title: Estimating In Situ Zooplankton Non-Predation Mortality in an Oligo-Mesotrophic Lake from Sediment Trap Data: Caveats and Reality Check.
abstract: 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.
  
  
  OBJECTIVE
  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.
  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.
authors.affiliation: Institute of Biophysics, Siberian Branch of the Russian Academy of Sciences, 50/50 Akademgorodok, Krasnoyarsk, 660036, Russia; Siberian Federal University, 79 Svobodny avenue, Krasnoyarsk, 660041, Russia.
authors.forename: Olga P
authors.initials: OP
authors.lastname: Dubovskaya
authors.affiliation: Department of Biosciences and Centre for Sustainable Aquatic Research (CSAR), Swansea University, Swansea, SA2 8PP, United Kingdom.
authors.forename: Kam W
authors.initials: KW
authors.lastname: Tang
authors.affiliation: Institute of Biophysics, Siberian Branch of the Russian Academy of Sciences, 50/50 Akademgorodok, Krasnoyarsk, 660036, Russia; Siberian Federal University, 79 Svobodny avenue, Krasnoyarsk, 660041, Russia.
authors.forename: Michail I
authors.initials: MI
authors.lastname: Gladyshev
authors.affiliation: Department of Ecohydrology, Leibniz-institute of Freshwater Ecology and Inland Fisheries, MU, 310 Ggelseedamm, Berlin, 12587, Germany.
authors.forename: Georgiy
authors.initials: G
authors.lastname: Kirillin
authors.affiliation: Scientific and Practical Center of the National Academy of Sciences of Belarus for Bioresources, 27 Akademicheskaya Street, 220072, Minsk, Belarus.
authors.forename: Zhanna
authors.initials: Z
authors.lastname: Buseva
authors.affiliation: Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 2 Alte Fischerhütte, 16775, Neuglobsow, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Kasprzak
authors.affiliation: Institute of Biophysics, Siberian Branch of the Russian Academy of Sciences, 50/50 Akademgorodok, Krasnoyarsk, 660036, Russia.
authors.forename: Aleksandr P
authors.initials: AP
authors.lastname: Tolomeev
authors.affiliation: Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 2 Alte Fischerhütte, 16775, Neuglobsow, Germany; Institute for Biochemistry and Biology, PotsdamUniversity, Maulbeeralle 2, 14469, Potsdam, Germany.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Grossart
mesh_terms: D000818:Animals; D017753:Ecosystem; D020387:Food Chain; D060106:Lakes; D011157:Population Dynamics; D012621:Seasons; D015048:Zooplankton / Q000502:physiology*