Abstract

Seven sampling localities were established within the intertidal zone of Santa Monica Bay, California. Weekly collections of sand samples were made during the period from Sept. 22, 1956 to Apr. 18, 1957, and a total of 30 samples was collected at each station. The sand was analyzed for foraminiferal content, median grain size, and degree of sorting in order to determine seasonal variations in both the sand and the Foraminifera. A total of 53 genera and 129 species of Foraminifera was found. Only 17 of these species were found living in this intertidal environment. One new species, Scutuloris redondoensis, is described. There is evidence that planktonic Foraminifera are carried into shore at times of storm activity. Also, a reworking of fossil fauna both from offshore sediments of Miocene and Pliocene age and from the Pleistocene strata cropping out in the marine cliffs bordering the beaches is indicated. A correlation is established between the abundance of Foraminifera and the median grain size of the sand. The temperature of the sea water has a direct bearing on seasonal variations in living foraminiferal assemblages, and affects the total number of specimens found in the beach sands. Wave activity and longshore current, on the other hand, cause a seasonal variation in the number of reworked and displaced Foraminifera, since these are the prime methods by which the tests are brought to the beach. During the course of this survey, data as to the pH, salinity, heavy mineral concentration, and calcium carbonate percentage were collected. These factors varied very slightly, and, therefore, did not noticeably affect the seasonal trends of the foraminiferal assemblages.

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