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62 Generally, all sampled benthic substrates (surface sediment, rocks, stones, submerged vegetation) show a relatively high diversity of benthic diatoms compared to lakes for example in Northwest Greenland (Blake et al. 1992). The seemingly most abundant diatom genera are Pinnularia, Tabellaria and Navicula (Fig. 6.3-3). Again, these findings have to be confirmed by detailed taxonomical analyses which will also reveal differences in the species composition and diversity of diatom communities in dependence of specific lake water characteristics. 6.4 Measurement of trace gas emissions from soils and lakes Svenja Kobabe, Nadja Hultzsch Fig. 6.3-3: Examples of living benthic diatoms from various substrats from lakes on Store Koldewey. A. Chain of Melosira from the submerged moss Drepanocladus. B. Pinnularia sp. (left) and Stauroneis sp. (right) from a soft sediment surface. C, D. Long zig-zag chain of Tabellaria sp. washed from Drepanocladus. The exchange of the climate relevant trace gases methane (CH4) and carbon dioxide (CO2) in northern terrestrial environments has attracted much attention in recent years. One reason for this is, that about 14% of the global soil carbon are stored in the soils of arctic and sub arctic regions. These regions constitute a substantial part of the global natural wetlands and form the largest single source of atmospheric methane (e.g., Fung et al. 1991, Christensen et al. 1996). Trace gas fluxes have been studied in some detail in northern temperate/boreal (e.g., Silvola et al. 1996, Moosavi & Crill 1997), sub arctic (Whalen & Reeburgh 1990, Svensson et al. 1999) and low arctic systems (Whalen & Reeburgh 1990, Christensen 1993, Wagner et al. 2003), but about the high arctic just a few data exist (Christensen et al. 2000), probably most because of its inaccessibility. One aim of our study is to receive more information about trace gas fluxes in this region. The emitted methane is the result of two main processes: 1.) the production by micro organisms as the final step in the anaerobic decomposition of organic material. 2.) The oxidation of methane to CO2 by another group of micro organisms. To
understand these processes a more detailed knowledge about the activity and composition of the bacteria community is important. The main scientific objectives are: - Determination of CO2 and CH4 fluxes at different sites (soils and lakes) of Store Koldewey and Geographical Society Ø - Investigation of pedogenic and microbial parameters, which control the emission rates of trace gases at different sites - Analysis of the microbial community structure in the different soils and sediments The investigations include field measurements of methane and carbon dioxide emissions at several sites. Additional to the emission measurements, the soils and sediments were described and samples for the analysis of the main soil properties and the microbial process studies were taken. Field work and methods Soils: Methane emission measurements and soil sampling were done on 5 different sites on the islands Store Koldewey and Geographical Society Ø. At every investigation site first the methane emissions were measured for several days in succession. At the same time soil temperature at different depth (surface, 1, 2, 5, 10 cm) was measured. Fig. 6.4-1: Principle of the closed chamber method. chamber frame membrane pump gas collecting tube connected by rubber tubes For the measurement of the methane emission the static chamber method was used (Fig. 6.4.-1). The chambers and frames were built out of PVC. The frames with a U- 63
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the Expedition ARKTIS-XIX/4 of the
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1 Cruise summary W. Jokat The exped
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6 1.1 Wetterverlauf ARK XIX/4a Bei
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8 noch vor der Küste, fern davon a
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10 northerly wind increased steadil
Page 14 and 15: 12 In the latest stages of the proj
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Page 22 and 23: Date Flight Start Time End Time No
Page 32 and 33: 30 Preliminary results Along profil
Page 34 and 35: 32 In addition to the deep seismic
Page 36 and 37: 34 Fig. 2-5: Flight statistics for
Page 38 and 39: 36 Fig. 3-1: Seafloor topography of
Page 40 and 41: 38 In total, the PARASOUND system o
Page 42 and 43: 40 Figure 4.1-3: Example of PARASOU
Page 44 and 45: 42 Station Latitude Longitude Date
Page 46 and 47: 44 After PCR was finished, samples
Page 48 and 49: 46 Potsdam Lake (Shannon Island) Sc
Page 50 and 51: 48 In den Schmelzwassertümpeln kon
Page 52 and 53: Temp. Sal. Tiefe max. Tiefe Trübe
Page 54 and 55: 52 Store Koldewey Store Koldewey is
Page 56 and 57: 54 In the shallow ponds the hydrolo
Page 58 and 59: 56 The low amounts of solubles in t
Page 60 and 61: 58 lake core no. latitude longitude
Page 62 and 63: 60 6.3 Diatom phytoplankton and phy
Page 66 and 67: 64 shaped profile at the top were i
Page 68 and 69: 66 depth horizon description sample
Page 70 and 71: 68 measured in the field, and the c
Page 72 and 73: 70 Summary of results The summit pl
Page 74 and 75: 72 Pre-Holocene shell material Pre-
Page 76 and 77: 74 Christensen, T.R. (1993): Methan
Page 78 and 79: 76 No EVK2-2001-00215 (ASOF-N). The
Page 80 and 81: 78 Altimeters Model 2110-2, SN 189
Page 82 and 83: 80 Mooring Latitude Longitude Water
Page 84 and 85: 82 Mooring Latitude Longitude Water
Page 86 and 87: 84 30° W 20° W 30° W Greenland 2
Page 88 and 89: Fig. 7-4: Vertical transects of pot
Page 90 and 91: 88 8 Bericht zur akustischen Vermes
Page 92 and 93: 90 Quality control sheet - Profile
Page 94 and 95: 92 Quality control sheet - Profile
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142 Beteiligte Institutionen / Part
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144 Fahrtteilnehmer / Participants
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