Coastal microbial community response to Hurricanes Helene and Milton

The increasing frequency and severity of landfalling tropical cyclones pose significant risks to communities, economies, and ecosystems worldwide. In 2024, hurricanes Helene and Milton wreaked havoc on Florida's coastal regions, particularly around Tampa Bay, causing extensive damage and reshaping nearshore ecosystems. Following the storms, satellite observations indicated an emerging coastal phytoplankton bloom, prompting the rapid organization of a research cruise to evaluate the plankton community and identify factors driving bloom development. Using high-throughput autonomous imaging microscopy (PlanktoScope), we found a dense diatom bloom within and immediately adjacent to Tampa Bay. However, as we moved offshore, diatoms gradually declined, giving way to the harmful algal bloom (HAB) dinoflagellate Karenia brevis, which was replaced by small flagellates further offshore. We collected surface and near-bottom seawater and sequentially filtered samples for size-fractionated community nucleic acid analysis, while separate aliquots were preserved for flow cytometry to enumerate bacterial cells. RNA sequencing will reveal active micro- and nano-eukaryotic community structure and investment, and provide insight into particle-associated and free-living bacterial communities linked to distinct phytoplankton populations. Our results will highlight the impacts of major hurricanes on coastal microbial ecology and reveal potential downstream effects on ecosystem processes, including altered carbon cycling or increased pathogenicity.

Presentation Preference: Oral

Primary Presenter: Margaret Mars Brisbin, University of South Florida (mmarsbrisbin@usf.edu)

Authors:

Jean Lim, University of South Florida  (jeanlim@usf.edu)

Arianna Krinos, Brown Univeristy  (akrinos@whoi.edu)

Jason Law, University of South Florida  (jlaw@usf.edu)

Katherine Hubbard, Florida Fish and Wildlife Research Institute  (katherine.hubbard@myfwc.com)

Chuanmin Hu, University of South Florida  (huc@usf.edu)

Yonggang Liu, University of South Florida  (huc@usf.edu)