Microbial metabolic response to throughfall exclusion and feedback on soil carbon dynamics along a tropical forest precipitation gradient
- 1Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.Department of Ecosystem Sciences and Sustainability, Colorado State University, CO, USA.
- 2Department of Life and Environmental Sciences, University of California Merced, CA, USA.
- 3Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- 4Department of Ecosystem Sciences and Sustainability, Colorado State University, CO, USA.
- 5US Army Engineer Research and Development Center, Environmental Laboratory, MS, USA.
- 6River Basin Center, University of Georgia, GA, USA.
- 7Smithsonian Tropical Research Institute, Apartado, 0843-03092, Balboa, Ancon, Panama
Tropical forest soils represent some of Earth's largest stores of soil carbon. Humid and warm conditions promote high primary productivity offsetting high ecosystem respiration rates, and this balance has resulted in significant carbon accumulation in plant biomass and soils. These vast carbon stocks can be destabilized under a changing climate, and model projections predict tropical and subtropical regions will experience disturbance to the hydrological cycle, with an increased likelihood of more frequent and prolonged droughts interspersed with periods of intense precipitation. Herein, we examine the functional response of belowground communities to a reduction in throughfall across a 1 m precipitation gradient (2350 to 3400 mm) spanning three sites from the Caribbean coast to the interior of Panama. At each site, 4 throughfall exclusion plots (10 x 10 m) were established to reduce precipitation, and exacerbate the natural variability in seasonal hydrological cycles. In January 2020, approximately 18 months since the inception of throughfall exclusion, each plot was sampled at six locations and two depths (0-10 and 10-20 cm). To identify the traits and mechanisms involved in responding to drought perturbation, we sequenced the microbiomes of the soil samples from the throughfall exclusion and corresponding controls at each site, and measured metabolite accumulation within the soils. Here we report on the accumulation of distinct metabolites along the precipitation gradient and under throughfall exclusion. We note that constitutive production of compatible solutes increases from the wettest to the driest site, indicative of trait selection due to climate history. However, under throughfall exclusion the gradient end members show a more muted metabolic response than the intermediate site. We discuss these responses with respect specific pathways invoked under drying stress, and soil carbon dynamics.
How to cite: Chacon, S. S., Karaoz, U., Louie, K., Bowen, B., Northen, T., Dietterich, L. H., Cusack, D. F., and Bouskill, N.: Microbial metabolic response to throughfall exclusion and feedback on soil carbon dynamics along a tropical forest precipitation gradient, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9543, https://doi.org/10.5194/egusphere-egu23-9543, 2023.
