According to records from Boothbay Harbor (region 2), the nearshore salinity 

 cycle proceeds from a November maximum to a May minimum (figure 4-5). No 

 significant correlation between salinity and precipitation has been recorded 

 at Boothbay Harbor. Since the salinity recorder is below the depth of short- 

 term surface mixing and away from areas of energetic tidal mixing, usually a 

 period of a day or longer passes before a reduction in salinity due to 

 precipitation occurs, if it occurs at all. \ 



It is not possible to establish a strong correlation between river discharge 

 and surface salinity either. Local currents and distance from gaged 

 freshwater sources are two factors that obscure the relationship between 

 salinity and land runoff. 



In offshore waters at Boothbay Harbor (region 2), salinity data (Apollonio and 

 Applin 1972) indicate that upwelling of deeper water may be taking place at 

 certain times of the year and the boundary runoff may be diluting sea water at 

 other times. As with temperature, the actual distribution is much more 

 complex than can be represented by the number of stations sampled. 



Below approximately 400 feet (120 m) , neither temperature, salinity, nor 

 density show much seasonal variation. Water below this depth is removed from 

 direct atmospheric influences, and any short-term variability is caused by 

 other factors, such as changes in the sea water outside the Gulf of Maine. 



Spatial variability of coastal waters . Organisms have specific ranges of 

 temperatures and salinities outside which they cannot survive or reproduce; 

 therefore, variability among these parameters is significant. A great deal of 

 alongshore (see figure 4-6 for station locations) variability in temperature 

 and salinity was found by Speirs and coworkers (1976). Generally, temperature 

 and salinity variability was greatest at the stations most exposed to river 

 discharge and least at offshore stations. (The data from these stations are 

 given in appendix B) . Generally, river discharge, besides potentially 

 carrying pollutants, creates a variable environment to which organisms must 

 adapt. 



In the characterization area temperature variability decreases from west to 

 east (Graham 1970a). Summer salinities are generally lower than winter 

 salinities, due to river discharge. In both summer and winter, surface 

 salinity shows a trend of increasing values from west to east. Both the 

 smaller temperature range and the higher salinities in the east are 

 attributable to increased tidally induced mixing (see "Processes influencing 

 coastal water" below) toward the Bay of Fundy (see also appendix C) . This 

 decreased environmental variability may allow for the development of more 

 diverse biotic communities. 



The 1975 summer distribution of surface temperature and salinity (Yentsch et 

 al. 1976; see appendix D) , indicates the same trends. A major difference in 

 the eastern distribution of temperature is evident. In 1963 temperature 

 decreased in the offshore direction, while in 1975 temperature increased in 

 the offshore direction. The 1975 distribution is typical of an upwelling area 

 (see "Processes influencing coastal waters" below), whereas Graham (1970a) 

 states that the 1963 distribution is due to the presence of a tongue of cold 

 water that exists in summer between warmer inshore and offshore waters. 



4-14 



