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Title: External nutrient sources, internal nutrient pools, and phytoplankton production in Chesapeake Bay

Abstract

External nutrient loadings, internal nutrient pools, and phytoplankton production were examined for three major subsystems of the Chesapeake Bay Estuary-the upper Mainstem, the Patuxent Estuary, and the Potomac Estuary-during 1985-1989. The atomic nitrogen to phosphorus ratios (TN:TP) of total loads were 51, 29 and 35, respectively. Most of these loads entered at the head of the estuaries from riverine sources and major wastewater treatment plants. Seven-16% of the nitrogen load entered the head of each estuary as particulate matter in contrast to 48-69% for phosphorus. The difference seems to favor a greater loss of phosphorus than nitrogen through sedimentation and burial. A major storm event in the Potomac watershed greatly increased the particulate fraction of nitrogen and phosphorus and lowered the TN:TP in the river-borne loads and accounted for 11% of the nitrogen and 31% of the phosphorus delivered to the estuary by the Potomac River during the entire 60- month period examined here. Within the Mainstem estuary, salinity dilution plots revealed strong net sources of ammonium and phosphate in the oligohaline to upper mesohaline region. indicating considerable internal recycling of nutrients to surface waters. A net sink of nitrate was indicated during summer. Phytoplankton biomass in the mesohaline Mainstemmore » reached a peak in spring and was relatively constant throughout the other seasons. In the Patuxent and Potomac, the TN:TP ratios of external loads are 2-4 times higher than those observed over the previous two decades. These changes are attributed to point-source phosphorus controls and the likelihood that nitrogen-rich nonpoint source inputs, including contributions from the atmosphere, have increased. These higher N:P ratios now suggest a greater overall potential for phosphorus-limitation rather than nitrogen-limitation of phytoplankton in the areas studied. 66 refs., 6 figs., 7 tabs.« less

Authors:
;  [1];  [2]
  1. (Maryland Department of the Environment, Baltimore (United States))
  2. (Benedict Estuarine Research Lab., MD (United States))
Publication Date:
OSTI Identifier:
6200637
Resource Type:
Journal Article
Journal Name:
Estuaries; (United States)
Additional Journal Information:
Journal Volume: 15:4; Journal ID: ISSN 0160-8347
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; CHESAPEAKE BAY; PHYTOPLANKTON; WATER POLLUTION; NITROGEN; ECOLOGICAL CONCENTRATION; PHOSPHORUS; AIR POLLUTION; BIOMASS; DILUTION; ESTUARIES; NUTRIENTS; PLANTS; POTOMAC RIVER; PRODUCTIVITY; SALINITY; SEASONAL VARIATIONS; SEDIMENTATION; SURFACE WATERS; WASTE PROCESSING; WASTE WATER; ZONES; AQUATIC ORGANISMS; ATLANTIC OCEAN; BAYS; COASTAL WATERS; ELEMENTS; ENERGY SOURCES; HYDROGEN COMPOUNDS; LIQUID WASTES; MANAGEMENT; NONMETALS; OXYGEN COMPOUNDS; PLANKTON; POLLUTION; PROCESSING; RENEWABLE ENERGY SOURCES; RIVERS; SEAS; STREAMS; VARIATIONS; WASTE MANAGEMENT; WASTES; WATER; 540320* - Environment, Aquatic- Chemicals Monitoring & Transport- (1990-); 560300 - Chemicals Metabolism & Toxicology

Citation Formats

Magnien, R.E., Summers, R.M., and Sellner, K.G. External nutrient sources, internal nutrient pools, and phytoplankton production in Chesapeake Bay. United States: N. p., 1992. Web. doi:10.2307/1352393.
Magnien, R.E., Summers, R.M., & Sellner, K.G. External nutrient sources, internal nutrient pools, and phytoplankton production in Chesapeake Bay. United States. doi:10.2307/1352393.
Magnien, R.E., Summers, R.M., and Sellner, K.G. Tue . "External nutrient sources, internal nutrient pools, and phytoplankton production in Chesapeake Bay". United States. doi:10.2307/1352393.
@article{osti_6200637,
title = {External nutrient sources, internal nutrient pools, and phytoplankton production in Chesapeake Bay},
author = {Magnien, R.E. and Summers, R.M. and Sellner, K.G.},
abstractNote = {External nutrient loadings, internal nutrient pools, and phytoplankton production were examined for three major subsystems of the Chesapeake Bay Estuary-the upper Mainstem, the Patuxent Estuary, and the Potomac Estuary-during 1985-1989. The atomic nitrogen to phosphorus ratios (TN:TP) of total loads were 51, 29 and 35, respectively. Most of these loads entered at the head of the estuaries from riverine sources and major wastewater treatment plants. Seven-16% of the nitrogen load entered the head of each estuary as particulate matter in contrast to 48-69% for phosphorus. The difference seems to favor a greater loss of phosphorus than nitrogen through sedimentation and burial. A major storm event in the Potomac watershed greatly increased the particulate fraction of nitrogen and phosphorus and lowered the TN:TP in the river-borne loads and accounted for 11% of the nitrogen and 31% of the phosphorus delivered to the estuary by the Potomac River during the entire 60- month period examined here. Within the Mainstem estuary, salinity dilution plots revealed strong net sources of ammonium and phosphate in the oligohaline to upper mesohaline region. indicating considerable internal recycling of nutrients to surface waters. A net sink of nitrate was indicated during summer. Phytoplankton biomass in the mesohaline Mainstem reached a peak in spring and was relatively constant throughout the other seasons. In the Patuxent and Potomac, the TN:TP ratios of external loads are 2-4 times higher than those observed over the previous two decades. These changes are attributed to point-source phosphorus controls and the likelihood that nitrogen-rich nonpoint source inputs, including contributions from the atmosphere, have increased. These higher N:P ratios now suggest a greater overall potential for phosphorus-limitation rather than nitrogen-limitation of phytoplankton in the areas studied. 66 refs., 6 figs., 7 tabs.},
doi = {10.2307/1352393},
journal = {Estuaries; (United States)},
issn = {0160-8347},
number = ,
volume = 15:4,
place = {United States},
year = {1992},
month = {12}
}