Enteromorpha is driven locally extinct in 

 the subtidal zone or occurs only in small 

 refuge areas. 



The most extensive studies of the 

 spatial distributions of seaweeds in the 

 bight focus on the distinctions between 

 nearshore and offshore species and on how 

 they are distributed north-to-south along 

 the U. S. coastline (Schneider 1975, 1976; 

 Searles and Schneider 1980; Searles 1984). 

 Of the 303 seaweeds known from North 

 Carolina, approximately two-thirds occur 

 in shallow coastal habitats and are 

 potential residents of rubble structures. 

 Approximately one-half (109 species) of 

 the 204 species found in shallow water are 

 not known to occur in deep offshore 

 waters. Of the 194 species that do occur 

 in deep offshore waters, approximately 

 one-half (108) are known only from those 

 depths. About one-third (96 species) of 

 the total flora have been collected in 

 both shallow and deep habitats. 



For the shallow water species, 21 

 reach their northern limit and 27 reach 

 their southern limit of distribution in 

 North Carolina. Within North Carolina, 

 the Cape Lookout jetty appears to be the 

 northernmost limit in the intertidal zone 

 for tropical and subtropical seaweeds 

 (Williams 1948; Humm 1969; Schne'ider 

 1976). The Continental Shelf off Cape 

 Lookout plays a similar role for the 

 offshore seaweeds (Schneider 1976). A few 

 reach the southern limit of their 

 distribution off Cape Lookout (only 1%), 

 but many (37%) reach their northern-most 

 limit there. This indicates the more 

 tropical affinity of the offshore flora. 

 Of the 303 seaweeds known from North 

 Carolina, 44% reach their northern limits 

 and 10% reach their southern limits within 

 the State. 



In the Carol inas, seasonal changes in 

 the occurrence, abundance, and 

 reproduction of algal species can be 

 dramatic (Schneider 1975, 1976; Richardson 

 1979, 1981, 1982; Kapraun and Zechman 

 1982; Peckol 1982; Peckol and Searles 

 1983; Van Dolah et al . 1984). In a study 

 of seaweeds on an intertidal jetty, 

 Kapraun and Zechman (1982) noted that the 

 red algae were most diverse in summer, 

 brown algae were most diverse in winter, 

 and green algae were relatively aseasonal . 



They also suggested that there were three 

 components of the North Carolina algal 

 community they studied: 1) a eurythermal 

 cool -temperate element in winter 

 (comprising 37% of the species at their 

 site); 2) a eurythermal tropical element 

 in summer (comprising 18% of the species 

 at their site); and 3) a larger, warm- 

 temperate element that occurred year round 

 (comprising 45% of the species at their 

 site). Schneider (1975, 1976) studied the 

 flora of the Continental Shelf and noted 

 maximal development in mid-summer. The 

 number of species and total biomass 

 decreased in fall, reached a yearly low in 

 winter, and then increased spring through 

 summer. Ninety-nine percent of all 

 species were present in mid-summer, 59% 

 were present in the fall, and only 33% 

 were present in the winter. 



Successional patterns have not been 

 adequately documented for shallow water 

 seaweeds in the bight. Van Dolah et al . 

 (1984) documented the summertime abundance 

 of seaweeds on jetties at Murrells Inlet, 

 SC, every year for 4 years after 

 construction. Between the first and 

 second year there was an increase in the 

 number of algal species and in algal 

 abundance. Changes between the second and 

 fourth years were nondirectional . 



Patterns of Recruitment 



Seaweeds may recruit via various 

 types of spores or, in some species, by 

 fragmentation and reattachment of adult 

 portions (Dixon 1965). Given the 

 seasonally changing nature of the flora of 

 the South Atlantic Bight, reinvasion 

 following seasons of inhospitable 

 conditions could be a major problem for 

 benthic seaweeds. Many seaweeds appear to 

 have adapted to these conditions by 

 persisting throughout unfavorable periods 

 as stunted forms or persistent holdfasts; 

 Sarqassum f i 1 ipendul a , Botrvocl adi a 

 occidental is , and Gracilaria mammillaris 

 do this in Continental Shelf habitats 

 (Schneider 1976). Several species on 

 shallow jetties in the bight produce early 

 developmental stages that are capable of 

 withstanding long periods of unfavorable 

 conditions. This phenomenon has been 

 studied in greatest detail by Richardson 

 (1978, 1979, 1981, 1982). 



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