Nitrate-Ammonium Interactions And Nitrate Supply In The Regulation Of Arabian Sea Regional New Production.

阿拉伯海区域新生产调节中的硝酸盐-铵相互作用和硝酸盐供应。

• 批准号: 9310629
• 负责人: James McCarthy
• 金额: $ 49万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-04-15 至 1997-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9310629&HistoricalAwards=false
• 关键词: Nitrate; Ammonium; Interactions; Supply; Regulation

McCarthy 9310629 Quantitative elcucidation of the processes that regulate biological production in the sea is fundamental to an understanding of the role the oceans play in the earth's climate system. Temporal and spatial variability in the processes that govern the upward rate of nutrient flux from the deep-sea, and the drift of currents in the upper ocean, determine the distribution of marine plankton and set limits for their production. Pursuit of JGOFS objectives requires investigation into these physical-biological linkages. They influence the global rates of carbon sequestration and release by the sea. How balance between these processes was regulated in the past, and how it is regulated today is an important research component of US national and international endeavors to understand and predict responses to global change. The monsoonal system of the Arabian Sea affords unique opportunity for the pursuit of these studies. Its intense seasonal cycle in air-sea interaction allows for the development and testing of models relating to the physical climate-driven process linkages to biological responses and consequent feedback via air-sea exchange of gases. In addition to the intensity of these processes, and hence their strong seasonal signal in the Arabian Sea, the record of the past, recorded in marine fossil assemblages and isotopes in ocean sediments, is valuable in the development and testing of time varying models treating coupled physical and biological aspects of the ocean climate system. This study relates to one particular link in the system: the regulation of primary planktonic production by the supply rate of the limiting nutrient, nitrogen. The coarse seasonal pattern in Arabian Sea production is one of the most intense, production being associated with the summer SW monsoon. Upwelling delivers a pulse of nutrients to surface waters, which in turn stimulates a plankton bloom in the northern Arabian Sea. During the balance of the year, production rates are lower, but remain generally higher than those typical of oceanic waters elsewhere. In this study the availability of nitrogen, both in the upwelled form of nitrate and in the recycled form of ammonium, will be assessed regionally during the low production NE winter monsoon and the two inter-monsoon transition periods. The interplay between dependence on the "new" and "regenerated" forms of nitrogen determine what fraction of total primary production is at any time available for export to the deep- sea. The techniques applied will permit the quantification of new production and its regulation throughout the low nutrient portion of the year. Nutrient analyses sensitive in the nanomolar range will be employed for quantifying the abundance, and with 15N labeled substrates, the rates of supply and utilization of nitrite, nitrate and ammonium in the upper ocean. This study will be conducted in collaboration with investigators who are addressing other aspects of the nitrogen cycle and biological production. New understanding resulting from these complementary projects will contribute to the formulation and testing of regional models that use remotely sensed information on biological and physical features and processes to better predict how production processes in the Arabian Sea will respond to future climate change. ***

McCarthy 9310629 定量阐明海洋中生物生产的调节过程对于理解海洋在地球气候系统中所扮演的角色至关重要。 控制深海养分通量上升速率和上层海洋洋流漂移的过程的时间和空间变化决定了海洋浮游生物的分布并为其生产设定了限制。 追求 JGOFS 目标需要对这些物理-生物联系进行调查。 它们影响全球碳封存和海洋释放的速度。 过去如何监管这些过程之间的平衡以及今天如何监管它是美国国家和国际努力理解和预测对全球变化的反应的重要研究组成部分。 阿拉伯海的季风系统为开展这些研究提供了独特的机会。 其海气相互作用的强烈季节性循环允许开发和测试与物理气候驱动过程与生物反应的联系以及通过气海气体交换产生的反馈相关的模型。 除了这些过程的强度及其在阿拉伯海的强烈季节性信号之外，海洋化石组合和海洋沉积物同位素中记录的过去记录对于开发和测试处理耦合的时变模型也很有价值。海洋气候系统的物理和生物方面。 这项研究涉及系统中的一个特定环节：通过限制性营养物氮的供应率来调节初级浮游生物的生产。 阿拉伯海生产的粗略季节性模式是最强烈的季节模式之一，其生产与夏季西南季风有关。 上升流向地表水域输送营养物质，进而刺激阿拉伯海北部的浮游生物大量繁殖。 在这一年的剩余时间里，生产率较低，但总体上仍高于其他地方典型海域的生产率。 在本研究中，将在低产量的东北冬季季风和两个季风间过渡期期间对氮的可用性（无论是上升形式的硝酸盐还是回收形式的铵）进行区域评估。 对“新”和“再生”形式氮的依赖之间的相互作用决定了初级生产总量中随时可出口到深海的比例。 所采用的技术将允许在一年中的低营养部分对新产量进行量化及其调节。 纳摩尔范围内敏感的营养物分析将用于量化上层海洋中亚硝酸盐、硝酸盐和铵的丰度以及 15N 标记底物的供应和利用率。 这项研究将与研究氮循环和生物生产其他方面的研究人员合作进行。 这些补充项目产生的新认识将有助于区域模型的制定和测试，这些模型利用有关生物和物理特征和过程的遥感信息，更好地预测阿拉伯海的生产过程将如何应对未来的气候变化。 ***