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- Lønborg, C., et al.
(författare)
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A global database of dissolved organic matter (DOM) concentration measurements in coastal waters (CoastDOM v1)
- 2024
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Ingår i: Earth System Science Data. - : Copernicus Publications. - 1866-3508 .- 1866-3516. ; 16:2, s. 1107-1119
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of dissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) concentrations are used to characterize the dissolved organic matter (DOM) pool and are important components ofbiogeochemical cycling in the coastal ocean. Here, we present the first edition of a global database (CoastDOMv1; available at https://doi.org/10.1594/PANGAEA.964012, Lønborg et al., 2023) compiling previously published and unpublished measurements of DOC, DON, and DOP in coastal waters. These data are complementedby hydrographic data such as temperature and salinity and, to the extent possible, other biogeochemical variables(e.g. chlorophyll a, inorganic nutrients) and the inorganic carbon system (e.g. dissolved inorganic carbon andtotal alkalinity). Overall, CoastDOM v1 includes observations of concentrations from all continents. However,most data were collected in the Northern Hemisphere, with a clear gap in DOM measurements from the SouthernHemisphere. The data included were collected from 1978 to 2022 and consist of 62 338 data points for DOC,20 356 for DON, and 13 533 for DOP. The number of measurements decreases progressively in the sequenceDOC > DON > DOP, reflecting both differences in the maturity of the analytical methods and the greater focuson carbon cycling by the aquatic science community. The global database shows that the average DOC concentration in coastal waters (average ± standard deviation (SD): 182±314 µmolC L−1; median: 103 µmolC L−1) is13-fold higher than the average coastal DON concentration (13.6 ± 30.4 µmol N L−1; median: 8.0 µmol N L−1),which is itself 39-fold higher than the average coastal DOP concentration (0.34 ± 1.11 µmol P L−1; median:0.18 µmol P L−1). This dataset will be useful for identifying global spatial and temporal patterns in DOM and willhelp facilitate the reuse of DOC, DON, and DOP data in studies aimed at better characterizing local biogeochemical processes; closing nutrient budgets; estimating carbon, nitrogen, and phosphorous pools; and establishing abaseline for modelling future changes in coastal waters.
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| 2. |
- Sala, M. M., et al.
(författare)
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Contrasting effects of ocean acidification on the microbial food web under different trophic conditions
- 2016
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Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 73:3, s. 670-679
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the effects of an increase in dissolved CO2 on the microbial communities of the Mediterranean Sea during two mesocosm experiments in two contrasting seasons: winter, at the peak of the annual phytoplankton bloom, and summer, under low nutrient conditions. The experiments included treatments with acidification and nutrient addition, and combinations of the two. We followed the effects of ocean acidification (OA) on the abundance of the main groups of microorganisms (diatoms, dinoflagellates, nanoeukaryotes, picoeukaryotes, cyanobacteria, and heterotrophic bacteria) and on bacterial activity, leucine incorporation, and extracellular enzyme activity. Our results showed a clear stimulation effect of OA on the abundance of small phytoplankton (pico- and nanoeukaryotes), independently of the season and nutrient availability. A large number of the measured variables showed significant positive effects of acidification in summer compared with winter, when the effects were sometimes negative. Effects of OA were more conspicuous when nutrient concentrations were low. Our results therefore suggest that microbial communities in oligotrophic waters are considerably affected by OA, whereas microbes in more productive waters are less affected. The overall enhancing effect of acidification on eukaryotic pico- and nanophytoplankton, in comparison with the non-significant or even negative response to nutrient-rich conditions of larger groups and autotrophic prokaryotes, suggests a shift towards medium-sized producers in a future acidified ocean.
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