Award Abstract # 1760704
Collaborative Research: RAPID-HARVEY: Response of plankton assemblages and trophodynamics to a historic, hurricane-induced floodwater plume in a subtropical, pelagic environment

NSF Org: OCE
Division Of Ocean Sciences
Recipient: LOUISIANA UNIV LAFAYETTE
Initial Amendment Date: December 1, 2017
Latest Amendment Date: December 1, 2017
Award Number: 1760704
Award Instrument: Standard Grant
Program Manager: Michael Sieracki
OCE
 Division Of Ocean Sciences
GEO
 Directorate For Geosciences
Start Date: December 1, 2017
End Date: November 30, 2019 (Estimated)
Total Intended Award Amount: $94,446.00
Total Awarded Amount to Date: $94,446.00
Funds Obligated to Date: FY 2018 = $94,446.00
History of Investigator:
  • Kelly Robinson (Principal Investigator)
    kelly.robinson@louisiana.edu
  • Beth Stauffer (Co-Principal Investigator)
Recipient Sponsored Research Office: University of Louisiana at Lafayette
104 E UNIVERSITY AVE
LAFAYETTE
LA  US  70503-2014
(337)482-5811
Sponsor Congressional District: 03
Primary Place of Performance: University of Louisiana at Lafayette
410 East Saint Mary Blvd.
Lafayette
LA  US  70503-2014
Primary Place of Performance
Congressional District:
03
Unique Entity Identifier (UEI): C169K7T4QZ96
Parent UEI: C169K7T4QZ96
NSF Program(s): Hurricane Harvey 2017
Primary Program Source: 01001819DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 1650, 7914, 9150
Program Element Code(s): 071Y
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.050

ABSTRACT

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.

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

The project team completed 3 research cruises on the TX-LA shelf in the northern Gulf of Mexico in the 6 months following Hurricane Harvey in 2017-2018. The collaborative team collected samples on those cruises to characterize the plankton communities ranging from the smallest (pico- and nanoplankton) through larval fish that comprise the ichthyoplankton. The team also completed 5 grazing experiments on each cruise to quantify how plankton food webs were changing in the aftermath of the storm and the freshwater plume it introduced to the coastal ocean.

The team was successful in documenting how plankton communities and food webs changed in the coastal ocean off Texas following Hurricane Harvey. At the base of the food web, biomass of the planktonic primary producers (phytoplankton) first increased and then decreased in the 3 weeks and 6 weeks following Harvey, respectively. These trends were relative to samples collected in the region in late July 2017, a month before Harvey made landfall. The decrease that occurred 6 weeks following the storm was much lower than the biomass typically seen in this region during Sept/Fall, based on samples analyzed from a long-term dataset (NOAA/GSMFC SEAMAP). These changes were most prevalent with the smallest phytoplankton, which also showed the highest rates of mortality by small, single-celled consumers (microzooplankton). These results suggest that the changes in phytoplankton biomass and community that we observed were likely due to a combination of both bottom-up and top-down (i.e. grazing) control on those organisms.

The numerical abundance and diversity of mesozooplankton communities (organisms typically 0.02 ? 20 cm in size which consume both larger phytoplankton and microzooplankton), varied across the Texas shelf and over time following the hurricane. Post-storm, densities were highest in September and then decreased 10-fold in three weeks when sampled again in October. Mesozooplankton were consistently more abundant at stations closest to Galveston Bay and lowest in offshore waters. Diversity peaked at the mid-point along the shelf. Temporal patterns suggest mesozooplankton may be highly resilient to hurricanes, with community structure only altered for a few weeks after a storm. Ongoing analysis of historical SEAMAP mesozooplankton samples will elucidate if observed temporal patterns indicate seasonality or deviations from the norm in community structure following Hurricane Harvey.

This project supported the research of two early-career faculty members (Robinson & Stauffer), two Ph.D. students at UL Lafayette who are basing at least part of their dissertations on this research, and three other graduate students and 10 undergraduate students who took part in research cruises, sample processing, and data analyses. We also engaged with K-12 classes in five states before, during, and after the research cruises through a Styrofoam cup activity and are rescheduling a science communication event on the project that was postponed in Spring 2020. The project has resulted in 10 presentations at scientific conferences, 1 manuscript submitted, and 2 more manuscripts in the revision process. Through this project, the PI and CoPI began working with a collaborative group that is working to advance a more general framework for understanding impacts of tropical cyclones on ecosystems from the ocean to land.


Last Modified: 04/14/2020
Modified by: Kelly Robinson

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