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Chen C, Huang JH, Li K, Osterwalder S, Yang C, Waldner P, Zhang H, Fu X, Feng X. Isotopic Characterization of Mercury Atmosphere-Foliage and Atmosphere-Soil Exchange in a Swiss Subalpine Coniferous Forest. Environ Sci Technol 2023; 57:15892-15903. [PMID: 37788478 DOI: 10.1021/acs.est.3c03576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
To understand the role of vegetation and soil in regulating atmospheric Hg0, exchange fluxes and isotope signatures of Hg were characterized using a dynamic flux bag/chamber at the atmosphere-foliage/soil interfaces at the Davos-Seehornwald forest, Switzerland. The foliage was a net Hg0 sink and took up preferentially the light Hg isotopes, consequently resulting in large shifts (-3.27‰) in δ202Hg values. The soil served mostly as net sources of atmospheric Hg0 with higher Hg0 emission from the moss-covered soils than from bare soils. The negative shift of δ202Hg and Δ199Hg values of the efflux air relative to ambient air and the Δ199Hg/Δ201Hg ratio among ambient air, efflux air, and soil pore gas highlight that Hg0 re-emission was strongly constrained by soil pore gas evasion together with microbial reduction. The isotopic mass balance model indicates 8.4 times higher Hg0 emission caused by pore gas evasion than surface soil photoreduction. Deposition of atmospheric Hg0 to soil was noticeably 3.2 times higher than that to foliage, reflecting the high significance of the soil to influence atmospheric Hg0 isotope signatures. This study improves our understanding of Hg atmosphere-foliage/soil exchange in subalpine coniferous forests, which is indispensable in the model assessment of forest Hg biogeochemical cycling.
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Affiliation(s)
- Chaoyue Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Jen-How Huang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Environmental Geosciences, University of Basel, 4056 Basel, Switzerland
| | - Kai Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Stefan Osterwalder
- Environmental Geosciences, University of Basel, 4056 Basel, Switzerland
- Institute of Agricultural Sciences, ETH Zurich, 8092 Zurich, Switzerland
| | - Chenmeng Yang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Peter Waldner
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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Méndez-López M, Eimil-Fraga C, Alonso-Vega F, Rodríguez-Soalleiro R, Álvarez-Rodríguez E, Arias-Estévez M, Nóvoa-Muñoz JC. Variation of Hg concentration and accumulation in the soil of maritime pine plantations along a coast-inland transect in SW Europe. Environ Res 2023; 231:116155. [PMID: 37196692 DOI: 10.1016/j.envres.2023.116155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 04/13/2023] [Accepted: 05/13/2023] [Indexed: 05/19/2023]
Abstract
Climatic conditions have been shown as a major driver of the fate of Hg in forest ecosystems at a global scale, but less is known about climatic effects at shorter scales. This study assesses whether the concentration and pools of Hg in soils collected from seventeen Pinus pinaster stands describing a coastal-inland transect in SW Europe vary along a regional climatic gradient. In each stand, samples of the organic subhorizons (OL, OF + OH) and the mineral soil (up to 40 cm) were collected and some general physico-chemical properties and total Hg (THg) were analyzed. Total Hg was significantly higher in the OF + OH than in the OL subhorizons (98 and 38 μg kg-1, respectively), favored by a greater organic matter humification in the former. In the mineral soil, mean THg values decreased with depth, ranging from 96 μg kg-1 in the 0-5 cm layers to 54 μg kg-1 in the deepest layers (30-40 cm), respectively. The average Hg pool (PHg) was 0.30 mg m-2 in the organic horizons (92% accumulated in the OF + OH subhorizons), and 27.4 mg m-2 in the mineral soil. Changes in climatic factors, mainly precipitation, along the coast-inland transect resulted in a remarkable variation of THg in the OL subhorizons, consistent with their role as the first receiver of atmospheric Hg inputs. The high precipitation rate and the occurrence of fogs in coastal areas characterized by the oceanic influence would explain the higher THg found in the uppermost soil layers of pine stands located close to the coastline. The regional climate is key to the fate of mercury in forest ecosystems by influencing the plant growth and subsequent atmospheric Hg uptake, the atmospheric Hg transference to the soil surface (wet and dry deposition and litterfall) and the dynamics that determine net Hg accumulation in the forest floor.
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Affiliation(s)
- Melissa Méndez-López
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias. As Lagoas S/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental. Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain.
| | - Cristina Eimil-Fraga
- Unidad de Gestión Ambiental y Forestal Sostenible, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela. Rúa Benigno Ledo S/n, 27002, Lugo, Spain
| | - Flora Alonso-Vega
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias. As Lagoas S/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental. Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
| | - Roque Rodríguez-Soalleiro
- Unidad de Gestión Ambiental y Forestal Sostenible, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela. Rúa Benigno Ledo S/n, 27002, Lugo, Spain
| | - Esperanza Álvarez-Rodríguez
- Departamento de Edafología y Química Agrícola, Escuela Politécnica Superior de Ingeniería, Universidade de Santiago de Compostela, Rúa Benigno Ledo S/n, 27002, Lugo, Spain
| | - Manuel Arias-Estévez
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias. As Lagoas S/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental. Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
| | - Juan Carlos Nóvoa-Muñoz
- Universidade de Vigo, Departamento de Bioloxía Vexetal e Ciencia do Solo, Área de Edafoloxía e Química Agrícola, Facultade de Ciencias. As Lagoas S/n, 32004, Ourense, Spain; Campus da Auga, Universidade de Vigo, Laboratorio de Tecnoloxía e Diagnose Ambiental. Rúa Canella da Costa da Vela 12, 32004, Ourense, Spain
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Huang JH, Berg B, Chen C, Thimonier A, Schmitt M, Osterwalder S, Alewell C, Rinklebe J, Feng X. Predominant contributions through lichen and fine litter to litterfall mercury deposition in a subalpine forest. Environ Res 2023; 229:116005. [PMID: 37116676 DOI: 10.1016/j.envres.2023.116005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/23/2023] [Accepted: 04/25/2023] [Indexed: 05/03/2023]
Abstract
Litterfall, typically referring to needles/leaves, may stand for >50% of the total mercury (Hg) deposition in forest ecosystems. By detailed categorisation, we reveal for the first time that the contributions through lichens and fine litter, together 9.98 μg Hg m-2 yr-1, could be as high as that in needle litter (9.96 μg m-2 yr-1) to the annual total Hg deposition (44.6 μg m-2 yr-1) in a subalpine forest in Switzerland. Noticeably, needle litter had the highest contribution (53%) to total Hg in the autumn litterfall but lichens and fine litter together predominated in other seasons (47-59%). Such a seasonal pattern is caused by the high ability of lichens and fine litter to accumulate Hg and the high needle litterfall in autumn, which is related to a good rainfall in summer followed by a dry period in autumn. The constantly higher Hg levels in lichens and fine litter than in needle litter together with similar seasonal patterns of litterfall during 2009-2019 and rainfall during 1980-2019 suggest that our finding can be generally valid. Here, we highlight not only the considerable role of non-needle litterfall in Hg deposition but also the association with weather for seasonal Hg dynamics in different litterfall components.
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Affiliation(s)
- Jen-How Huang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; Environmental Geosciences, University of Basel, 4056, Basel, Switzerland.
| | - Björn Berg
- Department of Forest Sciences, University of Helsinki, FIN-00014, Helsinki, Finland
| | - Chaoyue Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Anne Thimonier
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903, Birmensdorf, Switzerland
| | - Maria Schmitt
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903, Birmensdorf, Switzerland
| | - Stefan Osterwalder
- Environmental Geosciences, University of Basel, 4056, Basel, Switzerland; Institute of Agricultural Sciences, ETH Zurich, 8092, Zurich, Switzerland
| | - Christine Alewell
- Environmental Geosciences, University of Basel, 4056, Basel, Switzerland
| | - Jörg Rinklebe
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, 42285, Wuppertal, Germany
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
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