III-D-4 



Rhoads, D.C., K. Tenore, and M. Browne. 1975. The role of resuspended bottom 

 mud in nutrient cycles of shallow embayments. Pages 563-582 j_n L.E. Cronin, 

 ed., Estuarine research. Vol. 1. Academic Press, New York. 



The bottom of Buzzards Bay, Massachusetts, below a depth of about 

 13 meters, is dominated by silt-clay sediment. Water flowing near the 

 bottom is turbid because of resuspension of the bioturbated mud surface 

 by tidal -current scour. The turbid-water layer extends about 3 meters 

 above the bottom and may extend higher during spring tides. Maximum 

 turbidity develops during mid-ebb tide. A seasonal turbidity cycle 

 also exists. Minimum values of suspended carbon were measured in 

 April and May when bioturbating activities of the benthos were at a 

 minimum. 



The concentration of particulate organic carbon (POC), particulate 

 organic nitrogen (PON), and chlorophyll a^ in both surface and bottom 

 water were measured at one station over an 11 -month period. Seasonal 

 changes in these variables in surface and bottom waters showed two 

 maxima related to peak phytoplankton production: one in the winter 

 (December-January) and another in the autumn (September-October). 

 Throughout most of the year, concentration of these consumer nutrients 

 is higher in bottom water than at the surface. 



Although primary production takes place in surface water, detritus 

 from this production sinks and is concentrated on the muddy sea floor, 

 stimulating bacterial growth. The significance of this nutrient-rich 

 detrital resource for benthic productivity and aquaculture is discussed. 

 (A. A.) 



Keywords: detritus, productivity, nutrient cycles, Massachusetts 



III-D-5 



Haines, E.B. 1976. Stable carbon isotope ratios in the biota, soils and 



tidal water of a Georgia salt marsh. Estuarine and Coastal Marine 



Science 4:609-616. 



The stable carbon isotope composition of the biota, soils and tidal 

 water particulate material was surveyed in a salt marsh near Sapelo 

 Island, Georgia. Samples were taken in six intertidal zones: base 

 creekbank, Spartina alterni flora low marsh, S^. alterni flora high 

 marsh, Salicornia virginica high marsh, sand flat, and high marsh 

 mixed vegetation stands. 



The marsh plants analyzed segregated into three groups with respect 

 to their '^C/'^C ratios. The grasses, including S^. alterni flora , 

 had 6'-^C values of -12-3 to -13-6 ppt; the other vascular plants 

 had values between -22'8 and -26-0 ppt, and benthic diatoms had 



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