FCE-LTER scientists are measuring the effects of increased freshwater flow resulting
from restoration projects on the productivity of plants,
such as sawgrass and
mangrove trees, in the estuarine ecotone.
Primary production
has been shown to be higher in the estuarine ecotones than in the
nutrient-poor upstream marshes of the Everglades. In the Shark River Slough
ecotone, this was found to be due to mixing with phosphorus-rich marine waters,
while in the Taylor Slough ecotone, phosphorus-rich
groundwater might be mixing with surface water.
In Phase II of the FCE-LTER project, researchers are examining the effects of
increased freshwater flow on these estuaries. They believe it will enhance
oligotrophy by pushing the relatively
phosphorus-rich marine water away. Such a scenario could cause productivity to
decline. This decline in productivity, however, could be offset to some degree
by a greater availability of
organic matter as more of this material is
carried downstream. In the Taylor Slough ecotone, however, productivity could
decline with increased freshwater flow since the freshwater could suppress
phosphorus-rich groundwater discharge in this region. In Phase II of the project,
researchers are further investigating the impacts of phosphorus-rich groundwater
in the estuarine ecotone.
How do these factors affect people in south Florida?
Primary producers form the structure
that can help buffer coastal areas during extreme events,
like hurricanes, remove excess nutrients and contaminants
from water, regulate air quality and provide a mosaic
of food and habitat for a diversity of other organisms.
They also provide an indication of the status of the
ecosystem - their distribution and production are affected
by water use and management. By measuring their productivity
along with important water quality and quantity parameters
along the freshwater-to-marine gradients, researchers can determine
causes for changes in productivity that can be used to
guide human activities in a way that preserves the important
ecosystem services delivered by this feature.
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Measuring sawgrass at TS/Ph-1 in Taylor Slough
Sharon Ewe and Edward Castaneda measuring mangrove seedlings
along transects at SRS-6 in Shark River Slough
Dwarf mangrove forest in Taylor Slough (TS/Ph-6b)
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