Historical trends of atmospheric black carbon on Sanjiang Plain as reconstructed from a 150-year peat record

Abstract

Black carbon (BC), one of the major components of atmosphere aerosol, could be the second dominant driver of climate change. We reconstructed historical trend of BC fluxes in Sanjiang Plain (Northeast China) through peat record to better understand its long-term trend and relationship of this atmosphere aerosol with intensity of human activities. The BC fluxes in peatland were higher than other sedimentary archives. Although global biomass burning decreased in last 150 years, regional large scale reclaiming caused BC fluxes of the Sanjiang Plain increased dramatically between 1950s' and 1980s', most likely resulting from using fire to clearing dense pastures and forests for reclaiming. The BC fluxes have increased since 1900s with increasing of the population and the area of farmland; the increase trend has been more clearly since 1980s. Based on Generalized additive models (GAM), the proportional influence of regional anthropogenic impacts have increased and became dominant factors on BC deposition.

Impact of forest fires generated black carbon deposition fluxes in Great Hinggan Mountains (China)

“…BC deposition fluxes decreased after the 1980s, which suggests that natural fire control can decrease BC deposition fluxes directly and substantially (G. Liu, ). Although fire controlling policies (e.g., establish fire monitoring stations and forest firefighting brigade) clearly decrease fire frequency and intensity, with economic development and more industrial fossil fuel burning, BC deposition fluxes in several peatland cores increased after the 2000s, which were similar to other regions in previous studies (e.g., Cong et al, ; Gao et al, ). After the 2000s, industrial sources of BC were more prevalent than forest fires and became major source of BC in the Great Hinggan Mountains.…”

“…Unlike other wetland distribution regions in previous studies (Gao et al, ; Gao et al, ; He et al, ), the Great Hinggan Mountains are famous for a high frequency of fire events. Between 1966 and 2005, more than 1,500 fires occurred, affecting a region of more than 60,000 km 2 in the northern part of the Great Hinggan Mountains (Y. Zhang, ).…”

“…The average BC concentrations in five peat cores from the Great Hinggan Mountains were 14.6 ± 0.74 mg·g −1 , and the range were between 8.90 and 25.3 mg·g −1 , which were similar to those in the peatland from the Changbai Mountains and were slightly lower than those from the Sanjiang Plain (Gao et al, ; Gao et al, ). Industrial development can lead to increases in regional soil BC concentrations (Lehndorff et al, ).…”

“…In contrast, BC deposition fluxes at other worldwide sites (e.g., Tibet Plateau, China; Northern Europe) continued increasing, and the highest deposition fluxes appeared in approximately the 2000s (Cong et al, ; Ruppel et al, ). More intensive human activities in Northeast China, accompanied by accelerated BC production, have led to an increase in BC deposition fluxes in the Sanjiang Plain and Changbai Mountains over the last 150 years, especially after the 1980s (Gao et al, ; Gao et al, ). The Great Hinggan Mountains are located in the western part of Northeast China, where the main wind direction is from west to east, meaning that sources of the BC are mainly local sources and regional sources from the western part of the Great Hinggan Mountains.…”

“…Most past studies have focused on investigating BC concentrations and historical deposition in different ecosystems around the world (e.g., Lehndorff, Roth, Cao, & Amelung, ; X. Liu et al, ; Soucémarianadin, Quideau, & MacKenzie, ; X. Wang, Peng, & Ding, ; X. Wang, Xiao, Cui, & Ding, ) rather than peatland ecosystems. Nearly all of these studies focused on the relationship between anthropogenic BC emission during regional or global economic development and BC deposition in different depositional archives (e.g., Cong et al, ; Gao et al, ). BC concentrations in peatland ecosystems are easily influenced by the intensity and frequency of surrounding fire or smoldering processes.…”