Table of Contents

• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Ra-224, Ra-223, Th-228, and Ra-228 activity in ground, lake, river, and coastal ocean water of Alaska

Sampling and Analytical Methodology:
Discrete seawater, groundwater, lake, and river water samples were collected from Kasitsna Bay and Toolik Lake in August 2011 and July 2012 and the Beaufort Sea August 2012. Groundwater samples were collected in all locations from freshly dug pits or temporary PVC well points of variable depth depending on the depth of the water table. All water samples were collected by submersible pump. Sample water was passed through a plastic column containing manganese dioxide impregnated acrylic fiber at a rate of <2 L/min for collection of Ra isotopes (Moore 2008). Samples were shipped to the University of California Santa Cruz for Analysis on a Radium Delayed Coincidence Counter (RaDeCC) for measurement of Ra-223 and Ra-224 activities within less than 5 days (Moore and Arnold 1996). The fibers were analyzed on the RadeCC again 3-5 weeks after collection to correct for Th-228 supported Ra-224, and one year after collection for Ra-228 (Moore 2008; Young et al. 2008). Standards were run on a monthly basis as part of the quality control for maintenance of the instrument and analytical errors calculated using established methods and were less than 10% (Garcia-Solsona et al. 2008).

Parameter names, definitions and units:
Latitude and longitude are in decimal degrees. Site refers to whether samples were collected on the Pacific Coast (Kastisna), Arctic Coast (Barrow), or tundra lake (Toolik). Activity of Ra-224, Ra-223, Th-228, and Ra-228 are in disintegrations per minute per 100L of water (dpm/100L).

Data Processing:
Data were converted from decays per minute measured by the RaDeCC to dpm/100L of water by standard calculation methods (Moore and Arnold 1996, Moore 2008).

BCO-DMO Processing Notes
- Generated from original file "AK Radium Data.xlsx"  contributed by Alanna Lecher
- Parameter names edited to conform to BCO-DMO naming convention found at Choosing Parameter Name
- Longitude values converted to negative for West Longitude
- "nd" (no data) inserted into blank cells
- "#N/A" replaced with "nd" (no data)
- Date reformatted to YYYYMMDD
- Data version 12 Jun 2017 is an update of data version 14 Apr 2016.  Bad lat 59..44807 changed to 59.44807.

Extracted from the NSF award abstract:
The major objective of this proof of concept study is to evaluate the contribution of Subterranean Groundwater Discharge (SGD) in the Arctic to the global methane budget. Methane is a potent greenhouse gas and large natural reservoirs exist in Arctic soils and permafrost. The working hypothesis is that methane released from thawing permafrost in the Arctic is transported via groundwater flow (above and below the permafrost layer) and enters the atmosphere via coastal waters and lakes. This source of methane may be realized as an important source of natural methane to the atmosphere and may provide a positive feedback to global warming.

The objectives of the study are:

1) To estimate the magnitude of subterranean groundwater discharge and associated methane flux into lakes and coastal waters in Alaska at three representative sites.

2) To evaluate methane evasion rates from the water column to the atmosphere.

3) To determine if the contribution of methane input from subterranean groundwater discharge to the global methane budget is significant, and if so

4) To use the preliminary data to design a more through research plan that will enable precise estimates of fluxes and provide a basis for global extrapolation of results such that the contribution of this source to current and future climate changes and the global methane budget will be possible.

The project will support a graduate student full time for two years. Undergraduate students in the ACCESS program and the California Alliance for Minority Participation in Science, Engineering and Mathematics program at UCSC will also participate in the proposed work. The PIs will work with COSEE Alaska to ntegrate this work in their outreach and education activities including teacher workshops, symposia, and work with local communities in Alaska.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
Note:  When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

Ms. Alanna Lecher , Dr. Natasha Dimova , Ms. Katy Sparrow , Dr. Fenix Garcia-Tigreros , Mr. Joseph Murray , Dr. Slawek Tulaczyk , Dr. John Kessler. "Groundwater Discharge a Conduit for Methane Emissions in the Arctic," Nature Geoscience, 2015.