| 1. |
- Gonzalez-Gaya, Belen, et al.
(författare)
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Biodegradation as an important sink of aromatic hydrocarbons in the oceans
- 2019
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Ingår i: Nature Geoscience. - : Nature Publishing Group. - 1752-0894 .- 1752-0908. ; 12:2, s. 119-125+2
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric deposition of semivolatile aromatic hydrocarbons accounts for an important input of organic matter to the surface ocean. Nevertheless, the biogeochemical cycling and sinks of semivolatile aromatic hydrocarbons in the ocean remain largely uncharacterized. Here we present measurements of 64 polycyclic aromatic hydrocarbons in plankton and seawater from the Atlantic, Pacific, Indian and Southern Oceans, as well an assessment of their microbial degradation genes. Concentrations of the more hydrophobic compounds decreased when the plankton biomass was higher, consistent with the relevance of the biological pump. The mass balance for the global oceans showed that the settling fluxes of aromatic hydrocarbons in the water column were two orders of magnitude lower than the atmospheric deposition fluxes. This imbalance was high for low molecular weight hydrocarbons, such as phenanthrene and methylphenanthrenes, highly abundant in the dissolved phase. Parent polycyclic aromatic hydrocarbons were depleted to a higher degree than alkylated polycyclic aromatic hydrocarbons, and the degradation genes for polycyclic aromatic hydrocarbons were found to be ubiquitous in oceanic metagenomes. These observations point to a key role of biodegradation in depleting the bioavailable dissolved hydrocarbons and to the microbial degradation of atmospheric inputs of organic matter as a relevant process for the marine carbon cycle.
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| 2. |
- Hough, Rupert
(författare)
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A world view of pesticides
- 2021
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Ingår i: Nature Geoscience. - : Nature Publishing Group. - 1752-0894 .- 1752-0908. ; 14:4, s. 183-184
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Pesticide pollution is a widespread issue. A global risk assessment of 92 active pesticide ingredients suggests 2.5 billion hectares of agricultural land are at risk of pollution by more than one active ingredient.
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| 3. |
- Martinez-Garcia, Eduardo, et al.
(författare)
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Drought response of the boreal forest carbon sink is driven by understorey-tree composition
- 2024
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Ingår i: Nature Geoscience. - : Springer Nature. - 1752-0894 .- 1752-0908. ; 17, s. 197-204
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Tidskriftsartikel (refereegranskat)abstract
- The boreal forest is an important global carbon sink, but its response to drought remains uncertain. Here, we compiled biometric- and chamber-based flux data from 50 boreal forest stands to assess the impact of the 2018 European summer drought on net ecosystem production (NEP) across a 68 km2 managed landscape in northern Sweden. Our results reveal a non-uniform reduction in NEP (on average by 80 +/- 16 g C m-2 yr-1 or 57 +/- 13%) across the landscape, which was greatest in young stands of 20-50 years (95 +/- 39 g C m-2 yr-1), but gradually decreased towards older stands (54 +/- 57 g C m-2 yr-1). This pattern was attributed to the higher sensitivity of forest-floor understorey to drought and its decreasing contribution to production relative to trees during stand development. This suggests that an age-dependent shift in understorey-tree composition with increasing stand age drives the drought response of the boreal forest NEP. Thus, our study advocates the need for partitioning ecosystem responses to improve empirical and modelling assessments of carbon cycle-climate feedbacks in boreal forests. It further implies that the forest age structure may strongly determine the carbon sink response to the projected increase in drought events across the managed boreal landscape. Carbon sink in young boreal forests is more vulnerable to drought than in mature forests due to the greater contribution and drought sensitivity of understorey relative to trees, according to carbon flux assessments of managed boreal forests in northern Sweden during the 2018 European summer drought.
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