Lower Mississippi River Environmental Program. Report 9. An Ecological Investigation of Revetted and Natural Bank Habitats in the Lower Mississippi River PDF Download

Author: John A. Baker
Publisher:
ISBN:
Category :
Languages : en
Pages : 123

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Book Description
Chemical, physical, and biological attributes of the aquatic habitats associated with four revetments and two natural banks in the Lower Mississippi River were surveyed during summer and fall 1985. The revetments were located at approximately river miles 446, 370, 309, and 41; the two natural banks were located at river miles 368 and and 41. With the exception of water temperature in the fall, temperature, dissolved oxygen, pH, conductivity, turbidity, oxidation-reduction potential, total organic carbon, and dissolved and suspended solids showed relatively little variation over the entire study reach. Natural bank substrates were characterized by consolidated clays, with sand and silt, or sand and gravel, occurring frequently. Revetted banks were characterized by articulated concrete mattress (ACM), about one-half of which appeared to be overlayed with sand and silt. Macroinvertebrate community composition depended primarily upon the substrate type and current speed encountered at both revetted and natural banks. ACM surface modification experiments showed that mean densities, biomasses, and number of taxa of macroinvertebrates were greater on grooved blocks than on other modification type, or on control blocks. Both traditional fish collecting gears and hydroacoustics indicated differences in fish density between the two natural banks, among the three revetted banks, between the natural and revetted banks at sites at which both occurred, and between seasons. (fr).