RUI: Influences of Benthic Boundary-Layer Flow on Distributions and Feeding Rates of Protists in Subtidal Near-Bottom Water and Surficial Sediments

RUI：底栖边界层流对潮下近底层水和表层沉积物中原生生物分布和摄食率的影响

• 批准号: 9711441
• 负责人: Jeff Shimeta
• 金额: $ 25.4万
• 依托单位: Franklin and Marshall College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9711441&HistoricalAwards=false
• 关键词: RUI; Influences; Benthic; Boundary; Layer

Microbial processes at the sediment-water interface (SWI) and in near-bottom water are critical for benthic productivity, nutrient cycling, and benthic-pelagic coupling in numerous subtidal marine environments, including coastal waters, continental shelves, and the deep sea. The roles of protists in the microbial food webs of the benthic-planktonic transition zone, however, are poorly understood. This proposal describes a study of combined field sampling and laboratory experiments to elucidate influences of benthic boundary-layer (BBL) flow on protistan ecology. The project is designed to answer the following questions: (1) what are the vertical distributions and abundances of protists at the SWI and in near-bottom water, (2) to what extent, and by what mechanisms, does BBL flow influence these distributions, and (3) to what extent, and by what mechanisms, do variations in BBL flow affect feeding rates of heterotrophic protists at the SWI and in near-bottom water? To answer these questions, the objectives of the research are: (1) to characterize the vertical distributions of protists in the near-bottom water and surficial sediment of a coastal subtidal habitat, Buzzards Bay, MA, and to relate these distributions to tidal variations in flow speed; (2) to investigate in a laboratory flume the mechanisms by which flow influences vertical distributions of cells as seen in the field; and (3) to measure in a flume the influences of BBL flow on feeding rates of heterotrophic protists under conditions similar to the field. The results of this work will provide novel insights into physical-biological interactions in benthic microbial ecology and benthic-pelagic coupling in coastal habitats. Through these processes, the physical energy level of flow in subtidal coastal habitats may have far-reaching influences on microbial trophic dynamics, secondary production, and biogeochemical processes in the near-bottom and surficial-sedimentary zone.

在包括沿海水域、大陆架和深海在内的众多潮下海洋环境中，沉积物-水界面（SWI）和近底水的微生物过程对底栖生物生产力、养分循环和底栖-中上层耦合至关重要。然而，原生生物在底栖-浮游过渡带的微生物食物网中的作用却知之甚少。本文采用野外采样和室内实验相结合的方法研究底栖边界层（BBL）流动对原生生物生态的影响。该项目旨在回答以下问题：(1)SWI和近底水域原生生物的垂直分布和丰度是什么；(2)BBL流量对这些分布的影响程度和机制是什么；(3)BBL流量的变化在多大程度上和通过什么机制影响SWI和近底水域异养原生生物的摄食率？为了回答这些问题，本研究的目标是：(1)表征MA沿海Buzzards湾潮下栖息地近底水和表层沉积物中原生生物的垂直分布特征，并将这些分布与潮汐流速变化联系起来；(2)在实验室水槽中研究水流影响细胞垂直分布的机制，正如在现场看到的那样；(3)在类似野外条件下，在水槽中测量BBL流量对异养原生生物摄食率的影响。这项工作的结果将为底栖微生物生态学中的物理-生物相互作用和沿海栖息地的底栖-远洋耦合提供新的见解。通过这些过程，潮下海岸生境的水流物理能级可能对近底和表层沉积带的微生物营养动力学、次生生产和生物地球化学过程产生深远的影响。