Project description:Microbes are responsible for cycling carbon (C) through soils, and predicted changes in soil C stocks under climate change are highly sensitive to shifts in the mechanisms assumed to control the microbial physiological response to warming. Two mecha-nisms have been suggested to explain the long-term warming impact on microbial physiology: microbial thermal acclimation and changes in the quantity and quality of substrates available for microbial metabolism. Yet studies disentangling these two mechanisms are lacking. To resolve the drivers of changes in microbial physiology in response to long-term warming, we sampled soils from 13- and 28-year- old soil warming experiments in different seasons. We performed short-term laboratory incubations across a range of temperatures to measure the relationships between temperature sensitivity of physiology (growth, respiration, carbon use efficiency, and extracellular enzyme activity) and the chemical composition of soil organic matter. We observed apparent thermal acclimation of microbial respiration, but only in sum-mer, when warming had exacerbated the seasonally-induced, already small dissolved organic matter pools. Irrespective of warming, greater quantity and quality of soil carbon increased the extracellular enzymatic pool and its temperature sensitivity. We propose that fresh litter input into the system seasonally cancels apparent thermal acclimation of C-cycling processes to decadal warming. Our findings reveal that long-term warming has indirectly affected microbial physiology via reduced C availability in this system, implying that earth system models including these negative feedbacks may be best suited to describe long-term warming effects on these soils. Citation: Domeignoz-Horta LA, Pold G, Erb H, Sebag D, Verrecchia E, Northen T, Louie K, Eloe-Fadrosh E, Pennacchio C, Knorr MA, Frey SD, Melillo JM, DeAngelis KM. Substrate availability and not thermal acclimation controls microbial temperature sensitivity response to long-term warming. Glob Chang Biol. 2023 Mar;29(6):1574-1590. doi: 10.1111/gcb.16544.
The work (proposal:https://doi.org/10.46936/10.25585/60001340) conducted by the U.S. Department of Energy Joint Genome Institute (https://ror.org/04xm1d337), a DOE Office of Science User Facility, is supported by the Office of Science of the U.S. Department of Energy operated under Contract No. DE-AC02-05CH11231.
Project description:The earth’s climate is warming, and warming-induced biological feedbacks to climate threaten to further destabilize ecosystems. In a 30-year soil warming field experiment at the Harvard Forest in central Massachusetts, microbial isolates from heated (+5 degrees C above ambient) show signs of irreversible adaptation to warming in traits associated with altered soil biogeochemical cycling. Our labs have documented physiological adaptation in all three dimensions of microbial activities: growth, resource acquisition, and stress tolerance. We will use metabolomics to investigate the nature of adaptation due to long-term warming, where reduced soil organic matter, reduced soil water holding capacity and potentially increased niche partitioning may be a selective pressure. Specifically we hypothesize that increased drought tolerance of Actinobacteria exposed to long-term warming is due to production of more or different compatible solutes compared to isolates from controls.
The work (proposal:https://doi.org/10.46936/10.25585/60008103) conducted by the U.S. Department of Energy Joint Genome Institute (https://ror.org/04xm1d337), a DOE Office of Science User Facility, is supported by the Office of Science of the U.S. Department of Energy operated under Contract No. DE-AC02-05CH11231.
Project description:Clipping (i.e., harvesting aboveground plant biomass) is common in agriculture and for bioenergy production. However, microbial responses to clipping in the context of climate warming are poorly understood. We investigated the interactive effects of grassland warming and clipping on soil properties, plant and microbial communities, in particular microbial functional genes. Clipping alone did not change the plant biomass production, but warming and clipping combined increased the C4 peak biomass by 47% and belowground net primary production by 110%. Clipping alone and in combination with warming decreased the soil carbon input from litter by 81% and 75%, respectively. With less carbon input, the abundances of genes involved in degrading relatively recalcitrant carbon increased by 38-137% in response to either clipping or the combined treatment, which could weaken the long-term soil carbon stability and trigger a positive feedback to warming. Clipping alone also increased the abundance of genes for nitrogen fixation, mineralization and denitrification by 32-39%. The potentially stimulated nitrogen fixation could help compensate for the 20% decline in soil ammonium caused by clipping alone, and contribute to unchanged plant biomass. Moreover, clipping tended to interact antagonistically with warming, especially on nitrogen cycling genes, demonstrating that single factor studies cannot predict multifactorial changes. These results revealed that clipping alone or in combination with warming altered soil and plant properties, as well as the abundance and structure of soil microbial functional genes. The aboveground biomass removal for biofuel production needs to be re-considered as the long-term soil carbon stability may be weakened.
Project description:Microbes are responsible for cycling carbon (C) through soils, and predicted changes in soil C stocks under climate change are highly sensitive to shifts in the mechanisms assumed to control the microbial physiological response to warming. Two mecha-nisms have been suggested to explain the long-term warming impact on microbial physiology: microbial thermal acclimation and changes in the quantity and quality of substrates available for microbial metabolism. Yet studies disentangling these two mechanisms are lacking. To resolve the drivers of changes in microbial physiology in response to long-term warming, we sampled soils from 13- and 28-year- old soil warming experiments in different seasons. We performed short-term laboratory incubations across a range of temperatures to measure the relationships between temperature sensitivity of physiology (growth, respiration, carbon use efficiency, and extracellular enzyme activity) and the chemical composition of soil organic matter. We observed apparent thermal acclimation of microbial respiration, but only in sum-mer, when warming had exacerbated the seasonally-induced, already small dissolved organic matter pools. Irrespective of warming, greater quantity and quality of soil carbon increased the extracellular enzymatic pool and its temperature sensitivity. We propose that fresh litter input into the system seasonally cancels apparent thermal acclimation of C-cycling processes to decadal warming. Our findings reveal that long-term warming has indirectly affected microbial physiology via reduced C availability in this system, implying that earth system models including these negative feedbacks may be best suited to describe long-term warming effects on these soils. Citation: Domeignoz-Horta LA, Pold G, Erb H, Sebag D, Verrecchia E, Northen T, Louie K, Eloe-Fadrosh E, Pennacchio C, Knorr MA, Frey SD, Melillo JM, DeAngelis KM. Substrate availability and not thermal acclimation controls microbial temperature sensitivity response to long-term warming. Glob Chang Biol. 2023 Mar;29(6):1574-1590. doi: 10.1111/gcb.16544.
The work (proposal:https://doi.org/10.46936/10.25585/60001340) conducted by the U.S. Department of Energy Joint Genome Institute (https://ror.org/04xm1d337), a DOE Office of Science User Facility, is supported by the Office of Science of the U.S. Department of Energy operated under Contract No. DE-AC02-05CH11231.
2023-08-04 | MSV000092599 | GNPS
Project description:RNA sequencing for diatom under long-term ocean warming
| PRJNA1076079 | ENA
Project description:ChIP sequencing for diatom under long-term ocean warming