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Seagrass beds versus sand bottoms: the trophic importance of their associated benthic invertebrates.

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Date Issued:
1983
Title: Seagrass beds versus sand bottoms: the trophic importance of their associated benthic invertebrates.
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Name(s): Virnstein, Robert W.
Mikkelsen, Paul S.
Cairns, Kalani D.
Capone, Mary Ann
Harbor Branch Oceanographic Institute
Type of Resource: text
Genre: Article
Date Issued: 1983
Publisher: Florida Academy of Sciences.
Place of Publication: Orlando, FL
Physical Form: pdf
Extent: 20 p.
Language(s): English
Identifier: FA00007480 (IID)
Note(s): Seagrass beds in the Indian River lagoon, Florida, had 3 times the density of macrobenthic invertebrates found in unvegetated sediments a few meters away. Epifaunal abundance was 13 times greater in seagrass than sand. Most epifaunal species (e.g., amphipods, isopods, tanaids, gastropods and shrimps) were uncommon in the unvegetated sediments, presumably due to their dependence on sea grass for providing habitat, food, nursery area, and/or protection from predators. Not only were macrofaunal densities much higher in natural seagrass than in sand, those animals which were more abundant (primarily the epifauna) were also more heavily preyed upon and thus are trophically more important than infauna. Four 3-mm mesh cages were set up, each within a larger 12-mm mesh cage, 2 in seagrass and 2 in sand to test 1) the importance of associated macrobenthos to the local food web and 2) the effect of small decapod predators. After 2 mo the inner cages had the lowest macrobenthos density and the highest density of decapod crustaceans, the animals we intended to exclude. The only animals more abundant in the inner cages were the decapod crustaceans. Because cages with mesh sizes even smaller than 3 mm do not effectively exclude many crustacean predators, we conclude that it is nearly impossible to exclude predators from local seagrass meadows. The grazing epifauna of seagrass meadows forms a major trophic pathway to higher predators via the decapods; such a pathway is lacking in sand bottom communities.
Florida Atlantic University. Harbor Branch Oceanographic Institute contribution 281
This manuscript is an author version with the final publication available at and may be cited as: Virnstein, R. W., Mikkelsen, P. S., Cairns, K. D., & Capone, M. A. (1983). Seagrass beds versus sand bottoms: the trophic importance of their associated benthic invertebrates. Florida Scientist, 46(3-4), 363-381.
Subject(s): Seagrasses--Florida--Indian River (Lagoon)
Meiofauna
Aquatic invertebrates.
Food chains (Ecology)
Persistent Link to This Record: http://purl.flvc.org/fau/fd/FA00007480
Host Institution: FAU