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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
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Nordic Seas Expedition (up) Conference
Notes Approved no
Call Number refbase @ user @ ms Serial 5
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Author Gerland, S; Winther, J-G; Örbæk, JB; Ivanov, BV
Title Physical properties, spectral reflectance and thickness development of first year fast ice in Kongsfjorden, Svalbard Type Book Chapter
Year 1999 Publication Proceedings of the International Symposium on Polar Aspects of Global Change Abbreviated Journal
Volume Issue Pages 275-282
Keywords Fast ice; Ice properties; Reflectance; Ice thickness; Physical properties; PNE, Norway, Svalbard, Kongsfjorden
Abstract A ground truth study was performed on first year fast ice in Kongsfjorden, Svalbard, during spring 1997 and 1998. The survey included sea ice thickness monitoring as well as observation of surface albedo, attenuation of optical radiation in the ice, physical properties and texture of snow and sea ice. The average total sea ice thickness in May was about 0.9 m, including a 0.2 m thick snow layer on top. Within a few weeks in both years, the snow melted almost completely, whereas the ice thickness decreased by not more than 0.05 m. During spring, the lower part of the snow refroze into a solid layer. The sea ice became more porous. Temperatures in the sea ice increased and the measurable salinity of the sea ice decreased with time. Due to snow cover thinning and snow grain growth, maximum surface albedo decreased from 0.96 to 0.74. Texture analysis on cores showed columnar ice with large crystals (max. crystal length > 0.1 m) below a 0.11 m thick mixed surface layer of granular ice with smaller crystals. In both years, we observed sea ice algae at the bottom part of the ice. This layer has a significant effect on the radiation transmissivity.
Address Norwegian Polar Institute, Polar Environmental Centre, N-9296 Tromsoe, Norway
Corporate Author Thesis
Publisher Norsk Polarinstitutt Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Polar Research Abbreviated Series Title Polar Res
Series Volume 18 Series Issue 2 Edition
ISSN 0800-0395 ISBN Medium
Area Expedition (up) Conference International Symposium on Polar Aspects of Global Change, Tromso (Norway), 24-28 Aug 1998
Notes Conference Approved no
Call Number refbase @ user @ 726 Serial 6
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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
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN 952-91-6613-3 Medium
Area Expedition (up) 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.; Kaartokallio, H.; Kuosa, H.; Thomas, D.N.; Vainio, J.
Title Sea ice in the Baltic Sea – A review Type Journal Article
Year 2006 Publication Estuarine, Coastal and Shelf Science Abbreviated Journal Estuar Coast Shelf Sci
Volume 70 Issue 1-2 Pages 145-160
Keywords sea ice; Baltic Sea; biogeochemistry; plankton; seasons
Abstract Although the seasonal ice cover of the Baltic Sea has many similarities to its oceanic counterpart in Polar Seas and Oceans, there are many unique characteristics that mainly result from the brackish waters from which the ice is formed, resulting in low bulk salinities and porosities. In addition, due to the milder climate than Polar regions, the annual maximum ice extent is highly variable, and rain and freeze-melt cycles can occur throughout winter. Up to 35% of the sea ice mass can be composed from metamorphic snow, rather than frozen seawater, and in places snow and superimposed ice can make up to 50% of the total ice thickness. There is pronounced atmospheric deposition of inorganic nutrients and heavy metals onto the ice, and in the Bothnian Bay it is estimated that 5% of the total annual flux of nitrogen and phosphorus and 20&#150;40% of lead and cadmium may be deposited onto the ice fields from the atmosphere. It is yet unclear whether or not the ice is simply a passive store for atmospherically deposited compounds, or if they are transformed through photochemical processes or biological accumulation before released at ice and snow melt.As in Polar sea ice, the Baltic ice can harbour rich biological assemblages, both within the ice itself, and on the peripheries of the ice at the ice/water interface. Much progress has been made in recent years to study the composition of these assemblages as well as measuring biogeochemical processes within the ice related to those in underlying waters. The high dissolved organic matter loading of Baltic waters and ice result in the ice having quite different chemical characteristics than those known from Polar Oceans. The high dissolved organic material load is also responsible in large degree to shape the optical properties of Baltic Sea ice, with high absorption of solar radiation at shorter wavelengths, a prerequisite for active photochemistry of dissolved organic matter.Land-fast ice in the Baltic also greatly alters the mixing characteristics of river waters flowing into coastal waters. River plumes extend under the ice to a much greater distance, and with greater stability than in ice-free conditions. Under-ice plumes not only alter the mixing properties of the waters, but also result in changed ice growth dynamics, and ice biological assemblages, with the underside of the ice being encased, in the extreme case, with a frozen freshwater layer.There is a pronounced gradient in ice types from more saline ice in the south to freshwater ice in the north. The former is characteristically more porous and supports more ice-associated biology than the latter. Ice conditions also vary considerably in different parts of the Baltic Sea, with ice persisting for over half a year in the northernmost part of the Baltic Sea, the Bothnian Bay. In the southern Baltic Sea, ice appears only during severe winters.
Address
Corporate Author Thesis
Publisher Elsevier Science BV Place of Publication Amsterdam Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0272-7714 ISBN Medium
Area Expedition (up) Conference
Notes Review Approved no
Call Number refbase @ admin @ Granskog_etal2006 Serial 14
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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.
Address
Corporate Author Thesis
Publisher Springer-Verlag Place of Publication Heidelberg Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0722-4060 ISBN Medium
Area Expedition (up) Conference
Notes Approved no
Call Number refbase @ admin @ Granskog_etal2005 Serial 15
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