Increased incorporation of terrestrial organic matter (t-OM) into consumer biomass (allochthony) is believed to reduce growth capacity. In this study, we examined the relationship between crustacean zooplankton allochthony and production in a boreal lake that displays strong seasonal variability in t-OM inputs. Contrary to our hypotheses, we found no effect of allochthony on production at the community and the species levels. The high frequency seasonal sampling (time-for-space) allowed for estimating the efficiency of zooplankton in converting this external carbon source to growth. From the daily t-OM inputs in the lake (57 - 3027 kg C per day), the zooplankton community transferred 0.2% into biomass (0.01 - 2.36 kg C per day); this level was of the same magnitude as the carbon transfer efficiency for algal-derived carbon (0.4%). In the context of the boundless carbon cycle which integrates inland waters as a biologically active component of the terrestrial landscape, the use of the time-for-space approach for the quantifying of t-OM trophic transfer efficiency by zooplankton is a critical step toward a better understanding of the effects of increasing external carbon fluxes on pelagic food webs.

中文翻译：

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浮游甲壳类动物在北方湖泊中转移外来碳的效率

据信，增加将陆地有机物质 (t-OM) 纳入消费生物量（异地生物）会降低生长能力。在这项研究中，我们研究了甲壳类浮游动物异地生物与北湖中的产量之间的关系，该湖在 t-OM 输入中显示出强烈的季节性变化。与我们的假设相反，我们发现异地生物对群落和物种水平的生产没有影响。高频季节性采样（时间换空间）允许估计浮游动物将这种外部碳源转化为生长的效率。从湖中的每日 t-OM 输入（每天 57 - 3027 kg C）中，浮游动物群落将 0.2% 转化为生物量（每天 0.01 - 2.36 kg C）；该水平与藻源碳的碳转移效率 (0.4%) 具有相同的数量级。