Phytoplankton fuels Delta food web

Populations of certain fishes and invertebrates in the Sacramento-San Joaquin Delta have declined in abundance in recent decades and there is evidence that food supply is partly responsible. While many sources of organic matter in the Delta could be supporting fish populat...

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Main Authors: Alan D. Jassby, James E. Cloern, Anke B. Müller-Solger
Format: Article
Language:English
Published: University of California Agriculture and Natural Resources 2003-10-01
Series:California Agriculture
Online Access:http://calag.ucanr.edu/archive/?article=ca.v057n04p104
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spelling doaj-881fd46b162e4237988c9600c11d7fa22020-11-25T00:50:08ZengUniversity of California Agriculture and Natural ResourcesCalifornia Agriculture0008-08452160-80912003-10-0157410410910.3733/ca.v057n04p10410.3733/cav057n04_7Phytoplankton fuels Delta food webAlan D. Jassby0James E. Cloern1Anke B. Müller-SolgerA.D. Jassby is Research Ecologist, Department of Environmental Science and Policy, UC DavisJ.E. Cloern is Research Biologist, Water Resources Division, U.S. Geological Survey (USGS)Populations of certain fishes and invertebrates in the Sacramento-San Joaquin Delta have declined in abundance in recent decades and there is evidence that food supply is partly responsible. While many sources of organic matter in the Delta could be supporting fish populations indirectly through the food web (including aquatic vegetation and decaying organic matter from agricultural drainage), a careful accounting shows that phytoplankton is the dominant food source. Phytoplankton, communities of microscopic free-floating algae, are the most important food source on a Delta-wide scale when both food quantity and quality are taken into account. These microscopic algae have declined since the late 1960s. Fertilizer and pesticide runoff do not appear to be playing a direct role in long-term phytoplankton changes; rather, species invasions, increasing water transparency and fluctuations in water transport are responsible. Although the potential toxicity of herbicides and pesticides to plankton in the Delta is well documented, the ecological significance remains speculative. Nutrient inputs from agricultural runoff at current levels, in combination with increasing transparency, could result in harmful algal blooms.http://calag.ucanr.edu/archive/?article=ca.v057n04p104
collection DOAJ
language English
format Article
sources DOAJ
author Alan D. Jassby
James E. Cloern
Anke B. Müller-Solger
spellingShingle Alan D. Jassby
James E. Cloern
Anke B. Müller-Solger
Phytoplankton fuels Delta food web
California Agriculture
author_facet Alan D. Jassby
James E. Cloern
Anke B. Müller-Solger
author_sort Alan D. Jassby
title Phytoplankton fuels Delta food web
title_short Phytoplankton fuels Delta food web
title_full Phytoplankton fuels Delta food web
title_fullStr Phytoplankton fuels Delta food web
title_full_unstemmed Phytoplankton fuels Delta food web
title_sort phytoplankton fuels delta food web
publisher University of California Agriculture and Natural Resources
series California Agriculture
issn 0008-0845
2160-8091
publishDate 2003-10-01
description Populations of certain fishes and invertebrates in the Sacramento-San Joaquin Delta have declined in abundance in recent decades and there is evidence that food supply is partly responsible. While many sources of organic matter in the Delta could be supporting fish populations indirectly through the food web (including aquatic vegetation and decaying organic matter from agricultural drainage), a careful accounting shows that phytoplankton is the dominant food source. Phytoplankton, communities of microscopic free-floating algae, are the most important food source on a Delta-wide scale when both food quantity and quality are taken into account. These microscopic algae have declined since the late 1960s. Fertilizer and pesticide runoff do not appear to be playing a direct role in long-term phytoplankton changes; rather, species invasions, increasing water transparency and fluctuations in water transport are responsible. Although the potential toxicity of herbicides and pesticides to plankton in the Delta is well documented, the ecological significance remains speculative. Nutrient inputs from agricultural runoff at current levels, in combination with increasing transparency, could result in harmful algal blooms.
url http://calag.ucanr.edu/archive/?article=ca.v057n04p104
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