Juvenile morphology of the large Antarctic canopy-forming brown alga, Desmarestia menziesii J. Agardh

Abstract For many types of seaweeds in Polar Regions, open questions remain about how their life cycle contributes to their overall adaptation to the extreme abiotic environment. This applies in particular to the major canopy-forming brown algae in much of the Antarctic Peninsula of the genus Desmarestia, which was investigated here. Diving surveys around Rothera Research Station (Adelaide Island, Antarctica) during December 2017–February 2018 revealed the widespread presence of a hitherto-unknown life form of Desmarestia sp. of a tender, feather-like morphology. Further studies explored whether this could be (1) a new, hitherto undescribed Desmarestia species (2) a new record for the region of a known Desmarestia species previously recorded elsewhere or (3) a so-far unknown life form of a species recorded for the region. Collections enabled the extraction of PCR-friendly DNA and sequencing of ITS1, which unambiguously showed that the samples belonged to Desmarestia menziesii, the only Desmarestia species presently recorded for the Adelaide Island/Marguerite Bay region. The presence of the juvenile morphology was subsequently confirmed throughout much of the natural range of D. menziesii during cruise-based diving surveys along the Western Antarctic Peninsula in 2019 and from collections at Anvers Island in 1989. Our collections thus constitute its juvenile morphology, which is not previously documented in the literature. The wider significance for the Polar seaweeds is discussed in the context of Taxonomy and Ecology.

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High-concentration sediment plumes, Horseshoe Island, western Antarctic Peninsula

Antarctic Science ◽

10.1017/s0954102021000055 ◽

2021 ◽

pp. 1-4

Author(s):

CRISTIAN RODRIGO ◽

ANDRÉS VARAS-GÓMEZ ◽

ADRIÁN BUSTAMANTE-MAINO ◽

EMILIO MENA-HODGES

Keyword(s):

Antarctic Peninsula ◽

Short Note ◽

Sediment Concentration ◽

Change Scenario ◽

High Concentration ◽

Tidewater Glaciers ◽

Marguerite Bay ◽

Southern Side ◽

Reported Data ◽

The Antarctic

The variability in sediment concentration and spatial distribution of meltwater discharges from tidewater glaciers can be used to elucidate climatic evolution and glacier behaviour due to the association between sediment yield and glacier retreat (e.g. Domack & McClennen 1996). In an accelerated deglaciation environment, higher sediment concentrations in the water column can change the glacimarine costal dynamics and affect productivity and sea floor ecosystems (e.g. Marín et al. 2013). In the Antarctic Peninsula Region, meltwater or turbid plumes were previously believed to be rare or without an important role in the sedimentary glacimarine environment (e.g. Griffith & Anderson 1989), but recent studies have shown that this is a common phenomenon in subpolar and transition polar climates (Yoo et al. 2015, Rodrigo et al. 2016). In the current climate change scenario, accelerated glacier retreats and mass losses can produce an increasing input of glacial meltwater into the fjord regions, a situation that is not yet well evaluated in the Antarctic Peninsula. In this short note, after in situ observation of an unusual waterfall from the southern side of the main western tidewater glacier (Shoesmith Glacier) of Horseshoe Island (Lystad Bay), Marguerite Bay (Fig. 1), we report high turbidity values associated with plumes from the glacier, whose values were higher than reported data from subpolar/transition polar Antarctic climates.

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Recent dynamic changes on Fleming Glacier after the disintegration of Wordie Ice Shelf, Antarctic Peninsula

The Cryosphere ◽

10.5194/tc-12-1347-2018 ◽

2018 ◽

Vol 12 (4) ◽

pp. 1347-1365 ◽

Cited By ~ 11

Author(s):

Peter Friedl ◽

Thorsten C. Seehaus ◽

Anja Wendt ◽

Matthias H. Braun ◽

Kathrin Höppner

Keyword(s):

Antarctic Peninsula ◽

Remote Sensing Data ◽

Data Sets ◽

Ice Shelf ◽

Glacier Tongue ◽

Marguerite Bay ◽

Grounding Line ◽

Continuous Dynamic ◽

The 1960S ◽

The Antarctic

Abstract. The Antarctic Peninsula is one of the world's regions most affected by climate change. Several ice shelves have retreated, thinned or completely disintegrated during recent decades, leading to acceleration and increased calving of their tributary glaciers. Wordie Ice Shelf, located in Marguerite Bay at the south-western side of the Antarctic Peninsula, completely disintegrated in a series of events between the 1960s and the late 1990s. We investigate the long-term dynamics (1994–2016) of Fleming Glacier after the disintegration of Wordie Ice Shelf by analysing various multi-sensor remote sensing data sets. We present a dense time series of synthetic aperture radar (SAR) surface velocities that reveals a rapid acceleration of Fleming Glacier in 2008 and a phase of further gradual acceleration and upstream propagation of high velocities in 2010–2011.The timing in acceleration correlates with strong upwelling events of warm circumpolar deep water (CDW) into Wordie Bay, most likely leading to increased submarine melt. This, together with continuous dynamic thinning and a deep subglacial trough with a retrograde bed slope close to the terminus probably, has induced unpinning of the glacier tongue in 2008 and gradual grounding line retreat between 2010 and 2011. Our data suggest that the glacier's grounding line had retreated by ∼ 6–9 km between 1996 and 2011, which caused ∼ 56 km2 of the glacier tongue to go afloat. The resulting reduction in buttressing explains a median speedup of ∼ 1.3 m d−1 (∼ 27 %) between 2008 and 2011, which we observed along a centre line extending between the grounding line in 1996 and ∼ 16 km upstream. Current median ice thinning rates (2011–2014) along profiles in areas below 1000 m altitude range between ∼ 2.6 to 3.2 m a−1 and are ∼ 70 % higher than between 2004 and 2008. Our study shows that Fleming Glacier is far away from approaching a new equilibrium and that the glacier dynamics are not primarily controlled by the loss of the former ice shelf anymore. Currently, the tongue of Fleming Glacier is grounded in a zone of bedrock elevation between ∼ −400 and −500 m. However, about 3–4 km upstream modelled bedrock topography indicates a retrograde bed which transitions into a deep trough of up to ∼ −1100 m at ∼ 10 km upstream. Hence, this endangers upstream ice masses, which can significantly increase the contribution of Fleming Glacier to sea level rise in the future.

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Electrical Resistivity of Ice from the Antarctic Peninsula, Antarctica

Journal of Glaciology ◽

10.1017/s0022143000006110 ◽

1984 ◽

Vol 30 (106) ◽

pp. 289-295 ◽

Cited By ~ 10

Author(s):

John M. Reynolds ◽

J. G. Paren

Keyword(s):

Antarctic Peninsula ◽

Flow Line ◽

Polar Regions ◽

List Type ◽

Electrical Measurements ◽

Ice Shelf ◽

Ice Shelves ◽

History Of ◽

Surface Ice ◽

The Antarctic

AbstractGeoresistivity soundings have been carried out at four sites in the Antarctic Peninsula. The objective of the work was to investigate the electrical behaviour of ice from an area where substantial melting occurs in summer and from contrasting thermal regimes. Electrical measurements made at three sites along a flow line within George VI Ice Shelf reveal that:(a)the resistivity of deep ice is similar to that of other Antarctic ice shelves,(b)the resistivity of the ice-shelf surface, which is affected by the percolation and refreezing of melt water, is similar to that of deep ice and hence the ice is polar in character.A compilation of published resistivities of deep ice from polar regions shows that the range of resistivities is very narrow (0.4 –2.0) x 105Ω m between –2 and – 29°C, irrespective of the physical setting and history of the ice. Typically, resistivity is within a factor of two of 80 kΩ m at –20° C with an activation energy of 0.22 eV. In contrast, the resistivity of surface ice at Wormald Ice Piedmont, where the ice is at 0°C throughout, is two orders of magnitude higher and falls at the lower end of the range of resistivities for temperate ice.

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Aerial dispersal of springtails on the Antarctic Peninsula: implications for local distribution and demography

Antarctic Science ◽

10.1017/s0954102007000028 ◽

2007 ◽

Vol 19 (1) ◽

pp. 3-10 ◽

Cited By ~ 45

Author(s):

T.C. Hawes ◽

M.R. Worland ◽

P. Convey ◽

J.S. Bale

Keyword(s):

Antarctic Peninsula ◽

Potential Mechanism ◽

Local Distribution ◽

Aerial Dispersal ◽

Wind Speeds ◽

Terrestrial Arthropods ◽

Marguerite Bay ◽

Terrestrial Habitats ◽

The Antarctic ◽

Aerial Deposition

Aerial dispersal has been frequently proposed as a potential mechanism by which polar terrestrial arthropods are transported to, and settle the ice free habitats of Antarctica, but to date there has been little substantive evidence in support of this hypothesis. Using water traps we investigated aerial deposition of arthropods on Lagoon Island, Ryder Bay, on the Antarctic Peninsula. Over a period of five weeks, trapping at three different altitudes, we captured a total of nine springtails, Cryptopygus antarcticus, all alive. This is the first study to demonstrate conclusively the survival of wind-borne native arthropods within Antarctica. By scaling the modest trapping area and success against island surface area, it is clear that hundreds, if not thousands, of springtails are regularly relocated by winds between the terrestrial habitats of Marguerite Bay. We use known desiccation rates of C. antarcticus and wind speeds to predict the likelihood of successful dispersal between the principal terrestrial habitats of the larger Marguerite Bay. Implications for local and long-range dispersal are discussed in relation to C. antarcticus and other polar arthropods.

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Mercury Levels in Feathers of Penguins from the Antarctic Peninsula Area: Geographical and Inter-Specific Differences

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18189918 ◽

2021 ◽

Vol 18 (18) ◽

pp. 9918

Author(s):

Miguel Motas ◽

Silvia Jerez ◽

Marta Esteban ◽

Francisco Valera ◽

José Javier Cuervo ◽

...

Keyword(s):

Antarctic Peninsula ◽

Microwave Digestion ◽

Toxic Metal ◽

Dry Weight ◽

Anthropogenic Sources ◽

Polar Regions ◽

Ice Coverage ◽

Icp Ms ◽

Arctic Seabirds ◽

The Antarctic

Polar regions, symbols of wilderness, have been identified as potential sinks of mercury coming from natural and anthropogenic sources at lower latitudes. Changes in ice coverage currently occurring in some areas such as the Antarctic Peninsula could enhance these phenomena and their impacts on local biota. As long-lived species at the top of food chains, seabirds are particularly sensitive to this highly toxic metal with the capacity to be biomagnified. Specifically, their feathers can be useful for Hg monitoring since they mainly accumulate its most toxic and persistent form, methyl-Hg. To that end, feathers of gentoo (Pygoscelis papua), chinstrap (P. antarcticus), and Adélie penguins (P. adeliae) (n = 108) were collected by passive sampling in seven different locations throughout the Antarctic Peninsula area and analyzed by ICP-MS after microwave-digestion. More than 93% of the samples showed detectable Hg levels (range: 6.3–12,529.8 ng g−1 dry weight), and the highest ones were found in the feathers of chinstrap penguins from King George Island. Hg bioconcentration and biomagnification seem to be occurring in the Antarctic food web, giving rise to high but non-toxic Hg levels in penguins, similar to those previously found in Arctic seabirds.

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High-resolution topography of the Antarctic Peninsula combining the TanDEM-X DEM and Reference Elevation Model of Antarctica (REMA) mosaic

The Cryosphere ◽

10.5194/tc-15-4421-2021 ◽

2021 ◽

Vol 15 (9) ◽

pp. 4421-4443

Author(s):

Yuting Dong ◽

Ji Zhao ◽

Dana Floricioiu ◽

Lukas Krieger ◽

Thomas Fritz ◽

...

Keyword(s):

High Resolution ◽

Spatial Resolution ◽

Antarctic Peninsula ◽

Data Consistency ◽

Optical Data ◽

Small Scale ◽

Potential Contribution ◽

Polar Regions ◽

Elevation Model ◽

The Antarctic

Abstract. The Antarctic Peninsula (AP) is one of the widely studied polar regions because of its sensitivity to climate change and potential contribution of its glaciers to global sea level rise. Precise digital elevation models (DEMs) at a high spatial resolution are much demanded for investigating the complex glacier system of the AP at fine scales. However, the two most recent circum-Antarctic DEMs, the 12 m TanDEM-X DEM (TDM DEM) from bistatic interferometric synthetic aperture radar (InSAR) data acquired between 2013 and 2014 and the Reference Elevation Model of Antarctica mosaic (REMA mosaic) at an 8 m spatial resolution derived from optical data acquired between 2011 and 2017 have specific individual limitations in this area. The TDM DEM has the advantage of good data consistency and few data voids (approx. 0.85 %), but there exist residual systematic elevation errors such as phase-unwrapping errors in the non-edited DEM version. The REMA mosaic has high absolute vertical accuracy, but on the AP it suffers from extended areas with data voids (approx. 8 %). To generate a consistent, gapless and high-resolution topography product of the AP, we fill the data voids in the TDM DEM with newly processed TDM raw DEM data acquired in austral winters of 2013 and 2014 and detect and correct the residual systematic elevation errors (i.e., elevation biases) in the TDM DEM with the support of the accurately calibrated REMA mosaic. Instead of a pixelwise replacement with REMA mosaic elevations, these provide reference values to correct the TDM elevation biases over entire regions detected through a path propagation algorithm. The procedure is applied iteratively to gradually correct the errors in the TDM DEM from a large to small scale. The proposed method maintains the characteristics of an InSAR-generated DEM and is minimally influenced by temporal or penetration differences between the TDM DEM and REMA mosaic. The performance of the correction is evaluated with laser altimetry data from Operation IceBridge and ICESat-2 missions. The overall root mean square error (RMSE) of the corrected TDM DEM has been reduced from more than 30 m to about 10 m which together with the improved absolute elevation accuracy indicates comparable values to the REMA mosaic. The generated high-resolution DEM depicts the up-to-date topography of the AP in detail and can be widely used for interferometric applications as well as for glaciological studies on individual glaciers or at regional scales.

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Electrical Resistivity of Ice from the Antarctic Peninsula, Antarctica

Journal of Glaciology ◽

10.3189/s0022143000006110 ◽

1984 ◽

Vol 30 (106) ◽

pp. 289-295 ◽

Cited By ~ 1

Author(s):

John M. Reynolds ◽

J. G. Paren

Keyword(s):

Antarctic Peninsula ◽

Flow Line ◽

Polar Regions ◽

List Type ◽

Electrical Measurements ◽

Ice Shelf ◽

Ice Shelves ◽

History Of ◽

Surface Ice ◽

The Antarctic

AbstractGeoresistivity soundings have been carried out at four sites in the Antarctic Peninsula. The objective of the work was to investigate the electrical behaviour of ice from an area where substantial melting occurs in summer and from contrasting thermal regimes. Electrical measurements made at three sites along a flow line within George VI Ice Shelf reveal that: (a)the resistivity of deep ice is similar to that of other Antarctic ice shelves,(b)the resistivity of the ice-shelf surface, which is affected by the percolation and refreezing of melt water, is similar to that of deep ice and hence the ice is polar in character.A compilation of published resistivities of deep ice from polar regions shows that the range of resistivities is very narrow (0.4 –2.0) x 105 Ω m between –2 and – 29°C, irrespective of the physical setting and history of the ice. Typically, resistivity is within a factor of two of 80 kΩ m at –20° C with an activation energy of 0.22 eV. In contrast, the resistivity of surface ice at Wormald Ice Piedmont, where the ice is at 0°C throughout, is two orders of magnitude higher and falls at the lower end of the range of resistivities for temperate ice.

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Assessing the potential of multispectral remote sensing for lithological mapping on the Antarctic Peninsula: case study from eastern Adelaide Island, Graham Land

Antarctic Science ◽

10.1017/s0954102010000015 ◽

2010 ◽

Vol 22 (3) ◽

pp. 299-318 ◽

Cited By ~ 17

Author(s):

C.E. Haselwimmer ◽

T.R. Riley ◽

J.G. Liu

Keyword(s):

Remote Sensing ◽

Antarctic Peninsula ◽

Spectral Properties ◽

Volcanic Rocks ◽

Lithological Mapping ◽

Aster Data ◽

Intrusive Rocks ◽

Multispectral Remote Sensing ◽

The Antarctic ◽

Adelaide Island

AbstractThe results of lithological mapping using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data for the Wright Peninsula region of Adelaide Island, Antarctic Peninsula are compared with existing geological maps and recent field observations to assess the potential of multispectral remote sensing to undertake lithological mapping on the Antarctic Peninsula. The Wright Peninsula comprises calc-alkaline intrusive rocks ranging from granite to gabbro, volcanic rocks of acidic to intermediate composition, and arc-related sediments. The reflective and thermal bands of a single ASTER image were analysed with reference to reflectance spectra of rock samples from the study area. Assessment of the ASTER mapping outcomes was undertaken with a newly compiled geological map of Adelaide Island and observations made during recent fieldwork. The results demonstrate that ASTER can uniquely discriminate granitoid intrusive rocks and altered rhyolitic volcanic rocks that display distinctive spectral properties. The results are more ambiguous at discriminating more intermediate/mafic rocks such as diorite/gabbro, andesite/basalt and chlorite-bearing sediments due to the similarity in spectral properties. These results demonstrate that although ASTER data are limited in their ability to uniquely discriminate lithologies they can provide important lithological information in support of geological mapping on the Antarctic Peninsula.

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Climate-change indicators from archival aerial photography of the Antarctic Peninsula

Annals of Glaciology ◽

10.3189/1998aog27-1-636-642 ◽

1998 ◽

Vol 27 ◽

pp. 636-642 ◽

Cited By ~ 51

Author(s):

A.J. Fox ◽

A. P. R. Cooper

Keyword(s):

Antarctic Peninsula ◽

Aerial Photography ◽

Ice Cover ◽

Aerial Survey ◽

Ice Shelf ◽

Ice Shelves ◽

Bay Area ◽

Mapping Tool ◽

Marguerite Bay ◽

The Antarctic

Aerial photography has been used as a mapping tool in the Antarctic Peninsula region sinre the late 1920s. Following pioneering work by Wilkins in 1928, Ellsworth in 1934 and the British Graham Land Expedition in 1934-37, the Falkland Islands and Dependencies Aerial Survey Expedition carried out extensive aerial photography during the period 1955-57. Since then, many other aerial surveys have been carried out, and the result is an archive of aerial photography that, for some localities, spans 40 years. The production of maps both from different generations of photographs and satellite images has revealed many changes in the extent of ice cover with time. For example, changes in ice shelves such as the Wordie Ice Shelf, Larsen Ice Shelf and Müller Ice Shelf, are well recorded, and the termini of some glaciers have retreated. However, the most pervasive change is the consistent decline in the extent of small bodies of snow and ice. This paper shows how perennial snow or ice cover has decreased in the northern Marguerite Bay area, at 68°S. The correlation of the change with elevation and with climate records from Adelaide and Rothera research stations in the Antarctic Peninsula region is examined.

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Chrono- and lithostratigraphy of a Mesozoic–Tertiary fore- to intra-arc basin: Adelaide Island, Antarctic Peninsula

Geological Magazine ◽

10.1017/s0016756811001002 ◽

2011 ◽

Vol 149 (5) ◽

pp. 768-782 ◽

Cited By ~ 10

Author(s):

TEAL R. RILEY ◽

MICHAEL J. FLOWERDEW ◽

MARTIN J. WHITEHOUSE

Keyword(s):

Antarctic Peninsula ◽

Basaltic Andesite ◽

West Coast ◽

Volcanic Rocks ◽

Volcanic Group ◽

Volcaniclastic Rocks ◽

Definition Of ◽

The Antarctic ◽

Adelaide Island

AbstractThe Mesozoic fore-arc of the Antarctic Peninsula is exposed along its west coast. On Adelaide Island, a 2–3 km succession of turbiditic coarse sandstones and volcanic rocks is exposed. Four U–Pb (zircon) ages are presented here that, in combination with a new stratigraphy, have permitted a robust chrono- and lithostratigraphy to be constructed, which in turn has allowed tentative correlations to be made with the Fossil Bluff Group of Alexander Island, where the ‘type’ fore-arc sequences are described. The lithostratigraphy of Adelaide Island includes the definition of five volcanic/sedimentary formations. The oldest formation is the Buchia Buttress Formation (149.5 ± 1.6 Ma) and is correlated with the Himalia Ridge Formation of Alexander Island. The sandstone–conglomerate dominated succession of the Milestone Bluff Formation (113.9 ± 1.2 Ma) is tentatively correlated with the Pluto Glacier Formation of Alexander Island. Three dominantly volcanic formations are recognized on Adelaide Island, akin to the volcanic rocks of the Alexander Island Volcanic Group; the Mount Liotard Formation is formed of 2 km of basaltic andesite lavas, whilst the Bond Nunatak Formation is also dominated by basaltic andesite lavas, but interbedded with volcaniclastic rocks. The Reptile Ridge Formation has been dated at 67.6 ± 0.7 Ma and is characterized by hydrothermally altered rhyolitic crystal-lithic tuffs. Tentative correlations between Adelaide Island and Alexander Island preclude the two areas forming part of distinct terranes as has been suggested previously, and a proximal source for volcaniclastic sediments also indicates an exotic terrane origin is unlikely.

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