| 1. |
- Edman, Moa, et al.
(författare)
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Effect on pCO(2) by phytoplankton uptake of dissolved organic nutrients in the Central and Northern Baltic Sea, a model study
- 2014
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Ingår i: Journal of Marine Systems. - : Elsevier BV. - 0924-7963. ; 139, s. 166-182
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Tidskriftsartikel (refereegranskat)abstract
- Dissolved organic matter (DOM) has been added to an existing biogeochemical model and the phytoplankton were allowed to utilize the dissolved organic nutrients for primary production. The results show typical vertical structures for dissolved organic carbon (DOC), and improved or maintained model skill for both mean vertical profiles and mean seasonal variation of biogeochemical variables, evaluated by objective skill metrics. Due to scarce DOM measurements in the Baltic Sea it was hard to validate the new variables, but the model can recreate the general magnitude and distribution of terrestrial and in situ produced DOC, DON, and DOP, as far as we know them. The improvements are especially clear for the total nutrient levels and in recreating the biological drawdown of CO2 in the Eastern Gotland basin. Without phytoplankton uptake of dissolved organic nitrogen and phosphate, CO2 assimilation is lower during the summer months and the partial pressure of CO2 increases by about 200 mu atm in the Eastern Gotland Basin, while in the Bothnian Bay, both the duration and magnitude of CO2 assimilation are halved. Thus the phytoplankton uptake of dissolved organic nutrients lowers pCO(2) in both basins. Variations in the river transported DOM concentration mainly affect the magnitude of the summer cyanobacteria bloom. (C) 2014 Elsevier B.V. All rights reserved.
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| 2. |
- Edman, Moa
(författare)
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Kustzonsmodellen inom vattenförvaltningen : Vidareutveckling av användningsområden
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport presenterar förslag på hur Kustzonsmodellen kan användas för att effektivisera förvaltningen av Sveriges kustvatten.Rapporten riktar sig framförallt till handläggare på myndigheter och forskare som arbetar med vattenförvaltning. Resultatet kan användas för vidare metodutveckling, men också för exempelvis utplacering av representativa övervakningsstationer eller som grund för gruppering av vattenförekomster.Rapporten har tagits fram av SMHI, på uppdrag från Havs- och vattenmyndigheten.BakgrundI Sverige finns en modell uppsatt för hela kustlinjen för beräkning av vattenkvalitet. Uppdragets syfte har varit att utforska nya användningsområden för denna kustzonsmodell inom vattenförvaltningen. Då uppdragets syfte främst har varit att testa nya sätt att använda kustzonsmodellen inom förvaltningen, ges få rekommendationer. Istället ger uppdraget ett underlag som kan användas vidare.Förvaltningen av Sveriges kustvatten ställer krav på god kunskap om miljötillståndet. Information kan samlas in genom provtagningar av kustvattnet, men dessa kan aldrig bli heltäckande. Ett alternativ är att utifrån kunskap om mänsklig påverkan och kunskap om vattnens karakteristiska modellera tillståndet. Resultat från modellen kan sedan verifieras med provtagningar. Denna rapport presenterar förslag på hur Kustzonsmodellen kan användas för att effektivisera förvaltningen av Sveriges kustvatten.
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| 3. |
- Edman, Moa, et al.
(författare)
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Modeling the dissolved CO2 system in the redox environment of the Baltic Sea
- 2013
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Ingår i: Limnology and Oceanography. - : Wiley. - 0024-3590. ; 58:1, s. 74-92
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Tidskriftsartikel (refereegranskat)abstract
- Generation and depletion of total alkalinity (AT) were added to a Baltic Sea numerical model. The vertical distribution of generation and depletion of total alkalinity were described and attributed to different processes in the Eastern Gotland basin at the Gotland deep station (BY15) during the 1995–2004 period. At this site, the mean annual generation (28.2 µmol kg-1 yr-1) and depletion (-25.8 µmol kg-1 yr-1) were almost balanced, though the transient rates were much faster (+125/-340 µmol kg-1 yr-1). The mean volume-integrated AT content increased up to 50 µmol kg-1 when generation and depletion were added to the model. The AT changes were coupled to oxidation–reduction (redox) reactions and the model budget indicates that internal generation and depletions is as important as lateral transports, including riverine input, at this site. Model predictive capability in marine environments with strong biogeochemical gradients was improved by coupling within the dissolved CO2, and the biogeochemical, systems. This enables evaluation of eutrophication, acidification, and climate change simultaneously, and is important specifically in regions with permanent or periodic anoxia.
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| 4. |
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| 5. |
- Edman, Moa
(författare)
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Modelling the Dissolved Inorganic Carbon System in the Baltic Sea
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Oceans are capable of storing part of the emitted anthropogenic carbon dioxide (CO2) due to the formation of carbonic acid and subsequent dissociation. CO2 is also assimilated by biota and the inorganic carbon system is thus coupled to biogeochemical processes. Naturally, it is a substantial improvement of model realism if the inorganic carbon system is fully coupled to biogeochemistry in numerical models. The focus of this thesis has been to improve the accuracy of pH and the partial pressure of CO2 (pCO2) computations for a marine environment like the Baltic Sea, but the knowledge we have gained is generally applicable. A model system has been developed to consider several environmental threats simultaneously (eutrophication, acidification, and climate change) and the model skill has been certified by using objective skill metrics. To improve the coupling between biogeochemical processes and the dissolved inorganic carbon system, generation and depletion of total alkalinity (AT) due to several biogeochemical reactions was added to the model. In situ generation of AT was found to be important, specifically in regions with permanent or periodic anoxia, as the major AT changes were coupled to oxidation–reduction (redox) reactions. Without adding AT from these processes, the correct pH could not be calculated in anoxic waters and the mean volume AT content was found to be too low. The improvements were put to use when several environmental threats were evaluated simultaneously in a study of possible future changes in the Baltic Sea pH and oxygen balances. A coupled model for the catchment and sea was set up and forced by meteorological and hydrological datasets and scenarios. The results showed that increased nutrient loads will not inhibit future Baltic Sea acidification, but the seasonal pH cycle will be amplified by increased biological production and mineralization. The study indicated future acidification of the whole Baltic Sea and that the main factor controlling the direction and magnitude of the change was the atmospheric CO2 concentration. Through a previous investigation of the sensitivity of Baltic Sea surface water pH it was found that increased atmospheric CO2 can affect pH also through changing the river chemistry, especially with regard to AT. The latter could severely impact water in the northern Baltic region. To improve modelled seasonal pCO2 variations dissolved organic matter was added to a numerical model. The modelled phytoplankton were allowed to utilize the dissolved organic nutrients and the biological drawdown of CO2 in the Eastern Gotland basin was much improved by this. When phytoplankton used the organic nutrients the CO2 assimilation was higher during the summer months and the partial pressure of CO2 decreased by ~200 µatm in the Eastern Gotland Basin as a result. In the Bothnian Bay, both the duration and magnitude of CO2 assimilation was doubled when phytoplankton utilized dissolved organic nutrients.
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| 6. |
- Eilola, Kari, et al.
(författare)
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SMHI reportsSMHI rep., Oceanogr : Swedish Meteorological and Hydrological Institute reports. OceanographySMHISMHI report. Oceanography 2007:37OceanographyROSMHI RO
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report is related to the BONUS project “Nutrient Cocktails in COAstal zones of the Baltic Sea” alias COCOA. The aim of BONUS COCOA is to investigate physical, biogeochemical and biological processes in a combined and coordinated fashion to improve the understanding of the interaction of these processes on the removal of nutrients along the land -sea interface. The report is especially related to BONUS COCOA WP 6 in which the main objective is extrapolation of results from the BONUS COCOA learning sites to coastal sites around the Baltic Sea in general. Specific objectives of this deliverable (D6.4) were to connect observed process rates with modelling data and ecosystem characteristics.In the report we made statistical analyses of observations from BONUS COCOA study sites together with results from the Swedish Coastal zone Model (SCM). Eight structural variables (water depth, temperature, salinity, bottom water concentrations of oxygen, ammonium, nitrate and phosphate, as well as nitrogen content in sediment) were found common to both the experimentally determined and the model data sets. The observed process rate evaluated in this report was denitrification. In addition regressions were tested between observed denitrification rates and several structural variables (lat itude, longitude, depth, light, temperature, salinity, grain class, porosity, loss of ignition, sediment organic carbon, total nitrogen content in the sediment, sediment carbon/nitrogen-ratio, sediment chlorphyll-a as well as bottom water concentrations of oxygen, ammonium, nitrate, and dissolved inorganic phosphorus and silicate) for pooled data from all learning sites.The statistical results showed that experimentally determined multivariate data set from the shallow, illuminated stations was mainly found to be similar to the multivariate data set produced by the SCM model. Generally, no strong correlations of simple relations between observed denitrification and available structural variables were found for data collected from all the learning sites. We found some non-significant correlation between denitrification rates and bottom water dissolved inorganic phosphorous and dissolved silica but the reason behind the correlations is not clear.We also developed and evaluated a theory to relate process rates to monitoring data and nutrient retention. The theoretical analysis included nutrient retention due to denitrification as well as burial of phosphorus and nitrogen. The theory of nutrient retention showed good correlations with model results. It was found that area-specific nitrogen and phosphorus retention capacity in a sub-basin depend much on mean water depth, water residence time, basin area and the mean nutrient concentrations in the active sediment layer and in the water column.
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| 7. |
- Kratzer, Susanne, et al.
(författare)
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Synergy of Satellite, In Situ and Modelled Data for Addressing the Scarcity of Water Quality Information for Eutrophication Assessment and Monitoring of Swedish Coastal Waters
- 2019
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Ingår i: Remote Sensing. - : MDPI AG. - 2072-4292. ; 11:17
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Tidskriftsartikel (refereegranskat)abstract
- Monthly CHL-a and Secchi Depth (SD) data derived from the full mission data of the Medium Resolution Imaging Spectrometer (MERIS; 2002-2012) were analysed along a horizontal transect from the inner Braviken bay and out into the open sea. The CHL-a values were calibrated using an algorithm derived from Swedish lakes. Then, calibrated Chl-a and Secchi Depth (SD) estimates were extracted from MERIS data along the transect and compared to conventional monitoring data as well as to data from the Swedish Coastal zone Model (SCM), providing physico-biogeochemical parameters such as temperature, nutrients, Chlorophyll-a (CHL-a) and Secchi depth (SD). A high negative correlation was observed between satellite-derived CHL-a and SD (rho = -0.91), similar to the in situ relationship established for several coastal gradients in the Baltic proper. We also demonstrate that the validated MERIS-based estimates and data from the SCM showed strong correlations for the variables CHL-a, SD and total nitrogen (TOTN), which improved significantly when analysed on a monthly basis across basins. The relationship between satellite-derived CHL-a and modelled TOTN was also evaluated on a monthly basis using least-square linear regression models. The predictive power of the models was strong for the period May-November (R-2: 0.58-0.87), and the regression algorithm for summer was almost identical to the algorithm generated from in situ data in Himmerfjarden bay. The strong correlation between SD and modelled TOTN confirms that SD is a robust and reliable indicator to evaluate changes in eutrophication in the Baltic proper which can be assessed using remote sensing data. Amongst all three assessed methods, only MERIS CHL-a was able to correctly depict the pattern of phytoplankton phenology that is typical for the Baltic proper. The approach of combining satellite data and physio-biogeochemical models could serve as a powerful tool and value-adding complement to the scarcely available in situ data from national monitoring programs. In particular, satellite data will help to reduce uncertainties in long-term monitoring data due to its improved measurement frequency.
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| 8. |
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| 9. |
- Meier, H. E. Markus, et al.
(författare)
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Assessment of Eutrophication Abatement Scenarios for the Baltic Sea by Multi-Model Ensemble Simulations
- 2018
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- To assess the impact of the implementation of the Baltic Sea Action Plan (BSAP) on the future environmental status of the Baltic Sea, available uncoordinated multi-model ensemble simulations for the Baltic Sea region for the twenty-first century were analyzed. The scenario simulations were driven by regionalized global general circulation model (GCM) data using several regional climate system models and forced by various future greenhouse gas emission and air- and river-borne nutrient load scenarios following either reference conditions or the BSAP. To estimate uncertainties in projections, the largest ever multi-model ensemble for the Baltic Sea comprising 58 transient simulations for the twenty-first century was assessed. Data from already existing simulations from different projects including regionalized GCM simulations of the third and fourth assessment reports of the Intergovernmental Panel on Climate Change based on the corresponding Coupled Model Intercomparison Projects, CMIP3 and CMIP5, were collected.Various strategies to weigh the ensemble members were tested and the results for ensemble mean changes between future and present climates are shown to be robust with respect to the chosen metric. Although (1) the model simulations during the historical period are of different quality and (2) the assumptions on nutrient load levels during present and future periods differ between models considerably, the ensemble mean changes in biogeochemical variables in the Baltic proper with respect to nutrient load reductions are similar between the entire ensemble and a subset consisting only of the most reliable simulations.Despite the large spread in projections, the implementation of the BSAP will lead to a significant improvement of the environmental status of the Baltic Sea according to both weighted and unweighted ensembles. The results emphasize the need for investigating ensembles with many members and rigorous assessments of models’ performance.
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| 10. |
- Meier, H. E. Markus, et al.
(författare)
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Assessment of Uncertainties in Scenario Simulations of Biogeochemical Cycles in the Baltic Sea
- 2019
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 6
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Forskningsöversikt (refereegranskat)abstract
- Following earlier regional assessment studies, such as the Assessment of Climate Change for the Baltic Sea Basin and the North Sea Region Climate Change Assessment, knowledge acquired from available literature about future scenario simulations of biogeochemical cycles in the Baltic Sea and their uncertainties is assessed. The identification and reduction of uncertainties of scenario simulations are issues for marine management. For instance, it is important to know whether nutrient load abatement will meet its objectives of restored water quality status in future climate or whether additional measures are required. However, uncertainties are large and their sources need to be understood to draw conclusions about the effectiveness of measures. The assessment of sources of uncertainties in projections of biogeochemical cycles based on authors' own expert judgment suggests that the biggest uncertainties are caused by (1) unknown current and future bioavailable nutrient loads from land and atmosphere, (2) the experimental setup (including the spin up strategy), (3) differences between the projections of global and regional climate models, in particular, with respect to the global mean sea level rise and regional water cycle, (4) differing model-specific responses of the simulated biogeochemical cycles to long-term changes in external nutrient loads and climate of the Baltic Sea region, and (5) unknown future greenhouse gas emissions. Regular assessments of the models' skill (or quality compared to observations) for the Baltic Sea region and the spread in scenario simulations (differences among projected changes) as well as improvement of dynamical downscaling methods are recommended.
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