| 1. |
- Hindell, Mark A., et al.
(author)
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Circumpolar habitat use in the southern elephant seal : implications for foraging success and population trajectories
- 2016
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In: Ecosphere. - : Wiley. - 2150-8925 .- 2150-8925. ; 7:5
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Journal article (peer-reviewed)abstract
- In the Southern Ocean, wide-ranging predators offer the opportunity to quantify how animals respond to differences in the environment because their behavior and population trends are an integrated signal of prevailing conditions within multiple marine habitats. Southern elephant seals in particular, can provide useful insights due to their circumpolar distribution, their long and distant migrations and their performance of extended bouts of deep diving. Furthermore, across their range, elephant seal populations have very different population trends. In this study, we present a data set from the International Polar Year project; Marine Mammals Exploring the Oceans Pole to Pole for southern elephant seals, in which a large number of instruments (N = 287) deployed on animals, encompassing a broad circum-Antarctic geographic extent, collected in situ ocean data and at-sea foraging metrics that explicitly link foraging behavior and habitat structure in time and space. Broadly speaking, the seals foraged in two habitats, the relatively shallow waters of the Antarctic continental shelf and the Kerguelen Plateau and deep open water regions. Animals of both sexes were more likely to exhibit area-restricted search (ARS) behavior rather than transit in shelf habitats. While Antarctic shelf waters can be regarded as prime habitat for both sexes, female seals tend to move northwards with the advance of sea ice in the late autumn or early winter. The water masses used by the seals also influenced their behavioral mode, with female ARS behavior being most likely in modified Circumpolar Deepwater or northerly Modified Shelf Water, both of which tend to be associated with the outer reaches of the Antarctic Continental Shelf. The combined effects of (1) the differing habitat quality, (2) differing responses to encroaching ice as the winter progresses among colonies, (3) differing distances between breeding and haul-out sites and high quality habitats, and (4) differing long-term -regional trends in sea ice extent can explain the differing population trends observed among elephant seal colonies.
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| 2. |
- Mallett, Helen K. W., et al.
(author)
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Variation in the Distribution and Properties of Circumpolar Deep Water in the Eastern Amundsen Sea, on Seasonal Timescales, Using Seal-Borne Tags
- 2018
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In: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 45:10, s. 4982-4990
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Journal article (peer-reviewed)abstract
- In the Amundsen Sea, warm saline Circumpolar Deep Water (CDW) crosses the continental shelf toward the vulnerable West Antarctic ice shelves, contributing to their basal melting. Due to lack of observations, little is known about the spatial and temporal variability of CDW, particularly seasonally. A new data set of 6,704 seal tag temperature and salinity profiles in the easternmost trough between February and December 2014 reveals a CDW layer on average 49dbar thicker in late winter (August to October) than in late summer (February to April), the reverse seasonality of that seen at moorings in the western trough. This layer contains more heat in winter, but on the 27.76 kg/m(3) density surface CDW is 0.32 degrees C warmer in summer than in winter, across the northeastern Amundsen Sea, which may indicate that wintertime shoaling offshelf changes CDW properties onshelf. In Pine Island Bay these seasonal changes on density surfaces are reduced, likely by gyre circulation. Plain Language Summary In the Amundsen Sea, Antarctica, warm salty water crosses the continental shelf from the deep open ocean, toward the vulnerable West Antarctic ice shelves, bringing heat to help melt them from underneath. Due to lack of observations, little is known about how this flow of warm water varies in space and time, particularly seasonally. Between February and December 2014, in a trough in the eastern Amundsen Sea, 6,704 profiles were collected by sensors attached to seals, measuring temperature and salinity as the seals return from dives up to 1,200m deep. These data showed that this warm (similar to 1 degrees C) deep layer is on average similar to 50m thicker in late winter (August to October) than in late summer (February to April), the reverse seasonality of that seen within a trough in the western Amundsen Sea. This warm layer contains more heat in winter but on a surface of constant density is 0.32 degrees C warmer in summer than in winter, across the northeastern Amundsen Sea. This may indicate that in winter the deep waters offshelf rise, allowing different water onto the continental shelf. In Pine Island Bay these seasonal changes on density surfaces are reduced, probably because here the water circulates and mixes.
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| 3. |
- Roquet, Fabien, et al.
(author)
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A Southern Indian Ocean database of hydrographic profiles obtained with instrumented elephant seals
- 2014
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In: Scientific Data. - : Springer Science and Business Media LLC. - 2052-4463. ; 1
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Journal article (peer-reviewed)abstract
- The instrumentation of southern elephant seals with satellite-linked CTD tags has offered unique temporal and spatial coverage of the Southern Indian Ocean since 2004. This includes extensive data from the Antarctic continental slope and shelf regions during the winter months, which is outside the conventional areas of Argo autonomous floats and ship-based studies. This landmark dataset of around 75,000 temperature and salinity profiles from 20–140 °E, concentrated on the sector between the Kerguelen Islands and Prydz Bay, continues to grow through the coordinated efforts of French and Australian marine research teams. The seal data are quality controlled and calibrated using delayed-mode techniques involving comparisons with other existing profiles as well as cross-comparisons similar to established protocols within the Argo community, with a resulting accuracy of ±0.03 °C in temperature and ±0.05 in salinity or better. The data offer invaluable new insights into the water masses, oceanographic processes and provides a vital tool for oceanographers seeking to advance our understanding of this key component of the global ocean climate.
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| 4. |
- Roquet, Fabien, et al.
(author)
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Estimates of the Southern Ocean general circulation improved by animal-borne instruments
- 2013
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In: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 40:23, s. 6176-6180
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Journal article (peer-reviewed)abstract
- Over the last decade, several hundred seals have been equipped with conductivity-temperature-depth sensors in the Southern Ocean for both biological and physical oceanographic studies. A calibrated collection of seal-derived hydrographic data is now available, consisting of more than 165,000 profiles. The value of these hydrographic data within the existing Southern Ocean observing system is demonstrated herein by conducting two state estimation experiments, differing only in the use or not of seal data to constrain the system. Including seal-derived data substantially modifies the estimated surface mixed-layer properties and circulation patterns within and south of the Antarctic Circumpolar Current. Agreement with independent satellite observations of sea ice concentration is improved, especially along the East Antarctic shelf. Instrumented animals efficiently reduce a critical observational gap, and their contribution to monitoring polar climate variability will continue to grow as data accuracy and spatial coverage increase.
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| 5. |
- Treasure, Anne M., et al.
(author)
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Marine Mammals Exploring the Oceans Pole to Pole A Review of the MEOP Consortium
- 2017
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In: Oceanography. - : The Oceanography Society. - 1042-8275. ; 30:2, s. 132-138
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Journal article (peer-reviewed)abstract
- Polar oceans are poorly monitored despite the important role they play in regulating Earth's climate system. Marine mammals equipped with biologging devices are now being used to fill the data gaps in these logistically difficult to sample regions. Since 2002, instrumented animals have been generating exceptionally large data sets of oceanographic CTD casts (>500,000 profiles), which are now freely available to the scientific community through the MEOP data portal (http://meop.net). MEOP (Marine Mammals Exploring the Oceans Pole to Pole) is a consortium of international researchers dedicated to sharing animal-derived data and knowledge about the polar oceans. Collectively, MEOP demonstrates the power and cost-effectiveness of using marine mammals as data-collection platforms that can dramatically improve the ocean observing system for biological and physical oceanographers. Here, we review the MEOP program and database to bring it to the attention of the international community.
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| 6. |
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- 2019
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Journal article (peer-reviewed)
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