Life Sciences Commons^™

High Cyanobacterial Abundance In Three Northeastern Gulf Of Mexico Estuaries, Michael C. Murrell, Jane M. Caffrey

Gulf and Caribbean Research

Aquatic phytoplankton comprise a wide variety of taxa spanning more than 2 orders of magnitude in size, yet studies of estuarine phytoplankton often overlook the picoplankton, particularly chroococcoid cyanobacteria (cf. Synechococcus). Three Gulf of Mexico estuaries (Apalachicola Bay, FL; Pensacola Bay, FL; Weeks Bay, AL) were sampled during summer and fall 2001 to quantify cyanobacterial abundance, to examine how cyanobacterial abundance varied with hydrographic and nutrient distributions, and to estimate the contribution of cyanobacteria to the bulk phytoplankton community. Cyanobacterial abundances in all 3 estuaries were high, averaging 0.59 ± 0.76 X 10⁹ L^–1 in Apalachicola Bay, …

Benthic-Pelagic Coupling In Northern Gulf Of Mexico Estuaries: Do Benthos Feed Directly On Phytoplankton?, Gary R. Gaston, Carol M. Cleveland, Steven S. Brown, Chet F. Rakocinski

Gulf and Caribbean Research

Few of the dominant benthic taxa of the northern Gulf of Mexico feed directly on phytoplankton. Rather, most of them feed on near-bottom seston and detritus. This is in contrast to models for Chesapeake Bay and San Francisco Bay. We found that detritivores represented over 80% of the macrobenthic organisms and over 90% of the biomass in Gulf of Mexico estuaries. The paucity of benthos that consumed phytoplankton led us to hypothesize that macrobenthos in Gulf of Mexico estuaries had less effect on plankton communities than was documented in U.S. east coast and west coast estuaries, where benthic communities consumed …

Trophic Structure Of Macrobenthic Communities In Northern Gulf Of Mexico Estuaries, Gary R. Gaston, Steven S. Brown, Chet F. Rakocinski, Richard W. Heard, J. Kevin Summers

Gulf and Caribbean Research

Trophic structure of estuarine benthic communities in the northern Gulf of Mexico was characterized according to the functional roles and geographic distributions of the macrobenthos. Macrobenthic organisms collected during two years of study were assigned to trophic groups to assess the relative utilization of detritus and other resources. Three groups of detritivores (surface-deposit feeders, subsurface-deposit feeders, and filter feeders) were numerically dominant among the benthos, each of which accounted for 25-30% of total abundance across regions. Carnivorous macrobenthos also comprised an appreciable portion (12%), while omnivores (<3%) and other groups (<4%) were poorly represented. Dominance by detritivores is consistent with current concepts regarding the role of macrobenthos in processing detritus of Gulf of Mexico estuaries.

Primary Productivity Of Coastal Marshes In Mississippi, Armando A. De La Cruz

Gulf and Caribbean Research

The annual net primary production of nine types of marsh communities common in Mis­sissippi Gulf Coast estuaries were studied by means of the Harvest Method. Production values ranged from 600 g m^-2 yr^-1 for a Sagittaria lancifolia marsh to 2330 g m^-2 yr^-1 for a Phragmites communis marsh. Primary productivity values for the other marsh types are Juncus roemerianus - 1697 g m^-2 yr^-1, Scirpus robustus - 1056 g m^-2 yr^-1, Spartina cynosuroides - 2190 g m^-2 yr^-1, Spartina patens - 1922 g …

The Occurrence Of Lymphocystis In Micropogon Undulatus And Cynoscion Arenarius From Mississippi Estuaries, J.Y. Christmas, H.D. Howse

Gulf and Caribbean Research

Lymphocystis was observed in Atlantic croakers (Micropogon undulatus) and sand seatrouts (Cynoscion arenarius) collected from brackish waters of the Mississippi Gulf Coast. This is the first report of lymphocystis in Fishes of the Gulf of Mexico and adds one family and two species to host records.

Microscopic examination of the tumors revealed several histologic differences in the lesions of the two species. Mature tumor cells in the croakers were larger than those in the sand seatrout. In the croakers, these cells were closely packed and their hyaline capsules were usually confluent. In the sand seatrouts, the …

Studies Of Annual Abundance Of Postlarval Penaeid Shrimp In The Estuarine Waters Of Mississippi, As Related To Subsequent Commercial Catches, J.Y. Christmas, Gordon Gunter, Patricia Musgrave

Gulf and Caribbean Research

Several workers and several lines of evidence have shown that the shrimp life cycle is very short, probably about 15 to 16 months, for the very small fraction reaching the largest adult size. Additionally, a great deal of commercial fishing is carried out upon sub-adult populations within the bays and shallow Gulf. In fact most shrimp that are caught have never spawned. These shrimp grow up within one warm season and they are derived from larvae which make their way to inside waters from the offshore spawning areas. Thus, it has been surmised for a long time that prediction of …

Habits Of Juvenile Fishes In Two Rhode Island Estuaries, Mohammed Saeed Mulkana

Gulf and Caribbean Research

The basic purpose of this work was to gain information on the possible role of some Rhode Island estuaries as nursery grounds for young migrant and resident species of fishes.

The areas selected were, the lower Pettaquamscutt River and the lower Point Judith Pond, both in the town of Narragansett, Rhode Island. The seining operations were carried through summer and early fall of 1962 when these estuaries are heavily used as nursery grounds. Major features of the occurrence, abundance and distribution of young fishes were deduced by examining samples from seine hauls. Thirty-six species were recorded from the lower river …