Project Funding: 2014 - 2016

NRA: 2013 NASA: Carbon Cycle Science   

Funded by NASA

Abstract:
The West Antarctic Peninsula is experiencing some of the most dramatic climate change on the planet, with rapid ocean-atmosphere warming, melting of coastal glaciers, and reductions in seasonal ice cover. Substantial repercussions are occurring throughout the marine food web from phytoplankton to top predators. Based on satellite ocean color data, phytoplankton blooms have declined in the north and expanded in the south, tracking the sea-ice retreat. Plankton community structure has shifted as well, impacting key biogeochemical processes including net community production and carbon dioxide storage. With more than two decades of observational and process data, the Palmer Long Term Ecological Research (LTER) program (http://pal.lternet.edu/) provides a unique and ongoing resource to assess the ecological and biogeochemical impacts. The research proposed here combines advanced satellite ocean color products from SeaWiFS and MODIS-Aqua, passive microwave radiometer estimates of sea ice extent from SSM/I and SSMIS, and scatterometer wind measurements from SeaWinds with the extensive Palmer LTER field data set to improve our mechanistic understanding of ocean carbon and ecosystem dynamics in Antarctic waters. Both satellite and ship-based data have major limitations in remote polar environments, logistical challenges, harsh weather conditions, persistent cloud cover, low winter light levels; therefore an interdisciplinary effort is required merging complementary data from satellites, ships, and autonomous gliders. Using new syntheses of existing remotely-sensed and in situ data combined with a hierarchy of numerical models, we will test scientific hypotheses developed from observations in the West Antarctic Peninsula ecosystem: - Regional trends in sea-ice cover, freshwater inputs (sea-ice and glacial melt), and wind mixing modulate phytoplankton community structure (large vs. small cells, diatoms vs. flagellates), as well as bloom dynamics, leading to changes in food-web structure, net community production and export flux; - On local scales, glacial melt and upwelling of Circumpolar Deep Water along canyons supply micro-nutrients (e.g., iron) that alter phytoplankton physiology, and drive small-scale blooms and export events; - Positive net community production is enhanced when large-celled phytoplankton are more abundant, leading to increased export and CO2 storage. The opposite is the case when small cells dominate. The Palmer LTER region is an ideal natural laboratory for studying the effects of climate change on polar marine ecology and carbon cycle,with climate-warming impacts that may not begin in other parts of the Antarctic for decades. The relatively low latitude of the Palmer LTER region (64-70 deg. S) also is more accessible to polar-orbiting satellites than most other Antarctic coastal areas, and the information gained from our research will help improve projections of future impacts for the Antarctic shelf as a whole. The proposed research is directly responsive to the NASA Carbon Cycle Science Announcement Theme 1: Carbon Research in Critical Regions (High Latitude Oceans), taking full advantage of NASA satellite observations and suborbital data. The work addresses as well the broader goals of the NASA Earth Science program by connecting together marine ecology and biogeochemistry to better understand net community production and ocean CO2 storage.

Publications:

Bowman, J. S., Kavanaugh, M. T., Doney, S. C., Ducklow, H. W. 2018. Recurrent seascape units identify key ecological processes along the western Antarctic Peninsula. Global Change Biology. 24(7), 3065-3078. DOI: 10.1111/gcb.14161

Doney, S. C., Busch, D. S., Cooley, S. R., Kroeker, K. J. 2020. The Impacts of Ocean Acidification on Marine Ecosystems and Reliant Human Communities. Annual Review of Environment and Resources. 45(1), 83-112. DOI: 10.1146/annurev-environ-012320-083019

Kavanaugh, M., Abdala, F., Ducklow, H., Glover, D., Fraser, W., Martinson, D., Stammerjohn, S., Schofield, O., Doney, S. 2015. Effect of continental shelf canyons on phytoplankton biomass and community composition along the western Antarctic Peninsula. Marine Ecology Progress Series. 524, 11-26. DOI: 10.3354/meps11189

Kim, H. H., Bowman, J. S., Luo, Y., Ducklow, H. W., Schofield, O. M., Steinberg, D. K., Doney, S. C. 2022. Modeling polar marine ecosystem functions guided by bacterial physiological and taxonomic traits. Biogeosciences. 19(1), 117-136. DOI: 10.5194/bg-19-117-2022

Kim, H. H., Luo, Y., Ducklow, H. W., Schofield, O. M., Steinberg, D. K., Doney, S. C. 2021. WAP-1D-VAR v1.0: development and evaluation of a one-dimensional variational data assimilation model for the marine ecosystem along the West Antarctic Peninsula. Geoscientific Model Development. 14(8), 4939-4975. DOI: 10.5194/gmd-14-4939-2021

Kim, H., Ducklow, H. W. 2016. A Decadal (2002-2014) Analysis for Dynamics of Heterotrophic Bacteria in an Antarctic Coastal Ecosystem: Variability and Physical and Biogeochemical Forcings. Frontiers in Marine Science. 3. DOI: 10.3389/fmars.2016.00214

Rohr, T., Long, M. C., Kavanaugh, M. T., Lindsay, K., Doney, S. C. 2017. Variability in the mechanisms controlling Southern Ocean phytoplankton bloom phenology in an ocean model and satellite observations. Global Biogeochemical Cycles. 31(5), 922-940. DOI: 10.1002/2016GB005615

Schofield, O., Saba, G., Coleman, K., Carvalho, F., Couto, N., Ducklow, H., Finkel, Z., Irwin, A., Kahl, A., Miles, T., Montes-Hugo, M., Stammerjohn, S., Waite, N. 2017. Decadal variability in coastal phytoplankton community composition in a changing West Antarctic Peninsula. Deep Sea Research Part I: Oceanographic Research Papers. 124, 42-54. DOI: 10.1016/j.dsr.2017.04.014

2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Local and regional shifts in phytoplankton abundance and community structure along the western Antarctic Peninsula   --   (Maria T Kavanaugh, David M. Glover, Hugh Ducklow, Oscar Schofield, Scott Doney)   [abstract]

More details may be found in the following project profile(s):

• NASA Ocean Biology & Biogeochemistry (OBB) Project Profile