Collaborative Research: RAPID-HARVEY: Response of plankton assemblages and trophodynamics to a historic, hurricane-induced floodwater plume in a subtropical, pelagic environment

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This project will examine how plankton in the northwestern Gulf of Mexico respond to large floodwater plumes generated by extreme weather events like Hurricane Harvey at time scales relevant to its development and evolution (days to months). The goal is to understand how the timing, magnitude, and constituent loads of a massive pulse of freshwater to the Louisiana-Texas shelf are: (1) driving changes in phytoplankton, zooplankton, and larval fish communities and distributions over monthly, seasonal, and annual time scales and, (2) what the consequences of those changes are to food web interactions within the plankton. The timing of Hurricane Harvey flood water disturbance coincides with the summer-fall spawning seasons for economically important Gulf of Mexico fisheries (e.g. red drum, sea trouts, snappers), raising additional questions of longer term effects of food web disruptions on recruitment. This project will train two undergraduate students and four PhD-level graduate students across three institutions, as well as support three early-career investigators. Pre- and post-floodwater plume data and samples will be shared with the broader scientific community within one year of collection to facilitate their immediate use by scientists beyond the research team. The team will give coordinated public talks at established regional science communication series and through other existing regional outreach partnerships to extend the educational scope of the project. Finally, results from this research will be incorporated in course curriculum and shared through scientific presentations and publications in peer-reviewed journals.Record-breaking rain delivered by Hurricane Harvey to Southeast Texas in late August 2017 has resulted in a massive floodwater plume being delivered to coastal waters in the northern Gulf of Mexico (GOM). This project will investigate the short- and mid-term effects of that plume on planktonic (from pico- to ichthyoplankton) community composition and trophic interactions in that system. Building on data collected in July 2017 during a GOM Ecosystems and Carbon Cycle (GOMECC-3) cruise, and from historical datasets in the region, plankton assemblages, abundance, and food web interactions will assessed during three research cruises 2, 4, and 8 months after the event. Oceanographic data and samples will be collected and processed using standard and state of the art gear, including ZooScan, FlowCAM, flow cytometry, and next generation sequencing. Onboard micro- and mesozooplankton grazing experiments will be conducted to understand the trophodynamic interactions and relationships between different plankton groups under changing environmental conditions. Diet and growth rate analyses of larval fish will be undertaken and related to phyto- and zooplankton (i.e. prey) abundance and community composition data. Application of the same gear types and methods during the three project cruises will ensure comparability of these new data to existing samples and datasets. These post-Harvey data will be compared to immediately-preceding and long-term data collected in the area by NOAA's Southeast Area Monitoring and Assessment Program (SEAMAP), allowing for investigation of the temporal evolution of planktonic assemblages and interpretation of plankton regime shifts in seasonal, multiyear, and decadal contexts.