scholarly journals Responses of Southern Ocean Seafloor Habitats and Communities to Global and Local Drivers of Change

2021 ◽  
Vol 8 ◽  
Author(s):  
Madeleine J. Brasier ◽  
David Barnes ◽  
Narissa Bax ◽  
Angelika Brandt ◽  
Anne B. Christianson ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Indigenous Species ◽  
Drivers Of Change ◽  
Regional Warming ◽  
Commercial Fish ◽  
Key Species ◽  
Antarctic Shelf ◽  
Non Indigenous Species ◽  
The Antarctic ◽  
Slow Growing

Knowledge of life on the Southern Ocean seafloor has substantially grown since the beginning of this century with increasing ship-based surveys and regular monitoring sites, new technologies and greatly enhanced data sharing. However, seafloor habitats and their communities exhibit high spatial variability and heterogeneity that challenges the way in which we assess the state of the Southern Ocean benthos on larger scales. The Antarctic shelf is rich in diversity compared with deeper water areas, important for storing carbon (“blue carbon”) and provides habitat for commercial fish species. In this paper, we focus on the seafloor habitats of the Antarctic shelf, which are vulnerable to drivers of change including increasing ocean temperatures, iceberg scour, sea ice melt, ocean acidification, fishing pressures, pollution and non-indigenous species. Some of the most vulnerable areas include the West Antarctic Peninsula, which is experiencing rapid regional warming and increased iceberg-scouring, subantarctic islands and tourist destinations where human activities and environmental conditions increase the potential for the establishment of non-indigenous species and active fishing areas around South Georgia, Heard and MacDonald Islands. Vulnerable species include those in areas of regional warming with low thermal tolerance, calcifying species susceptible to increasing ocean acidity as well as slow-growing habitat-forming species that can be damaged by fishing gears e.g., sponges, bryozoan, and coral species. Management regimes can protect seafloor habitats and key species from fishing activities; some areas will need more protection than others, accounting for specific traits that make species vulnerable, slow growing and long-lived species, restricted locations with optimum physiological conditions and available food, and restricted distributions of rare species. Ecosystem-based management practices and long-term, highly protected areas may be the most effective tools in the preservation of vulnerable seafloor habitats. Here, we focus on outlining seafloor responses to drivers of change observed to date and projections for the future. We discuss the need for action to preserve seafloor habitats under climate change, fishing pressures and other anthropogenic impacts.

An account of the Mysidacea (Crustacea, Malacostraca) of the Southern Ocean

1998 ◽  
Vol 10 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Angelika Brandt ◽  
Ute Mühlenhardt-Siegel ◽  
Volker Siegel
Keyword(s):  
Southern Ocean ◽  
Present State ◽  
Distribution Patterns ◽  
Taxonomic Diversity ◽  
Shelf Break ◽  
Bathymetric Distribution ◽  
Antarctic Region ◽  
Magellan Region ◽  
Antarctic Shelf ◽  
The Antarctic

An inventory of Antarctic and Subantarctic mysid fauna is presented, together with a summary of the present state of knowledge of species and their taxonomic diversity, geographic and bathymetric distribution patterns. Fifty nine species of Mysidacea (Crustacea, Peracarida) are now known. Of these, 37 were reported for the Antarctic region and 31 for the Magellan region; six species occur further north in the Southern Ocean, but south of 40°S. 51% of the Antarctic Mysidacea are endemic, and the figure for the Magellan region is 48%. Most of the species live hyperbenthically, but some also occur bathy- or mesopelagically. Mysidetes has the most species in the Southern Ocean, and Eucopia australis is the species with the widest bathymetric distribution (600–6000 m depth). It is concluded that an emergence of species onto the Antarctic shelf in the Neogene was quite unlikely, because none of the mysid species is a true deepsea species, and most species occur on the shelf or at the shelf break. It is more probable that present day species colonized the Southern Ocean via shallower waters. The examples of the distribution of different genera suggest that the Mysidacea of the Southern Ocean probably had various geographical origins.

scholarly journals Disturbance, colonization and development of Antarctic benthic communities

2006 ◽  
Vol 362 (1477) ◽  
pp. 11-38 ◽  
Author(s):  
David K.A Barnes ◽  
Kathleen E Conlan
Keyword(s):  
Temperature Stress ◽  
Benthic Communities ◽  
Larval Abundance ◽  
Indigenous Species ◽  
Benthic Organisms ◽  
Community Recovery ◽  
Sea Floor ◽  
Wind Speeds ◽  
Non Indigenous Species ◽  
The Antarctic

A decade has yielded much progress in understanding polar disturbance and community recovery—mainly through quantifying ice scour rates, other disturbance levels, larval abundance and diversity, colonization rates and response of benthos to predicted climate change. The continental shelf around Antarctica is clearly subject to massive disturbance, but remarkably across so many scales. In summer, millions of icebergs from sizes smaller than cars to larger than countries ground out and gouge the sea floor and crush the benthic communities there, while the highest wind speeds create the highest waves to pound the coast. In winter, the calm associated with the sea surface freezing creates the clearest marine water in the world. But in winter, an ice foot encases coastal life and anchor ice rips benthos from the sea floor. Over tens and hundreds of thousands of years, glaciations have done the same on continental scales—ice sheets have bulldozed the seabed and the zoobenthos to edge of shelves. We detail and rank modern disturbance levels (from most to least): ice; asteroid impacts; sediment instability; wind/wave action; pollution; UV irradiation; volcanism; trawling; non-indigenous species; freshwater inundation; and temperature stress. Benthic organisms have had to recolonize local scourings and continental shelves repeatedly, yet a decade of studies have demonstrated that they have (compared with lower latitudes) slow tempos of reproduction, colonization and growth. Despite massive disturbance levels and slow recolonization potential, the Antarctic shelf has a much richer fauna than would be expected for its area. Now, West Antarctica is among the fastest warming regions and its organisms face new rapid changes. In the next century, temperature stress and non-indigenous species will drastically rise to become dominant disturbances to the Antarctic life. Here, we describe the potential for benthic organisms to respond to disturbance, focusing particularly on what we know now that we did not a decade ago.

scholarly journals Terrestrial ecosystems of the Antarctic Peninsula and their responses to climate change and anthropogenic impacts

2020 ◽  
pp. 84-97
Author(s):  
R. Bargagli ◽  
Keyword(s):  
Antarctic Peninsula ◽  
Native Species ◽  
Environmental Changes ◽  
Anthropogenic Impacts ◽  
Extreme Temperature ◽  
Terrestrial Ecosystems ◽  
Indigenous Species ◽  
Non Indigenous Species ◽  
Food Web Complexity ◽  
The Antarctic

Antarctica and the Southern Ocean are unique natural laboratories where organisms adapted to extreme environmental conditions have evolved in isolation for millions of years. These unique biotic communities on Earth are facing complex climatic and environmental changes. Terrestrial ecosystems in the Antarctic Peninsula Region (APR) have experienced the highest rate of climate warming and, being the most impacted by human activities, are facing the greatest risk of detrimental changes. This review provides an overview of the most recent findings on how biotic communities in terrestrial ecosystems of the Antarctic Peninsula Region (APR) are responding and will likely respond to further environmental changes and direct anthropogenic impacts. Knowledge gained from studies on relatively simple terrestrial ecosystems could be very useful in predicting what may happen in much more complex ecosystems in regions with less extreme temperature changes. The rapid warming of the APR has led to the retreat of glaciers, the loss of snow and permafrost and the increase of ice-free areas, with a consequent enhancement of soil-forming processes, biotic communities, and food web complexity. However, most human activity is concentrated in APR coastal ice-free areas and poses many threats to terrestrial ecosystems such as environmental pollution or disturbances to soilcommunities and wildlife. People who work or visit APR may inadvertently introduce alien organisms and/or spread native species to spatially isolated ice-free areas. The number of introduced non-indigenous species and xenobiotic compounds in the APR is likely to be greater than currently documented, and several biosecurity and monitoring activities are therefore suggested to Antarctic national scientific programs and tourism operators to minimize the risk of irreversible loss of integrity by the unique terrestrial ecosystems of APR.

Krill Fishery

2020 ◽  
pp. 137-158
Author(s):  
So Kawaguchi ◽  
Stephen Nicol
Keyword(s):  
Southern Ocean ◽  
Antarctic Krill ◽  
Management Approach ◽  
West Antarctica ◽  
Southwest Atlantic ◽  
Atlantic Sector ◽  
Key Species ◽  
Technological Developments ◽  
Ocean Ecosystem ◽  
The Antarctic

Antarctic krill is a key species in the Southern Ocean ecosystem as well as the target for the largest fishery in the Southern Ocean, which has been operating continuously since the early 1970s. The krill fishery began by operating all around the continent but gradually contracted to the West Antarctica in the 1990s, where it is currently concentrated on a few fishing grounds in the Southwest Atlantic sector. This fishery has regained some commercial attraction because of recent technological developments in harvesting and processing. These developments permit the production of high-value products, and the total annual catch has increased to nearly 400,000 t over the last decade. Climate change has already affected the krill fishery, with the reduced winter sea ice in the South Atlantic allowing current fishery operations farther south than what was previously possible. The Antarctic krill fishery is managed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). Its management system is unique in taking into account the state of the ecosystem as well as that of the harvested stock. The establishment of a feedback management approach for this fishery has been the major task for the Scientific Committee of CCAMLR to realize this ecosystem-based management objective. This chapter provides a general introduction to krill biology and ecology, followed by a narrative of the forces that prompted the development of a krill fishery and the current issues that surround its management.

The impact of sediment deposition and iceberg scour on the Antarctic soft shell clam Laternula elliptica at King George Island, Antarctica

2011 ◽  
Vol 23 (2) ◽  
pp. 127-138 ◽  
Author(s):  
Eva E.R. Philipp ◽  
Gunnar Husmann ◽  
Doris Abele
Keyword(s):  
Population Density ◽  
Sediment Deposition ◽  
Laternula Elliptica ◽  
Key Species ◽  
Rapid Changes ◽  
Western Side ◽  
The Antarctic ◽  
The Impact ◽  
Slow Growing ◽  
High Sediment

AbstractRecent rapid changes of air temperature on the western side of the Antarctic Peninsula results in increased sediment discharge and ice scouring frequencies in coastal regions. These changes are bound to especially affect slow growing, sessile filter feeders such as the Antarctic bivalve, Laternula elliptica, a long-lived and abundant key species with circumpolar distribution. We investigated the effect of sedimentation and ice scouring on small/young and large/old individuals at two closely located stations, distinctly influenced by both types of disturbance. Small individuals dealt better with disturbance in terms of their respiratory response to sediment exposure, reburrowing ability, and survival after injury, compared to larger animals. At the more disturbed station L. elliptica population density was lower, but larger animals reburrowed faster after iceberg disturbance and reduced their metabolic rate under strong sediment coverage, compared to larger animals of the less disturbed station, indicating that an adaptation or learning response to both types of disturbance may be possible. Smaller individuals were not influenced. Laternula elliptica seems capable of coping with the rapidly changing environmental conditions. Due to a decrease in population density and mean population lifespan, L. elliptica could however lose its key role in the bentho-pelagic carbon flux in areas of high sediment deposition.

scholarly journals Marine richness and gradients at Deception Island, Antarctica

2008 ◽  
Vol 20 (3) ◽  
pp. 271-280 ◽  
Author(s):  
David K.A. Barnes ◽  
Katrin Linse ◽  
Peter Enderlein ◽  
Dan Smale ◽  
Keiron P.P. Fraser ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Marine Species ◽  
South Shetland Islands ◽  
Indigenous Species ◽  
Deception Island ◽  
Shetland Islands ◽  
Antarctic Marine ◽  
Planktotrophic Larvae ◽  
Non Indigenous Species ◽  
Total Species

AbstractStudies of the recovery of the fauna following the 1967–70 eruptions at Deception Island, South Shetland Islands, have made it one of the best-studied marine sites of the Southern Ocean for biodiversity. Using SCUBA we surveyed the mega- and macro-epifauna of its subtidal zones in the entrance (Neptune's Bellows), immediately inside the caldera (Whaler's Bay) and well within the caldera (Fumarole Bay). Richness declined from 10 phyla, 13 classes and 35 species at Neptune's Bellows to three phyla, four classes and five species in Whaler's Bay and just two phyla, classes and species at Fumarole Bay. Amongst the 35 species we found at Neptune's Bellows, 14 were previously unrecorded from Deception Island. Despite many ship visits and amongst the warmest sea temperatures in the Southern Ocean, the Non Indigenous Species (NIS) algae were not found in our survey. Deception Island has been recolonized considerably since the recent eruptions, but many taxa are still very poorly represented and the colonizers present are mainly those with planktotrophic larvae. Examination of the literature revealed that to date 163 named marine species have been found within the caldera as well as at least 50 more morphospecies, which are yet to be identified. Species accumulation has consistently increased across eight recent samples reported and the number of species reported there is likely to reach 300 when taxa such as the nematodes are identified to species level. This represents a first meaningful total species estimate for an Antarctic marine area and, as the site is comparatively impoverished, indicates how rich the surrounding Antarctic shelf must be.

scholarly journals Population Dynamics Of Magellania Fragilis, a Brachiopod Dominating a Mixed-Bottom Macrobenthic Assemblage on the Antarctic Shelf

1995 ◽  
Vol 75 (4) ◽  
pp. 857-869 ◽  
Author(s):  
T. Brey ◽  
L.S. Peck ◽  
J. Gutt ◽  
S. Hain ◽  
W.E. Arntz
Keyword(s):  
Growth Function ◽  
Von Bertalanffy ◽  
Underwater Photography ◽  
Annual Productivity ◽  
Von Bertalanffy Growth Function ◽  
Antarctic Shelf ◽  
Size At Age ◽  
The Antarctic ◽  
Slow Growing ◽  
Strong Seasonality

A dense assemblage of the brachiopod Magellania fragilis was sampled by trawl and underwater photography during the expedition ANT IX/3 (1991) of RV ‘Polarstern’ on the shelf of the Lazarev Sea, Antarctica. Mean abundance and biomass estimates for M. fragilis were 26.15 individuals m2 and 1.13 g AFDM m2, respectively. Growth bands visible on the shell were interpreted as annual growth marks caused by the strong seasonality of food input to the benthos and were treated as size-at-age data. The von Bertalanffy growth function Lt (mm) = 51.67 (1 - e0020 (t +1.326))3.828 described these data best. The annual somatic P/B ratio was very low, 0.046 y1, and annual production amounted to 0.052 g AFDM m2 y1 at this particular site. These results indicate that M. fragilis is a comparatively slow-growing species with very low annual productivity.

scholarly journals Survey of Presence of Non-Indigenous Eurytemora Carolleeae in the Gulf of Riga (Baltic Sea) Five Years After its First Discovery

2018 ◽  
Vol 72 (4) ◽  
pp. 230-235
Author(s):  
Labuce Astra ◽  
Ikauniece Anda ◽  
Strāķe Solvita ◽  
Souissi Anissa
Keyword(s):  
Baltic Sea ◽  
Calanoid Copepod ◽  
Reproduction Rate ◽  
Indigenous Species ◽  
Physiological Plasticity ◽  
Eurytemora Affinis ◽  
Male And Female ◽  
Key Species ◽  
Gulf Of Riga ◽  
Non Indigenous Species

Abstract In the brackish ecosystem of the Gulf of Riga, the calanoid copepod Eurytemora affinis is a key species, but recently a new non-indigenous species Eurytemora carolleeae was discovered in the region. In the present study, we aimed to validate the presence of E. carolleeae in the southern part of the Gulf of Riga five years after its first discovery. The study area is the closest region to the Rīga harbour — the main source of non-indigenous species arrival in the Gulf. Recent studies have predicted the possible potential of E. carolleeae invasion due to its physiological plasticity. Male and female specimens of Eurytemora were collected in spring, summer, and autumn of 2013, and analysed based on three morphological indicators. Despite the higher reproduction rate of E. carolleeae, this intrusive species does not seem to have succeeded in establishing during the five-year period after its first discovery in the Gulf of Riga, and hence does not present a threat to the native E. affinis population in the study area.

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