fatty acid per milligrams of particulate matter (micron/milligram) 

 were recorded. On the micron/milligram basis, virtually no distinction 

 could be made between ebb and flood tides, and the fatty acid composition 

 was nearly the same. Values ranged from 2.5-7 microns fatty acid/mg 

 particulate matter. 



The fatty acid composition of the major marsh grass Spartina 

 alterniflora has also been determined monthly. The microns fatty acid 

 per milligrams of dry weight grass was recorded. In the dead grass, 

 which is thought to be the source of the major fraction of the partic- 

 ulate matter, the micron/milligram values were yery low: 0.8-1.3. 



A laboratory study on the breakdown of S. alterniflora was made 

 under aerobic and anaerobic conditions, and the particulate matter 

 was analyzed weekly on the aerobic, and after 18 weeks on the anaer- 

 obic. On a micron/milligram basis, the greatest change occurred within 

 the first eight weeks, starting at 1.2 microns/milligram grass. After 

 one week the particulate matter was 9.9 microns/milligram, then dropped 

 in value, leveling off at about 3.2 microns/milligram after six weeks. 

 The anaerobic system had a value of 7.6 microns of fatty acid/mg 

 particulate matter after 18 weeks. The study was repeated under field 

 conditions. (A. A.) 



Keywords: Spartina , salt marshes, food chain, Rhode Island 



III-D-7 



Odum, E.P. 1968. A research challenge: evaluating the productivity of 



coastal and estuarine water. Pages 63-64 vn_ Proceedings of the Second 



Sea Grant Conference, University of Rhode Island. 



These are brief remarks by one of America's foremost experts on 

 coastal marsh productivity. Odum points out that "most fertile zones 

 in coastal areas capable of supporting expanded fisheries result 

 either from the 'upwelling' of nutrients from deep water or from 

 'outwelling' of nutrients and organic detritus from shallow-water 

 nutrient traps such as reefs, banks, seaweed or sea grass beds, algal 

 mats and salt marshes. The importance of the latter as primary 

 production pumps that 'feed' large areas of adjacent waters has only 

 been recently recognized, and many of these production foci are need- 

 lessly endangered by pollution, dredging and filling." Apparently, 

 large rivers do not have so great a local effect on the productivity 

 of estuaries and coastal waters as was once assumed. The most 

 important discovery the author and his co-workers have made in their 

 15-year study of production dynamics on the Georgia coast is that the 

 high fertility of this region is self-produced within the salt marsh 

 estuary, and is not due to nutrients washed down the rivers. They 

 could find no statistical difference between carbon-14 on other measures 

 of primary production at the river mouths as compared with localities 

 at a distance from a river mouth. Carbon-14 productivity of coastal 



114 



