Date of Award

2001

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Sciences

First Advisor

John W. Fleeger

Abstract

Meiofaunal colonization of artificial substrates was investigated in a shallow estuarine embayment. Meiofauna colonized various artificial substrates rapidly, at a rate of 1000 individuals collector-1 day -1 regardless of season, suggesting that high abundances of meiofauna commonly exist in the water column. These water-column meiofauna may be important in fish diets and may serve as a dispersing pool that aids recolonization after disturbance events. Colonization of artificial substrates by transient meiofauna of unknown origin(s) occurred through the water column. To determine the source of meiofauna colonizing artificial substrates, sediment and pier-piling meiofauna were sampled and compared to artificial-substrate colonists. Assemblages of copepods and nematodes were significantly different among the three habitats. Artificial-substrate communities were more similar to pier-piling than sediment communities, and the morphology of most copepods colonizing artificial substrates resembled phytal dwellers. These observations suggest that most colonists primarily originated from microalgae-covered portions of pier pilings. There were also significant but smaller contributions from sediments. Selected pier-piling taxa were very good colonists, suggesting they migrate frequently into the water column and contribute to a rapidly dispersing pool of meiofauna. Habitat complexity and flow greatly influence meiofaunal colonization of artificial substrates. To investigate the effects of habitat complexity on meiofaunal colonization, the physical structure of plastic bottle brushes was altered by clipping and removing their bristles. Abundances of meiofauna increased with increased habitat complexity (the ratio of total surface area of bristles to volume of the brush) and surface area. Nematodes responded more to changes in bristle density and copepods and two constituent copepod species responded more to changes in substrate surface area. Flow fields around artificial substrates were observed in a laboratory flume at 5 and 15 cm s -1 flow velocities. Flow velocity, transmissivity, and turbulence intensity indicated important relationships between colonization and the structural properties of the substrates. These data suggest that meiofaunal colonization of artificial substrates is a function of water flow and filtration rate through the substrate, and that complexity and substrate shape influence capture rate.

ISBN

9780493213750

Pages

116

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