is acknowledged for help with the systematic and molecular data of the new species of Tantuloracida. The Botanical Institute is acknowledged for financial support that allowed us to include Niels Daugbjerg in the marine biological team of teacher, as well as the Geological Institute for financial support that allowed us to have guest teacher Bjørn Buchardt in geology and water analysis. The Faculty of Science covered travel expenses for 12 students and two teachers and additional support was given by the Arctic Station. Substantial support to students’ accommodation was given by the Danish Botanical Society (Mikroorganismefonden) and the Carlsberg Bequest to the Memory of Brewer J.C. Jacobsen for financial support. Finally, we are indebted to Jesper G. Hansen for editing this report. 4 5 Photo of the participants of the Arctic Biology Field course, 2002 and the technical staff of the Arctic Station 1. B. Thygesen 2. Wife of F. Grønvold 3. K. Worsaae 4. F. Grønvold 5. M. V. Sørensen 6. A. K. Katholm 7. L. S. Andersen 8. P. M. Pedersen 9. B. Christensen 10. N. Daugbjerg 11. K. A. Jønsson 12. S. W. Knudsen 13. J. G. Hansen 14. F. Nielsen 15. R. M. Kristensen 16. A. Geisler 17. Son of A. Geisler 18. A. M. Nielsen 19. M. T. Jensen 20. M. Smith 21. L. Munk 22. M. Kirkegaard 23. B. B. Westergaard 24. S. Fisker 25. Wife of S. Fisker 26. Wife of F. Nielsen 27. Daughter of F. Nielsen 6 Fairy shrimp (Branchinecta paludosa). Drawing by S. W. Knudsen 7 Oxygen Isotope Composition of Seawater and Spring Water at Disko Island: Implications for Origin of Water Bjørn Buchardt WESTERGAARD Geological Institute, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark e-mail: [email protected] Abstract. More that 100 samples of natural waters from Disko Island, North West Greenland have been sampled and analysed for their oxygen isotope composition. Marine waters were sampled in Disko Bay and adjacent waters at varying depths from surface to 300 m. Fresh-water samples come from springs, rivers, lakes and glaciers on Disko. Oxygen isotope compositions of marine waters are strongly correlated to salinity, and the results suggest that mixing between Atlantic water and glacial melt water is the most important oceanographic process in Disko Bay. Spring water analyses clearly demonstrate a meteoric water origin for the homothermic spring on Disko. The oxygen isotope data presented in this report are the first from the Disko Bay area, and further isotope studies of Disko area waters are recommended. Keywords. 1. INTRODUCTION The oxygen isotope composition of natural waters is a conservative parameter reflecting origin and modifications of a given water sample. During the field course in arctic biology at Arctic Station, Disko (NW Greenland) in the summer of 2002, more than 100 water samples were collected for oxygen isotope analyses. About half of the samples were seawater collected off Disko at depths from 0 to 300 meters. The remaining samples were fresh-water types from lakes, rivers, glacial ice and the well-known homothermic springs at Disko (KRISTENSEN 1988). Marine samples were analysed as a supplementary parameter to the standard identification of salinity and temperature variations in the waters around Disko, and the results have been interpreted in an oceanographic context. Spring-water samples on the other hand were obtained in an attempt to provide new understanding to the origin of the unique homothermic spring systems on Southern Disko. Other fresh-water samples were included to give better insight into the oxygen isotope composition of the meteoric water systems on Disko. No oxygen isotope analyses have been carried out before on Disko area waters, and the total number of isotopic data from Greenland waters is still very limited. An overview of southern Greenland isotope data is given in BUCHARDT et al. (2001). Background Oxygen has three stable isotopes: 16O, 17O and 18O, differing only in number of neutrons and therefore in mass. Their natural occurrence is roughly 99.8 : 0.04 : 0.2 measured as weight. Oxygen-bearing compounds in nature show small differences in isotopic concentrations as result of isotopic fractionation. Oxygen in carbonate minerals is thus 30 ‰ (permil) enriched in 18O (we normally exclude 17O from the calculations owing to its smaller concentration) compared to seawater, which again is enriched 30 to 50 ‰ compared to ice-sheet ice. These fractionations are caused by the tiny differences in kinetic and zero point energy of the oxygen-bearing molecules involved in the exchange processes. In the meteoric-water cycle (meteoric means "in the air") relating seawater, precipitation and major fresh-water reservoirs the most important isotopic fractionation processes are evaporation and condensation. Water molecules carrying an 16O isotope will evaporate slightly faster than 18O-carrying molecules, and water vapour will be depleted by about 10 ‰ in 18O compared to the evaporating water mass. Similarly, 18O-carrying molecules will condensate slightly faster than the 16O-carrying 8 B. B. WESTERGAARD molecules, and precipitation will be enriched in 18O by about 10 ‰ compared to the condensating vapour. In nature, precipitation falling in the temperate and arctic regions originates as evaporation formed in the subtropical high-pressure cells. As discussed above, this atmospheric water vapour will be about 10 ‰ depleted in 18O as compared to the seawater. As the air masses and their water vapour move northwards towards the temperate regions and the polar front, temperatures decrease, and increasingly larger amounts of water vapour condensate and leave the air mass as precipitation. The precipitation will be enriched in the heavy oxygen isotope 18O due to the condensation fractionation, and consequently the remaining water vapour will be depleted in 18O. As the fractionation between vapour and water remains approximately constant (actually it decreases slightly with lower temperature), precipitation formed from these increasingly more depleted vapour masses will itself be more depleted. In principle the whole system can be viewed as a major distillation column leading to gradually more depleted condensates. This isotopic depletion is termed the latitude effect (or rain-out effect) as the depletion generally is correlated to increasing latitudes. A similar effect is seen between summer and winter precipitation (seasonal effect) and in precipitation falling at elevated altitudes (altitude effect), both related to the temperature differences. The effects are important in the arctic, as temperature differences between high and low latitudes and between summer and winter are large. On a longer time scale, climatic differences also play an important role in the changing isotopic composition of precipitation. This is the basis for the Greenland ice-core analyses, where precipitation is preserved over long time spans as snow and ice. Generally, the Greenland ice sheet is depleted in 18O by 25 to 40 ‰ compared to normal seawater. Isotopic enrichments are normally expresses as differences relative to a standard by the * (delta)-function and expressed as ‰ deviations from a standard composition. In hydrological studies, Standard Mean Ocean Water or SMOW is used as the internationally standard, as the oceans have been found to function as a stable reservoir. Seawater thus has *18 values close to 0 ‰ SMOW. Precipitation falling in the temperate regions will typically have *18 values around -8 to -10 ‰, while arctic precipitation may have considerably more negative *18 values. Rain sampled at the Arctic Station was thus found to have *18 values around -18 ‰, while ice sheet samples are known to vary between -25 and -45 ‰. Where seawater and fresh water mixes, modifications in the seawater isotopic composition will reflect the isotopic composition of the fresh water component. As salinity and isotopic composition both are related to amount of fresh water contribution, these parameters will be linearly related. The slope of the "mixing line" as seen in a salinity-*18O diagram will differ according to the oxygen isotope composition of the fresh water component. Brackish water in a temperate area will thus be characterized by a lesser slope than similar water in an arctic area, as fresh water in temperate areas is less depleted in 18O than fresh water in the Arctic. Saline waters having obtained their dissolved ions from processes other than seawater mixing will keep their original *18O values and thus directly reflect the origin of the water. The basic principles of oxygen isotope hydrology were first treated by EPSTEIN & MAYEDA (1953). A comprehensive summary is given in the textbook by CLARK & FRITZ (1997). In the following we will treat the Disko water samples with these relations in mind. The *18O values of the marine samples will be compared to water depth, salinity and temperature as a mean of delineating different water masses and identifying differences in fresh water admixture. The isotopic composition of the spring water samples will be related to