Potential microbial bioindicators of phosphorus mining in a temperate deciduous forest.

AIMS: The soil microbial community plays a critical role in increasing phosphorus (P) availability in low-P, weathered soils by "mining" recalcitrant organic P through the production of phosphatase enzymes. However, there is a lack of data on the fungal and bacterial taxa which are directly involved in P mining, which could also serve as potential microbial bioindicators of low P availability. METHODS AND RESULTS: Leveraging a 5-year P enrichment experiment on low-P forest soils, high-throughput sequencing was used to profile the microbial community to determine which taxa associate closely with P availability. We hypothesized that there would be a specialized group of soil micro-organisms that could access recalcitrant P and whose presence could serve as a bioindicator of P mining. Community profiling revealed several candidate bioindicators of P mining (Russulales, Acidobacteria Subgroup 2, Acidobacteriales, Obscuribacterales and Solibacterales), whose relative abundance declined with elevated P and had a significant, positive association with phosphatase production. In addition, we identified candidate bioindicators of high P availability (Mytilinidales, Sebacinales, Chitinophagales, Cytophagales, Saccharimonadales, Opitulales and Gemmatales). CONCLUSIONS: This research provides evidence that mitigating P limitation in this ecosystem may be a specialized trait and is mediated by a few microbial taxa. SIGNIFICANCE AND IMPACT OF THE STUDY: Here, we characterize Orders of soil microbes associated with manipulated phosphorus availability in forest soils to determine bioindicator candidates for phosphorus. Likewise, we provide evidence that the microbial trait to utilize recalcitrant organic forms of P (e.g. P mining) is likely a specialized trait and not common to all members of the soil microbial community. This work further elucidates the role that a complex microbial community plays in the cycling of P in low-P soils, and provides evidence for future studies on microbial linkages to human-induced ecosystem changes.

From low to high gear: there has been a paradigm shift in our understanding of evolution.

Experimental studies of evolution performed in nature and the associated demonstration of rapid evolution, observable on a time scale of months to years, were an acclaimed novelty in the 1980-1990s. Contemporary evolution is now considered ordinary and is an integrated feature of many areas of research. This shift from extraordinary to ordinary reflects a change in the perception of evolution. It was formerly thought of as a historical process, perceived through the footprints left in the fossil record or living organisms. It is now seen as a contemporary process that acts in real time. Here we review how this shift occurred and its consequences for fields as diverse as wildlife management, conservation biology, and ecosystems ecology. Incorporating contemporary evolution in these fields has caused old questions to be recast, changed the answers, caused new and previously inconceivable questions to be addressed, and inspired the development of new subdisciplines. We argue further that the potential of contemporary evolution has yet to be fulfilled. Incorporating evolutionary dynamics in any research program can provide a better assessment of how and why organisms and communities came to be as they are than is attainable without an explicit treatment of these dynamics.