scholarly journals Soil-atmosphere exchange flux of total gaseous mercury (TGM) in subtropical and temperate forest catchments

2020 ◽  
Author(s):  
Jun Zhou ◽  
Zhangwei Wang ◽  
Xiaoshan Zhang ◽  
Charles T. Driscoll ◽  
Che-Jen Lin
Keyword(s):  
Solar Radiation ◽  
Open Field ◽  
Temperate Forest ◽  
Temperate Forests ◽  
Subtropical Forest ◽  
Pine Forest ◽  
Emission Rates ◽  
Soil Air ◽  
Soil Atmosphere ◽  
Soil Hg

Abstract. Evasion from soil is the largest source of mercury (Hg) to the atmosphere in terrestrial ecosystems. To improve understanding of controls and reduce uncertainty in estimates of forest soil-atmosphere exchange, soil-air total gaseous Hg (TGM) fluxes were measured for 130 and 96 days for each of four plots at a subtropical forest and a temperate forest, respectively. The soil-air TGM fluxes, measured using dynamic flux chambers (DFC), showed patterns of both emission and deposition at five study plots, with an area-weighted net emission rate of 3.2 and 0.32 ng m−2 hr−1 for the entire subtropical and temperate forests, respectively. At the subtropical forest, the highest fluxes and net soil Hg emission were observed for an open field, with lesser emission rates in coniferous (Masson pine) and broad-leaved (camphor) forests, and net deposition in a wetland. At the temperate forest, the highest fluxes and net soil Hg emission were observed for a wetland and an open field, with lesser emission rates in deciduous broad-leaved and deciduous needle-leaf (larch) forests, and net deposition in an evergreen pine forest (Chinese pine). High solar radiation and temperature in summer resulted in the high Hg emission at the subtropical forest, and open field and evergreen pine forest in the temperate forest. In the temperate deciduous plots, the highest Hg emission was in spring during leaf-off period due to direct solar radiation exposure to soils. Fluxes showed strong positive relationships with solar radiation and soil temperature, and negative correlations with ambient-air TGM concentration in both subtropical and temperate forests, with area-weighted compensation points of 6.82 and 3.42 ng m−3, respectively. The compensation points implicated that the atmospheric TGM concentration plays a critical role in inhibiting the TGM emission from forest floor. More attention should pay to the legacy Hg stored in terrestrial surface as a more important increasing Hg emission source with the decreasing air TGM concentration recently.

scholarly journals Soil–atmosphere exchange flux of total gaseous mercury (TGM) at subtropical and temperate forest catchments

2020 ◽  
Vol 20 (24) ◽  
pp. 16117-16133
Author(s):  
Jun Zhou ◽  
Zhangwei Wang ◽  
Xiaoshan Zhang ◽  
Charles T. Driscoll ◽  
Che-Jen Lin
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Solar Radiation ◽  
Open Field ◽  
Temperate Forest ◽  
Subtropical Forest ◽  
Pine Forest ◽  
Broad Leaved Forest ◽  
Leaved Forest ◽  
Soil Hg

Abstract. Evasion from soil is the largest source of mercury (Hg) to the atmosphere from terrestrial ecosystems. To improve our understanding of controls and in estimates of forest soil–atmosphere fluxes of total gaseous Hg (TGM), measurements were made using dynamic flux chambers (DFCs) over 130 and 96 d for each of five plots at a subtropical forest and a temperate forest, respectively. At the subtropical forest, the highest net soil Hg emissions were observed for an open field (24 ± 33 ng m−2 h−1), followed by two coniferous forest plots (2.8 ± 3.9 and 3.5 ±  4.2 ng m−2 h−1), a broad-leaved forest plot (0.18 ±  4.3 ng m−2 h−1) and the remaining wetland site showing net deposition (−0.80 ± 5.1 ng m−2 h−1). At the temperate forest, the highest fluxes and net soil Hg emissions were observed for a wetland (3.81 ± 0.52 ng m−2 h−1) and an open field (1.82 ± 0.79 ng m−2 h−1), with lesser emission rates in the deciduous broad-leaved forest (0.68 ± 1.01 ng m−2 h−1) and deciduous needle-leaved forest (0.32 ± 0.96 ng m−2 h−1) plots, and net deposition at an evergreen pine forest (−0.04 ± 0.81 ng m−2 h−1). High solar radiation and temperature during summer resulted in the high Hg emissions in the subtropical forest and the open field and evergreen pine forest at the temperate forest. At the temperate deciduous plots, the highest Hg emission occurred in spring during the leaf-off period due to direct solar radiation exposure to soils. Fluxes showed strong positive relationships with solar radiation and soil temperature and negative correlations with ambient air TGM concentration in both the subtropical and temperate forests, with area-weighted compensation points of 6.82 and 3.42 ng m−3, respectively. The values of the compensation points suggest that the atmospheric TGM concentration can play a critical role in limiting TGM emissions from the forest floor. Climate change and land use disturbance may increase the compensation points in both temperate and subtropical forests. Future research should focus on the role of legacy soil Hg in reemissions to the atmosphere as decreases in primary emissions drive decreases in TGM concentrations and disturbances of climate change and land use.

scholarly journals Soil emissions, soil air dynamics and model simulation of gaseous mercury in subtropical forest

2019 ◽  
Author(s):  
Jun Zhou ◽  
Zhangwei Wang ◽  
Xiaoshan Zhang ◽  
Charles Driscoll ◽  
Che-Jen Lin
Keyword(s):  
Model Simulation ◽  
Model Development ◽  
Terrestrial Ecosystems ◽  
Ambient Air ◽  
Emission Rates ◽  
Strong Correlations ◽  
Soil Air ◽  
Broad Leaved Forest ◽  
Emission Models ◽  
Soil Hg

Abstract. Evasion from soil is the largest source of mercury (Hg) to the atmosphere from terrestrial ecosystems. To reduce the uncertainty in estimates of Hg emissions from forest soils, soil-air total gaseous Hg (TGM) fluxes and vertical profiles of soil pore TGM concentrations were measured simultaneously for 130 days to improve parameterization of emission models. The soil-air TGM fluxes, measured using dynamic flux chambers (DFC), showed patterns of both emission and deposition at five study plots, with an area-weighted net emission rate of 3.2 ng m−2 hr−1. The highest fluxes and net soil Hg emission were observed for an open field, with lesser emission rates in coniferous (pine) and broad-leaved (camphor) forests, and net deposition in a wetland. Fluxes showed strong positive relationships with solar radiation, soil temperature and soil Hg concentrations, and negative correlations with ambient-air TGM concentration and soil moisture. Using experimental field flux observations and quadratic relationships with the five parameters, four empirical models were developed to estimate soil-air TGM fluxes. The highest TGM concentrations in soil gas consistently occurred in the upper mineral horizons in the coniferous (pine) forest and in the organic horizon in the broad-leaved forest. Strong correlations between fluxes and TGM concentrations in upper soil horizons (0–10 cm) suggest that TGM in the pores of surface soil acts as the source for diffusion to the atmosphere. The TGM diffusion coefficients (Ds) between soil and atmosphere was firstly investigated at the field sites, with the range of 0.0042–0.013 m2 hr−1. These values should provide a foundation for future model development.

scholarly journals Assessment of Soil Organic Carbon Stock of Temperate Coniferous Forests in Northern Kashmir

2015 ◽  
Vol 4 (1) ◽  
pp. 161-178
Author(s):  
Davood A. Dar ◽  
Bhawana Pathak ◽  
M. H. Fulekar
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Quality ◽  
Carbon Stock ◽  
Temperate Forest ◽  
Temperate Forests ◽  
Forest Site ◽  
Soil Organic Carbon Stock ◽  
Organic Carbon Stock

 Soil organic carbon (SOC) estimation in temperate forests of the Himalaya is important to estimate their contribution to regional, national and global carbon stocks. Physico chemical properties of soil were quantified to assess soil organic carbon density (SOC) and SOC CO2 mitigation density at two soil depths (0-10 and 10-20 cms) under temperate forest in the Northern region of Kashmir Himalayas India. The results indicate that conductance, moisture content, organic carbon and organic matter were significantly higher while as pH and bulk density were lower at Gulmarg forest site. SOC % was ranging from 2.31± 0.96 at Gulmarg meadow site to 2.31 ± 0.26 in Gulmarg forest site. SOC stocks in these temperate forests were from 36.39 ±15.40 to 50.09 ± 15.51 Mg C ha-1. The present study reveals that natural vegetation is the main contributor of soil quality as it maintained the soil organic carbon stock. In addition, organic matter is an important indicator of soil quality and environmental parameters such as soil moisture and soil biological activity change soil carbon sequestration potential in temperate forest ecosystems.DOI: http://dx.doi.org/10.3126/ije.v4i1.12186International Journal of Environment Volume-4, Issue-1, Dec-Feb 2014/15; page: 161-178

scholarly journals The Influence of Tree Structural and Species Diversity on Temperate Forest Productivity and Stability in Korea

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1113 ◽  
Author(s):  
Juhan Park ◽  
Hyun Seok Kim ◽  
Hyun Kook Jo ◽  
II Bin Jung
Keyword(s):  
Species Diversity ◽  
Tree Species ◽  
Temperate Forest ◽  
Temperate Forests ◽  
Basal Area ◽  
Stand Density ◽  
Structural Diversity ◽  
Forest Productivity ◽  
Tree Species Diversity ◽  
Positive Effect

Research Highlights: Using a long-term dataset on temperate forests in South Korea, we established the interrelationships between tree species and structural diversity and forest productivity and stability, and identified a strong, positive effect of structural diversity, rather than tree species diversity, on productivity and stability. Background and Objectives: Globally, species diversity is positively related with forest productivity. However, temperate forests often show a negative or neutral relationship. In those forests, structural diversity, instead of tree species diversity, could control the forest function. Materials and Methods: This study tested the effects of tree species and structural diversity on temperate forest productivity. The basal area increment and relative changes in stand density were used as proxies for forest productivity and stability, respectively. Results: Here we show that structural diversity, but not species diversity, had a significant, positive effect on productivity, whereas species diversity had a negative effect, despite a positive effect on diversity. Structural diversity also promoted fewer changes in stand density between two periods, whereas species diversity showed no such relation. Structurally diverse forests might use resources efficiently through increased canopy complexity due to canopy plasticity. Conclusions: These results indicate reported species diversity effects could be related to structural diversity. They also highlight the importance of managing structurally diverse forests to improve productivity and stability in stand density, which may promote sustainability of forests.

Two new species of the ladybird beetle Hong Ślipiński from Chile (Coleoptera: Coccinellidae: Microweiseinae)

Zootaxa ◽  
2013 ◽  
Vol 3616 (4) ◽  
pp. 387-395 ◽  
Author(s):  
GUILLERMO GONZÁLEZ ◽  
HERMES E. ESCALONA
Keyword(s):  
New Species ◽  
Temperate Forests ◽  
Subtropical Forest ◽  
Female Specimen ◽  
Southern Chile ◽  
Single Female ◽  
Ladybird Beetle ◽  
Two New Species

The ladybird beetle genus Hong Ślipiński was previously known from a single female specimen from a subtropical forest in South East Queensland, Australia. Hong guerreroi sp. nov. and H. slipinskii sp. nov. from a temperate forests of Central and Southern Chile are described and illustrated. A key for the species of the genus and complementary characters, in-cluding the first description of males, are provided.

scholarly journals Soil methane oxidation in both dry and wet temperate eucalypt forests shows a near-identical relationship with soil air-filled porosity

2017 ◽  
Vol 14 (2) ◽  
pp. 467-479 ◽  
Author(s):  
Benedikt J. Fest ◽  
Nina Hinko-Najera ◽  
Tim Wardlaw ◽  
David W. T. Griffith ◽  
Stephen J. Livesley ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Climate Change Scenarios ◽  
Soil Air ◽  
Eucalypt Forest ◽  
Soil Atmosphere ◽  
Forest Sites ◽  
Ch4 Uptake ◽  
Eucalypt Forests ◽  
The Impact

Abstract. Well-drained, aerated soils are important sinks for atmospheric methane (CH4) via the process of CH4 oxidation by methane-oxidising bacteria (MOB). This terrestrial CH4 sink may contribute towards climate change mitigation, but the impact of changing soil moisture and temperature regimes on CH4 uptake is not well understood in all ecosystems. Soils in temperate forest ecosystems are the greatest terrestrial CH4 sink globally. Under predicted climate change scenarios, temperate eucalypt forests in south-eastern Australia are predicted to experience rapid and extreme changes in rainfall patterns, temperatures and wild fires. To investigate the influence of environmental drivers on seasonal and inter-annual variation of soil–atmosphere CH4 exchange, we measured soil–atmosphere CH4 exchange at high-temporal resolution (<  2 h) in a dry temperate eucalypt forest in Victoria (Wombat State Forest, precipitation 870 mm yr−1) and in a wet temperature eucalypt forest in Tasmania (Warra Long-Term Ecological Research site, 1700 mm yr−1). Both forest soil systems were continuous CH4 sinks of −1.79 kg CH4 ha−1 yr−1 in Victoria and −3.83 kg CH4 ha−1 yr−1 in Tasmania. Soil CH4 uptake showed substantial temporal variation and was strongly controlled by soil moisture at both forest sites. Soil CH4 uptake increased when soil moisture decreased and this relationship explained up to 90 % of the temporal variability. Furthermore, the relationship between soil moisture and soil CH4 flux was near-identical at both forest sites when soil moisture was expressed as soil air-filled porosity (AFP). Soil temperature only had a minor influence on soil CH4 uptake. Soil nitrogen concentrations were generally low and fluctuations in nitrogen availability did not influence soil CH4 uptake at either forest site. Our data suggest that soil MOB activity in the two forests was similar and that differences in soil CH4 exchange between the two forests were related to differences in soil moisture and thereby soil gas diffusivity. The differences between forest sites and the variation in soil CH4 exchange over time could be explained by soil AFP as an indicator of soil moisture status.

scholarly journals Impact of cloudiness on net ecosystem exchange of carbon dioxide in different types of forest ecosystems in China

2010 ◽  
Vol 7 (2) ◽  
pp. 711-722 ◽  
Author(s):  
M. Zhang ◽  
G.-R. Yu ◽  
L.-M. Zhang ◽  
X.-M. Sun ◽  
X.-F. Wen ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Forest Ecosystem ◽  
Temperate Forest ◽  
Forest Ecosystems ◽  
Ecosystem Respiration ◽  
Net Ecosystem Exchange ◽  
Subtropical Forest ◽  
Strong Light ◽  
Sky Conditions ◽  
Temperate Forest Ecosystem

Abstract. Clouds can significantly affect carbon exchange process between forest ecosystems and the atmosphere by influencing the quantity and quality of solar radiation received by ecosystem's surface and other environmental factors. In this study, we analyzed the effects of cloudiness on net ecosystem exchange of carbon dioxide (NEE) in a temperate broad-leaved Korean pine mixed forest at Changbaishan (CBS) and a subtropical evergreen broad-leaved forest at Dinghushan (DHS), based on the flux data obtained during June–August from 2003 to 2006. The results showed that the response of NEE of forest ecosystems to photosynthetically active radiation (PAR) differed under clear skies and cloudy skies. Compared with clear skies, the light-saturated maximum photosynthetic rate (Pec,max) at CBS under cloudy skies during mid-growing season (from June to August) increased by 34%, 25%, 4% and 11% in 2003, 2004, 2005 and 2006, respectively. In contrast, Pec,max of the forest ecosystem at DHS was higher under clear skies than under cloudy skies from 2004 to 2006. When the clearness index (kt) ranged between 0.4 and 0.6, the NEE reached its maximum at both CBS and DHS. However, the NEE decreased more dramatically at CBS than at DHS when kt exceeded 0.6. The results indicate that cloudy sky conditions are beneficial to net carbon uptake in the temperate forest ecosystem and the subtropical forest ecosystem. Under clear skies, vapor pressure deficit (VPD) and air temperature increased due to strong light. These environmental conditions led to greater decrease in gross ecosystem photosynthesis (GEP) and greater increase in ecosystem respiration (Re) at CBS than at DHS. As a result, clear sky conditions caused more reduction of NEE in the temperate forest ecosystem than in the subtropical forest ecosystem. The response of NEE of different forest ecosystems to the changes in cloudiness is an important factor that should be included in evaluating regional carbon budgets under climate change conditions.

Seasonal patterns of soil CO2 efflux and soil air CO2 concentration in a Scots pine forest: comparison of two chamber techniques

2003 ◽  
Vol 9 (3) ◽  
pp. 371-382 ◽  
Author(s):  
JUKKA PUMPANEN ◽  
HANNU ILVESNIEMI ◽  
MARTTI PERÄMÄKi ◽  
PERTTI HARI
Keyword(s):  
Scots Pine ◽  
Co2 Concentration ◽  
Soil Co2 Efflux ◽  
Pine Forest ◽  
Seasonal Patterns ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil Air ◽  
Scots Pine Forest
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