Mortality of zooplankton in lake ecosystems and its contribution to vertical carbon fluxes (ZooFlux)

本研究的目的是量化死亡浮游动物（尸体）在水生生态系统碳循环中的作用。因此，我们将检验这样一个假设，即在尸体下沉过程中微生物的降解促进了更难降解的有机物的降解。该项目是德国和俄罗斯一个研究小组共同努力的一部分。为了估计浮游动物尸体对碳循环的贡献，我们结合了野外观测、中生态和实验室实验以及模型。利用现代水动力场技术对分层水柱上的湍流混合条件进行测量，同时对湖泊沉积物陷阱造成的浮游动物死亡率和下沉率进行现场估计。实验室实验将量化浮游动物尸体的微生物定植和降解率。现场和实验室数据将用于一个先进的模型，预测尸体在水柱中的停留时间及其对碳循环的贡献。各种模式情景将侧重于环境因素对死亡浮游动物沉降和降解的作用，以及气候驱动的湖泊低磷变暖造成的潜在变化。

The objective of the proposed study is to quantifying the role of dead zooplankton (carcasses) in the carbon cycle of aquatic ecosystems. Thereby, we will test the hypothesis that microbial degradation of carcasses during their sinking facilitates (primes) the degradation of more refractory organic matter. The project is part of the joint effort of a research team from Germany and Russia. In order to estimate the contribution of zooplankton carcasses to the carbon cycle, we combine field observations, mesocosm and laboratory experiments as well as modeling. In situ estimations of the zooplankton mortality and sinking rates by sediment traps in the lakes will be accompanied by measurements of turbulent mixing conditions across the stratified water column using modern hydrodynamic field techniques. Laboratory experiments will quantify microbial colonization and degradation rates of zooplankton carcasses. Both field and laboratory data will be used for an advanced model predicting retention time of carcasses in the water column and their contribution to the carbon cycle. Various model scenarios will focus on the role of environmental factors for settling and degradation of dead zooplankton and on potential changes due to climate-driven hypolimnion warming in lakes.