USAP-DC

Rapid changes in the extent and thickness of sea ice during the austral spring subject microorganisms within or attached to the ice to large fluctuations in temperature, salinity, light and nutrients. This project aims to identify cellular responses in sea-ice algae to increasing temperature and decreasing salinity during the spring melt along the western Antarctic Peninsula and to determine how associated changes at the cellular level can potentially affect dynamic, biologically driven processes. Understanding how sea-ice algae cope with, and are adapted to, their environment will not only help predict how polar ecosystems may change as the extent and thickness of sea ice change, but will also provide a better understanding of the widespread success of photosynthetic life on Earth. The scientific context and resulting advances from the research will be communicated to the general public through outreach activities that includes work with Science Communication Fellows and the popular Polar Science Weekend at the Pacific Science Center in Seattle, Washington. The project will provide student training to college students as well as provide for educational experiences for K-12 school children. There is currently a poor understanding of feedback relationships that exist between the rapidly changing environment in the western Antarctic Peninsula region and sea-ice algal production. The large shifts in temperature and salinity that algae experience during the spring melt affect critical cellular processes, including rates of enzyme-catalyzed reactions involved in photosynthesis and respiration, and the production of stress-protective compounds. These changes in cellular processes are poorly constrained but can be large and may have impacts on local ecosystem productivity and biogeochemical cycles. In particular, this study will focus on the thermal sensitivity of enzymes and the cycling of compatible solutes and exopolymers used for halo- and cryo-protection, and how they influence primary production and the biogeochemical cycling of carbon and nitrogen. Approaches will include field sampling during spring melt, incubation experiments of natural sea-ice communities under variable temperature and salinity conditions, and controlled manipulation of sea-ice algal species in laboratory culture. Employment of a range of techniques, from fast repetition rate fluorometry and gross and net photosynthetic measurements to metabolomics and enzyme kinetics, will tease apart the mechanistic effects of temperature and salinity on cell metabolism and primary production with the goal of quantifying how these changes will impact biogeochemical processes along the western Antarctic Peninsula. 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.

Person	Role
Young, Jodi	Investigator and contact
Deming, Jody	Co-Investigator

Antarctic Organisms and Ecosystems

Award # 1744645

USAP-1744645_1

Deployment	Type
B234N	ship expedition
B234P	general deployment

young_Data_management_Plan.pdf

Repository	Title (link)	Format(s)	Status
Metabolomics workbench	Sea-ice diatom compatible solute shifts	ASCII; JSON	exist
BCO-DMO	Dataset: Particulate Organic Carbon and Particulate Nitrogen	CSV	exist
BCO-DMO	Dataset: Photosynthetic Pigments	CSV	exist
BCO-DMO	Dataset: Physical Profiles of Temperature, Salinity, and Brine Volume	CSV	exist

1. Young, J. N., & Schmidt, K. (2020). It’s what’s inside that matters: physiological adaptations of high‐latitude marine microalgae to environmental change. New Phytologist. (doi:10.1111/nph.16648)
2. Dawson, H. M., Heal, K. R., Torstensson, A., Carlson, L. T., Ingalls, A. E., & Young, J. N. (2020). Large Diversity in Nitrogen- and Sulfur-Containing Compatible Solute Profiles in Polar and Temperate Diatoms. Integrative and Comparative Biology, 60(6), 1401–1413. (doi:10.1093/icb/icaa133)
3. Dawson, H.M., Boysen, A., Heal, K.R., Carlson, L., Ingalls, A., Young, J.N. (2020) Potential of temperature and salinity-driven shifts in diatom compatible solute concentrations to impact biogeochemical cycling within sea ice. Elementa Science of the Anthropocene (doi:10.1525/elementa.421)
4. Li, M., Young, J.N. (2022) Extracellular Carbonic Anhydrase Supports Constitutive HCO3− Uptake in Fragilariopsis cylindrus Regardless of Temperature Changes. bioRvix preprint (doi:https://biorxiv.org/cgi/content/short/2022.09.08.507187v1)
5. Torstensson, Anders and Young, Jodi N. and Carlson, Laura T. and Ingalls, Anitra E. and Deming, Jody W. and Valentin, K.. (2019). Use of exogenous glycine betaine and its precursor choline as osmoprotectants in Antarctic sea‐ice diatoms. Journal of Phycology. 55 (3) 663 to 675 (doi: 10.1111/jpy.12839)
6. Li, Meng and Young, Jodi N.. (2023). Temperature sensitivity of carbon concentrating mechanisms in the diatom Phaeodactylum tricornutum. Photosynthesis Research. 156 (2) (doi:10.1007/s11120-023-01004-2)
7. Dawson, H. M. and Connors, E. and Erazo, N. G. and Sacks, J. S. and Mierzejewski, V. and Rundell, S. M. and Carlson, L. T. and Deming, J. W. and Ingalls, A. E. and Bowman, J. S. and Young, J. N.. (2023). Microbial metabolomic responses to changes in temperature and salinity along the western Antarctic Peninsula. The ISME Journal. 17 (11) (doi:10.1038/s41396-023-01475-0)