C. Tue Errect or SEDIMENTATION ON PRIMARY PRODUCTION IN 
THE WETLANDS 
(By J. Macllvaine, Woods Hole Oceanographic Institution) 
INTRODUCTION 
There is presently no standard by which to measure the value of 
wetland areas. The value assigned to a given piece of land is commonly 
dependent upon the use to which the land is put, and much of the 
wet lands, especially such areas as swamps, marshes, and shallow bays 
are considered more valuable after they have been drained, dredged, 
or filled to allow commercial development. While fulfilling the de- 
mands of short-ranged economics, there are obvious shortcomings 
to such a system of land value appraisal, and in response to these, 
a program to establish a more realistic land use policy is developing. 
If such a program is to succeed, a much more widely based land 
appraisal system must be developed. It seems clear that the biological 
community in the wet lands will be considered in future evaluations. 
When such policies are formulated, therefore, it will be necessary 
to have as thorough an understanding as possible of the biological 
community in the wet lands, and the factors which are likely to 
influence that community. » 
This paper presents some of the information which has ‘been col- 
lected dealing with the effect of sedimentation upon the wetlands 
community. Specifically, the nature of the interaction between sedi- 
mentation and food production is discussed. The implications of 
these interactions for the formulation of land use policy will be 
touched upon. 
While it is not within the scope of this paper to discuss in any detail 
the genesis of the various communities, it should be noted that many 
arise from the interaction of sedimentation, plant growth, and tidal 
action as primary factors. A reasonable starting point is the estuary. 
Estuaries are the wide mouths of rivers, where the tides meet the 
river currents; or more broadly, an estuary may be defined as a 
body of water in which river water mixes with and dilutes sea water. 
This latter definition aptly suits the requirements of this paper, and 
can be taken to include areas commonly termed estuaries, lagoons, 
and lower deltaic regions. In addition, it sets no lower limit on the 
size of these features. 
Estuaries are areas of sedimentation; since they are often protected 
from surf action by their shape or by sand spits or bars, the water is 
quiet in at least some parts of the estuary. In addition, there is abun- 
dant sediment available to the estuary, from the watershed draining 
into the estuary, and from seaward, in some cases. The combination 
of abundant sediment supply and quiet water conditions causes dep- 
osition of sediment. Tidal action is strongest in the central channels, 
and may resuspend sediment in these areas, reducing the net deposi- 
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