Trophic relationships of benthic fauna at the Oman Margin: the impact of mass jelly falls.

阿拉伯海是世界海洋中最具生物生产力的地区之一。它还具有氧气最小区（OMZ）的特征; OMZ是氧气浓度非常低的水域。我们的研究区是阿曼大陆边缘，这里的OMZ的影响，在沉积物群落。这对生活在这里的动物群有影响。在氧气浓度低的地方，动物群落的特征是能够承受这些条件的软体动物，例如多毛类蠕虫，而不是软体动物或甲壳类动物。阿曼边缘受两个季风季节的影响;这导致水柱混合，将营养物质带到表面沃茨，喂养微型植物，这些植物下沉和死亡时形成沉积物动物群落的食物来源。此外，在低氧浓度的条件下，细菌可以利用硫固定碳作为能量。这被称为化学合成，这些细菌也为沉积物群落提供了潜在的食物来源。细菌可以自由生活，也可以在沉积物表面形成垫，供动物群吃草。食物来源和氧气浓度之间的平衡可能对底栖生物至关重要，任何扰动都可能导致群落结构的变化。我们打算调查沉积物群落的食物来源，并了解沉积物群落中存在的营养联系。我们认为，在氧浓度低，细菌的食物来源可能在营养动力学中发挥重要作用，而在氧浓度高，占主导地位的食物来源将是微观植物。我们有一个独特的机会来研究增强缺氧对沉积群落的影响，这是由于阿曼边缘的大面积腐烂水母的巨大下降，在OMZ内和以下，导致了化学合成的发展和底栖动物的潜在食物来源。我们将比较底栖生物群落结构与在巴基斯坦边缘，我们有一个现有的数据集的OMZ的样本收集在类似的时间，但有福尔斯的水母缺席。

The Arabian Sea is one of the most biologically productive areas of the world's oceans. It is also characterised by an oxygen minimum zone (OMZ); OMZ's are areas of water that have very low oxygen concentrations. Our study area is the Oman continental margin, here the OMZ impinges on the sediment community. This has implications for the fauna living here. Where oxygen concentrations are low, the faunal community will be characterised by soft bodied animals that are able to withstand these conditions e.g. polychaete worms and not molluscs or crustaceans. The Oman margin is subject to two monsoon seasons; these lead to mixing of the water column which brings nutrients to the surface waters feeding microscopic plants, which when they sink and die form a food source for the sediment faunal community. Additionally under conditions of low oxygen concentrations, bacteria can use sulphur to fix carbon for energy. This is known as chemosynthesis and these bacteria also provide a potential food source for the sediment community. The bacteria can be free living, or can form mats on the sediment surface for the fauna to graze on. The balance between food sources and oxygen concentrations is likely to be critical to the benthos and any perturbation may lead to a shift in community structure. We intend to investigate the food sources available to the sediment community and to understand the trophic linkages that exist within the sediment community. We believe that where oxygen concentrations are low, bacterial food sources may play an important role in trophic dynamics and where oxygen is high the dominant food source will be the microscopic plants. We have a unique opportunity to study the impact of enhanced hypoxia on sedimentary communities, as the result of a huge fall of decaying jellyfish across a large area of the Oman Margin, within and below the OMZ which led to the development of chemosynthesis and a potential food source for the benthic animals. We will compare the benthic community structure with that at the Pakistan Margin, where we have an existing data set for an OMZ where samples were collected at a similar time, but where there was falls of jelly fish were absent.