The occurrence of hypoxic bottom water off the upper Texas coast and its effects on the benthic biota.




Harper, D.E. Jr.
McKinney, L.D.
Salzer, R.R.
Case, R.J.

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Hypoxic bottom water occurred off the upper Texas coast in May-July 1979 after heavy spring runoff and a diatom bloom. Benthic assemblages at two study sites off Freeport, Texas decreased from spring densities of 3000-4000 individuals/m super (2) to 300-600 individuals/m super (2) by late July. Species diversity also decreased and perturbations occurred in the Shannon-Weiner diversity indices. Of the dominant taxa, polychaetes were least affected by hypoxia and amphipods and echinoderms the most affected. Storm-caused waves in late July initiated the breakup of hypoxic conditions these conditons had completely abated by late September. A short-lived irrupton occurred immediately afterward as depopulated bottoms were reinvaded. Diversity and abundances appeared to be returning to more normal conditions by early 1980.


p. 53-79.


hypoxia, benthic environment, density flow, species diversity, polychaetes, amphipods, echinoderms, abundance