Linking Microbial and Ecosystem Ecology Using Ecological Stoichiometry: A Synthesis of Conceptual and Empirical Approaches

Abstract

Currently, one of the biggest challenges in microbial and ecosystem ecology is to develop conceptual models that organize the growing body of information on environmental microbiology into a clear mechanistic framework with a direct link to ecosystem processes. Doing so will enable development of testable hypotheses to better direct future research and increase understanding of key constraints on biogeochemical networks. Although the understanding of phenotypic and genotypic diversity of microorganisms in the environment is rapidly accumulating, how controls on microbial physiology ultimately affect biogeochemical fluxes remains poorly understood. We propose that insight into constraints on biogeochemical cycles can be achieved by a more rigorous evaluation of microbial community biomass composition within the context of ecological stoichiometry. Multiple recent studies have pointed to microbial biomass stoichiometry as an important determinant of when microorganisms retain or recycle mineral nutrients. We identify the relevant cellular components that most likely drive changes in microbial biomass stoichiometry by defining a conceptual model rooted in ecological stoichiometry. More importantly, we show how X-ray microanalysis (XRMA), nanoscale secondary ion mass spectroscopy (NanoSIMS), Raman microspectroscopy, and in situ hybridization techniques (for example, FISH) can be applied in concert to allow for direct empirical evaluation of the proposed conceptual framework. This approach links an important piece of the ecological literature, ecological stoichiometry, with the molecular front of the microbial revolution, in an attempt to provide new insight into how microbial physiology could constrain ecosystem processes.

The phosphorus release pathways and their mechanisms driven by organic carbon and nitrogen in sediments of eutrophic shallow lakes

“…The growth of different organism need specific nutrient ratio, such as 108C:16N:1P for algae (Falkowski, 2010), 60C:7N:1P for bacteria (Cleveland and Liptzin, 2007;Hill et al, 2006). Departures from these ratios suggest that an organism's metabolism and growth will be limited by the element presented in limiting concentrations (Sinsabaugh et al, 2009;Hall et al, 2011). In this case, the excess input of organic carbon and nitrogen as well as strong P demand for organisms' growth (especially phytoplankton) inevitably caused the relative phosphorus deficiency, urging the microbes or phytoplankton to produce alkaline phosphatase to hydrolyze organic phosphorus to satisfy their P demand.…”

Linking community size structure and ecosystem functioning using metabolic theory

“…Understanding and quantifying the mechanisms that link the structure of biotic communities to the flux, storage and turnover of energy and elements in ecosystems is among the greatest challenges in ecology [18,20,31,43]. Here we have addressed this issue by analysing experimental mesocosm data using a mechanistic model of the carbon cycle that yields quantitative predictions by scaling metabolism from individuals to ecosystems [24,27].…”

Understanding How Microbiomes Influence The Systems They Inhabit: Moving From A Correlative To A Causal Research Framework

“…The potential to couple EDS analysis with a phylogenetic label presents the 452 opportunity to assay mixed microbial communities and assess the link between 453 phylogenetic identity and biomass stoichiometry under natural conditions 53 . Thus, 454 community biomass stoichiometry can potentially be deconstructed into the biomass 455 stoichiometry of its constituent taxa 53 .…”

“…Thus, 454 community biomass stoichiometry can potentially be deconstructed into the biomass 455 stoichiometry of its constituent taxa 53 . This approach would provide a direct link 456 between community membership and a community property (e.g., biomass C:N, 457 Figure 2, Letter E), that influences an important microbial process (i.e.…”