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Author |
Schnack-Schiel, S.B.; Dieckmann, G.S.; Gradinger, R.; Melnikov, I.A.; Spindler, M.; Thomas, D.N. |
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Title |
Meiofauna in sea ice of the Weddell Sea (Antarctica) |
Type |
Journal Article |
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Year |
2001 |
Publication |
Polar Biology |
Abbreviated Journal |
Polar Biol |
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Volume |
24 |
Issue |
10 |
Pages |
724-728 |
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Keywords  |
Sea ice biota; Foraminifera; Antarctic sea ice; Sea ice; Meiofauna; Community composition; Meiobenthos; Antarctic zone; Juveniles; Psw; Weddell Sea; Antarctica |
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Abstract |
Sea-ice meiofauna was studied during various cruises to the Weddell Sea. Foraminifers dominate (75%) the sea-ice community in terms of numerical abundance while turbellarians dominate (45%) in terms of biomass. Distribution of organisms is patchy and varies considerably between cruises but also between sampling sites within one cruise. The bulk of the meiofauna is concentrated in the lowest parts of the sea ice, especially during winter and autumn. However, in porous summer sea ice, sympagic organisms also occur in high densities in upper and intermediate layers of sea ice. Proto- and metazoans associated with Antarctic sea ice include organisms actually living in sea ice, as well as those on the underside of floes and in the underlying water. The sea-ice habitat serves as a feeding ground, as well as an important nursery for juveniles, providing energy-rich food resources. The ice also constitutes a shelter from predators. |
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Publisher |
Springer |
Place of Publication |
Heidelberg |
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ISSN |
0722-4060 |
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no |
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Call Number |
refbase @ admin @ Schnack-Schiel++2001 |
Serial |
751 |
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Author |
Thomas, D.N.; Lara, R.J.; Eicken, H.; Kattner, G.; Skoog, A. |
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Title |
Dissolved organic matter in Arctic multi-year sea ice during winter: major components and relationship to ice characteristics |
Type |
Journal Article |
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Year |
1995 |
Publication |
Polar Biology |
Abbreviated Journal |
Polar Biol |
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Volume |
15 |
Issue |
6 |
Pages |
447-483 |
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Keywords |
sea ice; Arctic; Dom |
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Abstract |
Ice cores were collected between 10.03.93 and 15.03.93 along a 200 m profile on a large ice floe in Fram Strait. The ice was typical of Arctic multi-year ice, having a mean thickness along the profile of 2.56 ±0.53 m. It consisted mostly of columnar ice (83%) grown through congelation of seawater at the ice bottom, and the salinity profiles were characterized by a linear increase from 0 psu at the top to values ranging between 3 and 5 psu at depth. Distributions of dissolved organic carbon (DOC) and nitrogen (DON) and major nutrients were compared with ice texture, salinity and chlorophyll a. DOC, DON, dissolved inorganic nitrogen (DIN), NH?? and NO?? were present in concentrations in excess of that predicted by dilution curves derived from Arctic surface water values. Only NO?? was depleted, although not exhausted. High DOC and DON values in conjunction with high NH?? levels indicated that a significant proportion of the dissolved organic matter (DOM) was a result of decomposition/grazing of ice algae and/or detritus. The combination of high NH?? and NO?? points to regeneration of nitrogen compounds. There was no significant correlation between DOC and Chl a in contrast to DON, which had a positively significant correlation with both salinity and Chl a, and the distribution of DOM in the cores might best be described as a combination of both physical and biological processes. There was no correlation between DOC and DON suggesting an uncoupling of DOC and DON dynamics in multi year ice. |
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Publisher |
Springer-Verlag |
Place of Publication |
Heidelberg |
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0722-4060 |
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Notes |
D |
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Call Number |
refbase @ admin @ Thomas++1995 |
Serial |
763 |
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Author |
Granskog, M.; Kaartokallio, H.; Kuosa, H.; Thomas, D.N.; Vainio, J. |
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Title |
Sea ice in the Baltic Sea – A review |
Type |
Journal Article |
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Year |
2006 |
Publication |
Estuarine, Coastal and Shelf Science |
Abbreviated Journal |
Estuar Coast Shelf Sci |
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Volume |
70 |
Issue |
1-2 |
Pages |
145-160 |
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Keywords |
sea ice; Baltic Sea; biogeochemistry; plankton; seasons |
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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 20–40% 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. |
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Address |
Granskog: Arctic Centre, University of Lapland, P.O. Box 122, FI-96101 Rovaniemi, Finland |
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Publisher |
Elsevier Science BV |
Place of Publication |
Amsterdam |
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Edition |
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ISSN |
0272-7714 |
ISBN |
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Area |
Baltic Sea |
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Notes |
Review |
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no |
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Call Number |
refbase @ admin @ Granskog++2006 |
Serial |
738 |
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Author |
Thomas, D.N.; Dieckmann, G.S. |
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Title |
Biogeochemistry of Antarctic sea ice |
Type |
Journal Article |
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Year |
2002 |
Publication |
Oceanography and Marine Biology: An Annual Review |
Abbreviated Journal |
Oceanogr Mar Biol Annu Rev |
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Volume |
40 |
Issue |
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Pages |
143-169 |
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Keywords |
Sea ice; Biogeochemistry; Nutrients (mineral); Dissolved gases; Dissolved organic matter; Ps; Antarctic Ocean |
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Abstract |
Antarctic sea ice at its maximum extent in winter covers 40% of the Southern Ocean in a frozen layer, on average, 1 m thick. Sea ice is not solid, rather it is an ice crystal matrix permeated by a labyrinth of brine filled channels and pores in which life thrives. Organisms are constrained by a set of physicochemical factors quite unlike anything they encounter in the plankton from where they are recruited. Because sea ice is increasingly viewed as a suitable proxy for life in previous periods of the Earth's history, and even for astrobiology, it is pertinent that the physicochemical constraints acting upon sea-ice biology are better understood. The, largely microbial, network that develops in the ice itself imparts a unique chemistry that influences the nature and chemical composition of biogenic material released from the ice. This chemistry can result in the export of material to the sediments with distinctive chemical signatures that are useful tools for reconstructing past sea-ice cover of the oceans. This review synthesises information on inorganic nutrient, dissolved organic matter and dissolved gases from a variety of Antarctic ice habitats. |
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Publisher |
Taylor & Francis |
Place of Publication |
London |
Editor |
Gibson, R.N.; Barnes, M.; Atkinson, R.J.A. |
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ISSN |
0415254620 |
ISBN |
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Notes |
Review; Marine |
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no |
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Call Number |
refbase @ admin @ Thomas+Dieckmann2002 |
Serial |
758 |
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Author |
Steffens, M.; Granskog, M.A.; Kaartokallio, H.; Kuosa, H.; Luodekari, K.; Papadimitriou, S.; Thomas, D.N. |
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Title |
Spatial variation of biogeochemical properties of landfast sea ice in the Gulf of Bothnia, Baltic Sea |
Type |
Conference Article |
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Year |
2006 |
Publication |
Annals of Glaciology |
Abbreviated Journal |
Ann Glaciol |
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Volume |
44 |
Issue |
1 |
Pages |
80-87 |
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Keywords |
Sea ice; Fast ice; Sea ice properties; Ice algae; Chlorophyll; Biogeochemistry; Nutrients (mineral); Particulate organic matter; Dissolved organic matter; Salinity; Spatial scale; Spatial variability; Horizontal patchiness; Sampling design; Brackish water; Ane; Baltic Sea; Gulf of Bothnia |
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Abstract |
Horizontal variation of landfast sea-ice properties was studied in the Gulf of Bothnia, Baltic Sea, during March 2004. In order to estimate their variability among and within different spatial levels, 72 ice cores were sampled on five spatial scales (with spacings of 10 cm, 2.5 m, 25 m, 250 m and 2.5 km) using a hierarchical sampling design. Entire cores were melted, and bulk-ice salinity, concentrations of chlorophyll a (Chl a), phaeophytin (Phaeo), dissolved nitrate plus nitrite (DIN) as well as dissolved organic carbon (DOC) and nitrogen (DON) were determined. All sampling sites were covered by a 5.5-23 cm thick layer of snow. Ice thicknesses of cores varied from 26 to 58 cm, with bulk-ice salinities ranging between 0.2 and 0.7 as is typical for Baltic Sea ice. Observed values for Chl a (range: 0.8-6.0 μg Chl a l-1; median: 2.9 μg Chl a l -1) and DOC (range: 37-397 μM; median: 95 μM) were comparable to values reported by previous sea-ice studies from the Baltic Sea. Analysis of variance among different spatial levels revealed significant differences on the 2.5 km scale for ice thickness, DOC and Phaeo (with the latter two being positively correlated with ice thickness). For salinity and Chl a, the 250 m scale was found to be the largest scale where significant differences could be detected, while snow depth only varied significantly on the 25 m scale. Variability on the 2.5 m scale contributed significantly to the total variation for ice thickness, salinity, Chl a and DIN. In the case of DON, none of the investigated levels exhibited variation that was significantly different from the considerable amount of variation found between replicate cores. Results from a principal component analysis suggest that ice thickness is one of the main elements structuring the investigated ice habitat on a large scale, while snow depth, nutrients and salinity seem to be of secondary importance. |
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Publisher |
International Glaciological Society |
Place of Publication |
Cambridge |
Editor |
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Language |
English |
Summary Language |
English |
Original Title |
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Series Volume |
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Edition |
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ISSN |
0260-3055 |
ISBN |
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Area |
Baltic Sea; Gulf of Bothnia |
Expedition |
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Conference |
International Symposium on Sea Ice, Dunedin (New Zealand), 5-9 Dec 2005 |
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Notes |
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Approved |
no |
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Call Number |
refbase @ admin @ Steffens++2006 |
Serial |
754 |
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