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Eutrophication And Macrobenthic Communities Of The Lower Chesapeake Bay: Effects Of Organic Enrichment In Pocomoke Sound, Saxis Virginia, Janice D. Mcdonnell

Biological Sciences Theses & Dissertations

The effects of organic enrichment on benthic community structure were evaluated in a field study conducted in Pocomoke Sound in the vicinity of a seafood processing plant. The empirically derived Species Abundance and Biomass (SAB) curves of Pearson and Rosenberg (1978) were used to model patterns of organic enrichment at the study site, called Pig Point, as well as two reference sites located within Pocomoke Sound. The Split Moving Windows (SMW) method was used to detect the ecotone point as defined in the Pearson and Rosenberg (1978) model and the Two Term Local Quadrat Variance (TTLQV) method was used to …

Evaluation Of Long Term Changes In The Macrobenthic Community Of The Southern Branch Of The Elizabeth River, Virginia, William S. Hunley

Biological Sciences Theses & Dissertations

Long-term changes in the macrobenthos of the Southern Branch of the Elizabeth River, Virginia were investigated by comparing the present study of community structure with that described ten years earlier by Hawthorne (1980). The results indicated that dominant organisms remained relatively constant in composition but exhibited considerable fluctuation in density. Differences in diversity and spatial distribution of fauna were also observed relative to the previous decade.

Multivariate statistical analyses indicated the macrobenthos exhibited significant spatial and seasonal patterns. Sediments characterized as silts and clays predominated down river while sandier sediment types were most common farther upriver. The spatial distributions of …

Community Structure Of The Macrobenthos In Back Bay, Virginia, Michael F. Lane

Biological Sciences Theses & Dissertations

A study of the subtidal macrobenthos in Back Bay, Virginia was conducted to examine community structure in relation to sedimentary and water quality characteristics. Samples were collected in August and November of 1987 and February and May of 1988 at ten stations.

Three site groups and three temporal groups were identified by cluster analyses of species abundance. Species composition between site groups was relatively homogeneous and eight species accounted for most of the variation between site groups. A comparison of plots of the biological and physical data in discriminant space suggested that variations in the biological data between site groups …

The Effects Of The Mud Snail Ilyanassa Obsoleta (Say) Upon The Benthic Community Of Broad Bay, Virginia, Wick Timothy Harlan

Biological Sciences Theses & Dissertations

The effects of the presence of the mud snail Ilyanassa obsoleta (Say) upon the benthic community of Broad Bay, Virginia were examined through artificial removal and exclusion of the snail and artificial increase of the snail population. The enclosure treatment exhibited a significantly higher number of macrofaunal individuals than the control. The control had a significantly higher number of meiofaunal individuals than either treatment. There were no significant differences for the chlorophyll a. The increase in macrofauna and corresponding decrease in meiofauna were probably due to cage effects and not snail densities. The presence of the fences can act as …

Macrobenthic Communities Of An Industrialized Seaport Ecosystem: The Southern Branch Of The Elizabeth River, Virginia, Steven D. Hawthorne

Biological Sciences Theses & Dissertations

Macrobenthic invertebrates of an industrialized seaport ecosystem were studied seasonally from October, 1977 through July, 1978. Five stations were selected along the Southern Branch of the Elizabeth River, Virginia. The stations ranged from an area of heavy industrialization to a non-urbanized environment. At each station, bottom water was measured for salinity, temperature, dissolved oxygen, and pH. Within each sampling area, macrobenthic infauna! invertebrates were collected from in and out of channel sites along with sediment samples for various types of physicochemical analysis.

Community structure was spatially homogeneous at station sites and throughout the stations along the River. Slightly acidic pH …

Structure Of A Subtidal Benthic Community Near Cape Charles, Virginia, R. Michael Ewing

Biological Sciences Theses & Dissertations

Species composition, distribution, and abundance of benthic invertebrates of a subtidal community were examined at a location on the lower Delmarva Peninsula near Cape Charles, Virginia. Macrobenthos was sampled quarterly between June, 1977 and June, 1978 at nine sites along a transect in Old Plantation Creek and the adjacent offshore area. Spatial and temporal patterns of numerically important species are discussed.

Sampling sites and species were grouped by a numerical classification strategy which consisted of the Bray-Curtis similarity measure and group-average clustering. Three faunal assemblages were identified with the aid of constancy and fidelity nodal analyses: (1) a tidal creek …

Test Variation In The Sand Dollar, Mellita Quinquiesperforata (Leske), George Glynn Rountree

OES Theses and Dissertations

Mellita quinguiesperforata is a common member of the benthos along the eastern coast of North America. This study considers variation of the test within the species, specifically: 1) variation in test weight, 2) variation in the length-width relationship, and 3) the average number of pore pairs in the ambulacral petals.

A total of 844 sand dollars from three localities was utilized: 1) Pass-a-Grill Beach, St. Petersburg, Florida,2) Bird Shoal, Beaufort, North Carolina, and 3) Fisherman Island, Virginia.

Animals were measured for length and width and the dry weight determined. Prediction equations for the size-weight relat1onships were computed for the three …