Predicting Terrestrial CDOM Fate and Impact on Plankton Productivity in the Rapidly Changing Arctic Ocean

有一个共识：北冰洋面临着一个海冰减少的未来。因此，更多的阳光到达表面沃茨，伴随着对生态系统功能、生产力和地球化学的重大影响。阳光对海洋中的生命至关重要。它驱动浮游植物对生物源物质进行光合作用，进而为整个远洋食物网的生产力提供燃料。长期以来，海洋地球化学建模者一直将其最小化，准确模拟浮游植物所经历的水下光环境对于强有力地预测北冰洋生态系统对气候变化的响应至关重要。这是特别真实的生产架沃茨的特点是复杂的光学性能。最近的一项研究预测，北极浮游生物的生产力将大幅增加，以应对海冰融化造成的更长时间的阳光照射。但是，这可能不是海洋中所有地方的普遍规则。北极大陆架经历了任何海洋中最高的淡水和溶解有机物（DOM）排放，由于北极变暖，这将增加。这种DOM的很大一部分是有色的（CDOM），因此强烈吸收阳光，减少浮游植物生长所需的光照水平。在迅速变化的北极，这种强烈的阳光吸收剂会在多大程度上降低浮游生物的生产力？嵌入河流的CDOM的地球化学模型需要回答这个紧迫的问题，并进一步产生强大的气候变化情景的北冰洋。将使用一个高分辨率的海洋-海冰-浮游生物生态系统模型，模拟巴伦支海/喀拉海正常海冰覆盖率和相对较低海冰覆盖率（即浮游植物日照率较高）年份的海洋和生物条件。模型中将河流CDOM作为一个受输运影响的变量，以绘制和验证其在沿海沃茨的时空分布。一个复杂的生物光学模型，然后将开发和嵌入到物理-生物耦合模型，以模拟TCDOM的阴影效应的水下光场联合其主要的光介导的去除过程（光降解）。这将允许更准确地模拟初级生产率，并将其与使用该项目的两个合作者开发的新方法获得的同步卫星得出的估计数进行比较。这一比较将是北极沃茨的第一次比较，因此构成了在这一生产和经济重要领域开展业务生物海洋学的一个重要框架。

There is a consensus: the Arctic Ocean faces a future with less sea ice. Therefore more sunlight reaches the surface waters accompanied with major implications for the ecosystem functioning, productivity, and biogeochemistry. Sunlight is essential for life in the ocean. It drives the photosynthesis of biogenic matter by phytoplankton that fuels in turn the productivity of the whole pelagic food web. Long minimized by biogeochemical modellers, simulating accurately the underwater light environment experienced by phytoplankton is pivotal to robustly predict the Arctic Ocean ecosystem response to climate change. It is particularly true for the productive shelf waters characterized by complex optical properties. A recent study predicts a substantial increase of Arctic plankton productivity in response to longer sunlight exposure caused by sea ice melt. However, it might not be a general rule everywhere in the ocean. Arctic shelves experience the highest freshwater and dissolved organic matter (DOM) discharge of any ocean and it this will increase due to Arctic warming. A large fraction of this DOM is coloured (CDOM) and therefore strongly absorbs sunlight, reducing light levels needed for phytoplankton growth. How much would this strong sunlight absorber contribute to lower plankton productivity in the rapidly changing Arctic? Embedding the riverine CDOM in biogeochemical models is required to answer this pressing question and to further produce robust climate change scenarios for the Arctic Ocean. A high-resolution ocean-sea ice-plankton ecosystem model will be used to simulate the ocean and biological conditions for years of normal and relatively low sea ice coverage (i.e. higher sunlight exposure for phytoplankton) in the Barents/Kara Sea. Riverine CDOM will be accounted in the model as a variable subject to transport to map and validate its spatio-temporal distribution in the coastal waters. A complex bio-optical model will be then developed and embedded in the physical-biological coupled model to simulate the TCDOM shading effect on the underwater light field jointly with its main light-mediated removal process (photodegradation). This will allow more accurate simulated primary production rates that will be compared with coincident satellite-derived estimates obtained using a new method developed by two collaborators of this project. This comparison will be the first for the Arctic waters and therefore constitutes an important framework for operational biological oceanography in this productive and economically important area.