scholarly journals Climate change and glacier retreat drive shifts in an Antarctic benthic ecosystem

2015 ◽  
Vol 1 (10) ◽  
pp. e1500050 ◽  
Author(s):  
Ricardo Sahade ◽  
Cristian Lagger ◽  
Luciana Torre ◽  
Fernando Momo ◽  
Patrick Monien ◽  
...  
Keyword(s):  
Climate Change ◽  
Glacier Retreat ◽  
Sediment Runoff ◽  
Ice Shelf ◽  
Ecosystem Responses ◽  
Antarctic Species ◽  
Current Scenario ◽  
Antarctic Benthos ◽  
The Antarctic ◽  
Species Being

The Antarctic Peninsula (AP) is one of the three places on Earth that registered the most intense warming in the last 50 years, almost five times the global mean. This warming has strongly affected the cryosphere, causing the largest ice-shelf collapses ever observed and the retreat of 87% of glaciers. Ecosystem responses, although increasingly predicted, have been mainly reported for pelagic systems. However, and despite most Antarctic species being benthic, responses in the Antarctic benthos have been detected in only a few species, and major effects at assemblage level are unknown. This is probably due to the scarcity of baselines against which to assess change. We performed repeat surveys of coastal benthos in 1994, 1998, and 2010, analyzing community structure and environmental variables at King George Island, Antarctica. We report a marked shift in an Antarctic benthic community that can be linked to ongoing climate change. However, rather than temperature as the primary factor, we highlight the resulting increased sediment runoff, triggered by glacier retreat, as the potential causal factor. The sudden shift from a “filter feeders–ascidian domination” to a “mixed assemblage” suggests that thresholds (for example, of tolerable sedimentation) and alternative equilibrium states, depending on the reversibility of the changes, could be possible traits of this ecosystem. Sedimentation processes will be increasing under the current scenario of glacier retreat, and attention needs to be paid to its effects along the AP.

scholarly journals Introduction. Antarctic ecology: from genes to ecosystems. Part 2. Evolution, diversity and functional ecology

2007 ◽  
Vol 362 (1488) ◽  
pp. 2187-2189 ◽  
Author(s):  
Alex D Rogers ◽  
Eugene J Murphy ◽  
Nadine M Johnston ◽  
Andrew Clarke
Keyword(s):  
Climate Change ◽  
Life Histories ◽  
Natural Populations ◽  
Environmental Parameters ◽  
Functional Ecology ◽  
Antarctic Species ◽  
Trade Offs ◽  
Genes To Ecosystems ◽  
Micro Organisms ◽  
The Antarctic

The Antarctic biota has evolved over the last 100 million years in increasingly isolated and cold conditions. As a result, Antarctic species, from micro-organisms to vertebrates, have adapted to life at extremely low temperatures, including changes in the genome, physiology and ecological traits such as life history. Coupled with cycles of glaciation that have promoted speciation in the Antarctic, this has led to a unique biota in terms of biogeography, patterns of species distribution and endemism. Specialization in the Antarctic biota has led to trade-offs in many ecologically important functions and Antarctic species may have a limited capacity to adapt to present climate change. These include the direct effects of changes in environmental parameters and indirect effects of increased competition and predation resulting from altered life histories of Antarctic species and the impacts of invasive species. Ultimately, climate change may alter the responses of Antarctic ecosystems to harvesting from humans. The unique adaptations of Antarctic species mean that they provide unique models of molecular evolution in natural populations. The simplicity of Antarctic communities, especially from terrestrial systems, makes them ideal to investigate the ecological implications of climate change, which are difficult to identify in more complex systems.

scholarly journals Modelled response of the volume and thickness of the Antarctic ice sheet to the advance of the grounded area

2010 ◽  
Vol 51 (55) ◽  
pp. 41-48 ◽  
Author(s):  
Fuyuki Saito ◽  
Ayako Abe-Ouchi
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Volume Change ◽  
Numerical Experiments ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Antarctic Ice Sheet ◽  
Ice Shelves ◽  
Ice Volume ◽  
The Antarctic

AbstractNumerical experiments are performed for the Antarctic ice sheet to study the sensitivity of the ice volume to variations in the area of grounded ice and to changes in the climate during the most recent deglaciation. The effect of the variations in the grounded area is found to be the major source of changes in the ice volume, while the effect of climate change was minor. The maximum possible contribution of the ice-volume change to sea-level rise during the deglaciation is estimated to be 36 m, which covers most values estimated in previous studies. The effect of the advance of the ice-sheet margin over those regions not connected to the major ice shelves contributes one-third of the total ice-volume change, which is comparable to the effect of the grounding of the Filchner–Ronne Ice Shelf and the contribution of the Ross and Amery Ice Shelves together.

scholarly journals Climate Change and Invasibility of the Antarctic Benthos

2007 ◽  
Vol 38 (1) ◽  
pp. 129-154 ◽  
Author(s):  
Richard B. Aronson ◽  
Sven Thatje ◽  
Andrew Clarke ◽  
Lloyd S. Peck ◽  
Daniel B. Blake ◽  
...  
Keyword(s):  
Climate Change ◽  
Antarctic Benthos ◽  
The Antarctic

scholarly journals Responses of Basal Melting of Antarctic Ice Shelves to the Climatic Forcing of the Last Glacial Maximum and CO2 Doubling

2017 ◽  
Vol 30 (10) ◽  
pp. 3473-3497 ◽  
Author(s):  
Takashi Obase ◽  
Ayako Abe-Ouchi ◽  
Kazuya Kusahara ◽  
Hiroyasu Hasumi ◽  
Rumi Ohgaito
Keyword(s):  
Climate Change ◽  
Heat Flux ◽  
Ocean Temperature ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Basal Melting ◽  
Atmospheric Heat ◽  
The Antarctic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract Basal melting of the Antarctic ice shelves is an important factor in determining the stability of the Antarctic ice sheet. This study used the climatic outputs of an atmosphere–ocean general circulation model to force a circumpolar ocean model that resolves ice shelf cavity circulation to investigate the response of Antarctic ice shelf melting to different climatic conditions (i.e., to a doubling of CO2 and to the Last Glacial Maximum conditions). Sensitivity experiments were also conducted to investigate the roles of both surface atmospheric change and changes of oceanic lateral boundary conditions. It was found that the rate of change of basal melt due to climate warming is much greater (by an order of magnitude) than that due to cooling. This is mainly because the intrusion of warm water onto the continental shelves, linked to sea ice production and climate change, is crucial in determining the basal melt rate of many ice shelves. Sensitivity experiments showed that changes of atmospheric heat flux and ocean temperature are both important for warm and cold climates. The offshore wind change, together with atmospheric heat flux change, strongly affected the production of both sea ice and high-density water, preventing warmer water approaching the ice shelves under a colder climate. These results reflect the importance of both water mass formation in the Antarctic shelf seas and subsurface ocean temperature in understanding the long-term response to climate change of the melting of Antarctic ice shelves.

scholarly journals The Multitrophic Effects of Climate Change and Glacier Retreat in Mountain Rivers

BioScience ◽  
2017 ◽  
Vol 67 (10) ◽  
pp. 897-911 ◽  
Author(s):  
Sarah C. Fell ◽  
Jonathan L. Carrivick ◽  
Lee E. Brown
Keyword(s):  
Climate Change ◽  
Physicochemical Characteristics ◽  
Model Systems ◽  
Glacier Retreat ◽  
Mountain Rivers ◽  
Aquatic Communities ◽  
Ecosystem Responses ◽  
Ice Melt ◽  
Climate Change Effects ◽  
Relative Paucity

Abstract Climate change is driving the thinning and retreat of many glaciers globally. Reductions of ice-melt inputs to mountain rivers are changing their physicochemical characteristics and, in turn, aquatic communities. Glacier-fed rivers can serve as model systems for investigations of climate-change effects on ecosystems because of their strong atmospheric–cryospheric links, high biodiversity of multiple taxonomic groups, and significant conservation interest concerning endemic species. From a synthesis of existing knowledge, we develop a new conceptual understanding of how reducing glacier cover affects organisms spanning multiple trophic groups. Although the response of macroinvertebrates to glacier retreat has been well described, we show that there remains a relative paucity of information for biofilm, microinvertebrate, and vertebrate taxa. Enhanced understanding of whole river food webs will improve the prediction of river-ecosystem responses to deglaciation while offering the potential to identify and protect a wider range of sensitive and threatened species.

scholarly journals Societal importance of Antarctic negative feedbacks on climate change: blue carbon gains from sea ice, ice shelf and glacier losses

2021 ◽  
Vol 108 (5) ◽  
Author(s):  
D. K. A. Barnes ◽  
C. J. Sands ◽  
M. L. Paulsen ◽  
B. Moreno ◽  
C. Moreau ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Multiple Stressors ◽  
Economic Benefits ◽  
Blue Carbon ◽  
Glacier Retreat ◽  
Indigenous Species ◽  
Carbon Sinks ◽  
Ice Shelf ◽  
Positive Feedbacks

AbstractDiminishing prospects for environmental preservation under climate change are intensifying efforts to boost capture, storage and sequestration (long-term burial) of carbon. However, as Earth’s biological carbon sinks also shrink, remediation has become a key part of the narrative for terrestrial ecosystems. In contrast, blue carbon on polar continental shelves have stronger pathways to sequestration and have increased with climate-forced marine ice losses—becoming the largest known natural negative feedback on climate change. Here we explore the size and complex dynamics of blue carbon gains with spatiotemporal changes in sea ice (60–100 MtCyear−1), ice shelves (4–40 MtCyear−1 = giant iceberg generation) and glacier retreat (< 1 MtCyear−1). Estimates suggest that, amongst these, reduced duration of seasonal sea ice is most important. Decreasing sea ice extent drives longer (not necessarily larger biomass) smaller cell-sized phytoplankton blooms, increasing growth of many primary consumers and benthic carbon storage—where sequestration chances are maximal. However, sea ice losses also create positive feedbacks in shallow waters through increased iceberg movement and scouring of benthos. Unlike loss of sea ice, which enhances existing sinks, ice shelf losses generate brand new carbon sinks both where giant icebergs were, and in their wake. These also generate small positive feedbacks from scouring, minimised by repeat scouring at biodiversity hotspots. Blue carbon change from glacier retreat has been least well quantified, and although emerging fjords are small areas, they have high storage-sequestration conversion efficiencies, whilst blue carbon in polar waters faces many diverse and complex stressors. The identity of these are known (e.g. fishing, warming, ocean acidification, non-indigenous species and plastic pollution) but not their magnitude of impact. In order to mediate multiple stressors, research should focus on wider verification of blue carbon gains, projecting future change, and the broader environmental and economic benefits to safeguard blue carbon ecosystems through law.

scholarly journals Do Antarctic benthic invertebrates show an extended level of eurybathy?

1996 ◽  
Vol 8 (1) ◽  
pp. 3-6 ◽  
Author(s):  
T. Brey ◽  
C. Dahm ◽  
M. Gorny ◽  
M. Klages ◽  
M. Stiller ◽  
...  
Keyword(s):  
Benthic Invertebrates ◽  
Depth Distribution ◽  
Benthic Invertebrate ◽  
Distribution Data ◽  
Antarctic Species ◽  
European Species ◽  
Invertebrate Species ◽  
Antarctic Benthos ◽  
Depth Ranges ◽  
The Antarctic

Depth distribution data were compared for 172 European and 157 Antarctic benthic invertebrate species occurring in the respective shelf areas. Antarctic species showed significantly wider depth ranges in selected families of the groups Bivalvia, Gastropoda, Amphipoda and Decapoda. No differences were found in Polychaeta, Asteroidea and Ophiuroidea, where European species also showed comparatively wide bathymetric ranges. These extended levels of eurybathy in the Antarctic benthos may be interpreted either as an evolutionary adaptation or pre-adaptation to the oscillation of shelf ice extension during the Antarctic glacial-interglacial cycle.

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