科研之友
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摘要
In many coastal marine ecosystems, microphytobenthos (MPB) can contribute a significant fraction of total system primary production, particularly in shallow lagoons or systems with broad photic shoals. While the role of MPB has been quantified in several shallow systems around the world, their contribution to primary production on the extensive shoals that line a number of deeper estuaries has often been overlooked. We assessed the contribution of MPB to total primary production within four regions of upper Narragansett Bay, RI, USA to quantify the significance of benthic production on the extensive shallow shoals that line this relatively deep estuarine system. Our results indicate that surface sediment chlorophyll-a concentrations and daily benthic gross primary production rates in shallow portions of upper Narragansett Bay are within the range of previous studies conducted along the northeastern U.S. coast. Despite these high rates, our results when scaled to the system level emphasize the importance of phytoplankton production in most of the upper bay under current conditions, although MPB were found to contribute a significant fraction (up to one third) of total primary production in certain regions at certain times. Despite the high rates of benthic gross primary production in some portions of the upper bay, the benthos remained net heterotrophic throughout the spring, summer, and fall at most sites, although production within the Greenwich Bay sub-estuary was enough to drive the benthos slightly net autotrophic for short periods in the fall. While the current role of MPB appears to be limited in terms of its overall contribution to total gross primary production, the importance of MPB in the future may increase due to changing climate and reductions in anthropogenic nutrient loading.
- 出版日期2011-12-10
