GCRC Project Summary |
Estuarine Creek Fronts: Biological Interfaces Between Tidal Creeks and Estuaries
PI: Merryl Alber (Dept of Marine Sciences, Univ of Georgia, Athens, GA, USA)
Support:
Georgia Sea Grant
College Program (Project number R/HAB -1)
Timeframe: 3/1/97
- 2/28/98 (complete)
Project Overview:
The fronts that occur as tidal creeks drain into estuaries (often visible as
a line of either foam or detrital particles) represent interfaces between intertidal
areas and estuaries and are potentially important zones for tropic linkages
between intertidal producers (e.g., salt marsh grasses) and macro-consumers
(e.g., larval fish and shrimp). Elucidating the fundamental processes that occur
in these estuarine system interfaces will improve our understanding of organic
matter cycling in estuarine food webs and be useful to managers and policymakers
involved in the protection and management of coastal resources. The
objectives of this project were:
- To document small-scale, estuarine creek fronts and to determine what hydrographic characteristics accompany their formation and dispersion,
- To determine whether organisms and particulate material accumulate in estuarine creek fronts, and
- To characterize
organic matter in fronts in order to determine whether it is derived from
marsh material and whether it is a food source for metazoan consumers
Findings:
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During the ebb tide, a well-defined estuarine creek front formed that acted as a dynamic barrier to mixing of creek and estuarine waters.
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During the flood tide, a topographically controlled eddy was revealed which acted as a retention zone to trap material at the mouth of the creek.
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When compared to surrounding water, the front acted to concentrate suspended sediment (36% higher), chlorophyll a (43% higher) and phaeopigment (500% higher).
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Some organisms found in the front, such as shrimp, sea spiders, and amphipods, were not found in the other sections. Copepods comprised 78% and 79% of the ebb and flood tows in the front, respectively.
Planned Publication:
Biological and physical interactions in an estuarine creek front in the
Ogeechee River Estuary. (with C. Chen)