Limnology of the Plußsee

Krambeck, Hans-Jürgen; Albrecht, Dieter; Hickel, Barbara; Hofmann, Wolfgang; Arzbach, Hans-Hermann

doi:10.1007/978-1-4612-2606-2_1

Cited by 19 publications

(22 citation statements)

References 10 publications

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“…M. leuckarti was typically found in the upper epilimnetic waters of the lake where the majority of primary production has been observed (Meffert & Overbeck 1994) and consequently exhibited δ 13 C values commonly reported for highly productive lakes (Grey et al 2000). D. bicuspidatus is known to tolerate very low oxygen concentrations (Einsle 1965), and was generally found in Plußsee just below the oxycline (Krambeck et al 1994). This zone is characterised by high concentrations of phytoplankton, especially cryptophytes (Santer & Grey, unpubl.…”

Section: Discussionmentioning

confidence: 93%

Food niches of cyclopoid copepods in eutrophic Plußsee determined by stable isotope analysis

Santer

Sommerwerk

Grey

2006

archiv_hydrobiologie

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Abstract:Feeding studies have suggested interspecific differences in the food sources and trophic position of cyclopoid copepod species. We measured δ 13 C and δ 15 N of five sympatric cyclopoid copepod species and of bulk POM from a eutrophic lake over a one-year period, to determine if stable isotope derived-data from the field supported the hypotheses from feeding studies. Cyclops abyssorum and C. vicinus differed significantly in δ 15 N but not in δ 13 C, inferring assimilation from similar carbon sources but differentiation in their trophic position. Cyclops abyssorum δ 15 N typically was 1-2 ‰ higher than C. vicinus, suggesting a more predatory feeding mode compared to its congener. The summer species Mesocyclops leuckarti, Thermocyclops oithonoides and Diacyclops bicuspidatus exhibited considerable differences in δ 13 C. The lower δ 13 C of the hypolimnetic D. bicuspidatus compared to the two epilimnetic species indicates a food niche differentiation by vertical separation. All copepod δ 13 C and δ 15 N signatures showed seasonal fluctuations, with low values in winter and high values in summer. The δ 13 C of seston was generally higher than copepod δ 13 C. We regard selective feeding from the bulk POM, spatial separation of feeding and assimilation of 13 C depleted food sources responsible for this phenomenon.

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Section: Discussionmentioning

confidence: 93%

Food niches of cyclopoid copepods in eutrophic Plußsee determined by stable isotope analysis

Santer

Sommerwerk

Grey

2006

archiv_hydrobiologie

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“…Seasonal changes of the ciliate community were not studied in Lake Schö hsee. In contrast to the latter and most other lakes in the Schleswig-Holstein area, Lake Plußsee is less strongly buffered by the carbonate system, and seasonal pH changes are, therefore, wider, ranging from 7.3 to 9.5 in the epilimnion (Reck 1987;Krambeck et al 1994). In accordance with the experimental results of the present study, U. farcta was the only Urotricha species that was recorded during all seasons in Lake Plußsee, whereas U. castalia was not found (Reck 1987).…”

Section: Discussionmentioning

confidence: 99%

“…Biologically-driven seasonal variation in temperate, moderately-productive and moderately-hard-water lakes is typically #1 pH unit (e.g., BfW 2002). Larger pH fluctuations, up to .2 pH units, occur in lakes where the buffering capacity of the carbonate system is less efficient, in highly productive small water bodies, and in the littoral zones of shallow lakes with intense primary production (Talling 1976;Krambeck et al 1994;Edmonson 2005).…”

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confidence: 99%

Effect of pH on growth, cell volume, and production of freshwater ciliates, and implications for their distribution

Weisse

Štádler

2006

Limnology & Oceanography

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We investigated the effect of pH on growth, cell volume, and production of the freshwater ciliates Urotricha farcta, U. furcata, and U. castalia in laboratory cultures with Cryptomonas sp. as food. Overall, pH had a significant, species-specific effect on all parameters investigated. The food alga, Cryptomonas sp., showed a wide pH tolerance, with positive growth rates between pH 4.4 and pH 9.65. Among the ciliates, U. farcta was the most pH-tolerant and U. castalia was the most pH-sensitive species, with positive growth being confined to pH 6.5-8.2. The pH optimum was derived from cellular production rates. The pH optima of the three ciliate species were shifted; their production rates peaked at pH 4.4-5.3 (U. farcta), pH 5.9-7.3 (U. furcata), and pH 6.8-7.9 (U. castalia). The pH effect on growth and survival of the ciliates was minor at circumneutral and moderately alkaline pH values, relative to the effect of temperature and food measured in earlier experiments. The widths of the pH tolerances of the ciliates were positively related to the widths of their temperature niches and to their natural distributions. U. farcta and U. furcata were characterized as euryoecious species, with broad pH and temperature tolerances and ubiquitous distribution; U. castalia is a rare, stenoecious species, requiring specific pH and temperature conditions.

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“…The study site was Lake PluBsee (54" 10' N, 10" 23' E) near Plon in SchleswigHolstein (northern Germany). Lake PluBsee is a eutrophic dimictic lake which is stratified during summer into the warm and oxic epilimnion and the cold and anoxic hypolimnion separated by the thermocline layer (metalimnion; Krambeck et al 1994). A detailed characterization of the sampling site during the sampling period can be found in Weinbauer & Hofle (1998).…”

Section: Methodsmentioning

confidence: 99%

Size-specific mortality of lake bacterioplankton by natural virus communities

Weinbauer¹,

Höfle²

1998

Aquat. Microb. Ecol.

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ABSTRACT. The potential effect that viral lysis has on the cell size distribution of bacterioplankton was investigated during late summer stratification In Lake Pluhsee, Germany Size-specific bactenal mortality due to viral lysis was estimated from in s~t u s a n~p l e s by a transmission electron mici-oscopy based examination of vislbly infected cells [VIC) and In an experiment with varying concentrations of the natural virus community. In all depth layers the highest percentage of cells was found in a cell length class that was smaller for the entire bacterial comn~unity (0.3-0 6 pm) than for VIC (0.6-0.9 pm). For cells < 2 4 pm the highest frequency of VIC (FVIC) was detected in the size classes 0 6-0 9 and 0.9-1.2 pm, and the FVIC was high in the size classes 1 2-1.5 (all depth layers) and 1 5-1 8 pm (meta-and hypolimnion). The estimated mortality d u e to viral lysis In these size classes was significant with maxima of 29 to 55"o In the epilimnion, 30 to 59% in the metalimnion and 56 to 107'% in the hypolimnion In all depth layers the FVlC of bacteria < O 3 pm in length was ca 3 0 % of that averaged for the entire bacte-I-ial community, and in the expel-iment the percentage of cells 2.4 pm) were not infected with viruses, and in enclosures with epilimnetic lake water the percentage of cells >2.4 pm was highest in enclosures w~t h highest viral abundance, suggestlng that resistance against infection favored large cells. However, In the meta-and hypolimnion the FVIC was high for cells > 2 4 pm and, since the burst size Increased with bacterial cell size, lysis of large ceUs could contribute sigi~ificantly to viral production. Also, a major portion of bioinass was found in sells > 2 4 pm. The finding that v~r a l lysis is size-specific and can affect the cell size distribution of bacteria in lake watel-has important implications for our understanding of the mechanlsms ivhich regulate bacterial production a n d nutrient cycliilg in pelagic environments KEY WORDS: Bacterioplankton size structure Size-specific viral lysis Lake PluBsee

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Limnology of the Plußsee

Cited by 19 publications

References 10 publications

Food niches of cyclopoid copepods in eutrophic Plußsee determined by stable isotope analysis

Food niches of cyclopoid copepods in eutrophic Plußsee determined by stable isotope analysis

Effect of pH on growth, cell volume, and production of freshwater ciliates, and implications for their distribution

Size-specific mortality of lake bacterioplankton by natural virus communities

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