The Fluxes of Dissolved Inorganic Nitrogen and Dissolved Organic Matter during the Spring Bloom in the Temperate North Atlantic: Magnitudes and Control Mechanisms

在北大西洋东部春季浮游生物水华期间，将对浮游植物和浮游细菌对溶解无机氮(DIN)和溶解有机物(DOM)(N和C)的转化进行合作研究。对DIN和DOM通量的观测研究促进了网络模型的建立，这些模型将DIN和DOM流动一起视为功能定义的生物体群体的输入和输出。浮游植物对DIN的固定和浮游细菌对DOM和NH4的固定往往主导着真光层中的氮素流动。受浮游生物动力学概念的启发，这项研究将跟踪氮的转化，从春季硝酸盐氮(NO3)向上层海洋的运输开始，它被浮游植物固定，以及细菌和其他微型浮游生物的再生和循环。目标包括：a)准确量化真光区N3的供应、储存和利用；b)通过新的高精度技术确定初级生产对新的和再生的营养物质的依赖；c)评估细菌生产的总体意义，以及细菌作为浮游植物对NH4的竞争对手；D)确定NH4的微生物再生对初级生产氮素有效性的影响；以及最后e)评估浮游植物和细菌生产之间的关系，以及从几天到几周的时间尺度上PON和POC的出口。

A collaborative study of the transformations of dissolved inorganic nitrogen (DIN) and dissolved organic matter (DOM) (both N and C) by phytoplankton and bacterioplankton will be conducted during the spring plankton bloom period in the Eastern North Atlantic Ocean. Observational studies of DIN and DOM fluxes have stimulated network models which consider together DIN and DOM flows as inputs and outputs of functionally-define groups of organisms. Fixation of DIN by phytoplankton and of DOM and NH4 by bacterioplankton often dominate the flow of nitrogen in the euphotic zone. Informed by this conceptualization of plankton dynamics, the study will follow the transformations of nitrogen, beginning with the transport of nitrate-nitrogen (NO3) to the upper ocean during the spring, its fixation by phytoplankton, and its regeneration and cycling by bacteria and other microplankton. The objectives include: a) precisely quantifying the euphotic zone supply, stock and utilization of NO3; b) determining via new high precision techniques, the reliance of primary production on new and regenerated nutrients; c) assessing the significance of bacterial production in general, of bacteria as competitors with phytoplankton for NH4; d) determining the impact of microbial regeneration of NH4 on the availability of nitrogen for primary production; and finally e) evaluating the relationship between phytoplankton and bacterial production and the export of PON and POC over time scales of days to weeks.