Preliminary data from the winter denudings substantiate findings 

 made in previous years, and in other sections of this report; namely, 

 the local intertidal communities are in a state of dynamic equilibrium. 

 Abundances and distributions of plants and animals reflect a balance 

 between physical processes, short-term growth and reproductive cycles, 

 longer cycles based on the life-span of the organisms, inter- and 

 intraspecif ic competition, and of course, the variability associated 

 with natural systems. Impact from a power plant could upset this 

 balance by disrupting any of the processes or cycles. This impact might 

 be seen immediately if it were to exclude a transient or motile species, 

 or interfere with the reproductive biology of any intertidal organism; 

 it might be appiirent only after a long period, if the impact were to the 

 growth of a long-lived perennial in an established population. It is a 

 goal of this monitoring program to characterize the communities 

 sufficiently well to allow us to detect such a disruption; therefore, in 

 addition to examination of the rocky shore community as a whole, 

 particular attention is paid Ascophyllum nodosum as an indicator 

 species. 



Ascophyllum Growth Studies 



Ascophyllum nodosum was selected as one of the indicator species 

 for a variety of reasons (Keser and Foertch 1982) . It is locally 

 abundant, covering wide areas of mid and low intertidal regions; any 

 impact that affected this plant would immediately alter the physical 

 structure of the community. It is a long-lived intertidal alga (ca. 

 13-16 yrs , Baardseth 1970; Keser et al . 1981), and therefore can 

 integrate the effects of long-term exposure to environmental conditions 

 (cf. Borowitzka 1972; Foertch et al. 1982). Further, tip elongation has 

 been shown to be a sensitive indicator of thermal stress (Stromgren 

 1977; Vadas et al. 1976, 1978; Wilce et al. 1978), and the mode of 

 growth allows tip length to be easily measured. 



Baardseth (1970) gives a general description of vegetative and 

 reproductive phenology for Ascophyllum throughout its geographic range; 

 development in our area is typical. In early spring (February) a small 

 swelling appears at the tip of each viable vegetative axis. By late 



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