| 1. |
- Anderson, Leif G, 1951, et al.
(författare)
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Arctic ocean shelf–basin interaction: An active continental shelf CO2 pump and its impact on the degree of calcium carbonate solubility
- 2010
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Ingår i: Deep Sea Research Part I: Oceanographic Research Papers. - : Elsevier BV. - 0967-0637. ; 57:7, s. 869-879
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Tidskriftsartikel (refereegranskat)abstract
- The Arctic Ocean has wide shelf areas with extensive biological activity including a high primary productivity and an active microbial loop within the surface sediment. This in combination with brine production during sea ice formation result in the decay products exiting from the shelf into the deep basin typically at a depth of about 150 m and over a wide salinity range centered around S 33. We present data from the Beringia cruise in 2005 along a section in the Canada Basin from the continental margin north of Alaska towards the north and from the International Siberian Shelf Study in 2008 (ISSS-08) to illustrate the impact of these processes. The water rich in decay products, nutrients and dissolved inorganic carbon (DIC), exits the shelf not only from the Chukchi Sea, as has been shown earlier, but also from the East Siberian Sea. The excess of DIC found in the Canada Basin in a depth range of about 50–250 m amounts to 90±40 g C m−2. If this excess is integrated over the whole Canadian Basin the excess equals 320±140×1012 g C. The high DIC concentration layer also has low pH and consequently a low degree of calcium carbonate saturation, with minimum aragonite values of 60% saturation and calcite values just below saturation. The mean age of the waters in the top 300 m was calculated using the transit time distribution method. By applying a future exponential increase of atmospheric CO2 the invasion of anthropogenic carbon into these waters will result in an under-saturated surface water with respect to aragonite by the year 2050, even without any freshening caused by melting sea ice or increased river discharge.
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| 2. |
- Anderson, Leif G, 1951, et al.
(författare)
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Out-gassing of CO2 from Siberian Shelf seas by terrestrial organic matter decomposition
- 2009
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Ingår i: Geophys. Res. Lett.. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- The Siberian shelf seas cover large shallow areas that receive substantial amounts of river discharge. The river runoff contributes nutrients that promote marine primary production, but also dissolved and particulate organic matter. The coastal regions are built up of organic matter in permafrost that thaws and result in coastal erosion and addition of organic matter to the sea. Hence there are multiple sources of organic matter that through microbial decomposition result in high partial pressures of CO2 in the shelf seas. By evaluating data collected from the Laptev and East Siberian Seas in the summer of 2008 we compute an excess of DIC equal to 10 · 1012 g C that is expected to be outgassed to the atmosphere and suggest that this excess mainly is caused by terrestrial organic matter decomposition.
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| 3. |
- Björk, Göran, 1956, et al.
(författare)
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Flow of Canadian Basin Deep Water in the Western Eurasian Basin of the Arctic Ocean
- 2010
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Ingår i: Deep Sea Research. - : Elsevier BV. - 0967-0637 .- 1879-0119. ; 57:4, s. 577-586
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Tidskriftsartikel (refereegranskat)abstract
- The LOMROG 2007 expedition targeted the previously unexplored southern part of the Lomonosov Ridge north of Greenland together with a section from the Morris Jesup Rise to Gakkel Ridge. The oceanographic data shows that Canadian Basin Deep Water (CBDW) passes the Lomonosov Ridge in the area of the Intra Basin close to the North Pole and then continues along the ridge towards Greenland and further along its northernmost continental slope. The CBDW is clearly evident as a salinity maximum and oxygen minimum at a depth of about 2000 m. The cross slope sections at the Amundsen Basin side of the Lomonosov Ridge and further south at the Morris Jesup Rise show a sharp frontal structure higher up in the water column between Makarov Basin water and Amundsen Basin water. The frontal structure continues upward into the Atlantic Water up to a depth of about 300 m. The observed water mass division at levels well above the ridge crest indicates a strong topographic steering of the flow and that different water masses tend to pass the ridge guided by ridge-crossing isobaths at local topographic heights and depressions. A rough scaling analysis shows that the extremely steep and sharply turning bathymetry of the Morris Jesup Rise may force the boundary current to separate and generate deep eddies.
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| 4. |
- Björk, Göran, 1956, et al.
(författare)
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The Passage of Canadian Basin Deep Water Over the Lomonosov Ridge and Through the Eurasian Basin of the Arctic Ocean: Results From the LOMROG-2007 Icebreaker Expedition
- 2008
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Ingår i: American Geophysical Union. ; 88(52)
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Konferensbidrag (refereegranskat)abstract
- During the LOMROG-2007 icebreaker expedition to the area where the Lomonosov Ridge attaches to the Greenland shelf, we observed a well defined signal in water mass properties of clear CBDW origin. The major part of CBDW passes the Lomonosov Ridge at the 1870 m deep channel near the North Pole (88 25' N, 150 E) as was discovered during the Beringia/Hotrax 2005 exploration of the sill area. During the LOMROG expedition we observed the signal of CBDW along the Amundsen Basin side of the Lomonosov Ridge slope north of Greenland and further along the Greenland shelf towards east and south. The signal with Canadian Basin properties is clearly seen in the TS structure as well as in the oxygen, silicate and CFC signals around 2000 m depth. No indication of a deep overflow across the Lomonosov Ridge at the channel just north of Greenland was seen.
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| 5. |
- Hjalmarsson, Sofia, 1980, et al.
(författare)
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Carbon dynamics in a productive coastal region—The Skagerrak
- 2010
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Ingår i: Journal of Marine Systems. - : Elsevier BV. - 0924-7963. ; 82:4, s. 245-251
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Tidskriftsartikel (refereegranskat)abstract
- The importance of the coastal seas as areas of CO2 uptake from the atmosphere has gained more attention during recent years. This study utilizes dissolved inorganic carbon and hydrographic data collected in the Skagerrak for 10 months in 2006 to assess the carbon dynamics over the year. The surface water is under-saturated in CO2 relative to the atmosphere during the first half of the year and stays close to equilibrium at least until November. Consequently primary production compensates for the increase in pCO2 caused by the temperature increase from 2 to 10 °C in spring. Integrating the annual air–sea CO2 flux as computed using the Wanninkhof (1992) parameterization gives a net uptake of 1.2 mol m− 2 year− 1 which, if representative for the whole Skagerrak area, equals 3.7 ∙ 1010 mol year− 1 or 0.45 Tg C year− 1. Converting the nitrate consumption in the surface mixed layer from January to May to carbon units through the RKR ratio (Redfield et al., 1963) gives a drawdown of 6 g C m− 2. This number increases by a factor of two if primary productivity also occurs in the waters below the surface mixed layer, i.e. an increase in depth from 10 to 25 m as a seasonal average.We estimated the effect of salinity, biological processes and air–sea CO2 exchange on the monthly DIC change. We found that salinity was one of the major drivers for the DIC change.
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| 6. |
- Hjalmarsson, Sofia, 1980
(författare)
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Carbon Dynamics in Northern Marginal Seas
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The marginal seas have, despite their relatively small area, an important role in the global carbon cycle. They are largely influenced by carbon and nutrient fluxes from land and a large part of the biological production occurs in the marginal seas. The carbon dynamic in two shelf areas – The Baltic Sea System (the Baltic Sea, the Kattegat and the Skagerrak) and the Siberian Shelf Seas (the Laptev Sea, the East Siberian Sea and the Chukchi Sea) has been studied in this thesis. Results from a study using historical data on Total Alkalinity (TA) from the Baltic Sea shows that there has been a change in the riverine TA concentrations. TA has increased in rivers draining areas where limestone dominates the bedrock while there has been a decrease in TA concentrations in granite dominated areas. We give two explanations to this change; acid precipitation and increased concentrations of CO2 from decay of organic matter. The Baltic Sea has high DIC concentration relative to its salinity (also due to river input) and as the surface water leaves the Baltic Sea also the DIC is exported and will in the end add to the North Sea carbon budget. We estimated the net carbon export from the Baltic Sea to 5.5 ± 0.3 Tg C year-1. Furthermore, the carbon dynamics in the Skagerrak during 2006 has been studied and we found it to be a sink of carbon with a sea-air flux of 1.3 • 1012 mol m-2 year-1. We also found Skagerrak to be a reasonable source of carbon to the North Sea by a continental shelf pump. In the Arctic and especially in the Laptev Sea, the large amounts of organic carbon transported by the major Russian rivers as well as from coastal erosion will decay in the shelf seas. This will result in a net efflux of CO2 to the atmosphere. However, in the eastern part of the East Siberian Sea and in the Chukchi Sea, the river discharge is much less and the biological activity is high. This will instead cause under-saturated surface waters in respect to CO2. The particulate organic carbon produced in the surface will sediment and starts to decay in the bottom water. As the water flows off the shelf and in to the Arctic Ocean this will result in surface waters under-saturated in pCO2 and subsurface waters over-saturated in pCO2. The marginal seas investigated in the thesis are located in the northern hemisphere and there are fundamental differences in temperature and population density along the coasts. Nevertheless, both areas are influenced by the properties and the carbon content in the entering river water and both areas appear to export carbon to the open ocean trough a continental shelf pump.
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| 7. |
- 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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| 8. |
- Hjalmarsson, Sofia, 1980, et al.
(författare)
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The exchange of dissolved inorganic carbon between the Baltic Sea and the North Sea in 2006 based on measured data and water transport estimates from a 3D model
- 2010
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Ingår i: Marine Chemistry. - : Elsevier BV. - 0304-4203. ; 121:1-4, s. 200-205
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Tidskriftsartikel (refereegranskat)abstract
- The Baltic Sea is one of the largest estuarine systems on earth. Two narrow straits, Öresund and The Belt Sea, together with a large transition area consisting of Kattegat and Skagerrak hamper interactions with the North Sea. The Baltic Sea water is low in salinity due to the large freshwater input from river runoff to the Baltic Sea but has an excess of inorganic carbon from dissolution of carbonate minerals in the river drainage basins. In this study we use dissolved inorganic carbon data from the Baltic Sea and the Kattegat together with modelled water transport to evaluate the dissolved inorganic carbon exchange between the Baltic Sea and the North Sea during 2006. The total inorganic carbon export from the Baltic Sea in the straits area is 5.5 ± 0.3 Tg C year−1, or 0.45 ± 0.03 1012 mol year−1. These numbers are about 1/3 lower than earlier reported export values and will hence have a corresponding effect on budget computations of the connected seas.
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| 9. |
- Wernström, Ida, et al.
(författare)
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Particle Tracing: Analysis of Airborne Infection Risks in Operating Theatres
- 2012
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Ingår i: COMOSOL Conference Milan 2012.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Patients undergoing surgery are very sensitive to infections. The operation staff may spread 104 particles per person per minute, of which ten percent are presumed bacteria- carrying. We visualize and analyse the influence of the personnel on the air and particle flows for the two most common ventilation systems in Swedish hospitals. Comsol Multiphysics is very suitable for the task with the new particle tracing module.The geometry was measured on two existing operating rooms in the hospital Östra Sjukhuset in Göteborg. Our study shows that the Laminar Air flow- ventilation gives a much more controlled flow where fewer particles reach the patient than with conventional mixed ventilation where it is more likely that the staff unconsciously disrupt the flow. We also find that even for Laminar Air- flow ventilation it takes more than two minutes for the particles in motion to leave the room having implications for the time preceeding the operation when particles are assumed to settle.
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| 10. |
- 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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