LU 

 O 



cc 



LU 

 O. 



1001 

 80 

 60-^ 



40 

 20 







NATURAL MARSH 

 note "edge effect " 



TOTAL ORGANICS 



40 



80 ft. 



B 

 ALTERED MARSH 



TOTAL ORGANICS 



40 



80 ft. 



DISTANCE FROM SHORE 



Figure 4. Example of qualitative change in the land-water interface, with 

 and without wetlands (Mock 1967). The percent organic material in the 

 estuarine sediments immediately adjacent to a natural marsh (A) increased 

 peripheral to the marsh, whereas no such increase was found adjacent to an 

 altered marsh (B) which had an artificial levee between the normal low-water 

 line and the higher wetland. 



< 

 oc 



liJ 500 

 Q. 



t- 

 liJ 



Q. 



cc 



^ 250 

 V) 



895 



D 



(0 



oc 



UJ 

 CD 



i 



CONTROL ALTERED 

 SITE AREA 



^ 



M 



^ 



SHORE 



50 ft. 100 ft. 

 OFFSHORE 



LOCATION 



Figure 5. Mean catch of juvenile shrimp per trawl sample at various dis- 

 tances from a wetland with and without an artificial levee (Mock 1967) 



117 



