TY - JOUR A1 - Dubovskaya, Olga P. A1 - Tang, Kam W. A1 - Gladyshev, Michail I. A1 - Kirillin, Georgiy A1 - Buseva, Zhanna A1 - Kasprzak, Peter A1 - Tolomeev, Aleksandr P. A1 - Grossart, Hans-Peter T1 - Estimating In Situ Zooplankton Non-Predation Mortality in an Oligo-Mesotrophic Lake from Sediment Trap Data: Caveats and Reality Check JF - PLoS one N2 - Background Mortality is a main driver in zooplankton population biology but it is poorly constrained in models that describe zooplankton population dynamics, food web interactions and nutrient dynamics. Mortality due to non-predation factors is often ignored even though anecdotal evidence of non-predation mass mortality of zooplankton has been reported repeatedly. One way to estimate non-predation mortality rate is to measure the removal rate of carcasses, for which sinking is the primary removal mechanism especially in quiescent shallow water bodies. Objectives and Results We used sediment traps to quantify in situ carcass sinking velocity and non-predation mortality rate on eight consecutive days in 2013 for the cladoceran Bosmina longirostris in the oligo-mesotrophic Lake Stechlin; the outcomes were compared against estimates derived from in vitro carcass sinking velocity measurements and an empirical model correcting in vitro sinking velocity for turbulence resuspension and microbial decomposition of carcasses. Our results show that the latter two approaches produced unrealistically high mortality rates of 0.58-1.04 d(-1), whereas the sediment trap approach, when used properly, yielded a mortality rate estimate of 0.015 d(-1), which is more consistent with concurrent population abundance data and comparable to physiological death rate from the literature. Ecological implications Zooplankton carcasses may be exposed to water column microbes for days before entering the benthos; therefore, non-predation mortality affects not only zooplankton population dynamics but also microbial and benthic food webs. This would be particularly important for carbon and nitrogen cycles in systems where recurring mid-summer decline of zooplankton population due to non-predation mortality is observed. Y1 - 2015 U6 - https://doi.org/10.1371/journal.pone.0131431 SN - 1932-6203 VL - 10 IS - 7 PB - PLoS CY - San Fransisco ER - TY - INPR A1 - Grossart, Hans-Peter A1 - Riemann, Lasse A1 - Tang, Kam W. T1 - Molecular and functional ecology of aquatic microbial symbionts T2 - Frontiers in microbiology Y1 - 2013 U6 - https://doi.org/10.3389/fmicb.2013.00059 SN - 1664-302X VL - 4 IS - 6125 PB - Frontiers Research Foundation CY - Lausanne ER - TY - GEN A1 - Dubovskaya, Olga P. A1 - Tang, Kam W. A1 - Gladyshev, Michail I. A1 - Kirillin, Georgiy A1 - Buseva, Zhanna A1 - Kasprzak, Peter A1 - Tolomeev, Aleksandr P. A1 - Grossart, Hans-Peter T1 - Estimating in situ zooplankton non-predation mortality in an oligo-mesotrophic lake from sediment trap data BT - caveats and reality check T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Background Mortality is a main driver in zooplankton population biology but it is poorly constrained in models that describe zooplankton population dynamics, food web interactions and nutrient dynamics. Mortality due to non-predation factors is often ignored even though anecdotal evidence of non-predation mass mortality of zooplankton has been reported repeatedly. One way to estimate non-predation mortality rate is to measure the removal rate of carcasses, for which sinking is the primary removal mechanism especially in quiescent shallow water bodies. Objectives and Results We used sediment traps to quantify in situ carcass sinking velocity and non-predation mortality rate on eight consecutive days in 2013 for the cladoceran Bosmina longirostris in the oligo-mesotrophic Lake Stechlin; the outcomes were compared against estimates derived from in vitro carcass sinking velocity measurements and an empirical model correcting in vitro sinking velocity for turbulence resuspension and microbial decomposition of carcasses. Our results show that the latter two approaches produced unrealistically high mortality rates of 0.58-1.04 d(-1), whereas the sediment trap approach, when used properly, yielded a mortality rate estimate of 0.015 d(-1), which is more consistent with concurrent population abundance data and comparable to physiological death rate from the literature. Ecological implications Zooplankton carcasses may be exposed to water column microbes for days before entering the benthos; therefore, non-predation mortality affects not only zooplankton population dynamics but also microbial and benthic food webs. This would be particularly important for carbon and nitrogen cycles in systems where recurring mid-summer decline of zooplankton population due to non-predation mortality is observed. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 501 KW - fresh-water KW - nonconsumptive mortality KW - crustacean zooplankton KW - nonpredatory mortality KW - siberian reservoir KW - seasonal dynamics KW - copepod carcasses KW - sinking speed KW - aniline blue KW - marine snow Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-408392 SN - 1866-8372 IS - 501 ER - TY - JOUR A1 - Bickel, Samantha L. A1 - Tang, Kam W. A1 - Grossart, Hans-Peter T1 - Ciliate epibionts associated with crustacean zooplankton in German lakes - distribution, motility, and bacterivory JF - Frontiers in microbiology N2 - Ciliate epibionts associated with crustacean zooplankton are widespread in aquatic systems, but their ecological roles are little known. We studied the occurrence of ciliate epibionts on crustacean zooplankton in nine German lakes with different limnological features during the summer of 2011. We also measured the detachment and re-attachment rates of the ciliates, changes in their motility, and the feeding rates of attached vs. detached ciliate epibionts. Epibionts were found in all lakes sampled except an acidic lake with large humic inputs. Epibiont prevalence was as high as 80.96% on the cladoceran Daphnia cucullata, 67.17% on the cladoceran Diaphanosoma brachyurum, and 46.67% on the calanoid copepod Eudiaptomus gracilis. Both cladoceran groups typically had less than 10 epibionts per individual, while the epibiont load on E. gracilis ranged from 1 to >30 epibionts per individual. After the death of the zooplankton host, the peritrich ciliate epibiont Epistylis sp. detached in an exponential fashion with a half-life of 5 min, and 98% detached within 30 min, leaving behind the stalks used for attachment. Immediately after detachment, the ciliates were immotile, but 62% became motile within 60 min. When a new host was present, only 27% reattached after 120 min. The average measured ingestion rate and clearance rate of Epistylis were 11,745 bacteria ciliate(-1) h(-1) and 24.33 mu l ciliate(-1) h(-1), respectively. Despite their high feeding rates, relatively low epibiont abundances were observed in the field, which suggests either diversion of energy to stalk formation, high metabolic loss by the epibionts, or high mortality among the epibiont populations. KW - ciliate epibionts KW - Epistylis KW - crustacean zooplankton KW - bacterivory KW - epibiont motility Y1 - 2012 U6 - https://doi.org/10.3389/fmicb.2012.00243 SN - 1664-302X VL - 3 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Günthel, Marco A1 - Donis, Daphne A1 - Kirillin, Georgiy A1 - Ionescu, Danny A1 - Bizic, Mina A1 - McGinnis, Daniel F. A1 - Grossart, Hans-Peter A1 - Tang, Kam W. T1 - Contribution of oxic methane production to surface methane emission in lakes and its global importance JF - Nature Communications N2 - Recent discovery of oxic methane production in sea and lake waters, as well as wetlands, demands re-thinking of the global methane cycle and re-assessment of the contribution of oxic waters to atmospheric methane emission. Here we analysed system-wide sources and sinks of surface-water methane in a temperate lake. Using a mass balance analysis, we show that internal methane production in well-oxygenated surface water is an important source for surface-water methane during the stratified period. Combining our results and literature reports, oxic methane contribution to emission follows a predictive function of littoral sediment area and surface mixed layer volume. The contribution of oxic methane source(s) is predicted to increase with lake size, accounting for the majority (>50%) of surface methane emission for lakes with surface areas >1 km(2). Y1 - 2019 U6 - https://doi.org/10.1038/s41467-019-13320-0 SN - 2041-1723 VL - 10 PB - Nature Publishing Group UK CY - London ER -