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Publications

Read publications and other informational products to learn more about USGS science occurring in the Mississippi Basin.

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Seagrasses, dredging and light in Laguna Madre, Texas, U.S.A. Seagrasses, dredging and light in Laguna Madre, Texas, U.S.A.

Light reduction resulting from maintenance dredging was the suspected cause of large-scale loss of seagrass cover in deep parts of Laguna Madre between surveys conducted in 1965 and 1974. Additional changes to 1988, together with an analysis of dredging frequency and intensity for different parts of the laguna, were consistent with this interpretation. Intensive monitoring of the...
Authors
Christopher P. Onuf

A summary of water-resources activities of the U.S. Geological Survey in Iowa, fiscal year 1994 A summary of water-resources activities of the U.S. Geological Survey in Iowa, fiscal year 1994

Water-resources programs and activities of the U.S. Geological Survey in Iowa consist principally of hydrologic data collection and investigative studies that address water-resource issues. The work is supported by direct Federal funding, by transfer of funds from other Federal agencies, and by joint-funding agreements with State or local agencies. The Iowa District of the Geological...
Authors
R.C. Buchmiller

The relationship between species richness and community biomass: The importance of environmental variables The relationship between species richness and community biomass: The importance of environmental variables

Several studies have used plant community biomass to predict species richness with varying success. In this study we examined the relationship between species richness and biomass for 36 marsh communities from two different watersheds. In addition, we measured several environmental variables and estimated the potential richness (the total number of species known to be able to occur in a...
Authors
L. Gough, J.B. Grace, K.L. Taylor

Intraspecific variation in the response of Taxodium distichum seedlings to salinity Intraspecific variation in the response of Taxodium distichum seedlings to salinity

Seedlings of 15 open-pollinated families of baldcypress (Taxodium distichum) were tested for their tolerance to combined salinty and flooding stress. Ten of the families were from coastal locations in Louisiana or Alabama, USA, that were slightly brackish. The other families were from locations not affected by saltwater intrusion. Five salinity levels were investigated--0,2,4,6, and 8 g...
Authors
J. A. Allen, J. L. Chambers, D. McKinney

A toxic equivalency factor scale for polychlorinated dibenzofurans A toxic equivalency factor scale for polychlorinated dibenzofurans

The ethoxyresorufin O-deethylase (EROD) induction of 20 polychiorinated dibenzofurans (PCDFs) was examined in the H4IIE rat hepatoma cell bioassay. The selection of the compounds tested was based on a multivariate chemical characterization laying the groundwork for covering the whole chemical series of PCDFs. The EROD induction potency was found to vary in ED50 values from 25 to 100,000...
Authors
M. Tysklind, D. Tillitt, L. Eriksson, K. Lundgren, C. Rappe
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