Collaborative Research:Influences of Cyclonic Eddy Activity on Planktonic Food Web Dynamics and Carbon Export in the Lee of Hawaii

0241645/OCE-0241897/OCE-0241121/OCE-0241852在这个项目中，南卡罗来纳大学、夏威夷大学、加州大学圣巴巴拉分校和国际科技组织的研究人员将对夏威夷主要岛屿背风处形成的冷核气旋的物理、化学和生物学特征进行跨学科的调查。该地区作为一个天然实验室，提供了极好的机会，即使不是独一无二的，也是在可进入的亚热带少营养环境中了解涡流增强的生产和碳输出的机会。计划进行三次巡航，在三个阶段对涡旋进行采样：自旋(巡航一号)、成熟(巡航二号)和自旋下降(巡航三号)。卫星数据将用于指导密集的舰载观测的时间和采样位置。通过涡流采样的目的是平衡水平分辨率(即XBT和CTD站之间的间距)和同视性。该研究小组将描述与夏威夷附近的少营养水域相比，涡流中浮游植物和食草动物的生物量、大小结构和分类组成。这些信息将与浮游植物生长和微型浮游动物放牧率的估计相结合，并与初级生产力和新的/出口产量的同时比率估计有关(Th-234通量估计、沉积物捕捉器、营养物质清单和稳定的碳同位素质量平衡)。将分别利用卫星(GOES-10、SeaWiFS、MODIS和TOPEX/ERS)和漂移器监测目标涡旋的轨迹和次表层温度结构，并估计局地气旋性涡场对碳输出的贡献。拟议的采样战略将提供一个4维(x，y，z，t)数据集，用于调查营养输入、生物反应和有机碳向下通量之间的联系和时间滞后。这些生物地球化学和物理数据集将提供缺少的环节，以促进我们对促进有机碳出口的旋涡的性质和重要性的理解，以及为建模人员测试其基本假设和公式提供硬数据。最终目标是提供对当地营养和食物网动态的中尺度涡旋影响的上限和下限的现场估计，以便可以用来测试、评估和重新制定正在开发的各种模型，以研究涡旋现象及其在区域和流域尺度上的生物地球化学后果。为此，将进行基于高度计的硝酸盐通量模型的实验模拟。这一比较应该能够利用混合的TOPEX/ERS产品和用当地现场数据校准的计算的硝酸盐通量，外推从夏威夷岛的背风处到北太平洋副热带环流的涡旋场的结果。

ABSTRACTOCE-0241645 / OCE-0241897 / OCE-0241121 / OCE-0241852In this project, investigators at the University of South Carolina, the University of Hawaii, the University of California - Santa Barbara, and Science and Technology International will conduct interdisciplinary investigation of the physical, chemical, and biological characteristics of cold-core cyclonic eddies that form in the lee of the main Hawaiian Islands. This area serves as a natural laboratory, providing excellent, if not unique, opportunities for understanding eddy-enhanced production and carbon export in an accessible subtropical oligotrophic setting. Three cruises are planned in which eddies will be sampled during three phases: spin-up (cruise I), maturity (cruise II), and spin-down (cruise III). Satellite data will be used to direct the timing and sampling locations of the intensive ship-based observations. Sampling through the eddy is designed to balance horizontal resolution (i.e., spacing between XBT and CTD stations) with synopticity. The team will characterize the biomass, size structure and taxonomic composition of phytoplankton and grazers in the eddy relative to the ambient oligotrophic waters off Hawaii. This information will be coupled with estimates of phytoplankton growth and microzooplankton grazing rates and related to concurrent rate estimates of primary productivity and new/export production (Th-234 flux estimates, sediment traps, nutrient inventories and stable carbon isotope mass balance). The trajectory and subsurface temperature structure of the target eddy will be monitored using satellites (GOES-10, SeaWiFS, MODIS, and TOPEX/ERS) and drifters, respectively, and the contribution of the local cyclonic eddy field to carbon export will be estimated. The proposed sampling strategy will provide a 4-dimensional (x,y,z,t) data set for investigating the linkages and temporal lags between nutrient inputs, biological responses, and the downward flux of organic carbon. These biogeochemical and physical data sets will provide missing links for advancing our understanding of the nature and importance of eddies in facilitating organic carbon export, as well as hard data for modelers to test their fundamental assumptions and formulations. The ultimate goal is to provide in situ estimates for the upper and lower limits of mesoscale eddy effects on local nutrient and food web dynamics such that they can be used to test, evaluate and reformulate the various models being developed to study eddy phenomena and their biogeochemical consequences on regional and basin scales. Towards that end, experimental simulations of altimeter-based nitrate flux models will be performed. This comparison should allow extrapolation of the results from the lee of the Island of Hawaii to the eddy field in the North Pacific Subtropical Gyre, using the blended TOPEX/ERS product and calculated nitrate fluxes calibrated with local in situ data.