Research Index
Consortium for Estuarine Ecoindicator Research for the Gulf of Mexico
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Crustacean Hypoxia
Dr. Marius Brouwer marius.brouwer@usm.edu
The University of Southern Mississippi Gulf Coast Research Laboratory, Ocean Springs, MS
Keywords: hypoxia; molecular indicators; crustacea; reproduction
Hypoxic conditions in estuaries, which are often associated with increased nutrient loading, are one of the major factors responsible for declines in habitat quality. In addition to chronic hypoxia, estuarine organisms are often subjected to daily variations in dissolved oxygen (DO) that may range from supersaturation at mid-day to hypoxic at night. Hypoxia and hypoxic-normoxic cycles can cause severe organ damage in mammalian species through the generation of reactive oxygen species. Little is known about the sublethal effects of chronic hypoxia, or DO cycles on estuarine organisms, and we do not have indicators for recognizing populations that are suffering from chronic DO stress. Our major objective is to develop molecular indicators of DO stress and validate their use through a combination of laboratory and field studies.
The specific objectives of the proposed study are:
- To develop molecular indicators of DO stress (hypoxia and cyclic DO) in blue crabs, Penaeid shrimp, and grass shrimp.
- To test indicator responses in controlled laboratory studies and to determine if they can serve as predictive indicators of reduced fitness (molting and reproduction).
- To use the population recruitment metrics of fecundity, fertility, hatching success and survival measured in grass shrimp from laboratory and field studies for modeling of population responses.
- To analyze tissues from organisms collected from reference and degraded sites in CEER-targeted estuaries for DO stress indicators and to integrate the indicators, with the individual community and ecosystem indicators to be developed by other CEER research teams, in a model that can be applied to assess the “health” status of Gulf estuaries.
Dr. Nancy Denslow denslow@biotech.ufl.edu
University of Florida, Gainesville, FL
Dr. Nancy Denslow will develop a membrane-based macroarray system to monitor molecular indicators of chronic hypoxia in these species in order to allow correlations with physiological end points. The Denslow laboratory will be responsible for preparing macroarrays (spotted nylon membranes) to simultaneously measure changes in at least 8 different parameters associated with chronic dissolved oxygen (DO) stress. Macroarrays will be developed, characterized and used for measuring DO stress in blue crabs, shrimp and grass shrimp.
