Community structure was studied at Morehead City, North Carolina, 

 on an intertidal sandy beach in an ocean inlet inside Beaufort Inlet 

 (Dexter, 1969] . The community was typified by low diversity, low 

 density, and a few dominant species, especially haustorid amphipods and 

 polychaetes. The four most abundant species were Neohaustevius sahmitsi 

 (803.96 individuals per square meter), Acanthohaustorius millsi (60.28 

 individuals per square meter), Donax vaviabitis (31.01 individuals per 

 square meter), and Saolelepis squamata (14.23 individuals per square 

 meter) . 



Croker (1967) discussed the niche diversity of five haustorid 

 amphipods occurring on sandy beaches. The distribution and niche 

 diversity of haustorid amphipods in North Carolina were studied by 

 Dexter (1967) . Amphiporeia virginiana was most abundant on surf- swept 

 beaches on the barrier islands; Parahaustorus longimerus was most 

 abundant in the inlet environment; and Lepidactylus dytisaus occurred 

 in various habitats in the sound. 



McDougall (1943) discussed the sessile marine invertebrates around 

 Beaufort and focused on population variations in pile-dwelling organisms. 

 Carriker (1967) reviewed estuarine benthic invertebrates, and emphasized 

 the need for work on all aspects of estuarine ecology. 



Several studies on estuarine benthic invertebrates were conducted in 

 North Carolina. Brett (1963) studied the relationship between inverte- 

 brate distribution and sediment type. Tenore, Horton, and Duke (1968) 

 reported the distribution of the bivalve, Rangia ouneata, in the 

 Pamlico River estuary and Pamlico Sound. Tenore (1970) studied the 

 macrobenthos of the Pamlico River estuary. He divided the estuary into 

 an oligohaline zone dominated by R. ouneata and Nereis suaoinea, a 

 mesohaline zone with a Maaroma balthiaa-Heteromastus filliformis-Mereis 

 suoainea association, and a polyhaline zone with a Macoma phenax- 

 Mulinia lateralis-Glyoera dihvanchiata association. 



This is an intensive, seasonal study of the benthic invertebrate 

 communities on a high-energy barrier island beach and on the estuarine 

 beach of the same strand. Species were characterized by location and 

 density, and communities are defined and related to the limiting 

 physical parameters. The species diversity of the communities is 

 determined and seasonal changes in densities and diversity are discussed. 



II. METHODS AND MATERIALS 



I. Transect Location. 



Three transects were established on both the ocean and sound 

 beaches (Fig. 2). On the ocean beach, transect II was due east of 

 bench mark 16, and 47 meters north of the pier on the FRF site. 



14 



