Award: OCE-1763167

In this project our major goal was to investigate the impact of Harvey, a category 4 hurricane, on water column and sediment of the Mission-Aransas Estuary in south Texas, with an overarching question of ?How did Hurricane Harvey affect water and sediment geochemistry of this estuary over both short and long time periods?? To address this question, we collected a series of biogeochemical parameters before and following Hurricane Harvey for more than three years, and we also evaluated nitrogen cycling rates through laboratory incubation experiments. We have three major findings from this project: (1) the phytoplankton community in this estuary was minimally affected despite the strong winds and storm surge during the hurricane, and (2) the sediment grain size became significantly coarser post-Harvey, and (3) nitrogen cycling rates, including denitrification, dissimilatory nitrate reduction to ammonium (DNRA) and anammox, all decreased significantly post-Harvey and had not recovered even one year post-hurricane. We also found that riverine water carries much more terrestrial organic matter to the estuary during high flow events than during base flow periods. This may be an important mechanism to supply materials and energy to the relatively oligotrophic coastal ecosystems in the arid south Texas region. All of the data, except some lipid data, have been uploaded to BCO-DOM (in final review now), and we will upload the remaining lipid data this summer when we expect to finish the lipid analyses. Three peer-reviewed papers have been published, 1 in press, and 4 manuscripts are in preparation at the moment. We have made 13 presentations in national and international conferences such as Ocean Science Meeting, Gordon Research Conference and Coastal & Estuarine Research Federation Conference, including organizing and chairing sessions focusing on hurricanes. We also gave a webinar invited by NOAA. This grant directly supported one Ph.D. candidate, and indirectly one postdoctoral research associate, and several undergraduate and graduate students at UTMSI and visiting graduate students from abroad through field work and laboratory analyses. We presented data of this project on a NOAA sponsored workshop in 2019: Teachers on the Estuary program, where about 10 teachers from all over Texas attended (see attached images). In addition, 100 students grades 5-8 participated in the University of Texas Marine Science Institute (UTMSI) Summer Science program in June 2019 in Port Aransas, where graduate students from the PIs' labs developed and led an activity focusing on watershed-estuary linkages. Last Modified: 02/17/2021 Submitted by: Zhanfei Liu