Collaborative Research: Interannual Variability of Coastal Phytoplankton Blooms in the Gulf of Maine and Their Relationships to Local and Remote Forcings

这项建议的目的是利用生物-物理耦合模型，探讨影响沿海和陆架地区浮游植物水华的基于气候的远程强迫与当地强迫的相互作用。浮游植物水华动力学是海洋中生物-物理相互作用的经典例子(Gran和Braarud，1935；Sverdrup，1953)。然而，要确定控制沿海和陆架海域浮游植物水华年际变化的主导过程仍然是一项挑战，在这些海洋中，多种尺度的生物和物理过程相互作用。非结构网格、有限体积、沿海海洋模式(FVCOM，在GLOBEC乔治斯海岸计划内建立)连接了缅因湾的多尺度物理过程，并包括本地和远程强迫。12年来的预报模拟和同化实验产品，加上与现场测量的仔细比较/验证，为探索缅因湾生态系统动态的年际变化提供了独特的背景和工具。这项提议将研究墨西哥湾春季和秋季浮游植物水华的动态与当地和远程强迫之间的关系。一个具体的重点是可变性的斯科特大陆架水和坡水流入。将进行一系列数值实验来检验长期存在的和新提出的假设，包括北大西洋涛动的影响，因为它影响温暖的坡水与拉布拉多坡水的动力学，这反过来又影响到缅因湾的营养物质通量以及表层和深水之间的垂直通量。地表水淡化(与斯科特大陆架水流入有关，据信受到全球变暖的影响)对水柱的垂直密度结构、冬季对流以及水华的时间/大小的影响也将被讨论。面向过程的生物和物理耦合模式试验将集中在1998-2001年数据丰富的时期，当时发生了明显的大尺度强迫条件。对大尺度强迫对沿海海洋生态系统动态和生产力的影响提供新的见解将是我们对浮游植物水华动力学的理解的重大进步，传统上浮游植物水华动力学一直专注于局部强迫和季节变化。该项目将提供1995-2006年每小时实物和生物产出耦合模型的网上开放档案，并制作一个经过测试的生物-物理耦合模型系统，可用于缅因湾和其他沿海海洋正在进行的其他生态系统研究(例如，ECOHAB)和今后的生态系统研究。UMASSD-WHOI正在开发的基于网络的海洋预报模式系统将直接受益于该项目，因为它有助于优化海洋观测站的设计，并有助于塑造相互依存的模式观测系统的未来。广泛影响：拟议工作的结果将广泛传播给普通研究、本科生和研究生教育界、K-12机构，以及通过使用建议书机构现有基础设施的基于网络的服务器向感兴趣的公众传播。基于网络的用户将能够访问项目描述、科学结果、模型输入和输出档案、各个物理和生物领域的动画等。与新贝德福德SEALAB海洋科学教育中心和WHOI/UMASS COSEE计划的合作将促进与K-12教师和学生以及国内和国际公众的交流。

The aim of this proposal is to explore the interaction of remote climate based forcing with local forcing to impact phytoplankton blooms in coastal and shelf regions with a coupled biological-physical model. Phytoplankton bloom dynamics are a classic example of biological-physical interactions in the ocean (Gran and Braarud, 1935; Sverdrup, 1953). Yet it is still a challenge to identify the dominant processes controlling the interannual variability of phytoplankton blooms in coastal and shelf seas where multiple-scale biological and physical processes interact. The unstructured-grid, finite-volume, coastal ocean model (FVCOM, built within the GLOBEC Georges Bank Program) bridges the multi-scale physical processes of the Gulf of Maine and includes both local and remote forcing. Twelve years of prognostic simulation and assimilation experiment products, with careful comparison/validation with field measurements, provide a unique background and tools with which to explore the interannual variability of ecosystem dynamics in the Gulf of Maine. This proposal will examine relationships between the dynamics of spring and fall phytoplankton blooms in the Gulf and local and remote forcing. A specific focus is the variability Scotian Shelf Water and Slope Water inflows. A series of numerical experiments will be conducted to test long-standing and newly-proposed hypotheses, including the impact of the North Atlantic Oscillation as it influences Warm Slope Water versus Labrador Slope Water dynamics, which in turn affect nutrient fluxes to the Gulf of Maine and vertical fluxes between surface and deep waters. The influence of surface water freshening (related to Scotian Shelf Water inflow, in turn believed to be affected by global warming) on the vertical density structure of the water column, winter convection, and consequently, the timing/magnitude of blooms, will also be addressed. The process-oriented coupled biological and physical model experiments will focus on the date-rich period 1998-2001 when pronounced large-scale forcing conditions occurred. Providing new insights into the influence of large-scale forcing on the dynamics and productivity of coastal ocean ecosystems will be a significant advance in our understanding of phytoplankton blooms dynamics, which has been traditionally focused on local forcing and seasonal changes. The project will provide a web-based open archive of the 1995-2006 coupled model hourly physical and biological output, and produce a tested coupled biological-physical model system available for other ongoing (e.g. ECOHAB) and future ecosystem studies in the Gulf of Maine and other coastal oceans. The web-based ocean forecast model system being developed by UMASSD-WHOI will benefit directly from this project by helping to optimize the design of ocean observatories and help shape the future of interdependent model-observing systems.Broader Impacts: Results of the proposed work will be broadly disseminated to the general research, undergraduate and graduate education communities, K-12 institutions, and to the interested public through web-based servers using existing infrastructure at the proposers' institutions. Web-based users will be able to access project description, scientific results, model input and output archives, animations of various physical and biological fields, etc. Collaboration with the New Bedford SEALAB Marine Science Education Center and the WHOI/UMASS COSEE program will foster communication with K-12 teachers and students and the public both nationally and internationally.