Seasonal and annual variability in the spatial patterns of plankton biomass in Chesapeake Bay
Seasonal and annual variability in the spatial patterns of plankton biomass in Chesapeake Bay
复制标题
切萨皮克湾浮游生物生物量空间格局的季节和年度变化
DOI：
--
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
W. Boicourt
中科院分区：
文献类型：
--
作者：
MR Roman;Xinsheng Zhang;Carey R. McGilliard;W. Boicourt
我们在4月、7月和10月对切萨皮克湾大河口进行了为期6年（1995-2000）的高分辨率采样。这一时期包括淡水输入的极端气候，强烈影响了浮游植物和浮游动物的总体储量和空间分布。当切萨皮克湾的淡水输入量高于平均流量时，春季浮游植物和浮游动物的生物量均较高。虽然整个海湾的生产力似乎受到淡水流量变化的影响，但浮游生物生物量的中尺度模式受到淡水输入、环流和水深测量的驱动。浮游生物生物量的持续最大值出现在物理和地形不连续的区域，如上海湾盐锋、羽流锋、水力控制区、潮汐锋和地形诱导涡附近。尽管这些热点对整个海湾浮游生物存量的贡献可能会因浮游生物背景水平的变化而变化，部分受淡水排放的控制，但它们仍然代表了浮游生物鱼类可预测的高级饲料区域。在这些物理不连续性处，浮游生物和鱼类之间的营养耦合增强，这可能是河口与其初级生产相比渔业产量高于湖泊和其他海洋系统的原因之一。
We conducted high‐resolution, underway sampling in April, July, and October for 6 yr (1995–2000) in the large estuary, Chesapeake Bay. This period included climatological extremes in freshwater inputs that strongly influenced both the overall stocks and spatial distribution of phytoplankton and zooplankton. Higher biomass of both phytoplankton and zooplankton occurred in springs, when freshwater input into Chesapeake Bay was above the average discharge. While whole‐Bay productivity appears to be influenced by freshwater flow variability, mesoscale patterns in plankton biomass are driven by freshwater inputs, circulation, and bathymetry. Persistent maxima in plankton biomass occurred in areas of physical and topographic discontinuities such as the upper‐Bay salt front, plume fronts, the hydraulic control region, tidal fronts, and near a topographically induced eddy. Although the contribution of these hot spots to the whole‐Bay standing stock of plankton may vary due to changes in the background levels of plankton, controlled in part by freshwater discharge, they nevertheless represent predictable areas of higher forage for planktivorous fish. Enhanced trophic coupling between plankton and fish at these physical discontinuities may be one reason why estuaries have higher fisheries yields in relation to their primary production than lakes and other marine systems.