Buffering effect of global vegetation on the air-land exchange of mercury: Insights from a novel terrestrial mercury model based on CESM2-CLM5
The vegetation uptake of atmospheric elemental mercury [Hg(0)] and its subsequent littering are critical processes of the terrestrial Hg cycles. There is a large uncertainty in the estimated global fluxes of these processes due to the knowledge gap in the underlying mechanisms and their relationship...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-04-01
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| Series: | Environment International |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0160412023001770 |
| _version_ | 1797840020521877504 |
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| author | Tengfei Yuan Peng Zhang Zhengcheng Song Shaojian Huang Xun Wang Yanxu Zhang |
| author_facet | Tengfei Yuan Peng Zhang Zhengcheng Song Shaojian Huang Xun Wang Yanxu Zhang |
| author_sort | Tengfei Yuan |
| collection | DOAJ |
| description | The vegetation uptake of atmospheric elemental mercury [Hg(0)] and its subsequent littering are critical processes of the terrestrial Hg cycles. There is a large uncertainty in the estimated global fluxes of these processes due to the knowledge gap in the underlying mechanisms and their relationship with environmental factors. Here, we develop a new global model based on the Community Land Model Version 5 (CLM5-Hg) as an independent component of the Community Earth System Model 2 (CESM2). We explore the global pattern of gaseous elemental Hg [Hg(0)] uptake by vegetation and the spatial distribution of litter Hg concentration constrained by observed datasets as well as its driving mechanism. The annual vegetation uptake of Hg(0) is estimated as 3132 Mg yr−1, which is considerably higher than previous global models. The scheme of dynamic plant growth including stomatal activities substantially improves the estimation for global terrestrial distribution of Hg, compared to the leaf area index (LAI) based scheme that is often used by previous models. We find the global distribution of litter Hg concentrations driven by vegetation uptake of atmospheric Hg(0), which are simulated to be higher in East Asia (87 ng/g) than in the Amazon region (63 ng/g). Meanwhile, as a significant source for litter Hg, the formation of structural litter (cellulose litter + lignin litter) results in a lagging effect between Hg(0) deposition and litter Hg concentration, implying the buffering effect of vegetation on the air-land exchange of Hg. This work highlights the importance of vegetation physiology and environmental factors in understanding the vegetation sequestration of atmospheric Hg globally, and calls for greater efforts to protect forests and afforestation. |
| first_indexed | 2024-04-09T16:07:39Z |
| format | Article |
| id | doaj.art-90714e3520874a52a9bcb31185188326 |
| institution | Directory Open Access Journal |
| issn | 0160-4120 |
| language | English |
| last_indexed | 2024-04-09T16:07:39Z |
| publishDate | 2023-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Environment International |
| spelling | doaj.art-90714e3520874a52a9bcb311851883262023-04-25T04:07:43ZengElsevierEnvironment International0160-41202023-04-01174107904Buffering effect of global vegetation on the air-land exchange of mercury: Insights from a novel terrestrial mercury model based on CESM2-CLM5Tengfei Yuan0Peng Zhang1Zhengcheng Song2Shaojian Huang3Xun Wang4Yanxu Zhang5School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, ChinaSchool of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, ChinaSchool of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, ChinaSchool of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, ChinaState Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, ChinaSchool of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, China; Corresponding author at: School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China.The vegetation uptake of atmospheric elemental mercury [Hg(0)] and its subsequent littering are critical processes of the terrestrial Hg cycles. There is a large uncertainty in the estimated global fluxes of these processes due to the knowledge gap in the underlying mechanisms and their relationship with environmental factors. Here, we develop a new global model based on the Community Land Model Version 5 (CLM5-Hg) as an independent component of the Community Earth System Model 2 (CESM2). We explore the global pattern of gaseous elemental Hg [Hg(0)] uptake by vegetation and the spatial distribution of litter Hg concentration constrained by observed datasets as well as its driving mechanism. The annual vegetation uptake of Hg(0) is estimated as 3132 Mg yr−1, which is considerably higher than previous global models. The scheme of dynamic plant growth including stomatal activities substantially improves the estimation for global terrestrial distribution of Hg, compared to the leaf area index (LAI) based scheme that is often used by previous models. We find the global distribution of litter Hg concentrations driven by vegetation uptake of atmospheric Hg(0), which are simulated to be higher in East Asia (87 ng/g) than in the Amazon region (63 ng/g). Meanwhile, as a significant source for litter Hg, the formation of structural litter (cellulose litter + lignin litter) results in a lagging effect between Hg(0) deposition and litter Hg concentration, implying the buffering effect of vegetation on the air-land exchange of Hg. This work highlights the importance of vegetation physiology and environmental factors in understanding the vegetation sequestration of atmospheric Hg globally, and calls for greater efforts to protect forests and afforestation.http://www.sciencedirect.com/science/article/pii/S0160412023001770Mercury budgetCLM5-HgHg(0) vegetation uptakelitter Hg concentrationLagging effectPhysiology |
| spellingShingle | Tengfei Yuan Peng Zhang Zhengcheng Song Shaojian Huang Xun Wang Yanxu Zhang Buffering effect of global vegetation on the air-land exchange of mercury: Insights from a novel terrestrial mercury model based on CESM2-CLM5 Environment International Mercury budget CLM5-Hg Hg(0) vegetation uptake litter Hg concentration Lagging effect Physiology |
| title | Buffering effect of global vegetation on the air-land exchange of mercury: Insights from a novel terrestrial mercury model based on CESM2-CLM5 |
| title_full | Buffering effect of global vegetation on the air-land exchange of mercury: Insights from a novel terrestrial mercury model based on CESM2-CLM5 |
| title_fullStr | Buffering effect of global vegetation on the air-land exchange of mercury: Insights from a novel terrestrial mercury model based on CESM2-CLM5 |
| title_full_unstemmed | Buffering effect of global vegetation on the air-land exchange of mercury: Insights from a novel terrestrial mercury model based on CESM2-CLM5 |
| title_short | Buffering effect of global vegetation on the air-land exchange of mercury: Insights from a novel terrestrial mercury model based on CESM2-CLM5 |
| title_sort | buffering effect of global vegetation on the air land exchange of mercury insights from a novel terrestrial mercury model based on cesm2 clm5 |
| topic | Mercury budget CLM5-Hg Hg(0) vegetation uptake litter Hg concentration Lagging effect Physiology |
| url | http://www.sciencedirect.com/science/article/pii/S0160412023001770 |
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