Seaweed biodiversity in the south-western Antarctic Peninsula: surveying macroalgal community composition in the Adelaide Island/Marguerite Bay region over a 35-year time span

AbstractThe rapid warming observed in the western Antarctic Peninsula gives rise to a fast disintegration of ice shelves and thinning and retreat of marine-terminating continental glaciers, which is likely to raise global sea levels in the near future. In order to understand the contemporary changes in context and to provide constraints for hindcasting models, it is important to understand the Late Quaternary history of the region. Here, we build on previous work on the deglacial history of the western Antarctic Peninsula and we present four new cosmogenic 10Be exposure ages from Horseshoe Island in Marguerite Bay, which has been suggested as a former location of very fast ice stream retreat. Four samples collected from erratic pink granite boulders at an altitude of ~80 m above sea level yielded ages that range between 12.9 ± 1.1 ka and 9.4 ± 0.8 ka. As in other studies on Antarctic erratics, we have chosen to report the youngest erratic age (9.4 ± 0.8 ka) as the true age of deglaciation, which confirms a rapid thinning of the Marguerite Trough Ice Stream at the onset of Holocene. This result is consistent with other cosmogenic age data and other proxies (marine and lacustrine 14C and optically stimulated luminescence) reported from nearby areas.

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

Polar Biology ◽

10.1007/s00300-019-02584-3 ◽

2019 ◽

Vol 42 (11) ◽

pp. 2097-2103 ◽

Cited By ~ 1

Author(s):

Frithjof C. Küpper ◽

Charles D. Amsler ◽

Simon Morley ◽

Bruno de Reviers ◽

Aurelia Reichardt ◽

...

Keyword(s):

Antarctic Peninsula ◽

Life Form ◽

Research Station ◽

Polar Regions ◽

Marguerite Bay ◽

Open Questions ◽

Natural Range ◽

The Antarctic ◽

Adelaide Island ◽

Desmarestia Menziesii

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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Cenozoic stress field in the southwestern Antarctic Peninsula from brittle mesostructures in Wright Peninsula, Adelaide Island

Polish Polar Research ◽

10.2478/v10183-011-0006-8 ◽

2011 ◽

Vol 32 (1) ◽

pp. 39-58 ◽

Cited By ~ 1

Author(s):

Adolfo Maestro ◽

Jerónimo López-Martínez

Keyword(s):

Stress Field ◽

Antarctic Peninsula ◽

Bimodal Distribution ◽

Horizontal Stress ◽

Early Miocene ◽

Western Antarctic Peninsula ◽

Compressional Stress ◽

Stress States ◽

Maximum Horizontal Stress ◽

Adelaide Island

Cenozoic stress field in the southwestern Antarctic Peninsula from brittle mesostructures in Wright Peninsula, Adelaide IslandPalaeostresses inferred from brittle mesostructures in the southern Wright Peninsula show a stress field characterized by compressional, strike-slip and extensional regime stress states. The compressional stress (σ1) shows a main NW-SE direction and the extensional stress (σ3) shows a relative scattering with two main modes: NE-SW to E-W and NW-SE. The maximum horizontal stress (σy) has a bimodal distribution with NW-SE and NE-SW direction. The compressional orientation is related to subduction of the former Phoenix Plate under the Antarctic Plate from the Early Jurassic to the Early Miocene. Extensional structures within a broad-scale compressional stress field can be related to both the decrease in relative stress magnitudes from active margins to intraplate regions and stretching processes occurring in eastern Adelaide Island, which develop a fore-arc or intra-arc basin from the Early Miocene. Stress states with NW-SE-trending σ1are compatible with the dominant pattern established for the western Antarctic Peninsula. NW-SE orientations of σ3suggest the occurrence of tectonic forces coming from fore-arc extension along the western Antarctic Peninsula.

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Invertebrate micronekton and macrozooplankton in the Marguerite Bay region of the Western Antarctic Peninsula

Deep Sea Research Part II Topical Studies in Oceanography ◽

10.1016/j.dsr2.2010.08.020 ◽

2011 ◽

Vol 58 (13-16) ◽

pp. 1580-1598 ◽

Cited By ~ 11

Author(s):

Melanie L. Parker ◽

Joseph Donnelly ◽

Joseph J. Torres

Keyword(s):

Antarctic Peninsula ◽

Western Antarctic Peninsula ◽

Marguerite Bay

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Silica cycling and isotopic composition in northern Marguerite Bay on the rapidly-warming western Antarctic Peninsula

Deep Sea Research Part II Topical Studies in Oceanography ◽

10.1016/j.dsr2.2016.09.006 ◽

2017 ◽

Vol 139 ◽

pp. 132-142 ◽

Cited By ~ 5

Author(s):

Amber L. Annett ◽

Sian F. Henley ◽

Hugh J. Venables ◽

Michael P. Meredith ◽

Andrew Clarke ◽

...

Keyword(s):

Isotopic Composition ◽

Antarctic Peninsula ◽

Western Antarctic Peninsula ◽

Silica Cycling ◽

Marguerite Bay

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Transport of warm Upper Circumpolar Deep Water onto the western Antarctic Peninsula continental shelf

Ocean Science ◽

10.5194/os-8-433-2012 ◽

2012 ◽

Vol 8 (4) ◽

pp. 433-442 ◽

Cited By ~ 81

Author(s):

D. G. Martinson ◽

D. C. McKee

Keyword(s):

Continental Shelf ◽

Antarctic Peninsula ◽

Deep Water ◽

Antarctic Circumpolar Current ◽

Western Antarctic Peninsula ◽

Dominant Mechanism ◽

Circumpolar Deep Water ◽

Marguerite Bay ◽

Circumpolar Current ◽

The Antarctic

Abstract. Five thermistor moorings were placed on the continental shelf of the western Antarctic Peninsula (between 2007 and 2010) in an effort to identify the mechanism(s) responsible for delivering warm Upper Circumpolar Deep Water (UCDW) onto the broad continental shelf from the Antarctic Circumpolar Current (ACC) flowing over the adjacent continental slope. Historically, four mechanisms have been suggested: (1) eddies shed from the ACC, (2) flow into the cross-shelf-cutting canyons with overflow onto the nominal shelf, (3) general upwelling, and (4) episodic advective diversions of the ACC onto the shelf. The mooring array showed that for the years of deployment, the dominant mechanism is eddies; upwelling may also contribute but to an unknown extent. Mechanism 2 played no role, though the canyons have been shown previously to channel UCDW across the shelf into Marguerite Bay. Mechanism 4 played no role independently, though eddies may be advected within a greater intrusion of the background flow.

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The stratigraphy and geochronology of Adelaide Island

Antarctic Science ◽

10.1017/s095410209800056x ◽

1998 ◽

Vol 10 (4) ◽

pp. 462-475 ◽

Cited By ~ 7

Author(s):

Chris J. Griffiths ◽

Richard D. J. Oglethorpe

Keyword(s):

Antarctic Peninsula ◽

Volcanic Rocks ◽

South Shetland Islands ◽

The South ◽

Shetland Islands ◽

Step Heating ◽

Show Evidence ◽

Cretaceous Volcanism ◽

The Antarctic ◽

Adelaide Island

The Mesozoic-Cenozoic volcanic arc of the Antarctic Peninsula is represented on Adelaide Island by a sedimentary and volcanic succession intruded by plutons. 40Ar-39 Ar step-heating age spectra have been obtained from volcanic rocks and hornblende separates from sedimentary clasts of plutonic origin. These spectra show evidence for some argon loss, but, in general, have plateau ages which are consistent with the mapped stratigraphy and with other geochronological controls, suggesting that they approximate to original ages. As a result the following events in the evolution of Adelaide Island can be recognized:1) mostly marine Mesozoic sedimentation, 2) Early Cretaceous (c. 141 Ma) plutonism (recorded in clasts from conglomerates), 3) Cretaceous volcanism, 4) Late Cretaceous (possibly Tertiary) sedimentation, 5) Early Tertiary volcanism, which was acidic in eastern outcrops and intermediate elsewhere, and 6) Eocene intermediate volcanism and deposition of arc-derived conglomerates. Volcanism was possibly coeval with known Palaeocene-Eocene plutonic activity on Adelaide Island (part of the Antarctic Peninsula Batholith) and with volcanism of similar age in northern Alexander Island and the South Shetland Islands. The volcanism on Adelaide Island and the South Shetland Islands, at least, was associated with a westward migration of the Antarctic Peninsula arc.

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