Realm: Freshwater
Climate: Temperate
Biome: Small Lake Ecosystems
Central latitude: 52.440000
Central longitude: 13.650000
Duration: 21 years, from 1992 to 2012

6385 records

101 distinct species

Across the time series Keratella cochlearis is the most frequently occurring species

Methods

Density is given as individuals per litre. Lake Müggelsee is sampled at weekly intervals during the growing season and at biweekly intervals during periods with ice cover. Between 1979 and 1986, zooplankton samples were sampled biweekly at the deepest point of the lake (M7, Table 1, Figure 1) at 1m intervals from the surface to the bottom. A detailed description of the sampling strategy is given in Driescher et al. (1993). Since 1987, integrated samples were collected weekly at five different lake stations (see description below). We assume that change in the sampling strategy did not cause a significant bias in the plankton series, as analysis of synchronous zooplankton counts in 1987 (n-15) revealed no significant differences (Wilcoxon-Mann-Whitney: p>0.1). Moreover, Schellenberger and Stellmacher (1986) found that seston concentrations were quasi homogeneously distributed across the lake. Integration of water samples: The integrated water samples derive from samples taken at the differed sampling stations and water depths (Table 2). In Table 3 the sample integration scheme is summarized for ice free and ice covered periods, and for thermally stratified and non- stratified periods. MPO stands for the upper 0-4m; MPU stand for the lower 5-7 m. Sample number in table x is for internal use only. Co-ordinates of the different measuring stations are depicted in table 1. During thermally un-stratified conditions all samples are integrated into one sample (MPS in Table 3). During periods of thermal stratification samples from the upper 0-4 m depths and the lower 5-7 m depth are separated. The 4m water depths basically relates to the location of the thermocline. We consider the lake thermally stratified if oxygen concentrations decline by more than 20% between 2m and 5m water depth. During periods of thermal stratification an additional sample is taken at M7 above the sediment for chemical analysis. Samples at MS3 and MS3 Ice are routinely taken. Sample preparation and fixation for zooplankton analysis: Out of the integrated Müggelsee sample (105 L in total; see Table 1 and 2) 20 liters (Total Volume, see calculation below) are screened though a 30?m mesh and the animals are transferred via a wash bottle filled with filtered lake water into a ca. 100mL glass bottle. We slowly add a couple of drops of mineral water (CO2), in order to prevent strong contractions of the zooplankton prior to fixation. After ca. 10 minutes when all zooplankton have been narcotized, the sample is fixed with 37% formaldehyde to a final concentration of 4% and stored in a 100mL glass bottle. Work under an exhaust hood- as formaldehyde is harmful to health! The sample bottle is labelled as follows: Müggelsee Date 30 ?m 20 L 4% Formol Prior to counting of the sample all formaldehyde is removed. Therefore the fixed sample is poured into a net bucket with a 30?m mesh size. The formaldehyde is collected and disposed. The sample is gently rinsed with tab water until all formaldehyde is washed out. The collected zooplankton is transferred to a measuring cylinder (25ml, 50ml, 100ml). The size of the cylinder depends on the density of the zooplankton in the sample. In all processing steps we control that all animals have been transferred from the net bucket. After all animals have been transferred to the measuring cylinder the cylinder is filled to the respective volume using tap water. The cylinder volume is noted for the final density calculation of the zooplankton (see calculation below). Counting and taxonomy: Usually several aliquot volumes of the original sample volume are removed and counted. We use a graduated pipette, with a widened pipette tip in order to include small and large sized zooplankton. We take utmost care to gently but thoroughly mix the sample in the cylinder in order to guarantee a homogenous distribution of the zooplankton in the cylinder. The aliquot of the sample is transferred into a Sedgewick-Rafter counting chamber (see picture). Surface tension is diminished by adding a couple of drops of a detergence in order to prevent that some specimens adhere to the surface. Animals are identified and counted under a microscope at x40 (crustaceans) to x100 (rotifera) magnification. In most cases several parallel chambers are counted until at least 100 individuals of the most prominent species are recorded. The total volume of the processed aliquots is noted (Aliquot Volume; see calculation below). Calculation of the abundance: Abundances are given as Individuals / liter (X) X = Cylinder Volume* animal number in the Aliquot Volume/ ( Aliquot Volume* Total Volume) Cylinder Volume = Volume of the measuring cylinder (25ml, 50ml or 100ml) in which the entire condensed water sample (20L) is quantitatively transferred. Aliquot Volume = Volume of the counted aliquots Total Volume = Volume of the lake water taken for zooplankton analysis (20L).Driescher et al. (1993): Lake Müggelsee and its environment . Natural conditions and anthropogenic impacts. Int. Revue ges. Hydrobiol: 78 (3), 327-343. Einsle, U. (1993): Crustacea, Copepoda, Calanoida und Cyclopoida. In: J. Schwoerbel & P. Zwick (Hrsg.), Süßwasserfauna von Mitteleuropa Bd.8/4-1, Gustav Fischer Verlag, Stuttgart, Jena, New York: 208 pp. Flößner, D. (2000): Die Haplopoda und Cladocera (ohne Bosminidae) Mitteleuropas. Backhuys Publishers, Leiden: 428 pp. Kiefer, F. (1973): Ruderfusskrebse. In: Einführung in die Kleinlebewelt. Kosmos-Verlag Franckh`sche Verlagshandlung, Stuttgart: 99 pp. Kiefer, F. & Fryer, G. (1978): Freilebende Copepoda. In: Die Binnengewässer Bd. 26, 2.Teil. E. Schweizerbart`sche Verlagsbuchhandlung, Stuttgart: 380 pp. Korovchinsky, N.M. (1992): Sididae & Holopediidae (Crustacea: Daphniiformes). SPB Academic Publishing bv III.-, The Hague: 82 pp. Koste, W. (1978): Rotatoria: Die Rädertiere Mitteleuropas Bd I.(Textband) und Bd.II (Tafelband). Gebrüder Borntraeger, Berlin-Stuttgart: 673 pp. und 234 Tafeln Lieder, U. (1996): Crustacea, Cladocera/ Bosminidae. In: J. Schwoerbel & P. Zwick (Hrsg.), Süßwasserfauna von Mitteleuropa Bd.8 /2-3. Gustav Fischer Verlag, Stuttgart, Jena, Lübeck, Ulm: 80 pp. Ruttner-Kolisko, A. (1974): Plankton Rotifers. In: Die Binnengewässer Vol. XXVI/1; Supplement. E. Schweizerbart`sche Verlagsbuchhandlung, Stuttgart: 146 pp. J. Schwoerbel & P. Zwick (Hrsg.), Pontin, R.M. (1978): A key to the freshwater planktonic and semi-planktonic Rotifera of the British Isles. Freshwater Biological Association Scientific Publication No. 38: 176 pp. SCHELLENBERGER, G.,ANDR. STELLMACHER. 1986. Zur Frage der Quasihomogenität des Müggelsees. Acta Hydrophysica30:161173 Stemberger, R.S. (1979) A guide to rotifers of the Laurentian Great Lakes. Publisher: US Environmental Protection Agency, EPA Publ. 600/4-79-021: 186 pp.

Citation(s)

@Dataset{BioTIME_cit375, Study_id = {626}, Citation_id = {375}, Author = {Langenhaun, Daniel and Pilotto, Francesca}, Institution = {IGB Leibniz-Institute of Freshwater Ecology and Inland Fisheries}, Publisher = {{IGB Freshwater Research and Environmental Database (FRED)}}, Title = {NCOMMS-19-1757081A}, Doi = {10.18728/536.0}, Url = {http://doi.org/10.18728/536.0} }