| |
Records |
Links |
|
Author |
Arrigo, K.R.; Thomas, D.N. |
|
| |
Title |
Large scale importance of sea ice biology in the Southern Ocean |
Type |
Journal Article |
| |
Year |
2004 |
Publication |
Antarctic Science |
Abbreviated Journal |
Antarct Sci |
|
| |
Volume |
16 |
Issue |
4 |
Pages |
471-486 |
|
| |
Keywords |
algae; Antarctic; biogeochemistry; carbon cycle; primary production; Full Data Records |
|
| |
Abstract |
Despite being one of the largest biomes on earth, sea ice ecosystems have only received intensive study over the past 30 years. Sea ice is a unique habitat for assemblages of bacteria, algae, protists, and invertebrates that grow within a matrix dominated by strong gradients in temperature, salinity, nutrients, and UV and visible radiation. A suite of physiological adaptations allow these organisms to thrive in ice, where their enormous biomass makes them a fundamental component of polar ecosystems. Sea ice algae are an important energy and nutritional source for invertebrates such as juvenile krill, accounting for up to 25% of total annual primary production in ice-covered waters. The ability of ice algae to produce large amounts of UV absorbing compounds such as mycosporine-like amino acids makes them even more important to organisms like krill that can incorporate these sunscreens into their own tissues. Furthermore, the nutrient and light conditions in which sea ice algae thrive induce them to synthesize enhanced concentrations of polyunsaturated fatty acids, a vital constituent of the diet of grazing organisms, especially during winter. Finally, sea ice bacteria and algae have become the focus of biotechnology, and are being considered as proxies of possible life forms on ice-covered extraterrestrial systems. An analysis of how the balance between sea ice and pelagic production might change under a warming scenario indicates that when current levels of primary production and changes in the areas of sea ice habitats are taken into account, the expected 25% loss of sea ice over the next century would increase primary production in the Southern Ocean by approximately 10%, resulting in a slight negative feedback on climate warming. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Cambridge University Press |
Place of Publication  |
Cambridge |
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0954-1020 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
Review |
Approved |
no |
|
| |
Call Number |
refbase @ admin @ Arrigo+Thomas2004 |
Serial |
729 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Giannelli, V.; Thomas, D.N.; Haas, C.; Kattner, G.; Kennedy, H.; Dieckmann, G.S. |
|
| |
Title |
Behaviour of dissolved organic matter and inorganic nutrients during experimental sea-ice formation |
Type |
Journal Article |
| |
Year |
2001 |
Publication |
Annals of Glaciology |
Abbreviated Journal |
Ann Glaciol |
|
| |
Volume |
33 |
Issue |
1 |
Pages |
317-321 |
|
| |
Keywords |
|
|
| |
Abstract |
It is well established that during sea-ice formation, crystals aggregate into a solid matrix, and dissolved sea-water constituents, including inorganic nutrients, are rejected from the ice matrix. However, the behaviour of dissolved organic matter (DOM) during ice formation and growth has not been studied to date. DOM is the primary energetic substrate for microbial heterotrophic activity in sea water and sea ice, and therefore it is at the base of the trophic fluxes within the microbial food web. The aim of our study was to compare the behaviour of DOM and inorganic nutrients during formation and growth of sea ice. Experiments were conducted in a large indoor ice-tank facility (Hamburg Ship Model Basin, Germany) at -15°C. Three 1 m³ tanks, to which synthetic sea water, nutrients and dissolved organic compounds (diatom-extracted DOM) had been added, were sampled over a period of 5 days during sea-ice formation. Samples were collected throughout the experiment from water underlying the ice, and at the end from the ice as well. Brine was obtained from the ice by centrifuging ice cores. Inorganic nutrients (nitrate and phosphate) were substantially enriched in brine in comparison to water and ice phases, consistent with the processes of ice formation and brine rejection. Dissolved organic carbon (DOC) was also enriched in brine but was more variable and enriched in comparison to a dilution line. No difference in bacteria numbers was observed between water, ice and brine. No bacteria growth was measured, and this therefore had no influence on the measurable DOC levels. We conclude that the incorporation of dissolved organic compounds in newly forming ice is conservative. However, since the proportions of DOC in the brine were partially higher than those of the inorganic nutrients, concentrating effects of DOC in brine might be different compared to salts. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
International Glaciological Society |
Place of Publication |
Cambridge |
Editor |
Intl. Symp. on Sea Ice and its Interaction with the Ocean, A. and B., Fairbanks, Alaska(USA), 19-23 Jun 2000, |
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0260-3055 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
Conference |
Approved |
no |
|
| |
Call Number |
refbase @ admin @ Giannelli++2001 |
Serial |
732 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Granskog, M.A.; Virkkunen, K.; Thomas, D.N.; Ehn, J.; Kola, H.; Martma, T. |
|
| |
Title |
Chemical properties of brackish water ice in the Bothnian Bay, the Baltic Sea |
Type |
Journal Article |
| |
Year |
2004 |
Publication |
Journal of Glaciology |
Abbreviated Journal |
J Glaciol |
|
| |
Volume |
50 |
Issue |
169 |
Pages |
292-302 |
|
| |
Keywords |
Dependent Solute Redistribution; Dissolved Organic Matter; Phase Boundary; Sulfate; Binding; Summer; Oxygen; Core; Gulf |
|
| |
Abstract |
The behavior of majors, δ18O, dissolved organic carbon (DOC) and trace elements was studied during the initial freezing of low-saline water (3 practical salinity units) in a freezing experiment. Samples were also collected from first-year sea ice from pack ice in the Bothnian Bay, northern Baltic Sea. During initial ice formation, the major-ion ratios in sea ice indicated variable behavior, with some ions showing relative enrichment (sulfate, calcium and magnesium), conservative behavior (sodium) or relative depletion (potassium) compared to sea water at the same salinity DOC, iron and aluminum showed enrichment in the ice, while zinc was depleted to salinity. Lead was detected in surface snow-ice layers only, implying atmospheric accumulation. First-year sea ice, with a variable growth and thermal history, showed behavior for major ions similar to that observed in new ice. However, for trace elements the picture was much more complicated, most likely due to active secondary processes such as atmospheric supply and biological activity. Ice growth has a potential impact on the chemical budgets and cycling of some elements, especially those which are selectively rejected/retained during sea-ice formation, particularly in the shallow parts of the Bothnian Bay covered with a land-fast ice cover. |
|
| |
Address |
Granskog: Univ Helsinki, Dept Phys Sci, Div Geophys, FIN-00014 Helsinki, Finland |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
International Glaciological Society |
Place of Publication |
Cambridge |
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0022-1430 |
ISBN |
|
Medium |
|
|
| |
Area |
Baltic Sea; Bothnian Bay |
Expedition |
|
Conference |
|
|
| |
Notes |
ISI:000227720900014 |
Approved |
no |
|
| |
Call Number |
refbase @ admin @ Granskog++2004 |
Serial |
741 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Haas, C.; Thomas, D.N.; Bareiss, J. |
|
| |
Title |
Surface properties and processes of perennial Antarctic sea ice in summer |
Type |
Journal Article |
| |
Year |
2001 |
Publication |
Journal of Glaciology |
Abbreviated Journal |
J Glaciol |
|
| |
Volume |
47 |
Issue |
159 |
Pages |
613-625 |
|
| |
Keywords |
|
|
| |
Abstract |
Ice-core and snow data from the Amundsen, Bellingshausen and Weddell Seas, Antarctica, show that the formation of superimposed ice and the development of seawater-filled gap layers with high algal standing stocks is typical of the perennial sea ice in summer. The coarse-grained and dense snow had salinities mostly below 0.1ppt. A layer of fresh superimposed ice had a mean thickness of 0.04-0.12 m. Gap layers 0.04-0.08 m thick extended downwards from 0.02 to 0.14 m below the water level. These gaps were populated by diatom standing stocks up to 439 ?g L?¹ chlorophyll a. We propose a comprehensive heuristic model of summer processes, where warming and the reversal of temperature gradients cause major transformations in snow and ice properties. The warming also causes the reopening of incompletely frozen slush layers caused by flood-freeze cycles during winter. Alternatively, superimposed ice forms at the cold interface between snow and slush in the case of flooding with negative freeboard. Combined, these explain the initial formation of gap layers by abiotic means alone. The upward growth of superimposed ice above the water level competes with a steady submergence of floes due to bottom and internal melting and accumulation of snow. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
International Glaciological Society |
Place of Publication |
Cambridge |
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0022-1430 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
IPØ/Tvärrminne |
Approved |
no |
|
| |
Call Number |
refbase @ admin @ Haas++2001 |
Serial |
742 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Steffens, M.; Granskog, M.A.; Kaartokallio, H.; Kuosa, H.; Luodekari, K.; Papadimitriou, S.; Thomas, D.N. |
|
| |
Title |
Spatial variation of biogeochemical properties of landfast sea ice in the Gulf of Bothnia, Baltic Sea |
Type |
Conference Article |
| |
Year |
2006 |
Publication |
Annals of Glaciology |
Abbreviated Journal |
Ann Glaciol |
|
| |
Volume |
44 |
Issue |
1 |
Pages |
80-87 |
|
| |
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 |
|
| |
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. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
International Glaciological Society |
Place of Publication |
Cambridge |
Editor |
|
|
| |
Language |
English |
Summary Language |
English |
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0260-3055 |
ISBN |
|
Medium |
|
|
| |
Area |
Baltic Sea; Gulf of Bothnia |
Expedition |
|
Conference |
International Symposium on Sea Ice, Dunedin (New Zealand), 5-9 Dec 2005 |
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
refbase @ admin @ Steffens++2006 |
Serial |
754 |
|
| Permanent link to this record |
