Foraging patterns of Antarctic minke whales in McMurdo Sound, Ross Sea

2020 ◽  
Vol 32 (6) ◽  
pp. 454-465
Author(s):  
David G. Ainley ◽  
Trevor W. Joyce ◽  
Ben Saenz ◽  
Robert L. Pitman ◽  
John W. Durban ◽  
...  
Keyword(s):  
Foraging Behaviour ◽  
Ross Sea ◽  
Prey Availability ◽  
Dive Depth ◽  
Remotely Operated Vehicle ◽  
Mcmurdo Sound ◽  
Minke Whales ◽  
Fast Ice ◽  
Antarctic Silverfish ◽  
Ice Edge

AbstractEvidence indicates that Antarctic minke whales (AMWs) in the Ross Sea affect the foraging behaviour, especially diet, of sympatric Adélie penguins (ADPEs) by, we hypothesize, influencing the availability of prey they have in common, mainly crystal krill. To further investigate this interaction, we undertook a study in McMurdo Sound during 2012–2013 and 2014–2015 using telemetry and biologging of whales and penguins, shore-based observations and quantification of the preyscape. The 3D distribution and density of prey were assessed using a remotely operated vehicle deployed along and to the interior of the fast-ice edge where AMWs and ADPEs focused their foraging. Acoustic surveys of prey and foraging behaviour of predators indicate that prey remained abundant under the fast ice, becoming successively available to air-breathing predators only as the fast ice retreated. Over both seasons, the ADPE diet included less krill and more Antarctic silverfish once AMWs became abundant, but the penguins' foraging behaviour (i.e. time spent foraging, dive depth, distance from colony) did not change. In addition, over time, krill abundance decreased in the upper water column near the ice edge, consistent with the hypothesis (and previously gathered information) that AMW and ADPE foraging contributed to an alteration of prey availability.

 Seasonal variability of fast ice edge in the McMurdo Sound between 2017 and 2019 based on Sentinel-1 SAR

2020 ◽  
Author(s):  
Liyun Dai
Keyword(s):  
Climate Changes ◽  
Ecological Systems ◽  
Dominant Factor ◽  
Sar Images ◽  
Mcmurdo Sound ◽  
Northern Edge ◽  
Fast Ice ◽  
Ice Edge ◽  
Near Future ◽  
Seasonal And Interannual Variations

<p>The fast ice in the McMurdo Sound plays an important role in the coastal ecological systems and climate changes, but its seasonal and interannual variations are poorly understood. In this study, the fast ice phenology and extent variation are investigated using Sentinel-1 Synthetic Aperture Radar (SAR) images from 2017 to 2019, and the factors controlling the fast ice development are explored. The results showed that the fast ice edge presented obvious seasonal change. In 2017/2018 and 2018/2019 years it arrived at northernmost during May – July, and keeps north until the end of December or January, and then moves south, arriving at most south on February or March. However, there are some difference between these two years. The date the fast ice edge arrived at northernmost in 2018 was about two months later than in 2017, but the ending time at the northern edge was about one month earlier (31 Dec 2018 vs 30 Jan 2018). The time when it retreated to the southernmost in 2019 was about one month before that in 2017 or 2018. It seems the longer the edge stays in the northernmost, the later it retreats to the southernmost, and it may not completely disappear; the shorter the edge stays in the northernmost, the earlier it retreats to the southernmost, and it may completely disappear. The dominant factor controlling the beginning and end dates are air temperature. This statement still needs to be confirmed when more data will be processed and analyzed in near future.</p>

Over-winter movements and diving behavior of female Weddell seals (Leptonychotes weddellii) in the southwestern Ross Sea, Antarctica

1994 ◽  
Vol 72 (10) ◽  
pp. 1700-1710 ◽  
Author(s):  
J. Ward Testa
Keyword(s):  
Ross Sea ◽  
Diving Behavior ◽  
Winter Period ◽  
Pleuragramma Antarcticum ◽  
Long Distance ◽  
Leptonychotes Weddellii ◽  
Mcmurdo Sound ◽  
Weddell Seals ◽  
Pack Ice ◽  
Fast Ice

The movements and diving behavior of 18 adult female Weddell seals (Leptonychotes weddellii) were determined by satellite telemetry during the over-winter period in 1990 and 1991. Nine seals provided diving and movement data for 8 – 9 months. Seals that normally bred in the eastern part of McMurdo Sound spent most of the winter in the middle and northern parts of McMurdo Sound before the annual shore-fast ice had formed in those areas, or in the pack ice 0–50 km north of the sound and Ross Island. This is a greater use of pack ice, as opposed to shore-fast ice, in winter than was previously believed. Some long-distance movements (one over 1500 km in total) to the middle and northwestern parts of the Ross Sea also occurred. Although highly variable within and between individuals, dives indicative of foraging were primarily to mid-water regions (100 – 350 m) in both years, and were similar to those that have been observed in spring and summer, when Pleuragramma antarcticum is the primary prey of Weddell seals in McMurdo Sound.

Local climatology of fast ice in McMurdo Sound, Antarctica

2018 ◽  
Vol 30 (2) ◽  
pp. 125-142 ◽  
Author(s):  
Stacy Kim ◽  
Ben Saenz ◽  
Jeff Scanniello ◽  
Kendra Daly ◽  
David Ainley
Keyword(s):  
Sea Ice ◽  
Ross Sea ◽  
Wind Waves ◽  
Marine Ecosystem ◽  
Sea Ice Concentration ◽  
Ice Dynamics ◽  
Mcmurdo Sound ◽  
High Resolution Imagery ◽  
Pack Ice ◽  
Fast Ice

AbstractFast ice plays important physical and ecological roles: as a barrier to wind, waves and radiation, as both barrier and safe resting place for air-breathing animals, and as substrate for microbial communities. While sea ice has been monitored for decades using satellite imagery, high-resolution imagery sufficient to distinguish fast ice from mobile pack ice extends only back to c. 2000. Fast ice trends may differ from previously identified changes in regional sea ice distributions. To investigate effects of climate and human activities on fast ice dynamics in McMurdo Sound, Ross Sea, the sea and fast ice seasonal events (1978–2015), ice thicknesses and temperatures (1986–2014), wind velocities (1973–2015) and dates that an icebreaker annually opens a channel to McMurdo Station (1956–2015) are reported. A significant relationship exists between sea ice concentration and fast ice extent in the Sound. While fast/sea ice retreat dates have not changed, fast/sea ice reaches a minimum later and begins to advance earlier, in partial agreement with changes in Ross Sea regional pack ice dynamics. Fast ice minimum extent within McMurdo Sound is significantly correlated with icebreaker arrival date as well as wind velocity. The potential impacts of changes in fast ice climatology on the local marine ecosystem are discussed.

scholarly journals Brief communication: The anomalous winter 2019 sea ice conditions in McMurdo Sound, Antarctica

2021 ◽  
Author(s):  
Greg H. Leonard ◽  
Kate E. Turner ◽  
Maren E. Richter ◽  
Maddy S. Whittaker ◽  
Inga J. Smith
Keyword(s):  
Sea Ice ◽  
Strong Correlation ◽  
Ross Sea ◽  
Ice Cover ◽  
Katabatic Wind ◽  
Mcmurdo Sound ◽  
Southerly Wind ◽  
Ice Conditions ◽  
Fast Ice ◽  
Wind Events

Abstract. McMurdo Sound sea ice can generally be partitioned into two regimes: (1) a stable fast-ice cover, forming south of approximately 77.6° S around March/April, then breaking out the following January/February; and, (2) a more dynamic region north of 77.6° S that the McMurdo Sound and Ross Sea polynyas regularly impact. In 2019, a stable fast-ice cover formed unusually late due to repeated breakout events. We analyse the 2019 sea-ice conditions and relate them to southerly wind events using a Katabatic Wind Index (KWI). We find there is a strong correlation between breakout events and several unusually large KWI events.

scholarly journals Brief communication: The anomalous winter 2019 sea-ice conditions in McMurdo Sound, Antarctica

2021 ◽  
Vol 15 (10) ◽  
pp. 4999-5006
Author(s):  
Greg H. Leonard ◽  
Kate E. Turner ◽  
Maren E. Richter ◽  
Maddy S. Whittaker ◽  
Inga J. Smith
Keyword(s):  
Sea Ice ◽  
Strong Correlation ◽  
Ross Sea ◽  
Ice Cover ◽  
Mcmurdo Sound ◽  
Southerly Wind ◽  
Ice Conditions ◽  
Fast Ice ◽  
Wind Events ◽  
Storm Index

Abstract. McMurdo Sound sea ice can generally be partitioned into two regimes: (1) a stable fast-ice cover, forming south of approximately 77.6∘ S around March–April and then breaking out the following January–February, and (2) a more dynamic region north of 77.6∘ S that the McMurdo Sound and Ross Sea polynyas regularly impact. In 2019, a stable fast-ice cover formed unusually late due to repeated break-out events. We analyse the 2019 sea-ice conditions and relate them to a modified storm index (MSI), a proxy for southerly wind events. We find there is a strong correlation between the timing of break-out events and several unusually large MSI events.

Influence of Late Holocene climate on Lake Eggers hydrology, McMurdo Sound

2021 ◽  
pp. 1-13
Author(s):  
E.J. Chamberlain ◽  
A.J. Christ ◽  
R.W. Fulweiler
Keyword(s):  
Late Holocene ◽  
Ross Sea ◽  
Regional Climate ◽  
Ice Cores ◽  
Lake Ice ◽  
Mcmurdo Sound ◽  
Ice Accumulation ◽  
History Of ◽  
Ground Penetrating ◽  
Western Ross Sea

Abstract Ice-covered lakes in Antarctica preserve records of regional hydroclimate and harbour extreme ecosystems that may serve as terrestrial analogues for exobiotic environments. Here, we examine the impacts of hydroclimate and landscape on the formation history of Lake Eggers, a small ice-sealed lake, located in the coastal polar desert of McMurdo Sound, Antarctica (78°S). Using ground penetrating radar surveys and three lake ice cores we characterize the ice morphology and chemistry. Lake ice geochemistry indicates that Lake Eggers is fed primarily from local snowmelt that accreted onto the lake surface during runoff events. Radiocarbon ages of ice-encased algae suggest basal ice formed at least 735 ± 20 calibrated years before present (1215 C.E.). Persisting through the Late Holocene, Lake Eggers alternated between periods of ice accumulation and sublimation driven by regional climate variability in the western Ross Sea. For example, particulate organic matter displayed varying δ15N ratios with depth, corresponding to sea ice fluctuations in the western Ross Sea during the Late Holocene. These results suggest a strong climatic control on the hydrologic regime shifts shaping ice formation at Lake Eggers.

Influence of environmental conditions on spatial distribution and abundance of early life stages of Antarctic silverfish,Pleuragramma antarcticum(Nototheniidae), in the Ross Sea

2010 ◽  
Vol 22 (3) ◽  
pp. 243-254 ◽  
Author(s):  
Mario La Mesa ◽  
Barbara Catalano ◽  
Aniello Russo ◽  
Silvio Greco ◽  
Marino Vacchi ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Early Life ◽  
General Circulation ◽  
Ross Sea ◽  
Life Stages ◽  
Early Life Stages ◽  
Pleuragramma Antarcticum ◽  
Antarctic Silverfish ◽  
The Antarctic ◽  
Western Ross Sea

AbstractThe Antarctic silverfishPleuragramma antarcticumBoulenger is the dominant fish species in the high Antarctic zone, playing a key role in the Ross Sea midwater shelf ecosystem. Unlike other notothenioids, it is holoplanktonic species, spending its entire life cycle in the water column. Early life stages ofP. antarcticumare generally found in the upper 200 m and their spatial distribution is largely affected by water masses and general circulation. To understand better the mechanisms involved in the geographical distribution of the Antarctic silverfish within the western Ross Sea, an analysis of abundance and distribution was carried out in relation to oceanographic conditions. Samples were collected in summer during the 1998, 2000 and 2004 Italian cruises, covering the majority of the western sector of the Ross Sea. Overall 127 stations were sampled using standard plankton nets for biological samples and CTD and XBT to record abiotic parameters. Although all surveys were in December–January, the yearly results differed in terms of relative abundance of larval developmental stages and of oceanographic characteristics. The 1997–98 samples were characterized by very low abundance overall and by the virtual absence of early larvae. In summers 1999–2000 and 2003–04 the abundance ofP. antarcticumwas one order of magnitude higher than in the earlier season. In 1999–2000 catches were mainly composed of pre-flexion larvae and late postlarvae, while in 2003–04 catches were made up of pre-flexion larvae and juveniles. In January 2000 the Ross Sea summer polynya was fully open as the pack ice was almost completely melted, whereas in January 1998 and 2004 the opening of the polynya was considerably delayed. As a consequence, a delay in phytoplankton blooms and a decrease in primary production were observed in the summer seasons 1998 and 2004 with respect to 2000. The spatial distribution of early life stages, that were confined to the continental shelf and shelf break of the Ross Sea, generally appeared to be positively influenced by transition zones (oceanographic fronts). In addition, most of catches were recorded on or in close proximity to the banks (Pennell, Mawson, Ross and Crary) that characterize the continental shelf of the Ross Sea. On the basis of present findings and literature data, a link between the general circulation in the western Ross Sea and the distribution pattern of the early life stages ofP. antarcticumhas been developed.

scholarly journals Sources And Movement of Icebergs in the South-West Ross Sea, Antarctica

1989 ◽  
Vol 12 ◽  
pp. 85-88 ◽  
Author(s):  
Harry Keys ◽  
Dennis Fowler
Keyword(s):  
Small Proportion ◽  
Ross Sea ◽  
The South ◽  
Ice Shelf ◽  
Sea Floor ◽  
Ross Ice Shelf ◽  
South West ◽  
Fast Ice ◽  
Western Side ◽  
Coastal Strip

The shape, surface features, composition, and thickness of icebergs trapped annually in a 200 km long coastal strip of fast ice have been examined to determine their sources and movement. The thin western ice front of the Ross Ice Shelf seems to produce about 40% of the icebergs while local glaciers produce the remainder. The ice-shelf icebergs are carried west towards Ross Island then north up the western side of the Ross Sea. A small proportion of them gets trapped mainly by grounding on shallow areas of the sea floor which protrude across the regional long-shore currents.

scholarly journals <i>Brief communication</i> "The 2013 Erebus Glacier tongue calving event"

2013 ◽  
Vol 7 (2) ◽  
pp. 1749-1760
Author(s):  
C. L. Stevens ◽  
P. Sirguey ◽  
G. H. Leonard ◽  
T. G. Haskell
Keyword(s):  
Ocean Circulation ◽  
Ocean Currents ◽  
Mcmurdo Sound ◽  
Glacier Tongue ◽  
Surface Ocean ◽  
Fast Ice

Abstract. The Erebus Glacier Tongue, a~small floating glacier in southern McMurdo Sound, is one of the best-studied ice tongues in Antarctica. Despite this, its calving on the 27 February 2013 (UTC) was around 10 yr earlier than previously predicted. The calving was likely a result of ocean currents and the absence of fast ice. The subsequent trajectory of the newly-created iceberg supports previous descriptions of the surface ocean circulation in southern McMurdo Sound.

Impact of the B-15 iceberg “stranding event” on the physical and biological properties of sea ice in McMurdo Sound, Ross Sea, Antarctica

2008 ◽  
Vol 20 (6) ◽  
pp. 593-604 ◽  
Author(s):  
J.-P. Remy ◽  
S. Becquevort ◽  
T.G. Haskell ◽  
J.-L. Tison
Keyword(s):  
Sea Ice ◽  
Ross Sea ◽  
Ice Cores ◽  
Ice Cover ◽  
Biological Properties ◽  
Trophic Relationships ◽  
Oceanic Circulation ◽  
Mcmurdo Sound ◽  
Algae Biomass ◽  
Second Year

AbstractIce cores were sampled at four stations in McMurdo Sound (Ross Sea) between 1999 and 2003. At the beginning of year 2000, a very large iceberg (B-15) detached itself from the Ross Ice Shelf and stranded at the entrance of the Sound, preventing the usual oceanic circulation purging of the annual sea ice cover from this area. Ice textural studies showed that a second year sea ice cover was built-up at three out of the four stations: ice thickness increased to about 3 m. Repeated alternation of columnar and platelet ice appeared, and bulk salinity showed a strong decrease, principally in the upper part of the ice sheet, with associated brine volume decrease. Physical modification influenced the biology as well. By decreasing the light and space available for organisms in the sea ice cover, the stranding of B-15 has i) hampered autotrophic productivity, with chlorophyllaconcentration and algae biomass significantly lower for second year ice stations, and ii) affected trophic relationships such as the bacterial biomass/chlaconcentration correlation, or the autotrophic to heterotrophic ratio.

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