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Provedor de dados:  Inra
País:  France
Título:  Xylem sap as a pathway for total mercury and methylmercury transport from soils to tree canopy in the boreal forest
Autores:  Bishop, K.H.
Lee, Y.H.
Munthe, J.
Dambrine, E.
Data:  1998
Ano:  1998
Palavras-chave:  FORET BOREALE
MERCURE
METHYLMERCURE
FEUILLE
SOL
TRANSPORT SOL PLANTE
XYLEME
LITIERE FORESTIERE
POLLUANT
METAL LOURD NORWAY SPRUCE
LITTER 
DEPOSITION
EMISSION
ENVIRONMENT
PLANTS
VAPOR
AIR
HG
ATMOSPHERIC DEPOSITION
LITTERFALL
MERCURY
METHYLMERCURY
XYLEM SAP 
Resumo:  Conifer needles are an important link in the cycling of Total Mercury (THg) and Methylmercury (MeHg) in the boreal ecosystem due to the high THg andMeHg concentrations in litterfall.Translocationwithin the tree ofHg fromsoils to the crowncanopy has been assumed to be a minor source of the Hg in litterfall. This paper, however, is the first to present direct observations of THg/MeHg transport from the soil via xylem sap. Xylem sap concentrations of THg and MeHg were measured in sap drained from different levels along the boles of freshly cut 100 year old Norway spruce (Picea abies) and Scots pine (Pinus sylvestris). The treescame from a mixed stand growing on podzolized till soils at the Svartberget Forest Research Station in N. Sweden. Soil solution concentrations of THg and MeHg at different levels in the soil profile were measured for comparison. Concentrations of THg in xylem sap ranged from 10–15 ng L-1 in both the Scots pine and Norway spruce. Concentrations of MeHg varied from 0.03 ng L-1 to 0.16 ng L-1, with higher values in Scots pine than Norway spruce. If these concentrations are representative of the transport from soils to needles in xylem sap at this site, then only 3% of the MeHg in litterfall (0.12 mg ha-1 yr-1) and 11% of the THg (26 mg ha-1 yr-1) can originate via this pathway. The upward transport via xylem sap is larger relative to the open field inputs (84% of THg and 17% of MeHg). Comparison of soil solution and xylem sap THg/MeHg suggested some degree of THg exclusion during water uptake in Scots pine and Norway spruce, but MeHg exclusion only in Norway spruce.
Tipo:  Journal Article
Idioma:  Inglês
Identificador:  http://www.prodinra.inra.fr/prodinra/pinra/doc.xsp?id=PROD2010da7bd4d&uri=/notices/prodinra1/2010/10/
Fonte:  Biogeochemistry. 1998, 40 (2-3) : 101-113
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