Characterization of Benthic Habitats in Proximity to The Lower Colorado River, Texas




Montagna, Paul A.
Kalke, Richard
Palmer, Terence A.
Gossmann, April


Journal Title

Journal ISSN

Volume Title




Freshwater inflow from the lower Colorado River supports a diverse ecological community in Matagorda Bay, East Matagorda Bay, and Oyster Lake. The region is part of the larger Lavaca-Colorado Estuary, which includes the adjacent Lavaca River and Lavaca Bay. The Lavaca-Colorado Estuary has been the subject of long-term benthic and water quality studies since 1988, but only six stations (two in Lavaca Bay and four in Matagorda Bay) have been sampled. The purpose of the current study is to sample over broader spatial scales in Matagorda Bay to determine how well the long-term stations characterize the spatial variability of benthic communities directly influenced by the Colorado River. Samples were collected from 18 stations to measure benthic community structure, hydrographic characteristics (depth, salinity, temperature, nutrients, and chlorophyll), and sediment characteristics (grain size, carbon and nitrogen content). Adjacent to the Colorado River, water quality and water column depth had higher correlations with macrobenthic community structure than sediment characteristics, but sediments were important overall. At a 40 % similarity level, macrobenthic communities were divided into five groups based on distance from the freshwater source, distance to the Gulf of Mexico, and bottom depth. Benthic communities in sheltered shallow habitats (< 0.5 m) were not represented by the current long-term stations, however all other community groups were represented. Apart from areas close to the Gulf Intracoastal Waterway and within 5 km of the Colorado River mouth, water quality in Matagorda Bay was well-characterized by the six long-term stations in low inflow conditions.






Montagna, P. A. R. Kalke, T. Palmer, and A. Gossmann. 2006. Characterization of Benthic Habitats in Proximity to The Lower Colorado River, Texas. Final report the Lower Colorado River Authority, Contract Number 1573, Task Order 4, Purchase Order Number 40673. Harte Research Institute, Texas A&M University-Corpus Christi, Corpus Christi, Texas, USA, 34 pp.