Life Sciences Commons^™

Namalycastis Abiuma (Müller In Grube) 1871, An Aberrant Nereidid Polychaete Of A Georgia Salt Marsh Area And Its Faunal Associations, Erik Rasmussen

Gulf and Caribbean Research

The morphology of the aberrant nereidid Namalycastis abiuma, Namanereidinae is described on the basis of material collected 1971-72 and 1976 in the brackish water drainage ditch system of Sapelo Island, Georgia, USA. The systematics of the species is briefly reviewed. The habitat and ecological conditions under which the species lives in these brackish ditches are described.

At various times, N. abiuma lives out of water under the bark of trunks and branches of fallen trees. Decaying wood is ingested. It is suggested that future studies should concentrate on the reproductive biology of the widely spread, mainly tropical populations of what …

Distribution Of The Marsh Periwinkle Littorina Irrorata (Say) In A Virginia Salt Marsh, R. Wyle Crist, William C. Banta

Gulf and Caribbean Research

Littorina irrorata varies over its geographic range in maximum size, preferred elevations relative to tidal datum planes, and in the type of vegetation it inhabits. On Wallops Island, Virginia, postlarvae of Littorina irrorata with shell lengths < 5 mm long live almost exclusively in dead, curled-up leaves of Spartina alterniflora at elevations near mean tide level, below elevations occupied by larger conspecifics. Snails longer than 5 mm in length increase in average size with decreasing elevation. This distribution is opposite to that found by Hamilton (1978) in a marsh in Florida. No difference was found in our study area in growth rate of marked snails at two different elevations, so the size-elevation …

Community Structure Of Diatoms Epiphytic On Pneumatophores Of The Black Mangrove, Avicennia Germinans, In A Louisiana Salt Marsh, Robert S. Maples

Gulf and Caribbean Research

The taxonomy, diversity, and similarity of diatom assemblages epiphytic on pneumatophores of black mangrove, Avicennia germinans (L.) L., in southeastern Louisiana were investigated. A total of 109 taxa representing 27 genera were identified in samples from five sites. The most abundant taxa were Nitzschia brittonii Hagelstein, Nitz. frustulum (Kutz.) Grun., Navicula diserta Hust., Denticula subtilis Grun., and Amphora tenuissima Hust. Comparisons with previous studies indicate that the diatom flora epiphytic on A. germinans in this study is much more characteristic of temperate salt marshes than of subtropical mangrove communities.

Elevational Variations In The Lowest Limit Of Spartina Colonization In A Virginia Salt Marsh, Thomas G. Reidenbaugh, William C. Banta, Santoria Mendoza, Robert P. Strieter, Michele Varricchio

Gulf and Caribbean Research

Elevations of lowest colonization of smooth cordgrass, Spartina alterniflora, were surveyed along the edge of a juvenile salt marsh at Wallops Island, Virginia. This lowest limit of Spartina varied over one-third of the local mean tidal range, with lowest occurrences between mean low water and mean low water neaps. Four geographical factors appeared to influence the lowest limit of Spartina: (1) tidal scouring in areas where tidal channels were constricted, (2) scalloping of the marsh edge over a sloping substrate, (3) patterns of historical development of the marsh, and (4) ice scouring of previously colonized Spartina over winter. …

Size-Specific Emergence Of The Marsh Snail, Littorina Irrorata: Effect Of Predation By Blue Crabs In A Virginia Salt Marsh, Hilary S. Stanhope, William C. Banta, Michael H. Temkin

Gulf and Caribbean Research

Marsh periwinkles of 5 to 7 mm in shell height were eaten regularly by blue crabs. Fractures marking unsuccessful crab attacks were present in about 25% of medium-sized (10-16 mm) snails and over 60% of larger snails (over 16 mm). Medium-sized snails, subject to predation, leave the water more frequently than larger snails, but only about a quarter of the snail population leaves the water during high tide. We found no evidence that the snails leave the water because they sense blue crabs in the water.

Origins And Effects Of Spartina Wrack In A Virginia Salt Marsh, Thomas G. Reidenbaugh, William C. Banta

Gulf and Caribbean Research

Movements of mats of tidal wrack (dead Spartina alterniflora) and impacts of the wrack were followed in color infrared aerial photographs of a sloping foreshore salt marsh on Wallops Island, Virginia. Tidal wrack may be stranded in high marsh, where it decomposes, or it may be temporarily stranded at lower elevations. The wrack kills underlying Spartina alterniflora in low marsh and in the transition zone from low to high marsh. Wrack is the major cause of devegetated areas within the marsh, but these areas eventually revegetate, and do not evolve into pans. There are substantial short-term reductions in S. …