Editorial: The Role of Priming in Terrestrial and Aquatic Ecosystems

Journal Article · 03 December 2019 · Frontiers in Earth Science

DOI: https://doi.org/10.3389/feart.2019.00321 · OSTI ID:1582411

Bianchi, Thomas S. ^[1]; Ward, Nicholas D.  ^[2]

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1. Univ. of Florida, Gainesville, FL (United States)
2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Univ. of Washington, Seattle, WA (United States)

Carbon-containing organic matter (OM) is constantly synthesized from atmospheric carbon dioxide (CO₂) by primary producing flora in Earth’s biosphere. The fate of this OM—i.e., how long it persists in the environment before being recycled back to atmospheric CO₂ by heterotrophic microbes and fauna—is highly variable, and largely dependent on the diversity of environmental conditions it is exposed to both at its origin and during transport to distant locations. This dynamic cycling of carbon, energy, and matter between the atmosphere and biosphere occurs within and across all types of terrestrial, aquatic, and marine ecosystems. While the underlying biological functions and chemical reactions related to carbon fixation and decomposition are generally common across ecosystems, the disciplines of terrestrial and aquatic biogeochemistry have historically pursued this topic along separate paths with differing strengths and weaknesses. Although this continues today, several focus areas have recently brought more cross-fertilization between these disciplines. One such focus area where terrestrial and aquatic communities have begun converging is the study of interactive effects on OM decomposition that occur when OM of different origins and reactivities mix. This line of research has embraced the necessity to consider reactivity within the context of the past history and present state of OM in all of its highly diverse forms. Interactive effects on OM cycling were first explored about 100 years ago in the context of soil humus mineralization and have since been termed priming effects. Priming can be defined as the enhancement of recalcitrant (stable) OM breakdown via microbial decay with the addition of a more labile (less-stable) OM source. Priming can involve dissolved and/or particulate OM, in some cases accompanied by nutrients, and results in more efficient decay/consumption of stable OM material than would have occurred otherwise in the absence of the less-stable OM. While much of the work on this topic began in terrestrial systems, aquatic researchers have followed suit and gained momentum in the last decade. Observations of priming in aquatic environments are becoming more widespread, but little consensus has been reached on their role, perhaps because we lack the mechanistic understanding to accurately predict when and where priming effects should occur. The motivation for the collection of studies summarized below is to progress towards a common language, set of experimental approaches, and perspective on the role of priming effects in both terrestrial and aquatic ecosystems.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
• Grant/Contract Number: AC05-76RL01830; SC0019382
• OSTI ID: 1582411
• Report Number(s): PNNL-SA--148208
• Journal Information: Frontiers in Earth Science, Journal Name: Frontiers in Earth Science Vol. 7; ISSN 2296-6463
• Publisher: Frontiers Research FoundationCopyright Statement
• Country of Publication: United States
• Language: English