Characterizing mycoplankton and the mycobenthos in the Benguela upwelling system

“生物泵”将表层海洋中的生物产生的有机物输出到深海和海底。生物泵的效率通过控制向深海输出多少碳来对地球气候产生重大影响，沉积在沉积物中的有机物质的生物降解控制着最终被隔离在地下的大量(太克)有机碳汇。浮游真菌和底栖生物是两类异养真核微生物，它们被认为有助于控制海水和沉积物中的碳通量，但人们对这两类微生物的丰度、多样性和活性了解很少。它们已经在世界海洋的几个地点被检测到。因此，通过它们的新陈代谢，它们被认为有助于控制全球范围内最终埋藏和隔离在海底的有机物质的数量。然而，在本格拉上升流系统中还没有浮游真菌和真菌底栖生物的特征。由于这是海洋生产力最高的上升区之一，拟议工作的主要研究目标是量化浮游真菌和真菌底栖生物的多样性和代谢活动，以便更好地确定它们在这一重要海洋位置的生态作用。为此，我于2018年7月2日至7月20日参加了流星Reise M148-2至本格拉上升流系统(Erebus：控制本格拉上升流系统温室气体排放的过程)。从纳米比亚大陆架水柱中观察到的氧垂直梯度的六个地点采集了水样本。此外，两个26厘米深的沉积物岩心是从大陆架上氧最小带以下的一个地点获得的。在流星从纳米比亚转移到加那利群岛时，还在安哥拉环流的八个近海地点采集了深达1,000米的水样。总共有90个样本正在等待处理，我建议使用最先进的定量DNA和RNA测序技术来确定浮游真菌和底栖真菌的丰度、活性和多样性。拟议的项目将解决以下问题：本格拉上升流系统中代谢活跃的浮游真菌和底栖真菌的主要类群是什么？本格拉上升流系统中浮游真菌和底栖真菌的生物地球化学代谢特征是什么？解决这些问题很重要，因为它将提高我们对生物泵中新的生物机制(浮游真菌和底栖真菌)的理解，这是一个有助于在地质时间尺度上控制地球气候的全球过程。

The "biological pump" exports biologically produced organic matter in the surface ocean to the deep sea and seafloor. The efficiency of the biological pump exerts a strong influence on Earth’s climate by controlling how much carbon is exported to the deep sea and biodegradation of the organic matter deposited in sediments controls massive (teragrams) sinks of organic carbon that are ultimately sequestered in the subsurface. The mycoplankton and mycobenthos are two groups of heterotrophic eukaryotic microbes that are hypothesized to help control the flux of carbon in seawater and sediments, but the abundance, diversity, and activity of these groups are poorly understood.Mycoplankton and the mycobenthos are Fungi and fungal-analogs that live in seawater (mycoplankton) and sediments (mycobenthos), respectively. They have been detected in several locations of the world’s oceans. Thus, through their metabolism they are hypothesized to help control how much organic matter is ultimately buried and sequestered in the seafloor on a global scale. However, mycoplankton and the mycobenthos have not yet been characterized in the Benguela upwelling system. Because this is one of the most productive upwelling regions of the ocean, the overarching research aim of the proposed work is to quantify mycoplankton and mycobenthos diversity and metabolic activity, in order to better define their ecological role in this important oceanographic location. To this end, I participated in the Meteor Reise M148-2 to the Benguela upwelling system ('EreBUS': Processes controlling the Emissions of greenhouse gases from the Benguela Upwelling System) from July 2nd – July 20th, 2018. Waters were sampled from six sites exhibiting vertical oxygen gradients that were observed in the water column on the Namibian shelf. In addition, two 26 cm deep sediment cores were obtained from one site below the oxygen minimum zone on the shelf. Water samples up to a depth of 1,000 m were also collected at eight offshore sites in the Angola Gyre, as the Meteor transited from Namibia to the Canary Islands. In total there are 90 samples that now await processing, and I propose to use state-of-the-art quantitative DNA and RNA sequencing techniques to determine the abundance, activity, and diversity of the mycoplankton and mycobenthos.The proposed project will address the questions: What are the dominant groups of metabolically active mycoplankton and mycobenthos in the Benguela upwelling system? What are the biogeochemically relevant metabolic features of mycoplankton and mycobenthos in the Benguela upwelling system? Addressing these questions is important because it will improve our understanding of a new biological mechanism (mycoplankton and mycobenthos) within the biological pump, a global process that helps control Earth’s climate over geological timescales.