EXCESS FLUX,/ig cm'^y"' 



1972 

 1952 

 1932 

 1912 

 Q: 1892 

 UJ 1872 

 1852 

 1832 

 181 2r 

 1792 



4 



— r- 



Cu 



12 



1 r 



4 8 12 4 8 12 



+ 



+ 



Zn 



J I ■ . 



■+- 



+ 



+ 



T 



■ ' 



+ 



^l—L. 



-I l_ 



Figure 28. Historical variation 

 and lead recorded in the high 

 (McCaffrey 1977). 



in the anthropogenic fluxes of copper, zinc, 

 marsh sediments at Farm Creek, Connecticut 



marsh functions as a sink for various 

 pollutants. Generally, it appears 

 that Pb, Cu, and Fe are held very 

 tightly in the high marsh, with Mn, 

 Zn, and Cr showing only about 50% 

 retention and Cd somewhat less 

 (Siccama and Porter 1972; Banus et al. 

 1974, 1975; McCaffrey 1977; Giblin 

 The retention of metals 

 intertidal marsh may be 

 less complete (Giblin 



et al. 198C). 

 by the lower 

 considerably 

 et al. 198C). 



In addition to providing us with 

 a record of pollution inputs, it also 

 has been suggested that marshes might 

 serve as "biological filters" for 

 urban sewage. To explore the 

 ecological consequences of this idea, 

 a long-term experimental study of the 

 effects of nutrient enrichment and 

 heavy metals was conducted at Great 

 Sippewissett Marsh on Cape Cod by 

 groups at Woods Hole Oceanographic 

 Institution and The Marine Biological 

 Laboratory at Woods Hole. Much of 

 that work has been cited throughout 

 this community profile. 



57 



The experiment involved the 

 application of metals in comnier- 

 cial sewage sludge fertilizer 

 (Table 13) and in dissolved form 

 without associated nutrients 

 650 mg/m^/week; Cu and 

 = 20 mg/m2/week) to plots of low 

 high marsh. In both treatments, 

 metals did not appear to have 

 effect on the growth of S partina 

 3aten s or S^. al ternif lora (Figure 29) 

 according to Giblin et al. (1980). 

 However, both grasses became enriched 

 in Cd, Cr, Cu, and Zn in plots treated 

 with large doses of the sludge mixture 

 (Table 14). The fate of these metals 

 is still uncertain and, as Giblin 

 et al. (1980) concluded at the end of 

 their paper, "The role of the grasses 

 in making metals available to marsh 

 organisms is presently being 

 investigated. " 



In 300 years we seem to have come 

 full circle, from viewing the New 

 England miarshes as a source of food 

 to exploring their value as sewage 

 treatment plants. I suppose it is 



