USAP-DC

Responses of the carbon balance of terrestrial ecosystems to warming will feed back to the pace of climate change, but the size and direction of this feedback are poorly constrained. Least known are the effects of warming on carbon losses from soil, and clarifying the major microbial controls is an important research frontier. This study uses a series of experiments and observations to investigate microbial, including autotrophic taxa, and plant controls of net ecosystem productivity in response to warming in intact ecosystems. Field warming is achieved using open-top chambers paired with control plots, arrayed along a productivity gradient. Along this gradient incoming and outgoing carbon fluxes will be measured at the ecosystem-level. The goal is to tie warming-induced shifts in net ecosystem carbon balance to warming effects on soil microbes and plants. The field study will be supplemented with lab temperature incubations. Because soil microbes dominate biogeochemical cycles in Antarctica, a major focus of this study is to determine warming responses of bacteria, fungi and archaea. This is achieved using a cutting-edge stable isotope technique, quantitative stable isotope probing (qSIP) developed by the proposing research team, that can identify the taxa that are active and involved in processing new carbon. This technique can identify individual microbial taxa that are actively participating in biogeochemical cycling of nutrients (through combined use of 18O-water and 13C-bicarbonate) and thus can be distinguished from those that are simply present (cold-preserved). The study further assesses photosynthetic uptake of carbon by the vegetation and their sensitivity to warming. Results will advance research in climate change, plant and soil microbial ecology, and ecosystem modeling.

Person	Role
van Gestel, Natasja	Investigator and contact
Hungate, Bruce A.
Dijkstra, Paul

Antarctic Integrated System Science	Award # 1947562
Antarctic Earth Sciences	Award # 1643871
Antarctic Organisms and Ecosystems	Award # 1643871

USAP-1947562_1

None in the Database

1. Purcell, A. M., Dijkstra, P., Hungate, B. A., McMillen, K., Schwartz, E., & van Gestel, N. (2023). Rapid growth rate responses of terrestrial bacteria to field warming on the Antarctic Peninsula. The ISME Journal, 17(12), 2290–2302. (doi:10.1038/s41396-023-01536-4)