is a stability plot for experimental samples from station 1 showing the post- 

 construction time lapse before faunal recovery appears evident. 



2. Hydrology . 



Water temperature and salinity data from the 1974-75 sampling at stations 

 A and B were compared to data from station 1 sampled during similar months in 

 1976-77 (Table 1). Both sets of data show normal seasonal trends in water 

 temperature, except for one abnormally low value of 9° Celsius recorded in 

 February 1977. 



Salinity was low at stations A and B in August 1975, but salinity during 

 other months was 32 parts per thousand or higher, and similar to station 1 

 records (Table 1). Appreciable declines in salinity apparently coincide with 

 periods of seasonally heavy rainfall. 



3. Sedimentology . 



The influence of dredging on sediment composition was determined by 

 analyses of base-line and control samples, compared to samples taken from 

 borrow pits. Base-line data came from seasonal sediment collections at 

 stations A and B, and from those taken before dredging at station 1 in April, 

 June, and July 1976. Control data were available from samples outside the 

 borrow pit at station 1, and from samples collected in an undredged bottom at 

 stations 1 to 6 in July 1977. Data from experimental samples also came from 

 periodic collections at station 1, and from borrow pit collections in the 

 single survey in July at stations 1 to 6. 



Textural, statistical, and chemical properties of base-line samples (Table 

 2) were used to describe natural features of offshore sediments, since these 

 samples were collected in all seasons prior to dredging at eastern, central, 

 and western locations within the study area (see App . A). 



a. Texture . Sediment composition was about 99-percent sand, and both 

 granules and silt-clay size particles contributed less than 1 percent. 



b. Statistical Properties . Values for mean grain size, standard deviation, 

 skewness, and kurtosis classified these sediments as fine sand that is 

 moderately well to well sorted, symmetrical to coarsely skewed, and leptokurtic 

 (sorted better in the center than at the ends of grain size distribution curves). 



c. Carbon Chemistry . Total carbon content of base-line samples was less 

 than 0.30 percent. Carbonate carbon contributed somewhat more to this total 

 than organic carbon, indicating that most carbon occurred in the form of shell 

 fragments rather than as organic deposits. 



For station 1, when these features were compared to control and experimental 

 samples, noteworthy differences appeared only in experimental samples. 



15 



