| 1. |
- Casas, Gemma, et al.
(författare)
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Inputs, amplification and sinks of perfluoroalkyl substances at coastal Antarctica
- 2023
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Ingår i: Environmental Pollution. - 0269-7491 .- 1873-6424. ; 338
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Tidskriftsartikel (refereegranskat)abstract
- The sources, biogeochemical controls and sinks of perfluoroalkyl substances, such as perfluoroalkyl acids (PFAAs), in polar coastal regions are largely unknown. These were evaluated by measuring a large multi-compartment dataset of PFAAs concentrations at coastal Livingston and Deception Islands (maritime Antarctica) during three austral summers. PFAAs were abundant in atmospheric-derived samples (aerosols, rain, snow), consistent with the importance of atmospheric deposition as an input of PFAAs to Antarctica. Such PFAAs deposition was unequivocally demonstrated by the occurrence of PFAAs in small Antarctic lakes. Several lines of evidence supported the relevant amplification of PFAAs concentrations in surface waters driven by snow scavenging of sea-spray aerosol-bound PFAAs followed by snow-melting. For example, vertical profiles showed higher PFAAs concentrations at lower-salinity surface seawaters, and PFAAs concentrations in snow were significantly higher than in seawater. The higher levels of PFAAs at Deception Island than at Livingston Island are consistent with the semi-enclosed nature of the bay. Concentrations of PFOS decreased from 2014 to 2018, consistent with observations in other oceans. The sink of PFAAs due to the biological pump, transfer to the food web, and losses due to sea-spray aerosols alone are unlikely to have driven the decrease in PFOS concentrations. An exploratory assessment of the potential sinks of PFAAs suggests that microbial degradation of perfluoroalkyl sulfonates should be a research priority for the evaluation of PFAAs persistence in the coming decade.
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| 2. |
- Vila-Costa, Maria, et al.
(författare)
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Responses to organic pollutants in the tropical Pacific and subtropical Atlantic Oceans by pelagic marine bacteria
- 2023
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Ingår i: Frontiers in Environmental Science. - : Frontiers Media S.A.. - 2296-665X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background and chronic pollution by organic pollutants (OPs) is a widespread threat in the oceans with still uncharacterized effects on marine ecosystems and the modulation of major biogeochemical cycles. The ecological impact and toxicity of this anthropogenic dissolved organic carbon (ADOC) is not related to the presence of a single compound but to the co-occurrence of a myriad of synthetic chemicals with largely unknown effects on heterotrophic microbial communities. We have analyzed the metabolic capacity of metagenome-assembled genomes (MAGs) of natural oceanic communities from the north Pacific (Costa Rica dome) and Atlantic oceans challenged with environmentally relevant levels of ADOC. In the Atlantic, ADOC-exposed MAGs responded transcriptionally more strongly compared to controls than in the Pacific, possibly mirroring the higher relevance of ADOC compounds as carbon source in oligotrophic environments. The largest proportions of transcripts originated from MAGs belonging in the families Rhodobacteraceae and Flavobacteriaceae, known to play a role on consumption of several OPs. In the Atlantic, archaeal Poseidoniales showed the highest transcription levels after 2 h of ADOC exposure, although no increase of relative abundances in the DNA pool was recorded after 24 h, whereas Methylophaga showed the opposite pattern. Both taxa are suggested to be actively involved in the consumption of biogenic alkanes produced by cyanobacteria. We observed similar gene expression profiles of alkane degradation and methylotrophy signature genes. These findings, plus the chemical degradation of alkanes measured in the experiments, provides experimental evidence of the consumption of anthropogenic hydrocarbons and synthetic chemicals at the low concentrations found in the ocean, and modulation of microbiomes by ADOC.
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