Currently, oil and oil-dispersant mixtures are thought to be occurring at toxic concentrations in the Gulf of Mexico (GOM) in both subsurface plumes and at the sea surface. These toxic water masses are expected to have impacts in the near term and for months to years to come in offshore marine and coastal ecosystems and at multiple trophic levels, especially through impacts to meroplanktonic early life stages. It is therefore urgent that we begin to assess the toxicity of these water masses with variety of bioassays using GOM species, not hardy species commonly used in standard laboratory toxicity testing. Because development involves a myriad of complex processes known to be exquisitely sensitive to toxic insults, early life-stage tests will be included in the battery of bioassays.
It is urgent also that we begin to collect and evaluate early life stages in wild-caught plankton and neuston fro evidence of developmental toxicity. Accordingly, a collaborative team from FGCU and FAMU propose to carry out an integrated comprehensive study, incorporating students at both the graduate and undergraduate levels at both institutions, to produce the strength of evidence require3d to establish cause-and-effect. Within 24 months of award, we anticipate collecting and performing assays on over 100 samples, each of water (subsurface and sea surface microlayer) and plankton, collected along two transect across the west Florida shelf.
Assays will include:
- Ex situ bioassays using bacteria, copepods and ELS of urchin, oyster or finfish;
- Chemical assays for PAHs and dispersants of both water and bulk plankton; and
- Assays of wild-caught neuston and plankton for biochemical, morphological or cytogenetic biomarkers.
Confirmatory toxicity tests using known concentrations of dispersant-oil mixture will also be conducted. This study will begin to also evaluate reduced recruitment and potential population-level impacts from reproductive toxicity (e.g., alterations in gametogenesis and vitellogenesis in adults, in fertility of gametes, in fertilization rate, or in embryogenesis) through exposure and bioaccumulation of PAHs by adults. The resulting information on exposure pathways and viability of dispersal routes will support adaptive management in the development of remediation and restoration plans.