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Research Spending & Results

Award Detail

Awardee:BIGELOW LABORATORY FOR OCEAN SCIENCES
Doing Business As Name:Bigelow Laboratory for Ocean Sciences
PD/PI:
  • Benjamin S Twining
  • (207) 315-2567
  • btwining@bigelow.org
Award Date:07/16/2014
Estimated Total Award Amount: $ 243,548
Funds Obligated to Date: $ 243,548
  • FY 2014=$71,052
  • FY 2015=$86,452
  • FY 2016=$86,044
Start Date:12/01/2014
End Date:11/30/2018
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:GEOTRACES Arctic Section: Collaborative Research: Biogeochemical cycling of particulate trace elements in the western Arctic basin
Federal Award ID Number:1435862
DUNS ID:077474757
Program:Chemical Oceanography
Program Officer:
  • Henrietta Edmonds
  • (703) 292-7427
  • hedmonds@nsf.gov

Awardee Location

Street:60 Bigelow Drive
City:East Boothbay
State:ME
ZIP:04544-0380
County:East Boothbay
Country:US
Awardee Cong. District:01

Primary Place of Performance

Organization Name:Bigelow Laboratory for Ocean Sciences
Street:
City:
State:ME
ZIP:04544-0380
County:East Boothbay
Country:US
Cong. District:01

Abstract at Time of Award

As part of this project, two investigators will participate in the 2015 U.S. GEOTRACES Arctic expedition to determine the trace element composition of different suspended particles in the water column of the Arctic Ocean to identify the sources and scavenging capabilities of these particles. In common with other multinational 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. This team of trace element scientists will focus on the measurement of particulate trace elements, which will enable scientists to better estimate the sources of particulate metals to the Arctic Ocean and to better understand their contribution to biological processes. This project will also provide educational opportunities for undergraduate students, K-12 teachers, and the general public. Particulate trace element distributions, sources, sinks and cycling are predicted to be controlled by physical, biological, anthropogenic and geochemical processes in the Arctic. Furthermore, many trace elements are required nutrients for marine phytoplankton, playing a key role in oceanic primary productivity. However, few integrated oceanographic studies have been conducted to specifically investigate these relationships in this region, despite the changing conditions and global significance of the Arctic. This project will significantly advance understanding of the complete geochemical cycles of a number of trace elements in the Arctic Ocean basin by measuring the concentrations of particulate trace elements in bulk particles collected through the water column and in sediments, as well as in phytoplankton from the upper water column. These measurements will enable scientists to constrain the inputs of particulate elements from rivers, shelves and ice, and to assess the removal of dissolved trace elements via passive scavenging and biological uptake.

Publications Produced as a Result of this Research

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Marsay, C.M., J.N. Fitzsimmons, M. Hatta, L.T. Jensen, S.G. John, D. Kadko, W. Landing, N.T. Lanning, P.L. Morton, A. Pasqualini, S. Rauschenberg, R.M. Sherrell, A.M. Shiller, B.S. Twining, L.M. Whitmore, R. Zhang, C.S. Buck "Dissolved and particulate trace elements in late summer Arctic melt ponds" Marine Chemistry, v.204, 2018, p.70.


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 Arctic Ocean lies at the intersection of the Atlantic and Pacific Oceans, providing a direct link between these two ocean basins. In addition, six major rivers from North America and Eurasia supply the surface of the Arctic with large volumes of freshwater. For much of the year, the surface of the Arctic Ocean is covered with a layer of floating sea ice, thick enough to walk on and for organisms -- from microscopic plants to polar bears -- to call home. Ongoing measurements have shown that Arctic ice is melting, shrinking, and thinning, which will endanger the habitats of plants and animals that depend on the ice for survival. We participated in a 75-day research expedition with other chemical and physical oceanographers, focusing our attention on the relationship between microscopic Arctic plants and the nutrients that stimulate their growth and productivity.

Marine plants have many of the same nutritional requirements as terrestrial plants: nitrogen, phosphorus, carbon dioxide, sunlight, and trace concentrations of metals such as iron, zinc, nickel, copper and cobalt that they use to drive biochemical reactions. While terrestrial plants extract much of their metals from the soil, marine plants are often limited by low concentrations of essential metals. These metal concentrations are low due to limited inputs from the land (where they are plentiful) or low solubilities in seawater. The Arctic is unique among the major oceans in that most of the ocean is bordered by coastal shelves that collect material that rinses from the land. Arctic currents resuspend these nutrient-rich sediments and carry them far into the central basin, potentially providing remote regions of the Arctic with precious trace metals to fuel the growth of microorganisms.

We measured metal concentrations in marine particles and individual phytoplankton cells, discovering that chemically 'labile' particulate metal concentrations vary greatly across the Arctic Ocean, by a factor of 10-100. The highest concentrations of particles were found where the Pacific Ocean enters the Arctic over the shallow Bering and Chukchi shelves. There was also a plume of particulate manganese just below the ice near the North Pole. Manganese is an essential nutrient for phytoplankton, but the size and intensity of the plume suggested that marine bacteria or fungus were converting dissolved manganese supplied from rivers into particles in the ocean. These reactive manganese particles then adsorb other metals from the ocean, which aggregate and sink through the water to collect in large quantities on the ocean floor sediments. While the metals 'scavenged' by these manganese particles are not directly being used by marine microorganisms, they are being removed through biological processes.

When we compared the bulk labile metal concentrations against the individual plankton metal contents, we found that the two different analytical approaches produced different results. Of the seven primary metals we studied, only cobalt and copper were similar between the two treatments. This finding suggests that the labile fraction includes a significantly higher amount of metals from non-living sources such as manganese oxides.

The metal contents of Arctic phytoplankton differed from those of the algae that grow within the ice. While the cellular iron fractions were similar, the sea ice algae were found to contain higher relative concentrations of the other trace metals. The higher contents in sea ice algae could indicate a greater demand for these metals, or the algae could simply be storing the metals internally in preparation for possible metal-limiting conditions in the future. Overall, the metal contents of Arctic phytoplankton were most like those of phytoplankton from the North Atlantic Ocean, where phytoplankton were found to contain high iron concentrations and required more zinc than nickel to perform at their biochemical optimum.

In addition to enabling scientific advances, this project helped train several college researchers, local high school students, and post-doctoral researchers in Maine and Florida. Students and researchers attended international science meetings to present their findings. The project strengthened inter-state and international research collaborations and allowed participation by American scientists in worldwide research efforts including GEOTRACES. Several public talks and lectures were given via Bigelow's Cafe Scientifique and FSU's Science Cafe, open house events, and local homeschool cooperatives. These activities advanced public understanding of the scientific process and the environment. Data gathered by the project was also incorporated into college course materials via Bigelow's collaboration with Colby College. Data collected as part of this project are archived and available through the Biological and Chemical Oceanography Data Management Office, US Arctic GEOTRACES project page (https://www.bco-dmo.org/project/638812).


Last Modified: 03/28/2019
Modified by: Benjamin S Twining

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