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Research Spending & Results

Award Detail

Awardee:UNIVERSITY OF DELAWARE
Doing Business As Name:University of Delaware
PD/PI:
  • Wei-Jun Cai
  • (302) 831-2839
  • wcai@udel.edu
Award Date:10/31/2017
Estimated Total Award Amount: $ 40,933
Funds Obligated to Date: $ 40,933
  • FY 2018=$40,933
Start Date:11/01/2017
End Date:10/31/2018
Transaction Type:Grant
Agency:NSF
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.050
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:Collaborative Research: A RAPID response to Hurricane Harvey's impacts on coastal carbon cycle, metabolic balance and ocean acidification
Federal Award ID Number:1760660
DUNS ID:059007500
Parent DUNS ID:059007500
Program:Chemical Oceanography
Program Officer:
  • Henrietta Edmonds
  • (703) 292-7427
  • hedmonds@nsf.gov

Awardee Location

Street:210 Hullihen Hall
City:Newark
State:DE
ZIP:19716-0099
County:Newark
Country:US
Awardee Cong. District:00

Primary Place of Performance

Organization Name:LUMCON
Street:8124 Highway 56
City:Chauvin
State:LA
ZIP:70344-2110
County:Chauvin
Country:US
Cong. District:01

Abstract at Time of Award

Understanding how extreme events, like hurricanes, impact coastal ecosystems and the cycling of elements like carbon and oxygen, is important for improving our ability to predict how the global carbon cycle will respond to climate. This team of investigators, who have already been working together on understanding the carbon cycle in the Gulf of Mexico continental shelves, have important recent data against which to measure the effects of the passage of Hurricane Harvey in August, 2017. They will sample the waters and sediments of the northwestern Gulf of Mexico in September, October, and January to assess Harvey's impacts on a timescale of weeks to months. The researchers pose three specific questions: 1. Will the region become a major source of carbon dioxide to the atmosphere, releasing carbon accumulated in the bottom water and sediments, and will this potential impact be faster and greater than during normal fall and winter mixing events? Will this process acidify the surface water and for how long? 2. Will the metabolic balance be substantially pushed toward net heterotrophy as a result of the storm in comparison to other years? 3. Can the amount of material delivered or redeposited across the continental shelf by a tropical cyclone be considerably larger than that related to winter storm systems? The PIs will measure water column nutrients, oxygen, organic carbon, and inorganic carbon system parameters; determine water column and benthic metabolic and nutrient flux rates; and sediment organic matter deposition rates. They will also collect end member river samples. They will compare the immediate (mid-Sept) but limited post-hurricane data and one-month post-hurricane, more detailed data with those collected in July and April to study the impacts of the storms. they will also compare 2017-2018 seasonal data to seasonal data over the same region collected in the past (2006-2008 and 2009-2010). They will also compare the impacts of Hurricane Harvey to those of Hurricanes Katrina and Rita (2005) and Tropical Storm Cindy (June 2017). The project will involve graduate and postdoctoral research and work to communicate results to the public.


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.

Hurricane Harvey impacts on coastal carbon and oxygen cycling

The impacts of hurricanes Harvey in August and Nate in October 2017 on coastal carbon and oxygen (O2) concentrations and controlling processes on the Louisiana-Texas Shelf were investigated based on three research cruises conducted in July, September, and October. Prior to the cruises, we had hypothesized that the seasonal development of linked hypoxia and acidification would break down and reform differently following tropical storms because O2 can quickly respond to physical mixing and exchange with the atmosphere whereas CO2 is buffer by the dissolved inorganic carbon (DIC) system and would acidify the surface. Further, O2 and DIC would be impacted differently by the large amount of sediment resuspension that occurs during hurricanes. To test this hypothesis, we observed changes in water-column concentrations of O2, pCO2, pH, organic matter, and nutrients and changes in process rates for water-column primary production and respiration and sediment fluxes of dissolved O2, DIC, and alkalinity following hurricanes. Following Hurricane Harvey, average surface pCO2 was higher than that in normal summer season and net respiration prevailed in the water-column across the shelf. During the October cruise, Hurricane Nate crossed through our sampling area mid-cruise. Following Nate, the water-column was well-mixed and there was increased sediment resuspension and water-column and sediment respiration resulting in O2 uptake and DIC release.  These processes led to higher pCO2 and lower pH in the surface and bottom water than the pre-storm conditions. The impacts of hurricanes temporarily turned the region from a CO2 sink to a source and transiently acidified the surface water.  The results generally supported our hypothesis.  

Our group also found a massive remobilization of 4-8 cm of the surface sediment across much of the shelf as indicated by that 7Be activities in sediments. Total chlorophyll a concentrations during the Sep/Oct 2017 cruise period were highest around the Mississippi River birdfoot delta. Concentrations were also relatively higher for mid-shelf and offshore stations during Sep/Oct 2017 as compared to normal summers.

As hurricanes are predicted to be more frequent or stronger by climate models, this study will shed light on larger carbon cycle issues on global coastal ocean scales and under future climate scenarios. The large amount of data obtained from this work will also benefit synthesis and modeling community as well as to the publics. 

 


Last Modified: 07/15/2019
Modified by: Wei-Jun Cai

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