Arctic Field Projects



Project Title: Neglected fluxes: Understanding the evolution of weathering as continental ice sheets retreat (Award# 1603452)

PI: Martin, Ellen Eckels (eemartin@ufl.edu)
Phone: (352) 392.2141 
Institute/Department: U of Florida, Department of Geological Sciences 
IPY Project?
Funding Agency: US\Federal\NSF\GEO\OPP\ARC\ANS
Program Manager: Dr. Marc Stieglitz (mstiegli@nsf.gov )
Discipline(s): | Geological Sciences\Hydrogeochemistry | Geological Sciences\Weathering |

Project Web Site(s):
Data: http://www.ncdc.noaa.gov/
NSF_Award_Info: http://www.nsf.gov/awardsearch/showAward?AWD_ID=16...

Science Summary:
The Greenland Ice Sheet is the largest remaining continental ice sheet in the northern hemisphere. Past and future arctic warming leads to ice sheet retreat and alters the fundamental nature of weathering and the delivery of nutrients and elements to the ocean. The proposed work is focused on the hydrological, biological, biogeochemical, and isotopic signatures of proglacial watersheds, which are watershed that convey dilute but high volume glacial meltwater from the top and underneath the ice sheet to the ocean, and deglaciated watersheds, which are watersheds that are no longer physically connected to the ice sheet and sourced only by annual precipitation and permafrost melt. Although deglaciated watersheds have received less attention, preliminary work suggests they may be equally or more important than proglacial watersheds for oceanic and atmospheric fluxes. Moreover, as ice sheets melt, the area contributing to meltwater and constituent fluxes will increasingly be from deglaciated watersheds. The understanding gained from this work will provide a context for the prediction of future land-ocean and land-atmosphere fluxes in response to continued ice sheet retreat. This project therefore addresses the question of how mineral weathering reactions impact atmospheric CO2 and oceanic nutrient and isotope delivery across proglacial and deglacial watersheds in three environmentally distinct regions of Greenland. Results of the project have the potential to change our understanding of global CO2, nutrient, and isotope cycling in response to ice sheet collapse and permit predictions of future responses to global warming and ice sheet retreat. Results will also provide a context to interpret past high latitude ice sheet retreat and climate change based on marine isotope records. The project includes training for undergraduate, graduate, and postdoctoral researchers, as well as a collaboration with students and faculty at a Greenlandic academic institution. This study will test the hypotheses that (1) deglacial and proglacial watersheds contribute distinct elemental, isotopic, and nutrient fluxes to the ocean and atmosphere as a result of evolving weathering patterns, and (2) these reactions and associated fluxes will change within and between watersheds as the Greenland Ice Sheet retreats. The project focuses on three field areas: deglacial and proglacial watersheds near Kangerlussuaq and Narsasuaq and a deglacial watershed near Sisimiut. Each area has a distinct water balance, exposure age, and weathering characteristics, and will be sampled three times over two melt seasons to evaluate intra-seasonal and inter-annual variations. Mass balance models and PHREEQc modeling of solute data will be used to identify and assess extents of weathering reactions. Weathering extents will also be estimated based on trends in proportional contributions of minerals and offsets between dissolved and bedload strontium and lead isotope ratios, and will be linked to phosphorous fluxes and organic carbon lability and degradation. This holistic approach will provide a broad view of the relative elemental, nutrient and isotopic fluxes in proglacial and deglacial environments. These results will provide magnitudes, time scales, and drivers of weathering reactions, with a goal of linking fluxes to past records and future predictions of global climate change associated with continental ice sheet collapse.

Logistics Summary:
Researchers on this project will study two proglacial watersheds (the Watson River near Kangerlussuaq and the system draining Kiagtût Sermiat Narsarsuaq) and four deglaciated watershed (Lake Helen near Kangerlussuaq, Qôrnup Qua and a small unnamed watershed designated “1kywatershed” near Narsarsuaq, and a watershed outside of Sisimiut). They will set up discharge gauging stations on all four deglaciated watersheds as well as the proglacial system in Narsarsuaq, and collect and analyze water, sediment and bedrock samples from all six watersheds. They will also meet with and establish a scientific exchange with researchers at ARTEK in Sisimiut. Fieldwork consists of two, 5-person deployments in 2017, a 2-person deployment in April 2018, and one final 5-person deployment in summer 2018. The group will spend approximately ten days at each of the three field sites per deployment. Samples will be analyzed both in the field and returned to the researchers’ home institution for further analysis.

CPS will provide Air National Guard coordination for passengers/freight, KISS user days, truck use in Kangerlussuaq and rental truck in Sisimiut and Narsarsuaq, intra-Greenland commercial ticketing/freight, lodging in Nuuk for travel days, helicopter charters out of Narsarsuaq, lodging in Sisimiut & Narsarsuaq, and camp/safety and communications equipment from CPS inventory. All other support will be paid for by the PI from the grant.
SeasonField SiteDate InDate Out#People
2017Greenland - Kangerlussuaq05 / 15 / 2017 09 / 19 / 20177
2017Greenland - Narsarsuaq06 / 10 / 2017 09 / 12 / 20177
2017Greenland - Qôrnup Qua 06 / 12 / 2017 09 / 09 / 20177
2017Greenland - Sisimiut05 / 29 / 2017 08 / 29 / 20177
2018Greenland - Kangerlussuaq04 / 24 / 2018 08 / 15 / 20187
2018Greenland - Narsarsuaq04 / 25 / 2018 08 / 07 / 20185
2018Greenland - Nuuk07 / 24 / 2018 07 / 27 / 20185
2018Greenland - Qôrnup Qua 07 / 27 / 2018 08 / 07 / 20185
2018Greenland - Sisimiut04 / 28 / 2018 07 / 13 / 20186
 


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