scholarly journals A revised northern soil Hg pool, based on western Siberia permafrost peat Hg and carbon observations

2020 ◽  
Author(s):  
Artem G. Lim ◽  
Martin Jiskra ◽  
Jeroen E. Sonke ◽  
Sergey V. Loiko ◽  
Natalia Kosykh ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Carbon Budget ◽  
Western Siberia ◽  
Mineral Soil ◽  
Peat Soils ◽  
Run Off ◽  
Permafrost Soils ◽  
Siberian Permafrost ◽  
Soil Hg ◽  
Carbon Inventory

Abstract. Natural and anthropogenic mercury (Hg) emissions are sequestered in terrestrial soils over short, annual, to long, millennial time scales, before Hg mobilization and run-off impacts wetland and coastal Ocean ecosystems. Recent studies have used Hg to carbon (C) ratios, RHgC, measured in Alaskan permafrost mineral and peat soils, together with a northern soil carbon inventory, to estimate that these soils contain large amounts, 184 to 755 Gg of Hg in the upper 1 m. However, measurements of RHgC on Siberian permafrost peatlands are largely missing, leaving the size of estimated northern soil Hg budget, and its fate under arctic warming scenarios uncertain. Here we present Hg and carbon data for 6 peat cores, down to mineral horizons at 1.5–4 m depth, across a 1700 km latitudinal (56 to 67° N) permafrost gradient in the Western Siberian lowlands (WSL). Hg concentrations increase from south to north in all soil horizons, reflecting enhanced net accumulation of atmospheric gaseous Hg by the vegetation Hg pump. The RHgC in WSL peat horizons decreases with depth from 0.38 Gg Pg−1 in the active layer to 0.23 Gg Pg−1 in continuously frozen peat of the WSL. We estimate the Hg pool (0 1 m) in the permafrost-affected part of WSL peatlands to be 9.3 ± 2.7 Gg. We review and estimate pan-arctic organic and mineral soil RHgC to be 0.19 and 0.77 Gg Pg−1, and use a soil carbon budget to revise the northern soil Hg pool to be 67 Gg (37–88 Gg, interquartile range (IQR)) in the upper 30 cm, 225 Gg (102–320 Gg) in the upper 1 m, and 557 Gg (371–699 Gg) in the upper 3 m. Using the same RHgC approach, we revise the global upper 30 cm soil Hg pool to contain 1078 Gg of Hg (842–1254 Gg, IQR), of which 6 % (67 Gg) resides in northern permafrost soils. Additional soil and river studies must be performed in Eastern and Northern Siberia to lower the uncertainty on these estimates, and assess the timing of Hg release to atmosphere and rivers.

scholarly journals A revised pan-Arctic permafrost soil Hg pool based on Western Siberian peat Hg and carbon observations

2020 ◽  
Vol 17 (12) ◽  
pp. 3083-3097
Author(s):  
Artem G. Lim ◽  
Martin Jiskra ◽  
Jeroen E. Sonke ◽  
Sergey V. Loiko ◽  
Natalia Kosykh ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Mineral Soil ◽  
Permafrost Soil ◽  
Peat Soils ◽  
Run Off ◽  
Global Soil ◽  
Permafrost Soils ◽  
Siberian Permafrost ◽  
Soil Hg ◽  
Carbon Inventory

Abstract. Natural and anthropogenic mercury (Hg) emissions are sequestered in terrestrial soils over short, annual to long, millennial timescales before Hg mobilization and run-off impact wetland and coastal ocean ecosystems. Recent studies have used Hg-to-carbon (C) ratios (RHgC's) measured in Alaskan permafrost mineral and peat soils together with a northern circumpolar permafrost soil carbon inventory to estimate that these soils contain large amounts of Hg (between 184 and 755 Gg) in the upper 1 m. However, measurements of RHgC on Siberian permafrost peatlands are largely missing, leaving the size of the estimated northern soil Hg budget and its fate under Arctic warming scenarios uncertain. Here we present Hg and carbon data for six peat cores down to mineral horizons at 1.5–4 m depth, across a 1700 km latitudinal (56 to 67∘ N) permafrost gradient in the Western Siberian Lowland (WSL). Mercury concentrations increase from south to north in all soil horizons, reflecting a higher stability of sequestered Hg with respect to re-emission. The RHgC in the WSL peat horizons decreases with depth, from 0.38 Gg Pg−1 in the active layer to 0.23 Gg Pg−1 in continuously frozen peat of the WSL. We estimate the Hg pool (0–1 m) in the permafrost-affected part of the WSL peatlands to be 9.3±2.7 Gg. We review and estimate pan-Arctic organic and mineral soil RHgC to be 0.19 and 0.63 Gg Pg−1, respectively, and use a soil carbon budget to revise the pan-Arctic permafrost soil Hg pool to be 72 Gg (39–91 Gg; interquartile range, IQR) in the upper 30 cm, 240 Gg (110–336 Gg) in the upper 1 m, and 597 Gg (384–750 Gg) in the upper 3 m. Using the same RHgC approach, we revise the upper 30 cm of the global soil Hg pool to contain 1086 Gg of Hg (852–1265 Gg, IQR), of which 7 % (72 Gg) resides in northern permafrost soils. Additional soil and river studies in eastern and northern Siberia are needed to lower the uncertainty on these estimates and assess the timing of Hg release to the atmosphere and rivers.

scholarly journals Seasonal shifts in export of DOC and nutrients from burned and unburned peatland-rich catchments, Northwest Territories, Canada

2018 ◽  
Vol 22 (8) ◽  
pp. 4455-4472 ◽  
Author(s):  
Katheryn Burd ◽  
Suzanne E. Tank ◽  
Nicole Dion ◽  
William L. Quinton ◽  
Christopher Spence ◽  
...  
Keyword(s):  
Climate Change ◽  
Mineral Soil ◽  
Fire Regimes ◽  
Forest Litter ◽  
Early Spring ◽  
Permafrost Region ◽  
Spring Period ◽  
Discontinuous Permafrost ◽  
Run Off ◽  
Spring Freshet

Abstract. Boreal peatlands are major catchment sources of dissolved organic carbon (DOC) and nutrients and thus strongly regulate the landscape carbon balance, aquatic food webs, and downstream water quality. Climate change is likely to influence catchment solute yield directly through climatic controls on run-off generation, but also indirectly through altered disturbance regimes. In this study we monitored water chemistry from early spring until fall at the outlets of a 321 km2 catchment that burned 3 years prior to the study and a 134 km2 undisturbed catchment. Both catchments were located in the discontinuous permafrost zone of boreal western Canada and had  ∼  60 % peatland cover. The two catchments had strong similarities in the timing of DOC and nutrient yields, but a few differences were consistent with anticipated effects of wildfire based on peatland porewater analysis. The 4-week spring period, particularly the rising limb of the spring freshet, was crucial for accurate characterization of the seasonal solute yield from both catchments. The spring period was responsible for  ∼  65 % of the seasonal DOC and nitrogen and for  ∼  85 % of the phosphorous yield. The rising limb of the spring freshet was associated with high phosphorous concentrations and DOC of distinctly high aromaticity and molecular weight. Shifts in stream DOC concentrations and aromaticity outside the early spring period were consistent with shifts in relative streamflow contribution from precipitation-like water in the spring to mineral soil groundwater in the summer, with consistent relative contributions from organic soil porewater. Radiocarbon content (14C) of DOC at the outlets was modern throughout May to September (fraction modern carbon, fM: 0.99–1.05) but likely reflected a mix of aged DOC, e.g. porewater DOC from permafrost (fM: 0.65–0.85) and non-permafrost peatlands (fM: 0.95–1.00), with modern bomb-influenced DOC, e.g. DOC leached from forest litter (fM: 1.05–1.10). The burned catchment had significantly increased total phosphorous (TP) yield and also had greater DOC yield during summer which was characterized by a greater contribution from aged DOC. Overall, however, our results suggest that DOC composition and yield from peatland-rich catchments in the discontinuous permafrost region likely is more sensitive to climate change through impacts on run-off generation rather than through altered fire regimes.

CHARACTERISTICS OF THE EPIDERMAL LAYER OF CARROT ROOTS GROWN ON PEAT AND MINERAL SOIL

1971 ◽  
Vol 51 (6) ◽  
pp. 513-517
Author(s):  
E. W. CHIPMAN ◽  
F. R. FORSYTH
Keyword(s):  
Ascorbic Acid ◽  
Dry Matter ◽  
Reducing Sugars ◽  
Peat Soil ◽  
Mineral Soil ◽  
Epidermal Layer ◽  
Peat Soils ◽  
Anti Oxidant ◽  
Mineral Soils

The epidermal layer of carrot roots grown on peat soil contained more ascorbic acid and less phenols, carotene, reducing sugars, and dry matter than those from a mineral soil. The increased level of phenol and the decreased level of the anti-oxidant ascorbic acid are the likely contributing causes of the increased browning of carrots in mineral soils relative to peat soils.

Herbage biomass and its relationship to soil carbon under long-term grazing in northern temperate grasslands

2019 ◽  
Vol 99 (6) ◽  
pp. 905-916
Author(s):  
E.W. Bork ◽  
M.P. Lyseng ◽  
D.B. Hewins ◽  
C.N. Carlyle ◽  
S.X. Chang ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Root Biomass ◽  
Mineral Soil ◽  
Belowground Biomass ◽  
Cattle Grazing ◽  
Shoot Biomass ◽  
Positive Contribution ◽  
Temperate Grasslands ◽  
Soil C

While northern temperate grasslands are important for supporting beef production, it remains unclear how grassland above- and belowground biomass responds to long-term cattle grazing. Here, we use a comprehensive dataset from 73 grasslands distributed across a broad agro-climatic gradient to quantify grassland shoot, litter, and shallow (top 30 cm) root biomass in areas with and without grazing. Additionally, we relate biomass to soil carbon (C) concentrations. Forb biomass was greater (p < 0.05) in grazed areas, particularly those receiving more rainfall. In contrast, grass and total aboveground herbage biomass did not differ with grazing (total: 2320 kg ha−1 for grazed vs. 2210 kg ha−1 for non-grazed; p > 0.05). Forb crude protein concentrations were lower (p < 0.05) in grazed communities compared with those that were non-grazed. Grasslands subjected to grazing had 56% less litter mass. Root biomass down to 30 cm remained similar between areas with (9090 kg ha−1) and without (7130 kg ha−1) grazing (p > 0.05). Surface mineral soil C concentrations were positively related to peak grassland biomass, particularly total (above + belowground) biomass, and with increasing forb biomass in grazed areas. Finally, total aboveground shoot biomass and soil C concentrations in the top 15 cm of soil were both positively related to the proportion of introduced plant diversity in grazed and non-grazed grasslands. Overall, cattle grazing at moderate stocking rates had minimal impact on peak grassland biomass, including above- and belowground, and a positive contribution exists from introduced plant species to maintaining herbage productivity and soil C.

Carbon budget of oligotrophic mire sites in the Southern Taiga of Western Siberia

2008 ◽  
Vol 315 (1-2) ◽  
pp. 19-34 ◽  
Author(s):  
Eugenia A. Golovatskaya ◽  
Egor A. Dyukarev
Keyword(s):  
Carbon Budget ◽  
Western Siberia ◽  
Southern Taiga

scholarly journals Variability of above-ground litter inputs alters soil physicochemical and biological processes: a meta-analysis of litterfall-manipulation experiments

2013 ◽  
Vol 10 (11) ◽  
pp. 7423-7433 ◽  
Author(s):  
S. Xu ◽  
L. L. Liu ◽  
E. J. Sayer
Keyword(s):  
Soil Temperature ◽  
Soil Carbon ◽  
Meta Analysis ◽  
Mineral Soil ◽  
Biogeochemical Cycling ◽  
Litter Addition ◽  
Litter Removal ◽  
Litter Manipulation ◽  
Below Ground ◽  
Soil Temperature And Moisture

Abstract. Global change has been shown to alter the amount of above-ground litter inputs to soil greatly, which could cause substantial cascading effects on below-ground biogeochemical cycling. Despite extensive study, there is uncertainty about how changes in above-ground litter inputs affect soil carbon and nutrient turnover and transformation. Here, we conducted a meta-analysis on 70 litter-manipulation experiments in order to assess how changes in above-ground litter inputs alter soil physicochemical properties, carbon dynamics and nutrient cycles. Our results demonstrated that litter removal decreased soil respiration by 34%, microbial biomass carbon in the mineral soil by 39% and total carbon in the mineral soil by 10%, whereas litter addition increased them by 31, 26 and 10%, respectively. This suggests that greater litter inputs increase the soil carbon sink despite higher rates of carbon release and transformation. Total nitrogen and extractable inorganic nitrogen in the mineral soil decreased by 17 and 30%, respectively, under litter removal, but were not altered by litter addition. Overall, litter manipulation had a significant impact upon soil temperature and moisture, but not soil pH; litter inputs were more crucial in buffering soil temperature and moisture fluctuations in grassland than in forest. Compared to other ecosystems, tropical and subtropical forests were more sensitive to variation in litter inputs, as altered litter inputs affected the turnover and accumulation of soil carbon and nutrients more substantially over a shorter time period. Our study demonstrates that although the magnitude of responses differed greatly among ecosystems, the direction of the responses was very similar across different ecosystems. Interactions between plant productivity and below-ground biogeochemical cycling need to be taken into account to predict ecosystem responses to environmental change.

Sign in / Sign up

Export Citation Format

Share Document