New Production and Nitrogen Cycling in the Off-Shore Regions of the Black Sea

黑海近海地区的新生产和氮循环

• 批准号: 9731232
• 负责人: James McCarthy
• 金额: $ 16.22万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-15 至 2001-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9731232&HistoricalAwards=false
• 关键词: New; Production; Nitrogen; Cycling; Off

Many scientific papers have been written that detail environmental changes in the Black Sea, and many speculate regarding implications of further potential anthropogenic changes 1) in various drainage basins that provide freshwater to this sea, 2) along its coastal margins, and 3) in extraction of its resources. While the ecological effects of industrial activity and changing land and water use are most apparent in coastal regions of the Black Sea, they are also evident off shore. For example, the observed trend of increasing nutrient concentrations and doublings of both phytoplankton biomass and primary productivity throughout the central region of the sea between the mid 1970s and early 1990s, have been attributed to anthropogenic causes. Perhaps the most dramatic basin wide changes have, however, resulted from accidental introductions of carnivorous gelatinous zooplankton, most recently Mnemiopsis leydii. These species have profoundly affected Black Sea community structure, and probably community dynamics with respect to element and energy flow. There have been no studies of the annual nitrogen cycle and no determinations of new production in the Black Sea. Moreover, generalizations that have been made, such as in models, are predicated upon the generalized behavior of a Black Sea planktonic ecosystem prior to the environmental changes of the last decade. In conjunction with colleagues in Turkey, the off shore nitrogen cycle during all four seasons will be thoroughly investigated. Rates of nitrogen uptake, nitrogen fixation, and nitrogen flux among dissolved components will be measured with stable isotope techniques and interpreted within the context of plankton community structure and hydrography. This study will serve to document current conditions, provide a basis for inferring the effects of recent environmental changes, and contribute to more realistic modeling efforts of the Black Sea ecosystem. In the course of this work our Turkish colleagues will gain experience in the design, analysis and interpretation of results of nitrogen flux experiments, and our facilities will be available to them for follow on studies of changing conditions in the Black Sea. The physical scale of the Black Sea makes a comprehensive study of its pelagic ecosystem tractable. In this regard the Black Sea is an important resource for developing and testing understanding of ecosystem function and stability in more broadly applied coupled physical and biogeochemical models of the pelagic plankton realm.

已经写了许多科学论文，这些论文详细介绍了黑海的环境变化，许多人推测有关进一步潜在的人为变化的影响1）在各种排水盆地中，为海洋提供淡水，2）沿着沿海边缘和3）提取资源。虽然在黑海沿海地区，工业活动以及不断变化的土地和用水的生态影响最为明显，但它们也很明显。例如，在1970年代中期至1990年代初期，观察到的浮游植物生物量增加营养浓度和双重生产力的趋势归因于人为原因。 然而，也许最引人注目的盆地变化是由于近期Mnemiopsis leydii的意外引入而引起的。这些物种对黑海社区结构产生了深远的影响，并且可能在元素和能量流方面的动态。 没有对年度氮周期的研究，也没有确定黑海的新产量。此外，在过去十年的环境变化之前，已经进行了概括（例如模型中）的概括性。 与土耳其的同事一起，将彻底研究所有四个季节的海外氮气周期。溶解成分之间的氮摄取率，氮固定和氮气的速率将通过稳定的同位素技术测量，并在浮游生物群社区结构和水文学的背景下进行解释。这项研究将记录当前状况，为推断最近的环境变化的影响提供基础，并有助于黑海生态系统的更现实的建模工作。在这项工作中，我们的土耳其同事将获得氮通量实验结果的设计，分析和解释的经验，我们的设施将供他们使用，以遵循黑海变化状况的研究。 黑海的物理规模对其上层生态系统进行了全面研究。在这方面，黑海是在更广泛地应用的浮力浮游生物领域的耦合物理和生物地球化学模型中发展和测试对生态系统功能和稳定性的理解的重要资源。