The occurrence of the copepods Stephos longipes (Calanoida) and Drescheriella glacialis (Harpacticoida) in summer sea ice in the Weddell Sea, Antarctica

2001 ◽  
Vol 13 (2) ◽  
pp. 150-157 ◽  
Author(s):  
Sigrid B. Schnack-Schiel ◽  
David N. Thomas ◽  
Christian Haas ◽  
Gerhard S. Dieckmann ◽  
Ruth Alheit
Keyword(s):  
Total Population ◽  
Calanoid Copepod ◽  
Late Summer ◽  
Geographic Area ◽  
Weddell Sea ◽  
Air Temperatures ◽  
Pack Ice ◽  
Stephos Longipes ◽  
Surface Ice ◽  
The Antarctic

In January to March 1997, a RV Polarstern cruise that transected the Weddell Sea resulted in samples being taken in thick pack ice in the south-eastern Weddell Sea and then along the marginal ice edge towards the Antarctic Peninsula. Several ice types were thus sampled over a wide geographic area during late summer/early autumn. Common features of the first warm period was the occurrence of surface ponds, and that many floes had quasi-continuous horizontal gaps, underlying a layer of ice and metamorphic snow. With the onset of cold air temperatures in late February the gaps rapidly refroze. The calanoid copepod Stephos longipes occurred in all habitats encountered and showed highest numbers in the surface ice in summer, in the gap water during both seasons and in the refrozen gap water in autumn. Nauplii outnumbered copepodids in the surface ice and refrozen gap water, while in the gap water copepodids, mainly stages CI–CIII in summer and CII–CIV in autumn, comprised about 70% of the total population. The harpacticoid species Drescheriella glacialis did not occur in all habitats and was missing in surface ponds and new ice. Nauplii of D. glacialis were rarely found in gap water, but predominated in the refrozen gaps.

scholarly journals New observations of late summer bio-physical ice and snow conditions in the northwestern Weddell Sea

2020 ◽  
Author(s):  
Stefanie Arndt ◽  
Christian Haas ◽  
Ilka Peeken
Keyword(s):  
Sea Ice ◽  
Ice Cores ◽  
Late Summer ◽  
Weddell Sea ◽  
Sea Ice Extent ◽  
Snow Properties ◽  
Snow Conditions ◽  
Surface Ice ◽  
Remote Sensing Methods ◽  
The Antarctic

<p>Summer sea ice extent in the Weddell Sea has increased overall during the last four decades, with large interannual variations. However, the underlying causes and the related ice and snow properties are still poorly known. Here we present results of the interdisciplinary Weddell Sea Ice (WedIce) project carried out in the northwestern Weddell Sea on board the German icebreaker R/V Polarstern in February and March 2019, i.e. at the end of the summer ablation period. This is the region of the thickest, oldest ice in the Weddell Sea, at the outflow of the Weddell Gyre. Measurements included airborne ice thickness surveys and in-situ snow and ice sampling of mostly second- and third year ice. Preliminary results show mean ice thicknesses between 2.6 and 5.4 m, increasing from the Antarctic Sound towards the Larsen B region. The ice had mostly positive ice freeboard. Mean snow thicknesses ranged between 0.05 and 0.46 m. Snow was well below the melting temperature on most days and was highly metamorphic and icy, with melt-freeze forms as dominant snow type. In addition, as a result of the summer’s thaw, an average of 0.14 m of superimposed ice was found in all ice cores drilled during the cruise. Although there was rotten ice below a solid, ca. 30 cm thick surface ice layer, pronounced gap layers typical for late summer ice in the marginal ice zone were rare, and algal biomass was patchily distributed within individual sea ice cores. Overall, there was a strong gradient of increasing ice algal biomass from the Larsen B to the Antarctic Sound region. The presented results show that sea ice conditions in the northwestern Weddell Sea are still severe and have not changed significantly since the last observations carried out in 2004 and 2006. The presence of relatively thin, icy snow has strong implications for the ice and snow mass balance, for freshwater oceanography, and for the application of remote sensing methods. Overall sea ice properties strongly affect the biological productivity of this region and limit carbon fluxes to the seafloor in the northwestern Weddell Sea.</p>

The importance of sea ice biota for the ecosystem in the northwestern Weddell Sea

2020 ◽  
Author(s):  
Ilka Peeken ◽  
Stefanie Arndt ◽  
Markus Janout ◽  
Thomas Krumpen ◽  
Christian Haas
Keyword(s):  
Sea Ice ◽  
Control Variable ◽  
Late Summer ◽  
Weddell Sea ◽  
Trophic Levels ◽  
Nutrient Concentrations ◽  
Algae Biomass ◽  
Ice Shelves ◽  
Surface Ice ◽  
The Antarctic

<p>The western Weddell Sea along the northward branch of the Weddell Gyre is a region of major outflow of various water masses, thick sea ice, and biogeochemical matter, linking the Antarctic continent to the world oceans. It features a deep shelf and the second largest ice shelf (Larsen C) in the WS, and its perennial sea ice cover is among the thickest on earth. This region is undergoing dramatic changes due to the breakup of ice shelves along the Antarctic Peninsula, which results in oceanographic conditions unprecedented in the past 10,000 years. Since this region is difficult to access, comprehensive physical and biogeochemical information is still lacking. During the interdisciplinary Weddell Sea Ice (WedIce) expedition to the northwestern Weddell Sea on board the German icebreaker RV Polarstern in spring 2019, oceanographic and biogeochemical studies were conducted together with in-situ snow and ice sampling. Most stations visited contained second- and third-year ice. Additional airborne ice-thickness surveys revealed a mean ice thicknesses between 2.6 and 5.4 m, increasing from the Antarctic Sound towards the Larsen B region. Usually rotten ice was present below a solid, ~30 cm thick surface-ice layer, however, pronounced gap layers, typical for late summer ice in the marginal ice zone, were rare. The associated high algal biomass was only found north of the Antarctic Sound. Nevertheless, diatom-dominated standing stocks of integrated sea ice algae biomass were among the highest, previously described in Antarctic waters. In contrast, despite overall high macro-nutrient concentrations in the water, the biomass of the flagellate dominated phytoplankton was negligible for primary production in the entire region. Overall, it seems that despite changing light conditions for the phytoplankton due to the loss of ice shelves, the sea ice-derived carbon represents an important control variable for higher trophic levels in the western Weddell Sea.</p>

scholarly journals Albedo of the ice covered Weddell and Bellingshausen Seas

2012 ◽  
Vol 6 (2) ◽  
pp. 479-491 ◽  
Author(s):  
A. I. Weiss ◽  
J. C. King ◽  
T. A. Lachlan-Cope ◽  
R. S. Ladkin
Keyword(s):  
Sea Ice ◽  
Surface Albedo ◽  
Austral Summer ◽  
Open Water ◽  
Weddell Sea ◽  
First Year ◽  
Pack Ice ◽  
Bellingshausen Sea ◽  
The Mean ◽  
The Antarctic

Abstract. This study investigates the surface albedo of the sea ice areas adjacent to the Antarctic Peninsula during the austral summer. Aircraft measurements of the surface albedo, which were conducted in the sea ice areas of the Weddell and Bellingshausen Seas show significant differences between these two regions. The averaged surface albedo varied between 0.13 and 0.81. The ice cover of the Bellingshausen Sea consisted mainly of first year ice and the sea surface showed an averaged sea ice albedo of αi = 0.64 ± 0.2 (± standard deviation). The mean sea ice albedo of the pack ice area in the western Weddell Sea was αi = 0.75 ± 0.05. In the southern Weddell Sea, where new, young sea ice prevailed, a mean albedo value of αi = 0.38 ± 0.08 was observed. Relatively warm open water and thin, newly formed ice had the lowest albedo values, whereas relatively cold and snow covered pack ice had the highest albedo values. All sea ice areas consisted of a mixture of a large range of different sea ice types. An investigation of commonly used parameterizations of albedo as a function of surface temperature in the Weddell and Bellingshausen Sea ice areas showed that the albedo parameterizations do not work well for areas with new, young ice.

Life cycle strategy of the Antarctic calanoid copepod Stephos longipes

1995 ◽  
Vol 36 (1) ◽  
pp. 45-75 ◽  
Author(s):  
Sigrid B. Schnack-Schiel ◽  
David Thomas ◽  
Gerhard S. Dieckmann ◽  
Hajo Eicken ◽  
Rolf Gradinger ◽  
...  
Keyword(s):  
Life Cycle ◽  
Calanoid Copepod ◽  
Life Cycle Strategy ◽  
Stephos Longipes ◽  
The Antarctic

scholarly journals Albedo of the ice-covered Weddell and Bellingshausen Sea

2011 ◽  
Vol 5 (6) ◽  
pp. 3259-3289 ◽  
Author(s):  
A. I. Weiss ◽  
J. C. King ◽  
T. A. Lachlan-Cope ◽  
R. S. Ladkin
Keyword(s):  
Sea Ice ◽  
Antarctic Peninsula ◽  
Surface Albedo ◽  
Weddell Sea ◽  
Ice Age ◽  
Large Variability ◽  
Linear Temperature ◽  
Pack Ice ◽  
Bellingshausen Sea ◽  
The Antarctic

Abstract. This study investigates the surface albedo of the sea ice areas adjacent to the Antarctic Peninsula during the austral summer. Aircraft measurements of the surface albedo which were conducted in the sea ice areas of the Weddell and Bellingshausen Sea show significant differences between these two regions. The averaged surface albedo varied between 0.13 and 0.81. The ice cover of the Bellingshausen Sea consisted mainly of first year ice and the sea surface showed an averaged sea ice albedo of αi = 0.64 ± 0.2 (± standard deviation). The mean sea ice albedo of the pack ice area in the Western Weddell Sea was αi = 0.75 ± 0.05. In the Southern Weddell Sea, where new, young sea ice prevailed, a mean albedo value of αi = 0.38 ± 0.08 was observed. Relatively warm open water and thin, newly formed ice had the lowest albedo values, whereas relatively cold and snow-covered pack ice had the highest albedo values. All sea ice areas consist of a mixture of a large variability of different sea ice types. An investigation of commonly used parameterizations of albedo as a function of surface temperature in the Weddell and Bellingshausen Sea ice areas showed that the albedo parameterizations don't work well in particular for areas with new, young ice. We determined typical linear temperature-albedo functions for three sea ice areas adjacent to the Antarctic Peninsula, which are reflecting the differences in the mixture of ice age, thickness and sea ice surface cover.

Life in the Antarctic sea ice zone

Polar Record ◽  
1991 ◽  
Vol 27 (162) ◽  
pp. 249-253 ◽  
Author(s):  
Gotthilf Hempel
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Late Summer ◽  
Euphausia Superba ◽  
Breeding Population ◽  
Climatic Changes ◽  
Weddell Sea ◽  
Antarctic Sea Ice ◽  
Ice Floes ◽  
The Antarctic

AbstractSeasonal ice of the Southern Ocean, occupying some 15 x 106 km2, supports a distinctive biota based on algae that live on, within and immediately beneath the ice floes. How this annually-forming habitat recruits its biota, and the fate of the biota after the ice thaws in late summer, are little-known. Studies in the Weddell Sea in 1984–88 have shown that the seasonal ice is important as the wintering substrate of krill Euphausia superba which, together with other zooplankton and fish, supports a large breeding population of seals and penguins. Clearly a key habitat in the economy of the Southern Ocean, this seasonal ice is likely to be vulnerable to small climatic changes.

Aurora and the Otago Museum: the boundary between Antarctic science and seamanship

Polar Record ◽  
2017 ◽  
Vol 53 (2) ◽  
pp. 192-198 ◽  
Author(s):  
Moira White
Keyword(s):  
World War I ◽  
British Empire ◽  
Ross Sea ◽  
Weddell Sea ◽  
World War ◽  
Pack Ice ◽  
Antarctic Expedition ◽  
Antarctic Continent ◽  
Museum Staff ◽  
The Antarctic

ABSTRACTSir Ernest Shackleton's Imperial Trans-Antarctic Expedition famously did not succeed in traversing the Antarctic continent from the Weddell Sea to the Ross Sea. It was, nevertheless, an enterprise that engaged the interest of New Zealanders and the rest of the British Empire even as World War I was being fought. When one of the expedition ships, Aurora, broke from her moorings soon after arrival in McMurdo Sound and drifted trapped in pack ice for months, the construction of a temporary jury rudder while still at sea enabled her crew to make their way to Port Chalmers, Dunedin for more extensive repairs in 1916. This paper discusses interactions between the Otago Museum staff and the crew of Aurora while she was in port, the offer of the replaced jury rudder to the museum, and reflects on the concerns and interests that might have contributed to the offer and its rejection.

scholarly journals XXXI.—Shackleton Antarctic Expedition, 1914–1917: The Natural History of Pack-Ice as observed in the Weddell Sea

1921 ◽  
Vol 52 (4) ◽  
pp. 795-829 ◽  
Author(s):  
J. M. Wordie
Keyword(s):  
Natural History ◽  
Weddell Sea ◽  
The West ◽  
Pack Ice ◽  
Antarctic Expedition ◽  
History Of ◽  
The Antarctic ◽  
Land Water

The opportunities for observation were afforded by the voyage and subsequent drift of the S.Y. Endurance. During December 1914 and January 1915 for a period of six weeks she successfully bored her way through pack-ice of every description—drift-ice, open-pack, and very frequently even close-pack. Continually fighting, she penetrated from 59° to 72° S. lat., and finally reached the land water off Coats Land on the latter parallel. As the crow flies, therefore, she was navigated through ice for nearly 800 geographical miles on this voyage; her actual course among the ice-fields and floes was computed to exceed 2000 miles, an achievement without parallel in the Antarctic. The principle adopted was to keep to the east, where presumably there is less pack than in the west; if the Endurance experience is a normal one, however, the meridian of 20° W. long., which was followed, is certainly not far enough east.

Sign in / Sign up

Export Citation Format

Share Document