Comparisons of macrobenthic process indicators of estuarine condition in the Gulf of Mexico.
Rakocinski, Chet*,1, 1 University of Southern Mississippi, Ocean Springs, MS, USA
ABSTRACT- Macrobenthic communities provide reliable indicators of estuarine biotic integrity. Indeed, various broadly applicable macrobenthic indicators, such as the Benthic Index for the northern Gulf of Mexico (GOM), provide effective benchmarks. Since macrobenthic communities mediate estuarine processes via rates and pathways of exchange and transformation of energy and materials, they should also provide effective specific indicators of excessive nutrient loading and hypoxia, which are of primary concern in the northern GOM. Thus, other practical macrobenthic indicators related to ecosystem function should also be developed to gauge estuarine degradation within this region. Some candidate macrobenthic process-indicators include estimates of production, community turnover (e.g., P:B), and parameters of biomass-size spectra. Various scaling issues can also be addressed through the use of macrobenthic process indicators, which should facilitate: (1) comparisons across the entire estuarine gradient-landscape; (2) within region comparisons across estuarine systems; (3) inter-regional comparisons; (4) bridging indicators across organizational levels; (5) integration with process indicators representing other subsystems; (6) allometric scaling from individual physiological-level to landscape-level effects. The fourth and fifth scaling issues will likely need to be addressed to more effectively discern anthropogenic effects on ecosystem function. The sixth scaling issue should involve the use of predictive simulation models based on hypothetical cause-effect relationships.
Key words: macrobenthic, process, indicators, estuaries
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