Peatlands located at the northern edge of the East Asian monsoon (EAM) are well placed to provide a terrestrial record of past climate and hydrological changes for this globally sensitive region. Here we present a middle to late Holocene, diatom-derived water-table records from a peatland in the Greater Hinggan Mountains, northeastern China. An age-depth model was achieved through AMSC dating and Bayesian piece-wise linear accumulation modelling. The diatom-based water-table reconstructions show that the peatland water-table rose from 5100 to 3500 cal. yr BP, but fell approximately 3500 cal. yr BP. From about 2800 to 1500 cal. yr BP, the peatland water-table stabilized. After about 1500 cal. yr BP, several rapid hydrological shifts, which correspond with global climate anomalies such as ice-rafted debris (IRD) events, were registered in the reconstructed water-tables. Compared with other paleoclimate records in East Asia, the general trend of peatland water-table fluctuations follows the variations in the East Asian summer monsoon (EASM) intensity. Spectrum analysis of the water-table profile yielded a statistically significant periodicity of 470-year that may be related to the "~500-year" inherent solar irradiation cycles. In addition, positive correlation between the peatland water-table levels and cosmic-isotope-reconstructed sunspot numbers underscores the role of the sun in regulating hydrological processes in the EASM margin area. The data suggest that the regional climate and hydrological variations at the EASM margin were first triggered by changes in solar output, but may have been amplified by interactions with oceanic and atmospheric circulations.
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http://dx.doi.org/10.1016/j.scitotenv.2020.138272 | DOI Listing |
Appl Environ Microbiol
December 2024
Sarawak Tropical Peat Research Institute, Kota Samarahan, Sarawak, Malaysia.
Tropical peatlands significantly influence local and global carbon and nitrogen cycles, yet they face growing pressure from anthropogenic activities. Land use changes, such as peatland forests conversion to oil palm plantations, affect the soil microbiome and greenhouse gas (GHG) emissions. However, the temporal dynamics of microbial community changes and their role as GHG indicators are not well understood.
View Article and Find Full Text PDFGlob Chang Biol
December 2024
Earth and Climate, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
Rewetting peatlands is required to limit carbon dioxide (CO) emissions, however, raising the groundwater level (GWL) will strongly increase the chance of methane (CH) emissions which has a higher radiative forcing than CO. Data sets of CH from different rewetting strategies and natural systems are scarce, and quantification and an understanding of the main drivers of CH emissions are needed to make effective peatland rewetting decisions. We present a large data set of CH fluxes (FCH) measured across 16 sites with eddy covariance on Dutch peatlands.
View Article and Find Full Text PDFGlob Chang Biol
December 2024
Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado, USA.
To better understand linkages between hydrology and ecosystem carbon flux in northern aquatic ecosystems, we evaluated the relationship between plant communities, biofilm development, and carbon dioxide (CO) exchange following long-term changes in hydrology in an Alaskan fen. We quantified seasonal variation in biofilm composition and CO exchange in response to lowered and raised water table position (relative to a control) during years with varying levels of background dissolved organic carbon (DOC). We then used nutrient-diffusing substrates (NDS) to evaluate cause-effect relationships between changes in plant subsidies (i.
View Article and Find Full Text PDFSci Total Environ
December 2024
Department of Geography and Environmental Management, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
J Environ Manage
November 2024
Geological Survey of Finland (GTK), Vuorimiehentie 5, 02151 Espoo, Finland; University of Eastern Finland (UEF), Tulliportinkatu 1, 80130 Joensuu, Finland.
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