Assessment of Impacts from
Development-Driven Changes in Aquatic Organic Matter Composition in
the Lower St Johns River
Participants: J. Sickman (PI),
M. Teplitski (Co-PI) K. Sharma (Co-PI), W. Cooper (FSU, Co-PI), T.
Dittmar (FSU, Co-PI), A. Zimmerman (UF-Geology, Co-PI), T. Osborne
(Co-PI), D. Lucero
Funding Agency: St Johns Water
Management District
Problem Statement -
Eutrophication of surface waters presents one of the most pervasive
water quality problems in Florida and the U.S. Because
eutrophication impacts aquatic ecosystems by increasing the
productivity of primary producers, and thereby increasing the amount
of organic matter produced within a system, assessing its ecological
effects requires characterization of the sources, assimilation and
decomposition of nutrients and organic matter. Analytical methods
routinely applied to eutrophication investigations are capable of
quantifying the total amounts of nutrients and carbon in organic and
inorganic pools, but are incapable of characterizing forms within
the organic matter pool. This represents a significant hindrance to
eutrophication assessments performed on blackwater river systems,
since they contain large amounts of natural, refractory organic
matter. In order to define the anthropogenic contributions to
nutrient enrichment, it is necessary to distinguish between natural,
refractory organic carbon and nutrients from the labile organic
matter arising from point and non-point source pollution.
Research Activity - This
project, funded by the St Johns River Water Management District has
two objectives. First we will evaluate a set of non-traditional
laboratory analytical techniques for the characterization of aquatic
organic matter with the goal of identifying a sub-set of predictive
and cost effective methods that can be applied routinely in future
assessments of nutrient pollution and treatment technology
evaluations. And second, we will apply this set of organic carbon
and nutrient characterization techniques in an evaluation of: a)
non-point source runoff from a suite of landuse types and b) the
sources and lability of organic matter in the St. Johns River
present during summertime low dissolved oxygen events.
