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

预测快速变化的北冰洋陆地 CDOM 的命运及其对浮游生物生产力的影响

基本信息

批准号：
NE/G000611/1
负责人：
Vincent Lefouest
金额：
$ 10.98万
依托单位：
Scottish Association For Marine Science
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FG000611%2F1
关键词：
Predicting Terrestrial CDOM Fate Impact

项目摘要

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.

有一个共识：北冰洋面临着海冰减少的未来。因此，更多的阳光到达地表水，伴随着对生态系统功能、生产力和生物地球化学的重大影响。阳光对海洋生物来说是必不可少的。它通过浮游植物驱动生物物质的光合作用，反过来又为整个远洋食物网的生产力提供燃料。长期以来被生物地球化学建模者最小化，准确模拟浮游植物所经历的水下光环境对于可靠预测北冰洋生态系统对气候变化的响应至关重要。对于具有复杂光学性质的生产性陆架水来说尤其如此。最近的一项研究预测，由于海冰融化导致更长时间的阳光照射，北极浮游生物的生产力将大幅增加。然而，这可能不是海洋中所有地方的普遍规律。北极大陆架的淡水和溶解有机物（DOM）排放量是所有海洋中最高的，而且由于北极变暖，这种情况将会增加。这种DOM的很大一部分是有色的（CDOM），因此强烈吸收阳光，降低了浮游植物生长所需的光照水平。在快速变化的北极，这种强烈的阳光吸收剂会对浮游生物产量下降有多大影响？在生物地球化学模型中嵌入河流CDOM是回答这一紧迫问题的必要条件，并进一步为北冰洋产生强有力的气候变化情景。一个高分辨率的海洋-海洋-浮游生物生态系统模型将用于模拟巴伦支/喀拉海正常和相对较低海冰覆盖（即浮游植物较高的阳光照射）年份的海洋和生物条件。在模型中，将河流CDOM作为一个受运输影响的变量，绘制并验证其在沿海水域的时空分布。建立复杂的生物光学模型，并将其嵌入到物理-生物耦合模型中，模拟TCDOM对水下光场的遮蔽效应及其主要的光介导去除过程（光降解）。这将允许更准确的模拟初级产量，将与使用该项目的两位合作者开发的新方法获得的同步卫星估算值进行比较。这将是对北极水域的第一次比较，因此构成了在这一生产和经济上重要的地区进行生物海洋学操作的重要框架。