Assessing the impact of global change on the distribution and physicochemical speciation of bioactive trace elements in seawater

评估全球变化对海水中生物活性微量元素的分布和理化形态的影响

• 批准号: 262239-2008
• 负责人: Cullen, Jay
• 金额: $ 2.11万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=497066
• 关键词: Assessing; impact; global; change; distribution

The distribution and bioavailability of essential trace elements can impact marine productivity, ecosystem structure and air-sea exchange of greenhouse gases. An understanding of the response of marine biogeochemical cycles to global change must, therefore, include studies of trace element sources, sinks, and chemical speciation. This is because marine microbes have absolute requirements for trace element nutrients that can help explain temporal-spatial variability in microbial community structure and set upper limits on carbon and nitrogen fixation in the sea. The bioavailability of trace element nutrients to marine microbes is controlled not only by the concentration but the speciation, or chemical form, that essential elements take in seawater. In turn, microorganisms can affect the distribution and speciation of trace elements through biologically mediated uptake/exudation, redox reactions and the production of strong organic ligands that complex dissolved trace elements in the water column. The proposed research program will investigate how changing hydrography and ocean acidification will affect the bioavailability of trace element nutrients in marine surface waters and continue studies of the dominant mechanisms that control interactions between marine microbes and trace metals in coastal and open ocean environments. The long term goals of the program are to provide an understanding of how changes in the distribution and availability of bioactive trace metals to marine microbes affect: 1) the magnitude of C and N fluxes into and out of the surface ocean, and, 2) the elemental and isotopic composition of the sinking flux of particulate matter to the ocean interior.

必需微量元素的分布和生物利用度影响着海洋生产力、生态系统结构和温室气体的海气交换。因此，理解海洋生物地球化学循环对全球变化的响应必须包括对微量元素来源、汇和化学形态的研究。这是因为海洋微生物对微量元素营养物质有绝对需求，这有助于解释微生物群落结构的时空变异性，并设定海洋碳氮固定的上限。微量元素营养物质对海洋微生物的生物利用度不仅受其浓度的控制，还受其在海水中所占的形态或化学形式的控制。反过来，微生物可以通过生物介导的摄取/渗出、氧化还原反应和强有机配体的产生来影响微量元素的分布和形态，这些配体可以复杂地溶解水柱中的微量元素。拟议的研究计划将调查变化的水文和海洋酸化如何影响海洋表层水中微量元素营养物质的生物利用度，并继续研究沿海和开阔海洋环境中海洋微生物与微量金属相互作用的主要机制。该计划的长期目标是了解海洋微生物的生物活性微量金属分布和可用性的变化如何影响：1)进出海洋表面的C和N通量的大小，以及2)海洋内部颗粒物质下沉通量的元素和同位素组成。