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Award Detail

Awardee:UNIVERSITY OF HAWAII SYSTEMS
Doing Business As Name:University of Hawaii
PD/PI:
  • David T Ho
  • (808) 956-3311
  • ho@hawaii.edu
Award Date:07/23/2014
Estimated Total Award Amount: $ 233,265
Funds Obligated to Date: $ 233,265
  • FY 2016=$66,950
  • FY 2014=$102,205
  • FY 2015=$64,110
Start Date:01/01/2015
End Date:12/31/2018
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: US GEOTRACES Arctic Section - Water mass composition, circulation and mean residence times derived from measurements of natural and manmade tracers
Federal Award ID Number:1436125
DUNS ID:965088057
Parent DUNS ID:009438664
Program:Chemical Oceanography
Program Officer:
  • Henrietta Edmonds
  • (703) 292-7427
  • hedmonds@nsf.gov

Awardee Location

Street:2440 Campus Road, Box 368
City:Honolulu
State:HI
ZIP:96822-2234
County:Honolulu
Country:US
Awardee Cong. District:01

Primary Place of Performance

Organization Name:University of Hawaii
Street:1000 Pope Rd
City:Honolulu
State:HI
ZIP:96822-2336
County:Honolulu
Country:US
Cong. District:01

Abstract at Time of Award

In this project, investigators participating in the 2015 U.S. GEOTRACES Arctic expedition will measure six oceanic tracers in order to better understand oceanic water movement in the Arctic Ocean. With this information in-hand, it will be much easier for other investigators to interpret their own seawater chemistry data. In common with other national initiatives in the International GEOTRACES Program, the goals of the U.S. Arctic expedition are to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions. Some trace elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea. The tracers to be measured as part of this study have proven their value for studies of water mass composition, circulation, and mean residence times on short to long time scales. This project will also provide training for two high school teachers, and develop curriculum for high school students. The Arctic is presently undergoing system-scale environmental change at a pace not seen elsewhere on the globe. Thus, it is essential to establish a baseline of the distributions of trace elements and isotopes (TEIs) for future reference and to begin understanding the processes that determine the TEI distributions in the Arctic Ocean. Particularly with respect to the receding sea ice cover, it is imperative to understand how TEIs impact vital functions of the Arctic system, such as primary productivity or, more generally, the cycling of carbon under these rapidly changing environmental conditions. To further understanding on water movement and thus trace element distributions in the Arctic, this team of researchers will measure chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), tritium, helium isotopes, stable isotopes of water and C-14 along the transect. These tracers have been used successfully in past studies for determination of water mass composition, circulation pathways, and mean residence times on time scales from less than one year (CFCs/SF6 and tritium/He-3) to several hundred years (C-14). The researchers plan to make underway measurements of the saturations of CFCs and SF6 in partially and totally ice covered waters along the cruise track, and will also calculate forward and backward sea ice trajectories at all station locations to determine sources of sea ice samples. These trajectories will be used as a first step towards understanding the pathways of waters in the surface mixed layer.


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.

In this project, investigators from University of Hawaii and Columbia University participated in the U.S. Arctic GEOTRACES cruise to the Arctic Ocean aboard the USCGC Healy from August 9 to October 11, 2015. The overall goals of the U.S. Arctic GEOTRACES cruise were to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes (TEIs) in the Arctic Ocean, to determine how likely their distributions will change due to changing environmental conditions, and to establish a baseline of the distributions of TEIs for future reference, since the Arctic is presently undergoing system-scale environmental change at a pace not seen elsewhere on the globe. 

 

During the two-month long cruise, as the ship traversed the Arctic Ocean from Dutch Harbor, Alaska to the North Pole and back, samples were taken for measurements of six groups of oceanic tracers, including chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), tritium, helium isotopes, stable isotopes of water and radiocarbon. These are oceanic tracers that have been used to study of water mass composition, circulation, and mean residence times on short (less than one year) to long (several hundred years) time scales, and allow us to better understand oceanic water movement in the Arctic Ocean. They also allow other investigators to interpret their own TEIs data. Some of these elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea.

 

The data we produced on the stable isotopes of water are being used by several groups in their interpretation of TEIs to understand the freshwater sources. The transient tracers (CFCs, SF6, tritium, helium isotopes) are being used to advance our understanding of circulation patterns, spreading velocities and stability of circulation patters. Radiocarbon, in combination with transient tracers are shedding light on renewal of deep water (steady renewal versus ‘fossil’ deep water body).

 

The final CFCs and SF6data have been posted on publicly accessible databases at The Biological and Chemical Oceanography Data Management Office (BCO-DMO) and CLIVAR and Carbon Hydrographic Data Office (CCHDO).


Last Modified: 05/14/2019
Modified by: David T Ho

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