Chapter 60 



Mineralization of Organic Matter in 

 Santa Monica Bay, California 



Charles G. Gunnerson 

 INTRODUCTION 



K. 



knowledge of the regeneration of nitrogen and phosphorus in 

 the ocean has been obtained from field observations of the dis- 

 tribution of these nutrients over periods of time and from labora- 

 tory experiments. The data collected in Santa Monica Bay during 

 oceanographic investigations of the effects of municipal sewage 

 treatment plant effluent were examined. Local variations in nu- 

 trient concentrations suggested that mineralization rates could be 

 computed. The effluent discharge thus provides a convenient op- 

 portunity for studying processes which normally take place over 

 large, diffuse areas in the ocean, and which constitute part of 

 what Emery (1) has defined as man-made oceanography. 



Santa Monica Bay occupies a crescent-shaped indentation 

 about 45 km long and 18 km wide on the Southern California 

 Coast. The bathymetry is characterized by a broad shelf incised 

 by two submarine canyons. 



The oceanography of the bay reflects the influence of the 

 California current, frequent coastal counter-currents, and the lo- 

 cal diurnal wind regime. The afternoon sea breeze t^q^ically brings 

 surface water from the southwest into the bay where it divides 

 and subsequently leaves near Pt. Dume and Pt. Vicente ( 13 ) . 

 The net movement of near-shore water is generally up-coast or 

 northerly. This corresponds with the geostrophic effect of the 

 local density distribution. Littoral drift is down-coast due to the 

 predominant swell pattern. Upwelling frequently is observed 

 along the northern boundary of the bay, and cold spots or domes 

 of well-mixed bottom and intermediate waters frequently result 



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