Physical Sciences and Mathematics Commons^™

Macrobenthic Communities In The Northern Gulf Of Mexico Hypoxic Zone: Testing The Pearson-Rosenberg Model, Shivakumar Shivarudrappa

Dissertations

The Pearson and Rosenberg (P-R) conceptual model of macrobenthic succession was used to assess the impact of hypoxia (dissolved oxygen [DO] ≤ 2 mg/L) on the macrobenthic community on the continental shelf of northern Gulf of Mexico for the first time. The model uses a stress-response relationship between environmental parameters and the macrobenthic community to determine the ecological condition of the benthic habitat. The ecological significance of dissolved oxygen in a benthic habitat is well understood. In addition, the annual recurrence of bottom-water hypoxia on the Louisiana/Texas shelf during summer months is well documented.

The P-R model illustrates the decreasing …

Survey Of Two Perfluorinated Organic Compounds (Pfoa And Pfhxa) In Water And Biota Surrounding A Polyfluorinated Chemical Plant, Kevin S. Dillon

Gulf and Caribbean Research

Perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA) concentrations were measured in water and biota samples collected within and near a polyfluorinated chemical plant in coastal Mississippi. Effluents from the site and from the local public water treatment plant were sampled along with municipal water supplies, shallow groundwater beneath the site, nearby surface waters, and local biota. Highest concentrations were from stormwater ([PFOA] = 85—530 ng/l; PFHxA = 140—590 ng/l) and shallow groundwaters ([PFOA] = 44—1000 ng/l; PFHxA = 210—3100 ng/l) collected at the site. The local public water treatment effluent also had relatively high PFHxA concentrations (310—590 ng/l). Intermediate PFOA …