Accession Number : ADA201938


Title :   Benthic Faunal Colonization of an Offshore Borrow Pit in Southeastern Florida. Dredging Operations Technical Support Program


Descriptive Note : Final rept.


Corporate Author : FLORIDA ATLANTIC UNIV BOCA RATON COLL OF SCIENCE


Personal Author(s) : Bowen, Philip R ; Marsh, G A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a201938.pdf


Report Date : Oct 1988


Pagination or Media Count : 69


Abstract : When sediments are dredged offshore, either for a Corps project or a permitted activity, borrow pits are created. As part of a program to examine the environmental effects of dredging, this study addresses concerns about the changes that may occur in the benthic faunal associated with these dredged borrow sites. Benthic faunal colonization of a newly created borrow pit off Delray Beach, Florida, was monitored. For comparative purposes, a single sampling of an adjacent 5-year-old borrow pit was conducted concurrently with the final sampling of the new pit. Colonization of the new pit was rapid, with 35 species and 1,081 individuals/square metre collected at the initial sampling, 21 days postdredging. Abundance peaked at a mean density of 1,761 individuals/ square metre in the third sampling period (170 days postdredging) , and species richness peaked at the fifth sampling period (296 days postdredging) with 57 species. Polychaete annelids and peracarid crustaceans were numerically the most important initial colonizers of the new pit, together comprising 89.3 percent of the fauna. Species diversity (H') and equitability were lowest during the first sampling period (4.21 and 0.82, respectively) and, although variable, increased toward the end of the study (5.10 and 0.92, respectively). Relative to the old pit, the disturbed area showed complete recovery based on several aspects of community structure, although differences in species composition were evident.


Descriptors :   *OCEAN BOTTOM , *HABITATS , ENVIRONMENTAL IMPACT , HOLES(OPENINGS) , SAMPLING , NORTH ATLANTIC OCEAN , DREDGING , SEDIMENTS , FLORIDA , BENTHONIC ZONES , OFFSHORE , AQUATIC ANIMALS , CRUSTACEA , DENSITY , COMMUNITIES


Subject Categories : Ecology
      Civil Engineering


Distribution Statement : APPROVED FOR PUBLIC RELEASE