Original Article Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013
Antarctic krill (Euphausia superba) are a key species in SouthernOcean ecosystems,maintaining very large numbers of predators, and fluctuations in their abundance can affect the overall structure and functioning of the ecosystems. The interannual variability in the abundance and biomass of krill was...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.1026.4812 2023-05-15T13:36:21+02:00 Original Article Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013 Sophie Fielding Jonathan L. Watkins Philip N. Trathan Peter Enderlein Claire M. Waluda Gabriele Stowasser Geraint A. Tarling Eugene J. Murphy The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1026.4812 http://icesjms.oxfordjournals.org/content/71/9/2578.full.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1026.4812 http://icesjms.oxfordjournals.org/content/71/9/2578.full.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://icesjms.oxfordjournals.org/content/71/9/2578.full.pdf text ftciteseerx 2016-10-30T00:03:19Z Antarctic krill (Euphausia superba) are a key species in SouthernOcean ecosystems,maintaining very large numbers of predators, and fluctuations in their abundance can affect the overall structure and functioning of the ecosystems. The interannual variability in the abundance and biomass of krill was examined using a 17-year time-series of acoustic observations undertaken in theWestern Core Box (WCB) survey area to the northwest of South Georgia, Southern Ocean. Krill targets were identified in acoustic data using a multifrequency identification window and converted to krill density using the Stochastic Distorted-Wave Born Approximation target strength model. Krill density ranged over several orders of magnitude (0–10 000 g m22) and its distribution was highly skewedwithmany zero observations.Within each survey, themean krill density was significantly correlated with the top 7 % of themaximum krill densities observed. Hence, only the densest krill swarms detected in any one year drove themean krill density estimates for the WCB in that year. WCB krill density (m, mean density for the area) showed several years (1997/1998, 2001–2003, 2005–2007) of high values (m. 30 g m22) interspersed with years (1999/2000, 2004, 2009/2010) of low density (m, 30 g m22). This pattern showed three different periods, with fluctuations every 4–5 years. Cross correlation analyses of variability in krill density with current and lagged indices of ocean (sea surface temperature, SST and El Niño/Southern Oscillation) and atmospheric variability (Southern Annular Mode) found Text Antarc* Antarctic Antarctic Krill Euphausia superba Southern Ocean Unknown Antarctic Southern Ocean |
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description |
Antarctic krill (Euphausia superba) are a key species in SouthernOcean ecosystems,maintaining very large numbers of predators, and fluctuations in their abundance can affect the overall structure and functioning of the ecosystems. The interannual variability in the abundance and biomass of krill was examined using a 17-year time-series of acoustic observations undertaken in theWestern Core Box (WCB) survey area to the northwest of South Georgia, Southern Ocean. Krill targets were identified in acoustic data using a multifrequency identification window and converted to krill density using the Stochastic Distorted-Wave Born Approximation target strength model. Krill density ranged over several orders of magnitude (0–10 000 g m22) and its distribution was highly skewedwithmany zero observations.Within each survey, themean krill density was significantly correlated with the top 7 % of themaximum krill densities observed. Hence, only the densest krill swarms detected in any one year drove themean krill density estimates for the WCB in that year. WCB krill density (m, mean density for the area) showed several years (1997/1998, 2001–2003, 2005–2007) of high values (m. 30 g m22) interspersed with years (1999/2000, 2004, 2009/2010) of low density (m, 30 g m22). This pattern showed three different periods, with fluctuations every 4–5 years. Cross correlation analyses of variability in krill density with current and lagged indices of ocean (sea surface temperature, SST and El Niño/Southern Oscillation) and atmospheric variability (Southern Annular Mode) found |
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The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Sophie Fielding Jonathan L. Watkins Philip N. Trathan Peter Enderlein Claire M. Waluda Gabriele Stowasser Geraint A. Tarling Eugene J. Murphy |
spellingShingle |
Sophie Fielding Jonathan L. Watkins Philip N. Trathan Peter Enderlein Claire M. Waluda Gabriele Stowasser Geraint A. Tarling Eugene J. Murphy Original Article Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013 |
author_facet |
Sophie Fielding Jonathan L. Watkins Philip N. Trathan Peter Enderlein Claire M. Waluda Gabriele Stowasser Geraint A. Tarling Eugene J. Murphy |
author_sort |
Sophie Fielding |
title |
Original Article Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013 |
title_short |
Original Article Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013 |
title_full |
Original Article Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013 |
title_fullStr |
Original Article Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013 |
title_full_unstemmed |
Original Article Interannual variability in Antarctic krill (Euphausia superba) density at South Georgia, Southern Ocean: 1997–2013 |
title_sort |
original article interannual variability in antarctic krill (euphausia superba) density at south georgia, southern ocean: 1997–2013 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1026.4812 http://icesjms.oxfordjournals.org/content/71/9/2578.full.pdf |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic Antarctic Krill Euphausia superba Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Krill Euphausia superba Southern Ocean |
op_source |
http://icesjms.oxfordjournals.org/content/71/9/2578.full.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1026.4812 http://icesjms.oxfordjournals.org/content/71/9/2578.full.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766077522555961344 |