Effects of initial microbial biomass abundance on respiration during pine litter decomposition

Autor: Sanna Sevanto, Michaeline B. N. Albright, John Dunbar, Deanna Lopez, Jason D. Gans, Andreas Runde, Dominic Woolf
Rok vydání: 2020
Předmět:
0301 basic medicine
Atmospheric Science
Biomass
Abundance (ecology)
DNA extraction
Multidisciplinary
Ecology
Microbiota
Fungal genetics
Eukaryota
04 agricultural and veterinary sciences
Plant litter
Chemistry
Physical Sciences
Medicine
Cycling
Microcosm
Research Article
Ecological Metrics
Science
Mycology
Ecosystems
Carbon Cycle
Greenhouse Gases
03 medical and health sciences
Microbial Ecosystems
Extraction techniques
Genetics
Environmental Chemistry
Fungal Genetics
Ecosystem
Bacteria
Ecology and Environmental Sciences
Chemical Compounds
Organisms
Fungi
Biology and Life Sciences
Soil carbon
Carbon Dioxide
Pinus
Plant Leaves
Research and analysis methods
030104 developmental biology
Agronomy
Atmospheric Chemistry
Earth Sciences
040103 agronomy & agriculture
Litter
0401 agriculture
forestry
and fisheries
Environmental science
Zdroj: PLoS ONE
PLoS ONE, Vol 15, Iss 2, p e0224641 (2020)
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0224641
Popis: Microbial biomass is increasingly used to predict respiration in soil organic carbon (SOC) models. Its increased use combined with the difficulty of accurately measuring this variable points a need to directly assess the importance of microbial biomass abundance for carbon (C) cycling. To test the hypothesis that the initial microbial biomass abundance (i.e. biomass abundance on new plant litter) is a strong driver of plant litter C cycling, we manipulated biomass abundance by 10 and 100-fold dilution and composition using 12 source communities on sterile pine litter and measured respiration in microcosms for 30 days. In the first two days of microbial growth on fresh litter, a 100-fold difference in initial biomass abundance caused an average difference in respiration of nearly 300%, but the effect rapidly declined to less than 30% in 10 days and to 14% in 30 days. Parallel simulations with a soil carbon model, SOMIC 1.0, also predicted a 14% difference over 30 days, consistent with the experimental results. Model simulations predicted convergence of cumulative CO2 to within 10% in three months and within 4% in three years. Rapid microbial growth likely attenuates the effects of large initial differences in biomass abundance. In contrast, the persistence of source community as an explanatory factor in driving differences in respiration across microcosms supports the importance of microbial composition in C cycling. Overall, the results suggest that the initial abundance of microbial biomass on litter is a weak driver of C flux from litter decomposition over long timescales (months to years) when litter communities have equal nutrient availability. By extension, slight variation in the timing of microbial dispersal to fresh litter is likely to be a minor factor in long-term C flux.ImportanceMicrobial biomass is one of the most common microbial parameters used in land carbon (C) cycle models, however, it is notoriously difficult to measure accurately. To understand the consequences of mismeasurement, as well as the broader importance of microbial biomass abundance as a direct driver of ecological phenomena, greater quantitative understanding of the role of microbial biomass abundance in environmental processes is needed. Using microcosms, we manipulated the initial biomass of numerous microbial communities across a 100-fold range and measured effects on CO2 production during plant litter decomposition. We found that the effects of initial biomass abundance on CO2 production was largely attenuated within a week, while the effects of community type remained significant over the course of the experiment. Overall, our results suggest that initial microbial biomass abundance in litter decomposition within an ecosystem is a weak driver of long-term C cycling dynamics.
Databáze: OpenAIRE
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