| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | September 5, 2017 |
| Latest Amendment Date: | September 5, 2017 |
| Award Number: | 1726177 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Russell Kelz
EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2017 |
| End Date: | August 31, 2018 (Estimated) |
| Total Intended Award Amount: | $50,277.00 |
| Total Awarded Amount to Date: | $50,277.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
11066 AUKE LAKE WAY JUNEAU AK US 99801-8623 (907)796-6494 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
AK US 99801-8916 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Major Research Instrumentation |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
EAR-1726177
Fellman
This grant supports acquisition of a dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) analyzer that will be located in a lab shared by the USFS Pacific Northwest Research Station and the University of Alaska Southeast. Acquisition of this instrument will provide the infrastructure necessary to quantify DOC fluxes from watersheds of varying glacial coverage, thus creating a space-for-time substitution to determine how climate-glacier interactions are driving ecological change in the region. The DOC/TDN analyzer will replace an aging, non-functional instrument that is located off campus and is owned by the USFS. Acquisition of this instrument will allow the investigators to reinvigorate stream biogeochemistry research efforts aimed at understanding the biophysical impacts of glacial change on coastal watersheds in southeast Alaska, facilitate access to the instrument by outside users, and enhance undergraduate training. In particular, the instrument will strengthen the research training opportunities for undergraduates in Environmental Science as well as provide the opportunity to recruit and train members of two groups (rural and Alaska Native students) that are traditionally highly under-represented in the Environmental Sciences.
The DOC/TDN analyzer allows for rapid and precise measurement of concentrations of DOC and TDN. Research applications include: 1) determining how climatically-driven changes in snow/rainfall regimes that influence the timing and magnitude of glacial runoff are driving stream water DOC and nutrient fluxes in the region, 2) quantifying the relationship between disinfection byproduct formation, DOC concentrations and precipitation event size in watersheds that currently or may provide drinking water in rural watersheds, 3) testing the use of DOC as a proxy for methylmercury concentrations in forested and wetland-dominated watersheds, and 4) determining how seasonal changes in the movement of water from soils to streams controls the production, speciation and timing of lateral carbon export from forested ecosystems.
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.
Research activities:
We used this award to purchase a Shimadzu TOC/TN analyzer and installed it in a laboratory shared by the University of Alaska Southeast (UAS) and the USFS Pacific Northwest Research Station (USFS-PNW). The TOC/TN analyzer was installed and tested during November of 2017 to ensure that the instrument would be running smoothly before the 2018 field season. During 2018, we used the instrument to continue our proglacial stream sampling as well as expanded our research efforts by analyzing water from a wide range of projects and environments.
1) We continued our long-term sampling of seven streams that border the Juneau Icefield to determine how the ongoing loss of glaciers impacts the biogeochemical trajectory of proglacial streams. Streamwater was collected bi-weekly to monthly throughout 2018 for physical properties (temperature, turbidity, conductivity) and concentrations of dissolved organic carbon (DOC), N and P.
2) Streamwater was collected seasonally for DOC from glaciated Herbert River to trace the incorporation of glacial organic carbon into contemporary river food webs.
3) We intensively sampled a storm in mid-August from 3 headwater streams draining a forested wetland, poor fen and upland forest to determine how shifting sources of streamwater control concentrations of DOC and carbon dioxide (CO2).
4) Streamwater was collected for DOC opportunistically throughout 2018 from 8 watersheds of varying watershed wetland coverage to test the hypothesis that the expected increases in the frequency and magnitude of storms will result in enhanced fluxes of DOC, and in turn, increase mercury export to marine ecosystems.
5) Soil and streamwater were collected for DOC and molecular properties from three common landscape types (poor fen, forested wetland and upland forest) in southeast Alaska. Our goal was to evaluate how terrestrial-derived organic matter is produced and cycled from its source in soil waters to headwater streams and eventually the watershed outlet stream.
6) To evaluate whether tree-DOC delivered terrestrial ecosystems is greater than DOC export through streams, stemflow and throughfall from spruce and hemlock trees and streamwater were collected simultaneously during 5 storms over the course of 2018.
Training and education activities:
In addition to the PIs on the grant, two graduate students (Matt Dunkle of University of Idaho and Megan Behnke of Florida State University), two undergraduate students (Mollie Dwyer and Conner Johnson of UAS) and two research assistants (Emily Whitney of UAS and Mark Lukey of USFS-PNW) received training on the instrument and used it in research projects associated with the group of PIs. Matt Dunkle is a NSF-funded (IGERT) PhD student studying how stream biogeochemical (C, N and P) and physical (temperature, turbidity) properties impact the structure and dynamics of food webs in glacial, snowmelt and rainfall streams in southeast Alaska. Megan Behnke is a NSF-funded (GRFP) PhD student studying how DOC concentration and molecular properties change from their source in soil waters to the watershed outlet stream. Connor Johnson and Mollie Dwyer are UAS undergraduate students conducting research on how changes in the main sources of water (glacial, snow and rainfall) impact the physical (temperature, conductivity and turbidity) and biogeochemical properties (C, N and P) of southeast Alaskan streams. In the summer of 2019, we plan to train more undergraduate students to use the instrument.
Outreach Activities:
Our main outreach activity has been to develop external collaborations with other researchers who are interested in analyzing DOC concentrations. We are currently using the DOC/TN analyzer in projects with the USFS-PNW in Juneau, University of Idaho and Florida State University. We also just started an NSF-funded (EPSCoR) project with the University of Alaska Anchorage where we will analyze DOC from proglacial streams around the Gulf of Alaska. PI Hood presented data from the DOC analyzer at a training session for USFS interpreters at the Mendenhall Glacier Visitor Center in April, 2018. PI Bidlack included data from the analyzer in her Evening at Egan Lecture (University of Alaska Southeast) in October, 2018.
Major findings:
1) High resolution storm sampling of a forested watershed near Juneau showed that DOC increases with discharge while dissolved CO2 is negatively correlated with flow (Fig. 1). This is likely because saturated soils during storms direct precipitation through C-rich surface horizons, which entrains DOC as well as decreases soil water residence times (decrease potential DOC mineralization). However, decreased soil water residence times will reduce the buildup of CO2 in soil waters (from soil respiration) leading to decreasing CO2 concentrations and increasing DOC:CO2 as discharge peaks.
2) All throughfall and stemflow were highly enriched in DOC relative to streamwater (Fig. 2), suggesting tree-DOC provides substantial DOC yields to the forest floor and potentially to surface water over short time periods (storms). Stemflow DOC concentrations were greater than throughfall across both tree species, yet larger throughfall water yields produced greater DOC yields relative to stemflow.
Last Modified: 11/20/2018
Modified by: Jason B Fellman
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