These phytogeographic affinities are also evidenced in the temporal distribution of components of the 

 quarry flora, relative to that of the reference sites. Species with southern centers of distribution (i.e., 

 sub-tropical affinities), found mostly in summer and autumn in local rocky shore collections, had an 

 extended growing season in the quarry. For example, Agardhiella subulata ocurred mostly in summer 

 (May, June, .July) at the rocky intertidal collection sites, but occurred Ln every month in the quarry effluent. 

 Another red alga, Dasya baillouviana, was seasonal at reference stations (August- November) and found 

 only 83 times since 1979. Over the course of the quarry study, Dasya baillouviana could be found in any 

 month in the quarry. Similarly, Enteromorpha clathrata and Cladophora sericea, May-October greens at 

 most rocky intertidal sites, were much more common in the quarry and over a longer period. After 

 September 1984 at FE, Agardhiella subulata, Enteromorpha clathrata, and Cladophora sericea, among 

 others, were nearly as common at FE as at the quarry site. 



In contrast, algae with more northerly distributions (boreal affinities, especially browns) were less 

 common in the quarry. Laminaria saccharina occurred each month at qualitative collection sites, but only 

 in March and April at the quarry. Similarly, Petalonia fascia, a November-.Iuly brown at nearby coastal 

 stations, occurred only in January and February at the quarry. 



Qualitative algal collections from the MNPS effluent quarry are important because they characterize 

 a flora exposed to water temperature higher than those found at any nearby station. This flora therefore 

 reflects environmental conditions at one end of a thermal gradient; the floral characteristics of the reference 

 stations reflect ambient coastal thermal regimes. Differences in the quarry flora, i.e., reduced number of 

 species, especially browns, with increasing temperature, the resultant shift in divisional proportions, and 

 the temporal displacement (extension or reduction of an alga's growing season) are responses to this 

 thermal gradient. If the flora at a station farther from the discharge evidences similar floristic or vegetative 

 change, particularly after Unit 3 begins operation, a critical standard has been developed against which 

 thermal impact may be assessed. 



Undisturbed Transects 



One of the most noticeable biological features of local rocky shore communities is 7,onation; i.e., the 

 segregation of intertidal organisms into horizontal bands, each characterized by a particular complex of 



22 



