Evaluating Macrobenthic Indicators of Organic Enrichment and Hypoxia Within the Coastal Mississippi Hypoxic Zone

<p>Macrobenthic communities offer effective indicators of biotic integrity, but their use for distinguishing anthropogenic from natural stress is tricky because coastal taxa are eurytolerant. Effective coastal management calls for benthic indicators that respond to specific stressors, apply across different habitats, and reflect ecosystem function. Macrobenthic process metrics based on body-size descriptors should reflect ecosystem function and be useful for assessing the effects of eutrophication. Functional trait analysis should reflect the functional diversity of the community. Coastal Mississippi experienced widespread and sustained hypoxia throughout summer 2008. Site 6 located on the 10-m isobath in the center of the 2008 hypoxic zone and site 8 located on the 20-m isobath near the edge of the zone served as study areas for examining effects of this event. Samples taken in 2008 represented these sites in late spring prior to hypoxia, in mid-summer during severe hypoxia, and in autumn following a return to normoxia. Production potential and total abundance decreased dramatically after May 2008 at site 6. Declines in mean size and community turnover rate were not nearly as pronounced. Normalized biomass-size spectra (NBSS) varied among months of 2008. Prior to hypoxia in May, the NBSS comprised high abundances of organisms distributed across a very broad range of size classes, in July, all size classes were reduced or absent as a likely outcome of hypoxia, and in November, there was some recovery of smaller size classes. Functional trait analysis showed a decline in functional diversity after May 2008 with some recovery by November 2009.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Discipline thesis:degree_discipline

Coastal Sciences, Gulf Coast Research Laboratory

Year dc:date.available

2012

Author dc:creator

• Menke, Daneen P.

Contributors dc:contributor

• Chet Rakocinski
• Patrick Biber
• Bruce Comyns

• Life Sciences
• Marine Biology

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/436

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1509