The Effects of Mesoscale Eddies on Phytoplankton Community Structure, Total Production, and the F-Ratio in Open-Ocean Waters

夏威夷群岛附近形成的中尺度气旋涡流将被用来研究上升流事件对公海浮游植物种群的生产力、组成、生物量和生理学的影响。将利用最近的技术和方法进步，更准确地确定新产量与总产量的比率(f比率)以及该比率在公海的时间和空间变异性。无论是简单的经验模型，还是更复杂的隔室模型，都将测试它们描述和解释观察到的f比变化的能力。对新产量的估计将使用最近开发的硝酸盐分析方法，精度为/-2 NM。总产量将通过将C-14标记的无机碳结合到蛋白质中来估计。这种实验方法将消除与传统f比研究有关的许多潜在伪影和问题，包括添加非示踪剂N-15造成的扰动、底物池的同位素稀释、测量环境底物浓度的困难、需要测量至少三种形式的溶解N的吸收，细菌可能占了铵吸收的很大一部分。海洋的生物生产力在很大程度上因地理而异。在盆地中部的亚热带地区，如夏威夷群岛附近，产量通常相对较低。然而，当地水域的自然特征，如在岛屿以西发现的圆形涡流，可以通过增加向地表水供应植物生长所需的养分来提高生产力。劳和变方将使用最先进的技术来测量生物生产中的这些变化，并将其与浮游生物群落的结构联系起来。他们将对新的产量进行敏感的测量，这一参数对于估计地表水中有机物质的通量及其可开采资源的可用性至关重要。在发现海洋漩涡的区域进行研究，将提供很可能在公海发现的广泛的生物海洋学条件。

Mesoscale Cyclonic Eddies Formed Near the Hawaiian Islands will be utilized to study the effects of upwelling events on the productivity, composition, biomass, and physiology of open-ocean phytoplankton populations. Recent technical and methodological advances will be utilized to more accurately determine the ratio of new production to total production (f-ratio) and the temporal and spatial variability of that ratio in the open ocean. Both simple empirical models and more sophisticated compartmental models will be tested for their ability to describe and explain observed f-ratio variations. Estimates of new production will be obtained using a recently developed nitrate analysis method with a precision of +/- 2nM. Total production will be estimated from the incorporation of C-14 labeled inorganic carbon into protein. This experimental approach will eliminate many of the potential artifacts and problems associated with traditional f-ratio studies, including perturbations caused by the addition of non- tracer amounts of N-15, isotope dilution of the substrate pool, difficulty in measuring ambient substrate concentrations, the need to measure uptake of at least three forms of dissolved N, and the fact that bacteria may account for a significant fraction of the uptake of ammonium. The biological productivity of the ocean varies geographically to a great degree. In mid-basin subtropical areas such as thevicinity of the Hawaiian Islands, production is typically relatively low. However, physical features of the local waters such as the circular eddies found to the west of the islands can enhance productivity by increasing the supply of nutrients for plant growth to surface waters. Laws and Bienfang will use state of the art techniques to measure these variations in biological production and relate it to the structure of the planktonic community. They will make sensitive measurements of new production, a parameter that is critical in estimating the flux of organic material from surface waters and its availability for harvestable resources. Conducting the studies in an area where oceanic eddies are found will provide a wide range of biological oceanographic conditions likely to be found in the open ocean.