Phytoplankton dynamics of the fresh, tidal Potomac River, Maryland, for the summers of 1979 to 1981
Water Supply Paper
2234-C
By: Ronald R.H. Cohen
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Abstract
The distribution and abundance of phytoplankton in the fresh, tidal Potomac River, Md., was different during 1979-81 from that observed in the 1960's and 1970's. Concentrations
of phytoplankton in the 1960's and 1970's reached maximum attainable levels that were limited only by self-shading. A sag in phytoplankton abundance, apparent during the summers of 1980 and 1981 between Rosier Bluff and Marshall Hall, appears to have been caused by the Asiatic clam, Corbicula fluminea. Reduced abundance of phytoplankton throughout the entire fresh, tidal river during the summers of 1980 and 1981 may have been due to grazing by Corbicula, high discharge, and perhaps phosphorus limitation in late August at and downstream of Hallowing Point. Phytoplankton growth rates and chlorophyll-to-cell ratios were highest at Hatton Point and Marshall Hall (the sag reach). A model was constructed that predicted phytoplankton growth rates by varying only chlorophyll a concentration and light penetration. Nutrient concentrations were not required to make the model fit the data.
Primary productivity was highest for the year during August 1980 and August 1981. Productivity-per-unit chlorophyll was highest at Hatton Point, where reduced concentrations of phytoplankton permitted the deepest light penetration in the fresh, tidal river.
Suggested Citation
Cohen, R.R., 1988, Phytoplankton dynamics of the fresh, tidal Potomac River, Maryland, for the summers of 1979 to 1981: U.S. Geological Survey Water Supply Paper 2234, vii, 34 p., https://doi.org/10.3133/wsp2234C.
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Phytoplankton dynamics of the fresh, tidal Potomac River, Maryland, for the summers of 1979 to 1981 |
| Series title | Water Supply Paper |
| Series number | 2234 |
| Chapter | C |
| DOI | 10.3133/wsp2234C |
| Year Published | 1988 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Description | vii, 34 p. |
| Larger Work Type | Report |
| Larger Work Subtype | USGS Numbered Series |
| Larger Work Title | A water quality study of the tidal Potomac River and Estuary |
| Country | United States |
| State | Maryland |
| Other Geospatial | Potomac River |