Environmental Controls on the Magnitude of Organic Carbon Burial in Icelandic Fjords

Atmospheric carbon dioxide levels are strongly linked to modern global warming. Over long periods of time (thousands of years or longer), the planet regulates the balance of carbon in the in different components of Earth’s system. The ocean is the largest such component, where fjords store a disproportionately large volume of carbon compared to their total area in the global ocean. In this project, investigators will use a variety of geochemical indicators from three sediment cores, that were previously collected, to improve the understanding of the role that fjords have in the global carbon cycle. Specifically, the team will constrain how much carbon is stored in Icelandic fjords and evaluate how that storage may increase or decrease in a warmer world. The research conducted will benefit the scientific community by providing new data on carbon storage in fjordic systems, which is a critical component of climate change research. Educational and outreach activities will broaden participation in Colorado and Iceland through the GAMES (Girls at the Museum Exploring Science) program and by involving underrepresent undergraduate students in research. This project will also support an early career researcher. Fjord systems capture ~11% of global organic carbon (~18 Mt) in the ocean every year and play a major role in global carbon cycling and atmospheric carbon dioxide levels. While many regions are well studied in terms of fjord carbon storage, Iceland, which has extensive fjord systems, has comparatively limited data. In this project, the investigators will first provide needed quantitative constraint on total sedimentary organic carbon stored in Iceland’s largest fjord system using bulk geochemical proxies and seismic survey datasets. Second, they will reconstruct Holocene variations in organic carbon burial, climate, and redox conditions to decipher the controls on warm period (interglacial) organic carbon burial in Icelandic fjords using lipid biomarker and radiocarbon-dating techniques. These efforts will be critical to account for carbon storage more accurately on Quaternary timescales, better understand coastal carbon cycling, and better constrain predictive carbon cycling models at a global scale in a warmer future world. The modern and paleoclimate approach draws on a wide range of diagnostic geochemical and lipid biomarker sediment proxies and will be conducted through an experienced, international team of long-term collaborators, including native Icelanders. This project is funded by the Marine Geology and Geophysics and the Chemical Oceanography Programs in the Division of Ocean Sciences 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.