Drought impacts on microbial metabolic function along a tropical forest precipitation gradient

Abstract:

The frequency and intensity of environmental fluctuations play an important role in shaping microbial adaptive capacity, and metabolic response to future perturbation. Here we examine the metabolic pathways invoked under drought conditions across a 1 m precipitation gradient 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 by 50 %. In addition, 4 corresponding control plots were also constructed. 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). We hypothesize that microbial communities from the wetter end of the soil gradient (MAP: 3300 mm) will show a more pronounced response to enforced drought conditions, relative to the slightly drier end member (MAP: 2320 mm). 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. Our contribution will discuss how communities adapted to different precipitation regimes respond metabolically to drought conditions, and how these change feedback onto the structure and stability of soil organic matter.