Collaborative Research: RAPID: Quantifying and characterizing the origin of Arctic Ocean methane from the Alaska continental shelf to the North Pole

University Of Maryland, College Park, College Park MD

Investigators

Abstract

Methane is relatively rare in Earth’s atmosphere but plays a significant role in the global carbon cycle and climate change. It is therefore key to better understand the distribution and behavior of natural sources of methane emissions and how both may change in an evolving climate. In the Arctic, large reservoirs of methane are currently trapped as permafrost (frozen soil) or gas hydrates (an ice-like substance that contains methane in its structure) on Arctic Ocean continental shelves. As the Arctic warms, permafrost and gas hydrates may degrade, releasing more methane to the atmosphere. This project, part of the United States’ contribution to the international Synoptic Arctic Survey (SAS), is determining whether rates of Arctic methane release from those natural sources are being affected by the present warming by measuring methane in Arctic Ocean from northern Alaska to the North Pole. The team is focusing especially on how much methane released from the seafloor reaches the water surface and adds to atmospheric methane. The team is sharing methane data and other results with the larger US SAS effort and teaching community college students about seagoing research methods and climate change. This project is testing the hypothesis that a warming Arctic Ocean may have accelerated the release of methane from permafrost and gas hydrate dissociation in shelf and slope sediments. The research team is measuring water column dissolved methane concentrations and stable isotopologues, as well as continuous measurements of methane in air underway along a transect from the Alaska Shelf northward. The team members are investigating the sources and processes controlling the presence of methane using methane 13C and 2H stable isotopes. Clumped isotopes of methane in air are being analyzed on selected samples identified as possible methane endmembers in the Arctic system. The project is a US contribution to the international Synoptic Arctic Survey (SAS) and is providing a baseline for measurements in the future of Arctic conditions. The measurement of the stable isotope 2H-CH4 in the Arctic Basin is the first performed in deep Arctic waters and is greatly improving our understanding of the Arctic methane cycle. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.