Evaluation of Change in Benthic Health on the West Florida Shelf

This study provides a greater understanding of current and past benthic health on the West Florida Shelf (WFS) and helps to develop tools to better characterize the impacts of large events such as harmful algal blooms and hurricanes. It synthesizes a 5-year environmental monitoring program of the WFS benthos in a collaboration between Eckerd College and Florida Fish and Wildlife Conservation Commission-Fish and Wildlife Research Institute’s Harmful Algal Bloom group. Surface sediment grab samples and water column CTD measurements were collected over a 5-year period to evaluate spatial and temporal variability and potential drivers of environmental change. Benthic foraminifera, which are easy to collect, inexpensive to characterize, have short life cycles, and respond quickly to environmental change, were used as bioindicators. Monthly changes in their assemblages were characterized at the species-level along with abundance and diversity indices (Shannon, Fisher’s Alpha, Ammonia-Elphidium, etc.).  A foraminifera-based marine biotic index (F-AMBI), which was normalized to changes in total organic matter, was developed and coupled with the development of benthic health thresholds through TITAN analysis. These tools were combined with sedimentology and CTD measurements to provide physical context toward determining drivers of variability. This study connects major impact events to the seafloor by directly coupling environmental parameters to benthic communities. It also establishes baselines of benthic health that will help understand future impacts of major events.