Composition of the plankton community and its contribution to particle flux in the Sargasso Sea

马尾藻海浮游生物群落的组成及其对颗粒通量的贡献

• 批准号: 0752592
• 负责人: Susanne Neuer
• 金额: $ 64.59万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0752592&HistoricalAwards=false
• 关键词: Composition; plankton; community; its; contribution

The overall objective of this proposal is to investigate linkages between the presence of different key groups of phytoplankton in the euphotic zone and their contribution to particle flux at the subtropical North Atlantic time-series station BATS (Bermuda Atlantic Time-series Study) by applying a range of traditional and novel molecular techniques. The 'biological pump', the photosynthetically mediated transformation of dissolved inorganic carbon into particulate and dissolved organic carbon in surface ocean waters and its subsequent export to deep water, is a significant driver of the atmospheric carbon uptake by the oceans. But this "biologically pumped" production, inasmuch as it depends on the composition and activity of planktonic organisms, is susceptible to long-term climatic changes in surface ocean properties such as increased temperature and changes in nutrient supply, especially in subtropical gyres. The sub-tropical gyres and the transition zones at their boundaries play an important role in the global carbon cycle because of their vast size and generally high per area export production. As evidenced in recent studies, the biological mechanisms driving regional to basin scale variability in carbon export in these biomes is far from understood, thus limiting our ability to mechanistically explain the biological pump and to predict its possible responses in the face of environmental change. In an effort to improve this situation with an accurate assessment of the contribution of different plankton groups to overall fluxes, the investigators will test the following two specific hypotheses:1. The long held notion that large cells and those with mineral tests are major contributors to downward particle flux needs to be re-evaluated. We hypothesize that pico and nanoplankton (also those without mineral tests) are generally important contributors to downward particle flux at BATS. Consequently, the diversity of taxonomic groups contributing to particle flux is greater than previously expected. 2. The relative contribution of taxonomic groups to downward particle flux is a function of physical forcing. We hypothesize that episodic events (e.g., winter storms and eddies) lead to a reduction in diversity of sedimenting phytoplankton (e.g., dominance by a single group such as diatoms) compared to periods marked by more stable conditions in the water column. The broader impacts include furthering knowledge of the diversity and biology of phytoplankton groups that have a significant impact on the carbon export in subtropical gyres, thereby advancing our understanding of regional to basin scale variability in the biogeochemistry of these biomes. The project provides new opportunities for undergraduate and graduate education, as well as offer research opportunities to local high school students and teachers as part of the "Ask-a-Biologist" initiative. The project also includes an international component through collaboration with a molecular ecology group in Barcelona, Spain.

该提案的总体目标是通过应用一系列传统和新颖的分子技术，研究真光带中不同关键浮游植物群的存在及其对亚热带北大西洋时间序列站 BATS（百慕大大西洋时间序列研究）的粒子通量的贡献之间的联系。 “生物泵”是通过光合作用介导将表层海水中溶解的无机碳转化为颗粒和溶解的有机碳，然后将其输出到深水，是海洋吸收大气碳的重要驱动力。但这种“生物泵送”生产，因为它取决于浮游生物的组成和活动，容易受到海洋表面特性的长期气候变化的影响，例如温度升高和养分供应变化，特别是在亚热带环流中。副热带环流及其边界的过渡带由于面积巨大且单位面积出口产量普遍较高，因此在全球碳循环中发挥着重要作用。正如最近的研究所证明的那样，驱动这些生物群落中碳输出的区域到盆地尺度变化的生物机制尚不清楚，从而限制了我们从机械上解释生物泵并预测其在面对环境变化时可能做出的反应的能力。为了通过准确评估不同浮游生物群对总通量的贡献来改善这种情况，研究人员将测试以下两个具体假设：1。长期以来人们一直认为大细胞和经过矿物测试的细胞是向下颗粒通量的主要贡献者，需要重新评估。我们假设皮浮游生物和纳米浮游生物（以及未经矿物测试的浮游生物）通常是 BATS 向下颗粒通量的重要贡献者。因此，对粒子通量做出贡献的分类群的多样性比之前预期的要大。 2. 分类群对向下粒子通量的相对贡献是物理强迫的函数。我们假设，与水柱条件更稳定的时期相比，偶发事件（例如冬季风暴和涡流）会导致沉积浮游植物多样性（例如硅藻等单一群体的优势）减少。更广泛的影响包括进一步了解浮游植物群的多样性和生物学，这些浮游植物群对亚热带环流的碳输出具有重大影响，从而增进我们对这些生物群落生物地球化学的区域到盆地尺度变异性的理解。该项目为本科生和研究生教育提供了新的机会，并为当地高中生和教师提供了研究机会，作为“询问生物学家”计划的一部分。该项目还包括与西班牙巴塞罗那的一个分子生态学小组合作的国际部分。