LMER: Research in the Columbia River Estuary: The Role of Estuarine Turbidity Maxima (ETM) Processes Coupling Watershed, Estuary and Ocean

该项目将继续并扩展之前为期四年的NSF陆地边缘生态系统研究（LMER）研究（1990- 1994），研究河口最大浊度（ETM）对河口和沿海生态系统的重要性，以哥伦比亚河河口为例。在这些继续进行的调查中，该项目将以过去的结果为基础，并将集中研究五个领域：*粒子聚集/分解是ETM物理学、地球化学和生态学之间的关键联系；*受ETM动态影响的生物地球化学和生态过程；*针对流域和全球气候变化的选定情景，对这些过程进行建模，以量化质量、成分和能量通量以及化学转化；* ETM与周围河口生境、流域和沿海海洋的相互作用；*选择与其他河口，特别是LMER地点的比较。哥伦比亚河河口是陆地边缘生态系统（河口）的一个主要类别，在许多方面与其他LMER站点不同。由于其独特性和规模，以及大型河口对沿海海洋的重要性，将哥伦比亚河河口与LMER站点和选定的其他河口的关键过程和特性进行比较，将有助于理解陆地边缘系统的全球变率及其对人为输入和变化的响应。比较的努力将集中在粒子动力学的分析，微生物环过程，和营养转移跨LMER系统。这些比较的结果将纳入一个河口分类系统，该系统将考虑温带河口的物理、沉积学和地球化学方面。* * *

9412028 Simenstad This project will continue and expand upon a previous four year NSF Land-Margin Ecosystem Research (LMER) study (1990- 1994) of the importance of estruarine turbidity maxima (ETM) to river estuaries and coastal ecosystems, as exemplified by the Columbia River estuary. In these continuing investigations , the project will build on past results and will concentrate the research on five areas: * particle aggregation/disaggregation as a key linkage between ETM physics, geochemistry and ecology; * biogeochemical and ecological processes affected by ETM dynamics; * modeling of these proecesses to quantify mass, constituent and energy fluxes, and chemical transformations, with respect to selected scenarios of watershed and global climate change; * interactions of ETM with surrounding estuarine habitats, watershed and the coastal ocean; * selected comparisons with other estuaries, particularly LMER sites. The Columbia River estuary is characteristic of a major class of land-margin ecosystmes (river estuaries) and differs in many respects from other LMER sites. Because of its distinctiveness and scale, and the importance of large river estuaries to coastal oceans, comparisons of critical processes and properties in the Columbia River estuary with those of LMER sites and selected oterh estuaries will contribut significantly to understanding global variability in land-margin systems and their responses to anthropogenic inputs and changes. Comparative efforts will focus on analysis of particle dynamics, microbial-loop processes, and trophic transfers across LMER systems. Results of these comparisons will be embedded in an estuarine classificiation system that ecnompasses physical, sedimentological and geochemical aspects of temperate estuaries. ***