The role of pelagic foodfalls in subsidizing deep-sea bottom communities in a changing ocean

深海是地球上最大的环境，是碳的汇和未开发的生物多样性储存库。我们对海洋深层区域如何维持以及深海社区如何受到气候变化和其他人类压力的影响的理解存在很大差距。该项目结合深海取样和实验、实验室分析以及对独特的现场观测数据库的分析，以调查深海中上层和海底碳通量、生物多样性和食物网之间的联系。它将建立基本知识，这对于研究和预测气候变化和人类压力对深海群落及其生物多样性的影响至关重要。许多海洋碳收支中存在的一个生态悖论是，沉积物捕集器测得的到达海底的有机物数量无法解释许多底栖生物群落的呼吸率和生物量。我将检验这样一个假设，即中等大小（无脊椎动物）的食物瀑布可以解释区域碳预算中的部分差距。利用现有的深海海底观测数据库，并通过在海洋考察期间进行海底调查，我将描述和量化北极，北大西洋和北太平洋的自然食物瀑布。为了帮助检测消耗的食物瀑布，我将分析深海沉积物中的环境DNA，以鉴定游泳动物和大型浮游动物的eDNA。第二部分为了验证大型无脊椎动物食物瀑布是深海生物多样性驱动因素的假设，该项目将在北极、太平洋和大西洋进行诱饵着陆器实验，比较鱼类、头足类动物和大型凝胶状浮游动物的腐肉之间的食腐群落和演替阶段以及处理时间。这一信息将有助于预测由于营养级联和范围扩大而改变的水层群落如何可能改变海底拾荒群落的多样性和碳分配。第三部分：我们将在长期生态研究（LTER）地点豪斯加滕（HAUSGARTEN）建立一个中上层基线，以调查气候变化热点地区中上层腐肉物种的组成、丰度和分布。北极水层基线将与太平洋和大西洋水层动物的现有基线进行比较，并将作为一个出发点，以确定在迅速变化的（北极）海洋中海底环境与水层环境之间的相互关系。

The deep sea is the largest environment on the planet, a sink for carbon and an unexplored biodiversity reservoir. Large gaps exist in our understanding of how the deep regions of the oceans are sustained and how deep-sea communities are impacted by climate change and other human pressures. This project combines deep-sea sampling and experiments, laboratory analyses, and the analysis of unique databases of in situ observations to investigate the link between deep-sea pelagic and benthic carbon flux, biodiversity and food-webs. It will establish basic knowledge that is essential to study and predict the effect of climate change and human pressures on deep-sea communities, and their biodiversity. Part I An ecological paradox that exists in many ocean carbon budgets is that the amount of organic matter that reaches the seafloor, as measured by sediment traps, cannot explain the respiration rates and biomass of many benthic communities. I will test the hypothesis that medium size (invertebrate) foodfalls can explain part of the gap in regional carbon budgets. Using existing databases of deep seafloor observations and by performing benthic surveys during ocean expeditions, I will characterize and quantify natural foodfalls in the Arctic, North Atlantic and North Pacific. To aid the detection of consumed foodfalls, I will analyze environmental DNA in deep-sea sediment to qualify eDNA of nekton and large macrozooplankton. Part II To test the hypothesis that large invertebrate foodfalls are drivers of biodiversity in the deep ocean, this project will perform baited lander experiments in the Arctic, Pacific and Atlantic comparing the scavenging communities and successional stages, as well as processing time, between carrion of fish, cephalopods, and large gelatinous zooplankton. This information will serve to predict how changing pelagic communities as a result of trophic cascades and range expansion may alter diversity and carbon distribution by benthic scavenging communities. Part III We will establish a pelagic baseline at the LTER (Long-term Ecological Research) site HAUSGARTEN to investigate the composition, abundance and distribution of pelagic carrion species in a hotspot of climate change. The Arctic pelagic baseline will be compared to existing baselines of pelagic fauna in the Pacific and Atlantic, and will serve as a starting point to delineate the coupling between the benthic and pelagic environments in a rapidly changing (Arctic) ocean.