OCE-PRF: The Biogeochemical Importance of Marine Particles: Connecting Production and Export in the Northern Gulf of Alaska

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The biological carbon pump buffers carbon dioxide concentrations in the atmosphere by sequestering organic particles in deep ocean waters. Simultaneously the biological carbon pump supplies food to twilight zone ecosystems as sinking particles are ingested. Although the biological carbon pump consists of many different processes, the focus of the current project is on physical transport of particles and their transformations. Marine particles are primarily formed through biological and physical processes within the ocean’s sun-lit layer. Physical transport can then carry them in to the deep ocean. Even after decades of research, estimates of how much material is transported remains largely unknown. This uncertainty is a challenge to our predictions of how the Earth system is changing. Indeed, Sea Change (2015) identifies “What is the ocean’s role in regulating the carbon cycle?” and how might “the efficiency of carbon export to the deep ocean be better quantified?” as priority science questions for 2015-2025. This study seeks to improve data coverage in a high latitude coastal region while developing modeling tools to improve our local estimates and understanding of ecological and physical processes with respect to particle production, transport, and decay.While global and regional carbon budgets have been developed and refined over more than 5 decards of research, disagreement between these synthesis (+/- 50%) continues to be a source of frustration and research within the broader oceanographic community. To reduce uncertainty in current estimates of the biological carbon pump within a high latitude coastal biome, we propose to investigate the mechanistic relationships between marine nutrient uptake, particle production, and export processes through a combination of field work (3 cruises yr-1), data analysis, and cross-site collaboration. The core of this effort will involve the collection and integration of new datasets, including (1) standing stocks and tracers: biogenic silica, (2) productivity: silica production and nutrient uptake, and (3) export: carbon, nitrogen, biogenic silica, trace elements, and isotopes, with synthesis via Lagrangian tracer simulations, linear inverse ecosystem modeling, and biogeochemical parameter estimation. The geographical focus of this work will be in the Northern Gulf of Alaska where physical circulation and strong seasonality drive high variability in ecosystem processes in a region important for commercial and subsistence fisheries. Finally, efforts to standardize methods and collaborate across NSF Long Term Ecological Research sites will help to develop datasets and inter-comparisons of coastal export production.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.