(1979-1985) ranged from 44-47% for reds, browns 25-27%, and greens 26-30%. The divisional propor- 

 tions vary seasonally: reds are more prevalent in August- December, browns in February-May, and 

 greens in May-July. When represented as percent occurrence of reds, browns, and greens (46:25:29), the 

 local flora is consistent with those reported by other researchers in the northwest Atlantic. 



Quantitative studies show intertidal zonation patterns typical of rocky shores throughout New 

 England, with the high intertidal dominated by barnacles, the mid intertidal by barnacles and fucoids, 

 and the low intertidal dominated by Chondrus crispus, a perennial red alga. The abundances of these 

 major components of local rocky shore communities vary over time and space. Variations are predictable 

 and explainable in terms of seasonality, degree of exposure, intertidal height, inter- and intraspecific 

 competition, and life-history of the organisms. Changes to communities have been minor, indicating 

 stable environmental conditions during 2-unit operation. 



An exception to the local stability is the development of a community dominated by opportunistic 

 ephemeral algae after the opening of the second quarry cut in August 1983 at Fox Island -Exposed (FE), 

 the station closest to the discharges. This change was attributed to thermal incursion and water 

 temperatures in excess of 28 °C. High water temperatures in late summer 1984 were responsible for 

 the elimination of the perennial algae Chondrus crispus, Fucus vesiculosus and Ascophyllum nodosum from 

 the low intertidal at FE. Codium fragile, a large green alga, became and remains the dominant component 

 of the FE community. It is expected that the present FE community will continue to be dominated 

 by opportunistic, warm water-tolerant algae. 



Millstone Point, the second-closest station to the discharges, has shown a decrease in Fuct/s 

 vesiculosus coverage since 1981 when monitoring first began there. In addition, an increase in grazers, 

 especially Ijtlorina liltorea, has been observed since the second cut was opened. 



Rccolonization studies, employing transects and exclusion cages, allowed isolation and identification 

 of some factors that infiuence the structure of local rocky intertidal communities. Rccolonization was 

 influenced by time of year in which denuding occurred, and related to degree of exposure and intertidal 

 height, e.g., rapid in the high intertidal of an exposed station and slow in the low intertidal of a sheltered 

 station. Results from the exclusion cage studies have shown that rates and patterns of rccolonization, 

 both with and without the influence of grazers and predators, were unaffected by proximity to the discharge. 



