| 1. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 2. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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| 3. |
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| 4. |
- Teira, E., et al.
(författare)
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Bacterioplankton responses to riverine and atmospheric inputs in a coastal upwelling system (Ria de Vigo, NW Spain)
- 2016
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Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 542, s. 39-50
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic pressures are changing the magnitude and nature of matter inputs into the ocean. The Ria de Vigo (NW Spain) is a highly productive and dynamic coastal system that is likely affected by such alterations. Previous nutrient-addition microcosm experiments conducted during contrasting hydrographic conditions suggested that heterotrophic bacteria are limited by organic carbon (C) and occasionally co-limited by inorganic nutrients in this coastal area. In order to assess short-term responses in biomass, production, and respiration of heterotrophic bacteria from the Ria de Vigo to increasing amounts of natural inputs of matter, we conducted 6 microcosm experiments, wherein surface seawater collected in spring, summer, and autumn was mixed with increasing amounts of dissolved natural matter concentrates from riverine and atmospheric origin. Simultaneous experiments with controlled inorganic and/or organic additions indicated that bacteria were co-limited by inorganic nutrients and C in spring and summer and primarily limited by C in autumn. Production responded more than biomass to increasing inputs of matter, whereas respiration did not change. The bacterial production response to increasing dissolved organic C load associated with riverine and atmospheric inputs was strongly related to the relative phosphorus (P) content of the dissolved matter concentrates. Our data suggest that bacterial production might decrease with the increase of P-deficient allochthonous matter inputs, which would have important biogeochemical consequences for C cycling in coastal areas.
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| 5. |
- Aparicio, Fran L., et al.
(författare)
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Eutrophication and acidification : Do they induce changes in the dissolved organic matter dynamics in the coastal Mediterranean Sea?
- 2016
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 563, s. 179-189
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Tidskriftsartikel (refereegranskat)abstract
- Two mesocosms experiments were conducted in winter 2010 and summer 2011 to examine how increased pCO(2) and/or nutrient concentrations potentially perturbate dissolved organic matter dynamics in natural microbial assemblages. The fluorescence signals of protein-and humic-like compounds were used as a proxy for labile and non-labile material, respectively, while the evolution of bacterial populations, chlorophyll a (Chl a) and dissolved organic carbon (DOC) concentrations were used as a proxy for biological activity. For both seasons, the presence of elevated pCO(2) did not cause any significant change in the DOC dynamics (p-value < 0.05). The conditions that showed the greatest changes in prokaryote abundances and Chl a content were those amended with nutrients, regardless of the change in pH. The temporal evolution of fluorophores and optical indices revealed that the degree of humification of the organic molecules and their molecular weight changed significantly in the nutrient-amended treatment. The generation of protein-like compounds was paired to increases in the prokaryote abundance, being higher in the nutrient-amended tanks than in the control. Different patterns in the magnitude and direction of the generation of humic-like molecules suggested that these changes depended on initial microbial populations and the availability of extra nutrient inputs. Based on our results, it is expected that in the future projected coastal scenarios the eutrophication processes will favor the transformations of labile and recalcitrant carbon regardless of changes in pCO(2). (c) 2016 The Authors. Published by Elsevier B.V.
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