| 1. |
- Bednarsek, Nina, et al.
(författare)
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Polar Ocean Acidification : LOSS OF RESOURCES FROM THE “OTHER” CO2 PROBLEM
- 2015
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Ingår i: Thresholds and Closing December. RISKS OF IRREVERSIBLE CRYOSPHERE CLIMATE CHANGE. The International Cryosphere Climate Initiative. ; , s. 19-22
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Although technically not “cryosphere” (which is frozen water), the Arctic Ocean, and Southern Ocean around Antarctica make up some of the world’s richest fisheries, with diverse marine ecosystems. These cold waters are however highly vulnerable to ocean acidification from increased carbon dioxide (CO2) in the atmosphere. We already are crossing important ocean acidification thresholds in these regions, with early impacts possibly observed on some polar ocean species. There is substantial risk that ocean acidification will damage ecosystems and weaken the food chain in these important resource waters, even should countries meet the stated 2 degree goal, which entails atmospheric CO2 levels peaking at 450ppm. However, CO2 concentrations associated with current INDCs in the 2.7–3.5 degree range are far higher still, anticipated to peak potentially above 600ppm. At such high levels, and because of the very long time scales required for acidity to decrease, there is high risk for irreversible impacts on biodiversity in the Arctic and Southern oceans, with consequences for polar and near-polar fisheries and human activities.
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| 2. |
- Bellerby, Richard, et al.
(författare)
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Acidification in the Arctic Ocean
- 2013
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Ingår i: Chapter 2 in: AMAP, 2013. AMAP Assessment 2013: Arctic Ocean Acidification. Arctic Monitoring and Assessment Programme (AMAP). - Oslo, Norway : AMAP. - 9788279710820 ; , s. 9-36
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Bokkapitel (refereegranskat)abstract
- A consequence of the persistent release of carbon dioxide (CO2) to the atmosphere following fossil fuel combustion and changes in land use is that there is an increasing net air-to-sea transport of CO2. Although this oceanic uptake will reduce the potential for greenhouse warming that would have arisen had the gas remained in the atmosphere, it will also result in major changes in ocean chemistry. The most obvious signal in this respect is the fall in ocean pH and the change in the speciation of the marine carbonate system. The Arctic Ocean is one of the regions where ocean acidification is occurring fastest. From a baseline where the seawater is already poorly buffered and thus small changes in CO2 content have large changes in pH, there are a multitude of stressors that act on the Arctic Ocean amplifying the acidification. This chapter summarizes carbonate chemistry in seawater (Section 2.2) and reviews the major processes influencing the Arctic Ocean carbonate system (Section 2.3). The chapter also describes some of the biogeochemical processes sensitive to ocean acidification (Section 2.4). Section 2.5 addresses the major sources and sinks of carbon to the Arctic Ocean, and presents a regional breakdown of contemporary rates of ocean acidification. Finally, simulations from earth system models and regional models are analyzed to project potential changes to the Arctic Ocean carbonate system (Section 2.6).
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| 3. |
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| 4. |
- Briddon, Charlotte L., et al.
(författare)
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Acclimation to various temperature and pCO2 levels does not impact the competitive ability of two strains of Skeletonema marinoi in natural communities
- 2023
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Ingår i: Frontiers in Marine Science. - 2296-7745. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the long-term response of key marine phytoplankton species to ongoing global changes is pivotal in determining how oceanic community composition will respond over the coming decades. To better understand the impact of ocean acidification and warming, we acclimated two strains of Skeletonema marinoi isolated from natural communities to three pCO2 (400 μatm, 600 μatm and 1000 μatm) for 8 months and five temperature conditions (7°C, 10°C, 13°C, 16°C and 19°C) for 11 months. These strains were then tested in natural microbial communities, exposed to three pCO2 treatments (400 μatm, 600 μatm and 1000 μatm). DNA metabarcoding of the 16S and 18S gene for prokaryotes and eukaryotes respectively was used to show differences in abundance and diversity between the three CO2 treatments. We found there were no significant differences in acclimated S. marinoi concentrations between the three pCO2 treatments, most likely due to the high variability these strains experience in their natural environment. There were significant compositional differences between the pCO2 treatments for prokaryotes suggesting that indirect changes to phytoplankton-bacteria interactions could be a possible driver of bacterial community composition. Yet, there were no differences for eukaryotic community composition, with all treatments dominated by diatoms (but not the acclimated S. marinoi) resulting in similar biodiversity. Furthermore, strain-specific differences in community composition suggests interactions between prokaryotic and eukaryotic taxa could play a role in determining future community composition.
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| 5. |
- Jutterström, Sara, 1975, et al.
(författare)
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Evaluation of anthropogenic carbon in the Nordic Seas using observed relationships of N, P and C versus CFCs
- 2008
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Ingår i: Progress in Oceanography. - : Elsevier BV. - 0079-6611. ; 78:1, s. 78-84
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Tidskriftsartikel (refereegranskat)abstract
- Several methods to compute the anthropogenic component of total dissolved inorganic carbon () in the ocean have been reported, all in some way deducing (a) the effect by the natural processes, and (b) the background concentration in the pre-industrial scenario. In this work we present a method of calculating using nutrient and CFC data, which takes advantage of the linear relationships found between nitrate (N), phosphate (P) and CFC-11 in the Nordic Seas sub-surface waters. The basis of the method is that older water has lower CFC-11 concentration and also has been exposed to more sinking organic matter that has decayed, resulting in the slopes of P versus CFC-11 and N versus CFC-11 being close to the classic Redfield ratio of 1:16. Combining this with the slope in total alkalinity (AT) versus CFC-11 to correct for the dissolution of metal carbonates gives us the possibility to deduce the concentration of anthropogenic CT in the Nordic Seas. This further allowed us to compute the inventory of anthropogenic CT below 250 m in the Nordic Seas in spring 2002, to 1.2 Gt C.
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| 6. |
- Kasajima, Yoshie, et al.
(författare)
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A submesoscale coherent eddy in the Greenland Sea in 2003
- 2006
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH. - 0148-0227. ; 111
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Tidskriftsartikel (refereegranskat)abstract
- Submesoscale Coherent Vortices (SCVs) have been observed earlier in the Greenland Sea, but their overall characteristics, the formation and the dissolution mechanisms, and the effects on the large-scale hydrodynamics were not well understood. In order to improve the understanding of these features, a simultaneous investigation of hydrography, chemical tracers, and full-depth velocity profiles in a SCV was employed in September 2003. The observed eddy had a homogeneous cold core from 500 m to 2500 m depth with a radius of 8∼15 km. The velocity field of the eddy was higher than in the previous years, and the eddy was in strong anticyclonic rotation in the intermediate layer (1000∼2000 m). The high velocity field led to the estimate of eddy vorticity twice as high as previous observations, and this was accounted for the eddy migration while the earlier observed eddies were rather stationary around 75°N 0°E. The eddy migrated northeast ward with a speed of 3 km/day driven by the background mean flow under the strong effects of the background shear, which tilted the rotation axis in the upper layer. The concentrations of sulphur hexafluoride (SF6) and chlorofluorocarbons (CFCs) in the eddy provided firm information about the source water end-members. The Greenland Sea Arctic Intermediate Water and winter cold surface water were determined as the principal eddy source waters. This differs from the earlier conception of eddies being sourced from intermediate waters at the periphery of the Greenland Basin.
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| 7. |
- Kivimae, Caroline, et al.
(författare)
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A carbon budget for the Barents Sea
- 2010
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Ingår i: DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS. - 0967-0637. ; 57:12, s. 1532-1542
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Nondal, Gisle, et al.
(författare)
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Optimal evaluation of the surface ocean CO2 system in the northern North Atlantic using data from voluntary observing ships
- 2009
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Ingår i: Limnology and Oceanography : Methods. - 1541-5856. ; 7, s. 109-118
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Tidskriftsartikel (refereegranskat)abstract
- This work evaluates whether an accurate calculation of the entire CO2 system in the northern North Atlantic can be carried out using a combination of in situ fugacity of CO2 (fCO2) and ancillary data often measured on Voluntary Observing Ships (VOS), i.e., sea surface temperature (SST) and sea surface salinity (SSS), as well as nitrate (NO3 –). Two approaches are tested: (I) determination of At from SSS and then calculating Ct from measured fCO2 and estimated At; and (II) determination of Ct from SSS, SST, and NO3 – and then calculating At from measured fCO2 and estimated Ct. The optimal approach was found to be determination of At from SSS and then calculating Ct from measured fCO2 and estimated At. This allowed At to be determined with a mean bias of –1.8 μmol kg–1 and root mean square (rms) deviation 6.2 μmol kg–1 and then Ct to be calculated with a mean bias of –1.0 μmol kg–1 and standard error of calculation of 7.4 μmol kg–1, as validated using independent data sets.
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| 9. |
- Olsen, Are, 1972, et al.
(författare)
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Nordic seas transit time distributions and anthropogenic CO2
- 2010
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Ingår i: Journal of Geophysical Research Oceans. - 0148-0227. ; 115
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Tidskriftsartikel (refereegranskat)abstract
- The distribution and inventory of anthropogenic carbon (DICant) in the Nordic seas are determined using the transit time distribution (TTD) approach. To constrain the shape of the TTDs in the Nordic seas, CO2 is introduced as an age tracer and used in combination with water age estimates determined from CFC-12 data. CO2 and CFC-12 tracer ages constitute a very powerful pair for constraining the shape of TTDs. The highest concentrations of DICant appear in the warm and well-ventilated Atlantic water that flows into the region from the south, and concentrations are typically lower moving west into the colder Arctic surface waters. The depth distribution of DICant reflects the extent of ventilation in the different areas. The Nordic seas DICant inventory for 2002 was constrained to between 0.9 and 1.4 Gt DICant, corresponding to ∼1% of the global ocean DICant inventory. The TTD-derived DICant estimates were compared with estimates derived using four other approaches, revealing significant differences with respect to the TTD-derived estimates, which can be related to issues with some of the underlying assumptions of these other approaches. Specifically, the Tracer combining Oxygen, inorganic Carbon and total Alkalinity (TrOCA) method appears to underestimate DICant in the Nordic seas, the ΔC* shortcut and the approach of Jutterström et al. (2008) appear to overestimate DICant at most depths in this area, and finally the approach of Tanhua et al. (2007) appears to underestimate Nordic seas DICant below 3000 m and overestimate it above 1000 m.
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| 10. |
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