| 1. |
- Bergström, Lena, et al.
(författare)
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Interim Report of the ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea (WGIAB) : 18-22 April 2016 Helsinki, Finland
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea (WGIAB) meeting was held in Helsinki (Finland), 18-22 April 2016. The meeting was attended by 26 participants from five countries and chaired by Laura Uusitalo, Fin-land, Saskia Otto, Germany, Martin Lindegren, Denmark, and Lena Bergström, Swe-den. This was the first year of the new three-year Terms of Reference (ToR) for WGIAB. The main working activities in 2016 were to A) develop the trait-based ap-proach of understanding the ecosystem function, and B) explore the social-ecological system, including indicator development, revising the conceptual model, and devel-oping case studies. As a primary outcome of the ToR A, we built on our previous work on integrated ecosystem assessments (IEAs) in the Baltic Sea, but extended it beyond considering changes in abundances of a few dominant species, to accounting for community-wide changes in a number of key traits across multiple trophic levels. These traits represent various ecosystem functions upon which we derive important ecosystem services. By investigating temporal changes in the community weighted mean traits of phyto-plankton, zooplankton, zoobenthos, and fish, we demonstrated whether trait reor-ganizations at the level of entire communities occurred in the Central Baltic Sea as a result of the 1980s regime shift. Using in total 29 traits combined for all groups we found indications of two breakpoints across all four taxonomic groups over the last decades, i.e. one around 1990 and one around 2000. Further work will focus on ex-ploring the nature of the changes in trait composition and on standardizing the num-ber of traits and data types (i.e. binary, continuous or categorical) across taxonomic group.In addition, we collected data on key functional groups and abiotic variables in all main sub-basins of the Baltic Sea, setting the stage for a cross-regional comparison of temporal patterns and trends in lower trophic level in the face of recent develop-ments in climate-related drivers.With reference to Tor B, to explore how social indicators could be used in parallel with biological indicators in an integrated assessment framework, we developed a conceptual model of interrelationships between ecosystem and society. We used the model as a basis for mapping factors to be accounted for in the ecosystem-based management using the Baltic salmon and clupeid species as case studies. The models depict 1) the structure of the foodweb relevant to the target species, 2) the key com-munity level and population traits that contribute to the state of the species, 3) main pressures affecting the foodweb and their effects on the species, 4) key management measures, and 5) benefits that the species can produce for society.To support the development of Ecosystem Overview the group members evaluated the probability of occurrence and the magnitude of the effect of 15 pressures occur-ring in the Baltic Sea. The top five pressures identified were input of nutrients, in-creased temperature, decreased salinity, input of hazardous substances, and input or spread of non-indigenous species.The work will continue intersessionally and the next meeting of WGIAB is planned to be held in Lisbon, Portugal, back-to-back with WGCOMEDA and WGEAWESS.
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| 2. |
- Bergström, Lena, et al.
(författare)
-
Report of the ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea (WGIAB)
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea(WGIAB) was established in 2007 as a forum for developing and combining ecosystembasedmanagement efforts for the Baltic Sea. The group intends to serve as a scientificcounterpart and support for the ICES Baltic Fisheries Assessment Working Group(WGBFAS) as well as for efforts and projects related to Integrated Ecosystem Assessments(IEA) within ICES and HELCOM. The group works in cooperation with similargroups within the ACOM/SCICOM Steering Group on Integrated Ecosystem Assessments(SSGIEA).The 2015 WGIAB meeting was held in Cádiz, Spain, from 9–13 March, back-to-backwith the meeting of its counterpart in the Working Group on Ecosystem Assessmentof Western European Shelf Seas (WGEAWESS). The meetings had joint sessions as wellas WG specific work, and some participants effectively participated in both meetings.The WGIAB meeting was attended by 27 participants from nine countries. The meetingwas chaired by Christian Möllmann, Germany, Laura Uusitalo, Finland and Lena Bergström,Sweden.This was the last year of the ongoing three-year Terms of Reference (ToR) for WGIAB.The main working activities in 2015 were to i) conduct studies on Baltic Sea ecosystemfunctioning with the goal to publish case studies from different parts of the Baltic Seain peer-reviewed journals, ii) work on the demonstration exercise to develop ecosystem-based assessment and advice for Baltic fish stocks focusing on cod (DEMO) withmultiple approaches, iii) plan further how to integrate the social and economic aspectsmore tightly in the WGIAB work, and iv) discuss the future focus and format of theWGIAB work.The Baltic ecosystem functioning activity focused on identifying and exploring keytrends and linkages in the Baltic Sea foodweb. This was pursued by presentation andfurther discussion of ongoing intersessional work on foodweb modelling and integratedanalyses, and by exercises to develop conceptual models Baltic Sea foodwebsand the links to ecosystem function. Long-term monitoring datasets on the abiotic andbiotic parts of the Baltic Sea Proper ecosystem were updated for use in the continuedwork to develop environmental indicators for fisheries and marine management.The focus of the DEMO 3 (DEMOnstration exercise for Integrated Ecosystem Assessmentand Advice of Baltic Sea cod) was on finding a way to use the results from theDEMO1 and DEMO2 workshops in short and midterm projections/scenarios of Balticcod dynamics based on different types of modelling, as well as designing methodologyand modelling data for practical implementation of Integrated Advice for Baltic cod.The WGIAB was positively inclined towards including social and economic aspectsinto the integrated assessment. Openings to this path were provided by presentationon ongoing project work, and discussing their linkages to ecological aspects. It wasseen as crucial that experts on social and economic analysis should be included andtake an active part in the future work of the group.The group concluded that its upcoming work should focus more closely on functionaldiversity, which was identified as a recurring issue in the Baltic Sea. This approach wasalso identified as a useful connection point between scientific and management aspectsin order for the group to continue serving as a forum for developing ecosystem-basedmanagement efforts in the Baltic Sea. A focus on functional diversity was also seen as2 | ICES WGIAB REPORT 2015a potentially feasible way of bringing together management aspects for different sectors,by linking to ecosystem services concepts.The group proposed Saskia Otto, Germany and Martin Lindegren, Denmark as newincoming Chairs, together with Lena Bergström, Sweden and Laura Uusitalo, Finland.Having four Chairs is justified due to the wide scope of the group's work, as well asthe increased work load due to the planned new foci.
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| 3. |
- Hjalmarsson, Sofia, 1980, et al.
(författare)
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Distribution, long-term development and mass balance calculation of total alkalinity in the Baltic Sea
- 2008
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Ingår i: Continental Shelf Research. - : Elsevier BV. - 0278-4343. ; 28:4-5, s. 593-601
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Tidskriftsartikel (refereegranskat)abstract
- During the 20th century, extensively hydrographic investigations had been performed in the Baltic Sea. One of the parameters that have been determined during these historic investigations of the Baltic Sea is the total alkalinity (AT). In this study, this large data set is used together with a specifically developed box model to estimate the in- and outflows of salinity and AT within the different sub-basins. The Baltic Sea receives large amounts of freshwater through river runoff, and AT can be used as a chemical signature of the runoff as its concentration depends on the mineralogy of the drainage basin. Rivers entering the southern part of the Baltic Sea are draining areas rich in limestone, therefore having higher AT than rivers entering the northern part of the Baltic Sea where granite dominates the bedrock. The mean AT in rivers entering a specific region of the Baltic Sea is achieved by the intercept of the regression line when salinity is plotted versus AT for the corresponding data. In this study, the focus is on the Gulf of Finland and the Gulf of Bothnia where the longest time series data are available. There is a common trend with an increase in AT in rivers entering the Gulf of Finland and a decrease in AT in rivers entering the Gulf of Bothnia.
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| 4. |
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| 5. |
- Omstedt, Anders, 1949, et al.
(författare)
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A comparison between the ERA40 and the SMHI gridded meteorological databases as applied to Baltic Sea modelling
- 2005
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Ingår i: Nordic Hydrology. - 0029-1277. ; 36:4-5, s. 369-380
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Tidskriftsartikel (refereegranskat)abstract
- Two gridded meteorological data sets for the Baltic Sea region, both having 1 degrees x 1 degrees horizontal resolution, were compared and analysed for use in Baltic Sea modelling. The SMHI 1 degrees x 1 degrees data set covers surface parameters with a three-hour time resolution over the 1970-2004 period. The ERA40 data cover analysed and modelled parameters for several atmospheric layers with a six-hour time resolution over the 1957-2002 period. Meteorological variables considered in this analysis were air temperature, wind speed, total cloud cover, relative humidity and precipitation. In considering Baltic Sea modelling, we examined maximum ice extent, water temperature, salinity and net precipitation calculations. The two data sets are largely similar and can both be used in Baltic Sea modelling. However, their horizontal resolution is too coarse for resolving marine conditions over the Baltic Sea. This implies, for example, that the ERA40 original surface winds are too low for some Baltic Sea regions. The ERA40 precipitation values are also too low compared with those of the SMHI and other available data.
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| 6. |
- Omstedt, Anders, 1949, et al.
(författare)
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Modelling the uptake and release of carbon dioxide in the Baltic Sea surface water
- 2009
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Ingår i: Continental Shelf Research. ; 29, s. 870-885
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Tidskriftsartikel (refereegranskat)abstract
- We present and analyse a fully coupled physical–biogeochemical model of the uptake and release of carbon dioxide in the Baltic Sea. The modelling includes the interaction between physical (stratification, temperature, salinity, penetration of solar radiation, and ice), chemical (total alkalinity, pH, dissolved inorganic carbon, oxygen, and nutrients), and biological processes (plankton and dissolved organic carbon (DOC)). These processes have been built into an advanced process-oriented coupled basin ocean model that has been extensively explored and validated for the Baltic Sea. The model captures major physical–chemical and biological response patterns, as evaluated based on observations from the central Baltic Sea, and illustrate the need to include fractional nutrient release in the photic zone for consistency with CO2 observations. The study indicates that long-term values of the water partial pressure of carbon dioxide were above atmospheric values before industrialization, with a net release of CO2 to the atmosphere. Seasonal variability increased in the modern industrialization era with the inclusion of eutrophication, making the Baltic Sea both a sink and source of CO2 to the atmosphere. Modelling long-term variations in pH indicates the existence of stable conditions before industrialization and slight decrease due to increased atmospheric carbon dioxide concentrations during industrialization. Eutrophication effects may have damped acidification, but have caused increased seasonal pH variability with low values occurring during winter season.
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| 7. |
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| 8. |
- Wesslander, Karin, 1976, et al.
(författare)
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Observed carbon dioxide and oxygen dynamics in a Baltic Sea coastal region
- 2011
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Ingår i: Journal of Marine Systems. - : Elsevier BV. - 0924-7963 .- 1879-1573. ; 86:1-2, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- In April 2006, diurnal variations of carbon dioxide (CO2) and oxygen (O2) in the surface water east of Gotland in the Baltic Sea were investigated with a unique multitechnology approach. Several parameters were measured simultaneously providing an overviewof the CO2 system.Moored instrumentswere continuously recording partial pressure of CO2 in the surface water (pCO2 w), currents,mixing,waves, salinity, temperature and O2. Measurements of total alkalinity (AT) and dissolved inorganic carbon (CT) were taken from R/V Skagerak. These measurements were converted to pCO2 w to support the continuous pCO2 w data and also calculate the air–sea exchange of CO2. Additionally, the time derivatives of O2 and CT concentrations in the water were determined using incubations and a Productivity Autosampler (PA). O2 and pCO2 w were significantly anti-correlated and periods dominated of either biological processes, mixing, air–sea exchange or a combination of these were detected. O2 and pCO2 w had a daily cycle and variations occurred on the 1 h time scale. In April 2006, the seawas a CO2 sink and the averaged parameterized air–sea exchange was −1.0±0.6 mmol m−2 h−1.
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| 9. |
- Wesslander, Karin, 1976, et al.
(författare)
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On the carbon dioxide air-sea flux balance in the Baltic Sea.
- 2010
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Ingår i: Continental Shelf Research. - 0278-4343. ; 30:14, s. 1511-1521
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Tidskriftsartikel (refereegranskat)abstract
- We estimated the net annual air–sea exchange of carbondioxide (CO2) using monitoring data from the East Gotland Sea, Bornholm Sea, and Kattegat for the 1993–2009 period. Wind speed and the sea surface partial pressure of CO2 (pCO2w), calculated from pH, total alkalinity, temperature, and salinity, were used for the flux calculations. We demonstrate that regions in the central Baltic Sea and the Kattegat alternate between being sinks (-) and sources (+) of CO2 within the -4.2 to+5.2molm-2 y-1 range. On average,forthe1994–2008 period, the East Gotland Sea was a source of CO2 (1.64molm-2 yr-1), the Bornholm Sea was a source (2.34 molm-2 yr-1), and the Kattegat was a sink (-1.16 molm-2 yr-1). Large inter-annual and regional variations in the air–sea balance were observed. We used two parameterizations for the gas transfer velocity (k) and the choice varied the air–sea exchange by a factor of two. Inter-annual variations in pCO2w between summers were controlled by the maximum concentration of phosphate in winter. Inter-annual variations in the CO2 flux and gas transfer velocity were larger between winters than between summers. This indicates that the inter-annual variability in the total flux was controlled by winter conditions. The large differences between the central Baltic Sea and Kattegat were considered to depend partly on the differences in the mixed layer depth.
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| 10. |
- Wesslander, Karin, 1976
(författare)
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The Carbon Dioxide System in the Baltic Sea Surface Waters
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The concentration of carbon dioxide (CO2) in the atmosphere is steadily increasing because of human activities such as fossil fuel burning. To understand how this is affecting the planet, several pieces of knowledge of the CO2 system have to be investigated. One piece is how the coastal seas, which are used by people and influenced by industrialization, are functioning. In this thesis, the CO2 system in the Baltic Sea surface water has been investigated using observations from the last century to the present. The Baltic Sea is characterized of a restricted water exchange with the open ocean and a large inflow of river water. The CO2 system, including parameters such as pH and partial pressure of CO2 (pCO2), has large seasonal and inter-annual variability in the Baltic Sea. These parameters are affected by several processes, such as air–sea gas exchange, physical mixing, and biological processes. Inorganic carbon is assimilated in the primary production and pCO2 declines to ~150 µatm in summer. In winter, pCO2 levels increase because of prevailing mineralization and mixing processes. The wind-mixed surface layer deepens to the halocline (~60 m) and brings CO2-enriched water to the surface. Winter pCO2 may be as high as 600 µatm in the surface water. The CO2 system is also exposed to short-term variations caused by the daily biological cycle and physical events such as upwelling. A cruise was made in the central Baltic Sea to make synoptic measurements of oceanographic, chemical, and meteorological parameters with high temporal resolution. Large short-term variations were found in pCO2 and oxygen (O2), which were highly correlated. The diurnal variation of pCO2 was up to 40 µatm. The CO2 system in the Baltic Sea changed as the industrialization increased around 1950, which was demonstrated using a coupled physical-biogeochemical model of the CO2 system. Industrialization involved an increased nutrient load with eutrophication as a result. With more nutrients, primary production increased and amplified the seasonal cycle. Model results indicate that the Baltic Sea was clearly a source of atmospheric CO2 before 1950, and with eutrophication CO2 emissions decreased. The increased nutrient load may have counteracted the pH drop that otherwise would have been caused by the overall increase in atmospheric CO2. Observations from the period 1993-2009, indicate that the central Baltic Sea was a net source of atmospheric CO2 while Kattegat was a net sink. Total alkalinity (AT) is higher in the south-eastern Baltic Sea than in the northern parts, these differences are attributed to river runoff and geology in the drainage area. River runoff entering the south-eastern Baltic Sea drains regions rich in limestone, which have been exposed to long-term weathering. Weathering of limestone contributes to an increased AT. The analyze of historical data indicated that during the last century, AT increased in the river water entering the Gulf of Finland while decreasing in rivers entering the Gulf of Bothnia.
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