Grosbois Guillaume, Vachon Dominic, Del Giorgio Paul A, Rautio Milla
Group for Interuniversity Research in Limnology and Aquatic Environment (GRIL), Université de Montréal, C.P. 6128, Succ. Centre-ville, Montréal, H3C3J7, Québec, Canada.
Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boul. de l'Université, Chicoutimi, G7H2B1, Québec, Canada.
Ecology. 2020 Jun;101(6):e03013. doi: 10.1002/ecy.3013. Epub 2020 Apr 1.
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 (57-3,027 kg C/d), the zooplankton community transferred 0.2% into biomass (0.01-2.36 kg C/d); 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.
陆地有机物质（t-OM）在消费者生物量中的掺入增加（异养）被认为会降低生长能力。在本研究中，我们研究了在一个t-OM输入呈现强烈季节性变化的北方湖泊中，甲壳类浮游动物的异养与产量之间的关系。与我们的假设相反，我们发现在群落和物种水平上，异养对产量没有影响。高频季节性采样（以时间换空间）使我们能够估计浮游动物将这种外部碳源转化为生长的效率。根据湖泊中每日的t-OM输入量（57 - 3027千克碳/天），浮游动物群落将0.2%转化为生物量（0.01 - 2.36千克碳/天）；这一水平与藻类衍生碳的碳转移效率（0.4%）相当。在将内陆水域作为陆地景观的生物活性组成部分纳入其中的无界碳循环背景下，采用以时间换空间的方法来量化浮游动物对t-OM的营养转移效率，是朝着更好地理解增加的外部碳通量对远洋食物网的影响迈出的关键一步。
