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Author Amon, RMW; Budéus, G; Meon, B
Title Dissolved organic carbon distribution and origin in the Nordic Seas: Exchanges with the Arctic Ocean and the North Atlantic Type Journal Article
Year 2003 Publication Journal of Geophysical Research Abbreviated Journal J Geophys Res
Volume 108 Issue C7 Pages
Keywords dissolved organic matter; dissolved organic carbon; chromophoric dissolved organic matter; fluorescence; vertical carbon transport
Abstract Dissolved organic carbon (DOC) and in situ fluorescence were measured along with hydrographic parameters in the Greenland, Iceland, and Norwegian Seas (Nordic Seas). Surface (<100 m) concentrations of DOC ranged from 60 to 118 µM with elevated values in the East Greenland Current (EGC) which transports water from the Arctic Ocean to the North Atlantic. EGC surface waters also showed a pronounced fluorescence maximum between 30 and 120 m depth in all EGC sections indicating the abundance of Arctic river derived DOC in this current. Based on fluorescence we estimated that 20-50% of the annual river discharge to the Arctic Ocean was exported in the EGC. The fluorescence maximum was typically associated with salinity around 33 and temperatures below -1°C which are characteristic of surface and upper halocline water in the Arctic Ocean. The elevated fluorescence in this water mass suggests a strong Eurasian shelf component and also suggests that in situ fluorescence could be used to trace Eurasian shelf water in the central Arctic Ocean. DOC concentrations in the Nordic Sea basins (>1000 m) were relatively high (~50 µM DOC) compared with other ocean basins indicating active vertical transport of DOC in this region on decadal timescales. Based on existing vertical transport estimates and 15 µM of semilabile DOC we calculated an annual vertical net DOC export of 3.5 Tg C yr-1 in the Greenland Sea and about 36 Tg C yr-1 for the entire Arctic Mediterranean Sea (AMS) including the Greenland-Scotland Ridge overflow. It appears that physical processes play a determining role for the distribution of DOC in the AMS.
Address
Corporate Author Thesis
Publisher American Geophysical Union Place of Publication Washington, DC Editor
Language English Summary Language English Original Title (up)
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Nordic Seas Expedition Conference
Notes Approved no
Call Number refbase @ user @ ms Serial 5
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Author Granskog, M.
Title Investigations into the physical and chemical properties of Baltic Sea ice Type Book Whole
Year 2004 Publication Abbreviated Journal
Volume Issue Pages
Keywords sea ice; snow-ice; superimposed ice; meteoric ice; chemistry; nutrients; trace elements; Baltic Sea
Abstract Sea ice is a key component of polar and sub-polar seas, including the Baltic Sea. It not only affects climate, from global to local scales, but also strongly modifies the conditions in the marine environment through freezing and eventual melt in several ways. The role of snow in sea ice growth is presumed to be high in the Baltic Sea, although very little quantitative information is available on the contribution of precipitation to ice growth in the Baltic Sea. Even less is known about the chemistry of sea ice and its role as a moderator of (bio)geochemical cycling and budgets of elements in the Baltic Sea. The aim of this Thesis is to shed new light on these matters.The importance of snow and precipitation on the growth of Baltic Sea ice is vital. For the first time, the stable oxygen isotopic composition of ice, snow and water were used to quantify the amount of snow and precipitation incorporated into the sea ice cover. Results show that meteoric ice (precipitation transformed to ice) constitute up to 35% of the total sea ice mass, much higher than reported elsewhere. Furthermore, the formation of superimposed ice (refrozen snow melt or rain) seem to be important as well, presumably due to the mild ice climate conditions in the region.The atmospheric load is also important in the chemical budgets of several elements, in particular nitrogen and lead, in the sea ice cover. The sea ice cover acts as a buffer for accumulated substances until its inevitable melt. However, the accumulated nutrients are transported through the ice at times when the ice becomes permeable. This, in turn, makes the accumulated nutrients available in the lower ice layers as well as in under-ice water, potentially affecting algal growth. The chemical budgets and the seasonal cycling of elements with selective rejection/retention during freezing of seawater are potentially affected, especially in the shallow regions of the Bothnian Bay.
Address
Corporate Author Thesis Ph.D. thesis
Publisher University of Helsinki Place of Publication Helsinki Editor
Language Summary Language Original Title (up)
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 952-91-6613-3 Medium
Area Expedition Conference
Notes Academic dissertation in geophysics at the Faculty of Science of the University of Helsinki; Printed version includes 5 original papers; Online-ISBN: 952-10-1485-7 Approved no
Call Number refbase @ admin @ Granskog2004 Serial 13
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Author Granskog, M.A.; Kaartokallio, H.; Kuosa, H.; Thomas, D.N.; Ehn, J.; Sonninen, E.
Title Scales of horizontal patchiness in chlorophyll a, chemical and physical properties of landfast sea ice in the Gulf of Finland (Baltic Sea) Type Journal Article
Year 2005 Publication Polar Biology Abbreviated Journal Polar Biol
Volume 28 Issue 4 Pages 276-283
Keywords
Abstract Horizontal variation of first-year landfast sea ice properties was studied in the Gulf of Finland, the Baltic Sea. Several scales of variation were considered; a number of arrays with core spacings of 0.2, 2 and 20 m were sampled at different stages of the ice season for small-scale patchiness. Spacing between these arrays was from hundreds of meters to kilometers to study mesoscale variability, and once an onshore&#150;offshore 40-km transect was sampled to study regional scale variability. Measured variables included salinity, stable oxygen isotopes (δ¹8O), chlorophyll a (chl-a), nutrients and dissolved organic carbon. On a large scale, a combination of variations in the under-ice water salinity (ice porosity), nutrient supply and the stage of ice development control the build-up of ice algal biomass. At scales of hundreds of meters to kilometers, there was significant variability in several parameters (salinity, chl-a, snow depth and ice thickness). Analyses of the data from the arrays did not show evidence of significant patchiness at scales <20 m for algal biomass. The results imply that the sampling effort in Baltic Sea ice studies should be concentrated on scales of hundreds of meters to kilometers. Using the variations observed in the study area, the estimate for depth-integrated algal biomass in landfast sea ice in the Gulf of Finland (March 2003) is 5.5±4.4 mg chl-a m-².
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Corporate Author Thesis
Publisher Springer-Verlag Place of Publication Heidelberg Editor
Language Summary Language Original Title (up)
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0722-4060 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number refbase @ admin @ Granskog_etal2005 Serial 15
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Author Granskog, M.A.; Kaartokallio, H.; Thomas, D.; Ehn, J.; Kuosa, H.; Sonninen, E.
Title Horizontal variations in biogeochemical characteristics of landfast sea ice in the Gulf of Finland (the Baltic Sea) Type Book Chapter
Year 2004 Publication Abbreviated Journal
Volume Issue Pages 5-11
Keywords Fast Ice; Biogeochemical Properties; Salinity; Oxygen Isotope; Chlorophyll; Nutrients; Doc; Horizontal Patchiness; Spatial Variability; Patchiness; Baltic Sea; Oxygen Isotopes
Abstract In order to study the mesoscale variation in ice properties, horizontal variation of first-year landfast sea ice properties was investigated in the Gulf of Finland, the Baltic Sea. Several scales of variation were considered; samples at spacing of 0.2-, 2- and 20-m were sampled at several locations at different stages of the ice season. Spacing between these locations varied from hundreds of meters to kilometers. The variables measured included salinity, stable oxygen isotopes (δ¹8O), chlorophyll-a, nutrients, and dissolved organic carbon (DOC). Analyses of the data from the arrays did not show evidence of significant patchiness at scales <20-m. On scales of hundreds of meters to kilometers there was clear patchiness in several parameters (salinity, chl-a, snow depth and ice thickness). The results imply that the sampling effort in Baltic Sea ice studies should be concentrated at scales of hundreds of meters to kilometers.
Address
Corporate Author Thesis
Publisher International Association of Hydraulic Engineering and Research Place of Publication Editor 17th IAHR international symposium on ice, S.P., Russia, 21-25 June 2004,
Language Summary Language Original Title (up)
Series Editor Series Title Proceedings of the 17th IAHR international symposium on ice, Saint Petersburg, Russia, 21-25 June 2004 Abbreviated Series Title
Series Volume 2 Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number refbase @ admin @ Granskog_etal2004 Serial 16
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Author Granskog, M.A.; Kaartokallio, H.; Thomas, D.N.; Kuosa, H.
Title Influence of freshwater inflow on the inorganic nutrient and dissolved organic matter within coastal sea ice and underlying waters in the Gulf of Finland (Baltic Sea) Type Journal Article
Year 2005 Publication Estuarine, Coastal and Shelf Science Abbreviated Journal Estuar Coast Shelf Sci
Volume 65 Issue 1-2 Pages 109-122
Keywords coastal oceanography; sea ice; river plumes; estuarine chemistry; nutrients (mineral); dissolved organic matter; Baltic Sea
Abstract A study was conducted to measure the biogeochemical characteristics of freshwater plumes underlying Baltic Sea land-fast ice, and the overlying sea ice. A 40-km long transect was conducted in the northern Baltic Sea in March 2003, following a freshwater plume from its source into the fully mixed open-sea area. The spreading of river outflow below the ice resulted in a well-stratified low-salinity surface layer further out than normally occurs in the open-water period. The freshwaters were high in dissolved organic matter (DOC, DON and CDOM), and inorganic nutrients (ammonium, nitrate and silicate), although the levels of phosphate were low. In general these parameters changed concurrently with salinity in such a way that mixing was conservative. The characteristics of the ice varied from the freshwater source to the open water, with increasing salinity and brine volumes (porosity) occurring in the more open-sea stations. Coinciding with the changes in ice properties there was an increase in sea-ice algal growth in the more marine stations along the transect. Biological activity in the ice was largely confined to bottom ice assemblages. In contrast to the conditions in the underlying water, no relationship between salinity, inorganic nutrients and organic matter was observed in the ice. In particular ammonium, phosphate, DOC and DON were present in excess of those levels predicted from the dilution curves, indicating the presence of considerable DOM production by ice assemblages, inorganic nutrient uptake and remineralization within the ice.
Address
Corporate Author Thesis
Publisher Academic Press Place of Publication San Diego Editor
Language Summary Language Original Title (up)
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0272-7714 ISBN Medium
Area Expedition Conference
Notes Sampling: Nine stations along a 40km salinity gradient from inner Pojo Bay through the Archipelago to the edge of the open sea Approved no
Call Number refbase @ admin @ Granskog_etal2005_2 Serial 17
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