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Stratigraphic Evidence of Eutrophication in an Estuary
Author(s) -
Brush Grace S.
Publication year - 1984
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr020i005p00531
Subject(s) - estuary , eutrophication , sewage , environmental science , effluent , chlorophyll a , hydrology (agriculture) , watershed , algal bloom , productivity , nutrient , oceanography , environmental engineering , phytoplankton , geology , ecology , chemistry , biology , geotechnical engineering , biochemistry , macroeconomics , machine learning , computer science , economics
Vertical changes in chlorophyll degradation products preserved in sediments deposited in an urban estuary show a significant increase in algal productivity with the introduction of sewage effluent into the river. By comparison, algal production during intensive agriculture of the watershed, including heavy applications of fertilizers, was less by an order of magnitude where there was no sewage discharge from a point source. Concentrations of orthophosphorus correspond with concentrations of algal cells and chlorophyll in the water column and are greater by an order of magnitude where sewage is discharged into an estuary draining an urban‐agricultural watershed than where there is no sewage. The response of the estuary to short‐ and long‐term changes in the amount of sewage discharged is reflected by similar changes in chlorophyll production. However, chlorophyll production does not correspond with increases in the amount of fertilizers used in recent years over the amount used in the middle to late nineteenth century.