Twilight zone to deep-ocean floor. Developing an understanding of particle dynamics and trophic interactions using a molecular experimental approach

光合作用初级生产是许多海洋食物链的基础。浮游植物固定的能量被转移到食草动物和更高的消费者手中。生产者和消费者之间能量转移的效率反映了生态系统的状态，例如营养充足与营养缺乏。通过下沉，表层水中的颗粒有机物(POM)被转移到深海，在那里它是深海动物的重要资源，无论它们生活在中上层(在水中)还是底栖(在海底)环境中。我们知道，在中高纬度的北大西洋，POM的沉积是由地表水泉水华季节性驱动的。然而，POM的组成有相当大的变异性，这在一定程度上是由浮游植物的性质驱动的，但也受到以它们为食的生物体的影响。离开地表水的大部分POM丢失在所谓的黄昏地带；在那里发生的过程可能也改变了下沉POM的化学成分。我们几乎对发生在黄昏地带的POM的生物处理一无所知。到达海底喂养底栖动物的物质可能会发生很大的变化，并在许多化学物质中枯竭，然而，深海群落是高度多样化的。在这个项目中，我们将与南安普敦国家海洋学中心和布里斯托尔大学的科学家合作，试图阐明锁定在表层水域中的有机物中的能量是如何在生活在深海的消费者之间分配的。我们将详细研究颗粒物质的化学，包括以颗粒为食的浮游植物和小型生物(细菌和微型浮游动物)，浮游动物和生活在深海和海底的大型动物的生物化学。我们还将使用遥控运载工具Isis进行孵化实验，以评估微生物如何分解黄昏地带的有机物，以及生活在海底的大型动物如何以及是否能够对POM的涌入做出反应。

Photosynthetic primary production is the basis of much of the oceanic food chain. The energy fixed by phytoplankton is transferred to grazers and to higher consumers. The efficiency of the energy transfer between producer and consumer reflects the state of the ecosystem, for example nutrient replete vs nutrient deficient. Through sinking, particulate organic matter (POM) from surface waters is transferred to the deep sea, where it is an important resource for deep-dwelling animals, be they living in pelagic (in the water) or benthic (at the sea floor) environments. We know that in the northern Atlantic Ocean at mid- to high latitude, the deposition of POM is seasonally driven by the surface water spring bloom. However, there is considerable variability in the composition of the POM, which is driven partly by the nature of the phytoplankton, but also by the organisms that graze on them. Much of the POM leaving surface waters is lost in the so-called twilight zone; processes occurring there also presumably modify the chemical composition of the sinking POM. We know virtually nothing about the biological processing of POM that occurs in the twilight zone. The material arriving at the sea floor which feeds the benthic animals is potentially highly altered and depleted in many chemicals, nevertheless, the deep-sea community is highly diverse. In this project, we will work with scientists at the National Oceanography Centre, Southampton and the University of Bristol to try to shed some light on how the energy locked up in organic matter fixed in surface waters is partitioned between consumers living in the deep sea. We will study in detail, the chemistry of particulate material, which includes the phytoplankton and small size organisms that feed on it (bacteria and microzooplankton), the biochemistry of the zooplankton and larger animals living in the deep sea and at the sea floor. We will also carry out incubation experiments using the remotely operated vehicle, Isis, in order to assess how micro-organisms break down organic matter in the twilight zone and how and whether large animals living at the sea floor are able to react to an influx of POM.