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

Estuarine, Coastal and Shelf Science



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 underwater light regime and compilation of detailed environmental data for 3 months before and 15 months after a dredging project in 1988 revealed reduced light attributable to dredging in four of eight subdivisions of the study area, including the most extensive seagrass meadow in the study area. Dredging effects were strongest close to disposal areas used during this project but still were detectable on transects >1·2 km from the nearest dredge disposal area. In the subdivision of the study area where most of the dredge disposal occurred, light attenuation was increased throughout the 15 months of observation after dredging. In the seagrass meadow and the transition zone at the outer edge of the meadow, effects were evident up to 10 months after dredging. Resuspension and dispersion events caused by wind-generated waves are responsible for the propagation of dredge-related turbidity over space and time in this system.

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Publication type Article
Publication Subtype Journal Article
Title Seagrasses, dredging and light in Laguna Madre, Texas, U.S.A.
Series title Estuarine, Coastal and Shelf Science
DOI 10.1006/ecss.1994.1050
Volume 39
Issue 1
Year Published 1994
Language English
Publisher Elsevier
Contributing office(s) National Wetlands Research Center, Wetland and Aquatic Research Center
Description 17 p.
First page 75
Last page 91
Country United States
State Texas
Other Geospatial Laguna Madre
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