1
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Kim SH, Kim T, Son W, Kim JH, La HS. The complete mitochondrial genome of the ice krill Euphausia crystallorophias Holt & Tattersall, 1906 (Euphausiacea, Euphausiidae), from the Ross Sea, Antarctica. Mitochondrial DNA B Resour 2024; 9:500-505. [PMID: 38623177 PMCID: PMC11018016 DOI: 10.1080/23802359.2024.2337775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/27/2024] [Indexed: 04/17/2024] Open
Abstract
The mitogenome of Euphausia crystallorophias collected from the Ross Sea Region Marine Protected Area (RSR MPA) is described for the first time. The assembled mitogenome was 17,291 bp in length and consisted of two ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), 13 protein-coding genes (PCGs), and noncoding regions, all of which were identical to those of other euphausiid species. The most common start codon for the 13 PCGs was ATG, and the most common termination codon was TAA. The overall G + C content was 33.2% in the heavy strand. Euphausia crystallorophias was sister to E. superba in the phylogenetic analysis. The mitogenome of E. crystallorophias provided significant DNA molecular data for further identification and phylogenetic analysis within the euphausiids.
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Affiliation(s)
- Sung Hoon Kim
- Division of Ocean and Atmosphere Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
| | - Taeho Kim
- Strategic Planning Division, National Institute of Biological Resources, Incheon, Republic of Korea
| | - Wuju Son
- Division of Ocean and Atmosphere Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
- Department of Polar Science, University of Science and Technology, Daejeon, Republic of Korea
| | - Jeong-Hoon Kim
- Division of Life Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
| | - Hyoung Sul La
- Division of Ocean and Atmosphere Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
- Department of Polar Science, University of Science and Technology, Daejeon, Republic of Korea
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2
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Ryabov A, Berger U, Blasius B, Meyer B. Driving forces of Antarctic krill abundance. SCIENCE ADVANCES 2023; 9:eadh4584. [PMID: 38100594 PMCID: PMC10848738 DOI: 10.1126/sciadv.adh4584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 11/15/2023] [Indexed: 12/17/2023]
Abstract
Antarctic krill, crucial to the Southern Ocean ecosystem and a vital fisheries resource, is endangered by climate change. Identifying drivers of krill biomass is therefore essential for determining catch limits and designating protection zones. We present a modeling approach to pinpointing effects of sea surface temperature, ice cover, chlorophyll levels, climate indices, and intraspecific competition. Our study reveals that larval recruitment is driven by both competition among age classes and chlorophyll levels. In addition, while milder ice and temperature in spring and summer favor reproduction and early larval survival, both larvae and juveniles strongly benefit from heavier ice and colder temperatures in winter. We conclude that omitting top-down control of resources by krill is only acceptable for retrospective or single-year prognostic models that use field chlorophyll data but that incorporating intraspecific competition is essential for longer-term forecasts. Our findings can guide future krill modeling strategies, reinforcing the sustainability of this keystone species.
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Affiliation(s)
- Alexey Ryabov
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Section Polar Biological Oceanography, Am Handelshafen 12, D-27570 Bremerhaven, Germany
- Dresden University of Technology, Institute of Forest Growth and Computer Sciences, D-01062 Dresden, Germany
- Institute for Chemistry and Biology of the Marine Environment, Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Uta Berger
- Dresden University of Technology, Institute of Forest Growth and Computer Sciences, D-01062 Dresden, Germany
| | - Bernd Blasius
- Institute for Chemistry and Biology of the Marine Environment, Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
- Helmholtz Institute for Functional Marine Biodiversity (HIFMB), Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Bettina Meyer
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Section Polar Biological Oceanography, Am Handelshafen 12, D-27570 Bremerhaven, Germany
- Institute for Chemistry and Biology of the Marine Environment, Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
- Helmholtz Institute for Functional Marine Biodiversity (HIFMB), Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
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3
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Bahlburg D, Hüppe L, Böhrer T, Thorpe SE, Murphy EJ, Berger U, Meyer B. Plasticity and seasonality of the vertical migration behaviour of Antarctic krill using acoustic data from fishing vessels. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230520. [PMID: 37771962 PMCID: PMC10523065 DOI: 10.1098/rsos.230520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 09/06/2023] [Indexed: 09/30/2023]
Abstract
Understanding the vertical migration behaviour of Antarctic krill is important for understanding spatial distribution, ecophysiology, trophic interactions and carbon fluxes of this Southern Ocean key species. In this study, we analysed an eight-month continuous dataset recorded with an ES80 echosounder on board a commercial krill fishing vessel in the southwest Atlantic sector of the Southern Ocean. Our analysis supports the existing hypothesis that krill swarms migrate into deeper waters during winter but also reveals a high degree of variability in vertical migration behaviour within seasons, even at small spatial scales. During summer, we found that behaviour associated with prolonged surface presence primarily occurred at low surface chlorophyll a concentrations whereas multiple ascent-descent cycles per day occurred when surface chlorophyll a concentrations were elevated. The high plasticity, with some krill swarms behaving differently in the same location at the same time, suggests that krill behaviour is not a purely environmentally driven process. Differences in life stage, physiology and type of predator are likely other important drivers. Finally, our study demonstrates new ways of using data from krill fishing vessels, and with the routine collection of additional information in potential future projects, they have great potential to significantly advance our understanding of krill ecology.
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Affiliation(s)
- Dominik Bahlburg
- Forstliche Biometrie und Systemanalyse, Technische Universität Dresden, Pienner Straße 8, 01737 Tharandt, Dresden, Germany
- Helmholtz Centre for Environmental Research Leipzig, Permoserstraße 15, 04318 Leipzig, Germany
| | - Lukas Hüppe
- Neurobiology and Genetics, Julius-Maximilian-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Alfred-Wegener-Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Thomas Böhrer
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Schloßplatz 4, 91054 Erlangen, Germany
| | - Sally E. Thorpe
- Ecosystems, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Eugene J. Murphy
- Ecosystems, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Uta Berger
- Forstliche Biometrie und Systemanalyse, Technische Universität Dresden, Pienner Straße 8, 01737 Tharandt, Dresden, Germany
| | - Bettina Meyer
- Alfred-Wegener-Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26111 Oldenburg, Germany
- Helmholtz Institute for Functional Marine Biodiversity, Ammerländer Heerstraße 231, 26129 Oldenburg, Germany
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4
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Heneghan RF, Everett JD, Sykes P, Batten SD, Edwards M, Takahashi K, Suthers IM, Blanchard JL, Richardson AJ. Corrigendum to “A functional size-spectrum model of the global marine ecosystem that resolves zooplankton composition”, Ecological Modelling, 2020, 435: 109265. Ecol Modell 2023. [DOI: 10.1016/j.ecolmodel.2023.110309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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5
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Wilkie Johnston L, Bergami E, Rowlands E, Manno C. Organic or junk food? Microplastic contamination in Antarctic krill and salps. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221421. [PMID: 36998765 PMCID: PMC10049761 DOI: 10.1098/rsos.221421] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 03/06/2023] [Indexed: 06/19/2023]
Abstract
Microplastics (MP) have been reported in Southern Ocean (SO), where they are likely to encounter Antarctic zooplankton and enter pelagic food webs. Here we assess the presence of MP within Antarctic krill (Euphausia superba) and salps (Salpa thompsoni) and quantify their abundance and type by micro-Fourier transform infrared microscopy. MP were found in both species, with fibres being more abundant than fragments (krill: 56.25% and salps: 22.32% of the total MP). Polymer identification indicated MP originated from both local and distant sources. Our findings prove how in situ MP ingestion from these organisms is a real and ongoing process in the SO. MP amount was higher in krill (2.13 ± 0.26 MP ind-1) than salps (1.38 ± 0.42 MP ind-1), while MP size extracted from krill (130 ± 30 µm) was significantly lower than MP size from salps (330 ± 50 µm). We suggest that differences between abundance and size of MP ingested by these two species may be related to their food strategies, their ability to fragment MP as well as different human pressures within the collection areas of the study region. First comparative field-based evidence of MP in both krill and salps, two emblematic zooplankton species of the SO marine ecosystems, underlines that Antarctic marine ecosystems may be particularly sensitive to plastic pollution.
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Affiliation(s)
- Laura Wilkie Johnston
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
- University of St Andrews, St Andrews, Scotland KY16 9AJ, UK
| | - Elisa Bergami
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 213/D, Modena, Italy
| | - Emily Rowlands
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Clara Manno
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
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6
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Möller L, Vainstein Y, Wöhlbrand L, Dörries M, Meyer B, Sohn K, Rabus R. Transcriptome-proteome compendium of the Antarctic krill (Euphausia superba): Metabolic potential and repertoire of hydrolytic enzymes. Proteomics 2022; 22:e2100404. [PMID: 35778945 DOI: 10.1002/pmic.202100404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 06/24/2022] [Accepted: 06/28/2022] [Indexed: 11/06/2022]
Abstract
The Antarctic krill (Euphausia superba Dana) is a keystone species in the Southern Ocean that uses an arsenal of hydrolases for biomacromolecule decomposition to effectively digest its omnivorous diet. The present study builds on a hybrid-assembled transcriptome (13,671 ORFs) combined with comprehensive proteome profiling. The analysis of individual krill compartments allowed detection of significantly more different proteins compared to that of the entire animal (1,464 vs. 294 proteins). The nearby krill sampling stations in the Bransfield Strait (Antarctic Peninsula) yielded rather uniform proteome datasets. Proteins related to energy production and lipid degradation were particularly abundant in the abdomen, agreeing with the high energy demand of muscle tissue. A total of 378 different biomacromolecule hydrolysing enzymes were detected, including 250 proteases, 99 CAZymes, 14 nucleases and 15 lipases. The large repertoire in proteases is in accord with the protein-rich diet affiliated with E. superba's omnivorous lifestyle and complex biology. The richness in chitin-degrading enzymes allows not only digestion of zooplankton diet, but also the utilization of the discharged exoskeleton after moulting. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Lars Möller
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Yeheven Vainstein
- In-Vitro-Diagnostics, Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB), Stuttgart, Germany
| | - Lars Wöhlbrand
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Marvin Dörries
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany.,Biodiversity Change, Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Oldenburg, Germany
| | - Bettina Meyer
- Biodiversity and Biological Processes in Polar Oceans, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany.,Ecophysiology of Pelagic Key Species, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.,Biodiversity Change, Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Oldenburg, Germany
| | - Kai Sohn
- In-Vitro-Diagnostics, Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB), Stuttgart, Germany
| | - Ralf Rabus
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
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7
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Regional diet in Antarctic krill (Euphausia superba) as determined by lipid, fatty acid, and sterol composition. Polar Biol 2022. [DOI: 10.1007/s00300-022-03054-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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Pauli NC, Flintrop CM, Konrad C, Pakhomov EA, Swoboda S, Koch F, Wang XL, Zhang JC, Brierley AS, Bernasconi M, Meyer B, Iversen MH. Krill and salp faecal pellets contribute equally to the carbon flux at the Antarctic Peninsula. Nat Commun 2021; 12:7168. [PMID: 34887407 PMCID: PMC8660819 DOI: 10.1038/s41467-021-27436-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 11/15/2021] [Indexed: 11/09/2022] Open
Abstract
Krill and salps are important for carbon flux in the Southern Ocean, but the extent of their contribution and the consequences of shifts in dominance from krill to salps remain unclear. We present a direct comparison of the contribution of krill and salp faecal pellets (FP) to vertical carbon flux at the Antarctic Peninsula using a combination of sediment traps, FP production, carbon content, microbial degradation, and krill and salp abundances. Salps produce 4-fold more FP carbon than krill, but the FP from both species contribute equally to the carbon flux at 300 m, accounting for 75% of total carbon. Krill FP are exported to 72% to 300 m, while 80% of salp FP are retained in the mixed layer due to fragmentation. Thus, declining krill abundances could lead to decreased carbon flux, indicating that the Antarctic Peninsula could become a less efficient carbon sink for anthropogenic CO2 in future.
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Affiliation(s)
- Nora-Charlotte Pauli
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University of Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26111, Oldenburg, Germany. .,Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany.
| | - Clara M. Flintrop
- grid.10894.340000 0001 1033 7684Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany ,grid.7704.40000 0001 2297 4381MARUM and University of Bremen, Leobener Str. 8, 28359 Bremen, Germany
| | - Christian Konrad
- grid.10894.340000 0001 1033 7684Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany ,grid.7704.40000 0001 2297 4381MARUM and University of Bremen, Leobener Str. 8, 28359 Bremen, Germany
| | - Evgeny A. Pakhomov
- grid.17091.3e0000 0001 2288 9830Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, 2207 Main Mall, Vancouver, British Columbia V6T 1Z4 Canada ,grid.17091.3e0000 0001 2288 9830Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, British Columbia V6T 1Z4 Canada ,grid.484717.9Hakai Institute, PO Box 25039, Campbell River, British Columbia V9W 0B7 Canada
| | - Steffen Swoboda
- grid.7704.40000 0001 2297 4381MARUM and University of Bremen, Leobener Str. 8, 28359 Bremen, Germany
| | - Florian Koch
- grid.10894.340000 0001 1033 7684Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Xin-Liang Wang
- grid.43308.3c0000 0000 9413 3760Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071 China
| | - Ji-Chang Zhang
- grid.43308.3c0000 0000 9413 3760Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071 China
| | - Andrew S. Brierley
- grid.11914.3c0000 0001 0721 1626Pelagic Ecology Research Group, Gatty Marine Laboratory, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB UK
| | - Matteo Bernasconi
- grid.11914.3c0000 0001 0721 1626Pelagic Ecology Research Group, Gatty Marine Laboratory, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB UK
| | - Bettina Meyer
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University of Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26111, Oldenburg, Germany. .,Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany. .,Helmholtz Institute for Functional Marine Biodiversity (HIFMB), Ammerländer Heerstraße 231, 26129, Oldenburg, Germany.
| | - Morten H. Iversen
- grid.10894.340000 0001 1033 7684Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany ,grid.7704.40000 0001 2297 4381MARUM and University of Bremen, Leobener Str. 8, 28359 Bremen, Germany
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9
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Selective feeding in Southern Ocean key grazers-diet composition of krill and salps. Commun Biol 2021; 4:1061. [PMID: 34508174 PMCID: PMC8433442 DOI: 10.1038/s42003-021-02581-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 08/24/2021] [Indexed: 02/08/2023] Open
Abstract
Over the past decades, two key grazers in the Southern Ocean (SO), krill and salps, have experienced drastic changes in their distribution and abundance, leading to increasing overlap of their habitats. Both species occupy different ecological niches and long-term shifts in their distributions are expected to have cascading effects on the SO ecosystem. However, studies directly comparing krill and salps are lacking. Here, we provide a direct comparison of the diet and fecal pellet composition of krill and salps using 18S metabarcoding and fatty acid markers. Neither species' diet reflected the composition of the plankton community, suggesting that in contrast to the accepted paradigm, not only krill but also salps are selective feeders. Moreover, we found that krill and salps had broadly similar diets, potentially enhancing the competition between both species. This could be augmented by salps' ability to rapidly reproduce in favorable conditions, posing further risks to krill populations.
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10
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Xue M, Zhu G. Variation in fatty acids of Antarctic krill (
Euphausia superba
) preserved under constant dry conditions: Does storage time and ontogeny matter? J FOOD PROCESS PRES 2021. [DOI: 10.1111/jfpp.15357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Mei Xue
- College of Marine Sciences Shanghai Ocean University Shanghai China
- Center for Polar Research Shanghai Ocean University Shanghai China
| | - Guoping Zhu
- College of Marine Sciences Shanghai Ocean University Shanghai China
- Center for Polar Research Shanghai Ocean University Shanghai China
- National Engineering Research Center for Oceanic Fisheries Shanghai China
- Polar Marine Ecosystem Group The Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources Shanghai Ocean University, Ministry of Education Shanghai China
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11
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Comparative morphology of Southern Ocean Euphausia species: ecological significance of sexual dimorphic features. Polar Biol 2020. [DOI: 10.1007/s00300-020-02764-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Interannual variability in the lipid and fatty acid profiles of east Australia-migrating humpback whales (Megaptera novaeangliae) across a 10-year timeline. Sci Rep 2020; 10:18274. [PMID: 33106590 PMCID: PMC7589506 DOI: 10.1038/s41598-020-75370-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 10/12/2020] [Indexed: 02/02/2023] Open
Abstract
Southern hemisphere humpback whales are classified as high-fidelity Antarctic krill consumers and as such are vulnerable to variability and long-term changes in krill biomass. Evidence of heterogeneous feeding patterns of east coast of Australia migrating humpback whales has been observed, warranting a comprehensive assessment of interannual variability in their diet. We examined the lipid and fatty acid profiles of individuals of the east coast of Australia migrating stock sampled between 2008 and 2018. The use of live-sampled blubber biopsies showed that fatty acid profiles varied significantly among all years. The two trophic indicator fatty acids for Antarctic krill, 20:5ω3 and 22:6ω3 remained largely unchanged across the 10-year period, suggesting that Antarctic krill is the principal prey item. A distance-based linear model showed that 33% of the total variation in fatty acid profiles was explained by environmental variables and climate indices. Most of the variation was explained by the Southern Annular Mode (23.7%). The high degree of variability observed in this study was unexpected for a species that is thought to feed primarily on one prey item. We propose that the observed variability likely arises from changes in the diet of Antarctic krill rather than changes in the whale’s diet.
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13
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Drivers of concentrated predation in an Antarctic marginal-ice-zone food web. Sci Rep 2020; 10:7282. [PMID: 32350362 PMCID: PMC7190673 DOI: 10.1038/s41598-020-63875-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/03/2020] [Indexed: 02/05/2023] Open
Abstract
Predators impact preyscapes (3-D distribution of forage species) by consuming prey according to their abilities or by altering prey behavior as they avoid being consumed. We elucidate prey (Antarctic silverfish[Pleuragramma antarctica] and crystal krill[Euphausia chrystallorophias]) responses to predation associated with the marginal ice zone (MIZ) of the McMurdo Sound, Antarctica, polynya. Prey abundance and habitat was sampled across a 30 × 15 km area by remotely-operated vehicle, and included locations that were accessible (ice edge) or inaccessible (solid fast ice) to air-breathing predators. Prey and habitat sampling coincided with bio-logging of Adélie penguins and observations of other air-breathing predators (penguins, seals, and whales), all of which were competing for the same prey. Adélie penguins dived deeper, and more frequently, near the ice edge. Lowered abundance of krill at the ice edge indicated they were depleted or were responding to increased predation and/or higher light levels along the ice edge. Penguin diet shifted increasingly to silverfish from krill during sampling, and was correlated with the arrival of krill-eating whales. Behaviorally-mediated, high trophic transfer characterizes the McMurdo Sound MIZ, and likely other MIZs, warranting more specific consideration in food web models and conservation efforts.
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14
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Hellessey N, Johnson R, Ericson JA, Nichols PD, Kawaguchi S, Nicol S, Hoem N, Virtue P. Antarctic Krill Lipid and Fatty acid Content Variability is Associated to Satellite Derived Chlorophyll a and Sea Surface Temperatures. Sci Rep 2020; 10:6060. [PMID: 32269236 PMCID: PMC7142126 DOI: 10.1038/s41598-020-62800-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 03/19/2020] [Indexed: 11/23/2022] Open
Abstract
Antarctic krill (Euphausia superba) are a key component of the Antarctic food web with considerable lipid reserves that are vital for their health and higher predator survival. Krill lipids are primarily derived from their diet of plankton, in particular diatoms and flagellates. Few attempts have been made to link the spatial and temporal variations in krill lipids to those in their food supply. Remotely-sensed environmental parameters provide large-scale information on the potential availability of krill food, although relating this to physiological and biochemical differences has only been performed on small scales and with limited samples. Our study utilised remotely-sensed data (chlorophyll a and sea surface temperature) coupled with krill lipid data obtained from 3 years of fishery-derived samples. We examined within and between year variation of trends in both the environment and krill biochemistry data. Chlorophyll a levels were positively related to krill lipid levels, particularly triacylglycerol. Plankton fatty acid biomarkers analysed in krill (such as n-3 polyunsaturated fatty acids) increased with decreasing sea surface temperature and increasing chlorophyll a levels. Our study demonstrates the utility of combining remote-sensing and biochemical data in examining biological and physiological relationships between Antarctic krill and the Southern Ocean environment.
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Affiliation(s)
- Nicole Hellessey
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia. .,CSIRO Oceans and Atmosphere, Castray Esplanade, Battery Point, Tasmania, 7004, Australia. .,Antarctic Climate and Ecosystems Cooperative Research Centre, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia. .,School of Biological Sciences, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia, 30332, United States of America.
| | - Robert Johnson
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia
| | - Jessica A Ericson
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia.,CSIRO Oceans and Atmosphere, Castray Esplanade, Battery Point, Tasmania, 7004, Australia.,Antarctic Climate and Ecosystems Cooperative Research Centre, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia.,Cawthron Institute, Private Bag 2, Nelson, 7041, New Zealand
| | - Peter D Nichols
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia.,CSIRO Oceans and Atmosphere, Castray Esplanade, Battery Point, Tasmania, 7004, Australia
| | - So Kawaguchi
- Antarctic Climate and Ecosystems Cooperative Research Centre, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia.,Australian Antarctic Division, 203 Channel Highway, Kingston, Tasmania, 7050, Australia
| | - Stephen Nicol
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia.,Antarctic Climate and Ecosystems Cooperative Research Centre, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia
| | - Nils Hoem
- Aker BioMarine Antarctic AS, Oksenøyveien 10, P.O. Box 496, NO-1327, Lysaker, Norway
| | - Patti Virtue
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia.,CSIRO Oceans and Atmosphere, Castray Esplanade, Battery Point, Tasmania, 7004, Australia.,Antarctic Climate and Ecosystems Cooperative Research Centre, 20 Castray Esplanade, Battery Point, Tasmania, 7004, Australia
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Divergent trophic responses of sympatric penguin species to historic anthropogenic exploitation and recent climate change. Proc Natl Acad Sci U S A 2019; 116:25721-25727. [PMID: 31792174 DOI: 10.1073/pnas.1913093116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The Southern Ocean is in an era of significant change. Historic overharvesting of marine mammals and recent climatic warming have cascading impacts on resource availability and, in turn, ecosystem structure and function. We examined trophic responses of sympatric chinstrap (Pygoscelis antarctica) and gentoo (Pygoscelis papua) penguins to nearly 100 y of shared environmental change in the Antarctic Peninsula region using compound-specific stable isotope analyses of museum specimens. A century ago, gentoo penguins fed almost exclusively on low-trophic level prey, such as krill, during the peak of historic overexploitation of marine mammals, which was hypothesized to have resulted in a krill surplus. In the last 40 y, gentoo penguin trophic position has increased a full level as krill declined in response to recent climate change, increased competition from recovering marine mammal populations, and the development of a commercial krill fishery. A shifting isotopic baseline supporting gentoo penguins suggests a concurrent increase in coastal productivity over this time. In contrast, chinstrap penguins exhibited no change in trophic position, despite variation in krill availability over the past century. The specialized foraging niche of chinstrap penguins likely renders them more sensitive to changes in krill availability, relative to gentoo penguins, as evinced by their declining population trends in the Antarctic Peninsula over the past 40 y. Over the next century, similarly divergent trophic and population responses are likely to occur among Antarctic krill predators if climate change and other anthropogenic impacts continue to favor generalist over specialist species.
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16
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New insights into the seasonal diet of Antarctic krill using triacylglycerol and phospholipid fatty acids, and sterol composition. Polar Biol 2019. [DOI: 10.1007/s00300-019-02573-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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17
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Near-future ocean acidification does not alter the lipid content and fatty acid composition of adult Antarctic krill. Sci Rep 2019; 9:12375. [PMID: 31451724 PMCID: PMC6710253 DOI: 10.1038/s41598-019-48665-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 08/09/2019] [Indexed: 12/25/2022] Open
Abstract
Euphausia superba (Antarctic krill) is a keystone species in the Southern Ocean, but little is known about how it will respond to climate change. Ocean acidification, caused by sequestration of carbon dioxide into ocean surface waters (pCO2), alters the lipid biochemistry of some organisms. This can have cascading effects up the food chain. In a year-long laboratory experiment adult krill were exposed to ambient seawater pCO2 levels (400 μatm), elevated pCO2 levels mimicking near-future ocean acidification (1000, 1500 and 2000 μatm) and an extreme pCO2 level (4000 μatm). Total lipid mass (mg g-1 DM) of krill was unaffected by near-future pCO2. Fatty acid composition (%) and fatty acid ratios associated with immune responses and cell membrane fluidity were also unaffected by near-future pCO2, apart from an increase in 18:3n-3/18:2n-6 ratios in krill in 1500 μatm pCO2 in winter and spring. Extreme pCO2 had no effect on krill lipid biochemistry during summer. During winter and spring, krill in extreme pCO2 had elevated levels of 18:2n-6 (up to 1.2% increase), 20:4n-6 (up to 0.8% increase), lower 18:3n-3/18:2n-6 and 20:5n-3/20:4n-6 ratios, and showed evidence of increased membrane fluidity (up to three-fold increase in phospholipid/sterol ratios). These results indicate that the lipid biochemistry of adult krill is robust to near-future ocean acidification.
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Adult Antarctic krill proves resilient in a simulated high CO 2 ocean. Commun Biol 2018; 1:190. [PMID: 30456311 PMCID: PMC6233221 DOI: 10.1038/s42003-018-0195-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/10/2018] [Indexed: 11/08/2022] Open
Abstract
Antarctic krill (Euphausia superba) have a keystone role in the Southern Ocean, as the primary prey of Antarctic predators. Decreases in krill abundance could result in a major ecological regime shift, but there is limited information on how climate change may affect krill. Increasing anthropogenic carbon dioxide (CO2) emissions are causing ocean acidification, as absorption of atmospheric CO2 in seawater alters ocean chemistry. Ocean acidification increases mortality and negatively affects physiological functioning in some marine invertebrates, and is predicted to occur most rapidly at high latitudes. Here we show that, in the laboratory, adult krill are able to survive, grow, store fat, mature, and maintain respiration rates when exposed to near-future ocean acidification (1000-2000 μatm pCO2) for one year. Despite differences in seawater pCO2 incubation conditions, adult krill are able to actively maintain the acid-base balance of their body fluids in near-future pCO2, which enhances their resilience to ocean acidification.
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Lerosey-Aubril R, Pates S. New suspension-feeding radiodont suggests evolution of microplanktivory in Cambrian macronekton. Nat Commun 2018; 9:3774. [PMID: 30218075 PMCID: PMC6138677 DOI: 10.1038/s41467-018-06229-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/09/2018] [Indexed: 11/23/2022] Open
Abstract
The rapid diversification of metazoans and their organisation in modern-style marine ecosystems during the Cambrian profoundly transformed the biosphere. What initially sparked this Cambrian explosion remains passionately debated, but the establishment of a coupling between pelagic and benthic realms, a key characteristic of modern-day oceans, might represent a primary ecological cause. By allowing the transfer of biomass and energy from the euphotic zone-the locus of primary production-to the sea floor, this biological pump would have boosted diversification within the emerging metazoan-dominated benthic communities. However, little is known about Cambrian pelagic organisms and their trophic interactions. Here we describe a filter-feeding Cambrian radiodont exhibiting morphological characters that likely enabled the capture of microplankton-sized particles, including large phytoplankton. This description of a large free-swimming suspension-feeder potentially engaged in primary consumption suggests a more direct involvement of nekton in the establishment of an oceanic pelagic-benthic coupling in the Cambrian.
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Affiliation(s)
- Rudy Lerosey-Aubril
- Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia.
| | - Stephen Pates
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
- Institute of Earth Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland
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Dawson A, Huston W, Kawaguchi S, King C, Cropp R, Wild S, Eisenmann P, Townsend K, Bengtson Nash S. Uptake and Depuration Kinetics Influence Microplastic Bioaccumulation and Toxicity in Antarctic Krill ( Euphausia superba). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3195-3201. [PMID: 29397707 DOI: 10.1021/acs.est.7b05759] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The discarding of plastic products has led to the ubiquitous occurrence of microplastic particles in the marine environment. The uptake and depuration kinetics of ingested microplastics for many marine species still remain unknown despite its importance for understanding bioaccumulation potential to higher trophic level consumers. In this study, Antarctic krill ( Euphausia superba) were exposed to polyethylene microplastics to quantify acute toxicity and ingestion kinetics, providing insight into the bioaccumulation potential of microplastics at the first-order consumer level. In the 10 day acute toxicity assay, no mortality or dose-dependent weight loss occurred in exposed krill, at any of the exposure concentrations (0, 10, 20, 40, or 80% plastic diet). Krill exposed to a 20% plastic diet for 24 h displayed fast uptake (22 ng mg-1 h-1) and depuration (0.22 h-1) rates, but plastic uptake did not reach steady state. Efficient elimination also resulted in no bioaccumulation over an extended 25 day assay, with most individuals completely eliminating their microplastic burden in less than 5 days post exposure. Our results support recent findings of limited acute toxicity of ingested microplastics at this trophic level, and suggest sublethal chronic end points should be the focus of further ecotoxicological investigation.
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Affiliation(s)
- Amanda Dawson
- Environmental Futures Research Institute, Southern Ocean Persistent Organic Pollutants Program (SOPOPP), Griffith School of Environment , Griffith University , 170 Kessels Road , Nathan , Queensland 4111 , Australia
| | - Wilhelmina Huston
- School of Life Sciences, Faculty of Science , University of Technology Sydney , 15 Broadway , Ultimo , New South Wales 2007 , Australia
| | - So Kawaguchi
- Australian Antarctic Division , Department of the Environment and Energy , 203 Channel Highway , Kingston , Tasmania 7050 , Australia
| | - Catherine King
- Australian Antarctic Division , Department of the Environment and Energy , 203 Channel Highway , Kingston , Tasmania 7050 , Australia
| | - Roger Cropp
- Environmental Futures Research Institute, Southern Ocean Persistent Organic Pollutants Program (SOPOPP), Griffith School of Environment , Griffith University , 170 Kessels Road , Nathan , Queensland 4111 , Australia
| | - Seanan Wild
- Environmental Futures Research Institute, Southern Ocean Persistent Organic Pollutants Program (SOPOPP), Griffith School of Environment , Griffith University , 170 Kessels Road , Nathan , Queensland 4111 , Australia
| | - Pascale Eisenmann
- Environmental Futures Research Institute, Southern Ocean Persistent Organic Pollutants Program (SOPOPP), Griffith School of Environment , Griffith University , 170 Kessels Road , Nathan , Queensland 4111 , Australia
| | - Kathy Townsend
- School of Biological Sciences, Moreton Bay Research Station , University of Queensland , North Stradbroke Island , Queensland 4183 , Australia
| | - Susan Bengtson Nash
- Environmental Futures Research Institute, Southern Ocean Persistent Organic Pollutants Program (SOPOPP), Griffith School of Environment , Griffith University , 170 Kessels Road , Nathan , Queensland 4111 , Australia
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The potential role of Antarctic krill faecal pellets in efficient carbon export at the marginal ice zone of the South Orkney Islands in spring. Polar Biol 2017; 40:2001-2013. [PMID: 32009725 PMCID: PMC6961482 DOI: 10.1007/s00300-017-2118-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 03/24/2017] [Accepted: 03/26/2017] [Indexed: 11/23/2022]
Abstract
Antarctic krill (Euphausia superba) play a central role in the food web of the Southern Ocean, forming a link between primary production and large predators. Krill produce large, faecal pellets (FP) which can form a large component of mesopelagic particulate organic carbon (POC) fluxes. However, the patchy distribution of krill swarms, highly variable pellet composition, and variable sinking and attenuation rates means that these episodic, but potentially large, carbon fluxes are difficult to sample or model. We measured particle flux and type using Marine Snow Catchers (MSC) in the marginal ice zone near the South Orkneys, Antarctica. Krill FP were the dominant component of the POC flux in the upper 200 m (typically 60–85%). FP sinking velocities measured onboard were highly variable (15–507 m d−1) but overall high, with mean equivalent velocities of 172, 267, and 161 m d−1 at our three stations. The high numbers of krill FP sinking through the mesopelagic suggest that krill FP can be transferred efficiently and/or that rates of krill FP production are high. We compared our direct MSC-derived estimates of krill FP POC flux (33–154 mg C m−2 d−1) and attenuation to estimates of krill FP production based on previous measurements of krill density and literature FP egestion rates, and estimated net krill FP attenuation rates in the upper mesopelagic. Calculated attenuation rates are sensitive to krill densities in the overlying water column but suggest that krill FP could be transferred efficiently through the upper mesopelagic, and, in agreement with our MSC attenuation estimates, could make large contributions to bathypelagic POC fluxes. Our study contrasts with some others which suggest rapid FP attenuation, highlighting the need for further work to constrain attenuation rates and assess how important the contribution of Antarctic krill FP could be to the Southern Ocean biological carbon pump.
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Siegel V, Watkins JL. Distribution, Biomass and Demography of Antarctic Krill, Euphausia superba. BIOLOGY AND ECOLOGY OF ANTARCTIC KRILL 2016. [DOI: 10.1007/978-3-319-29279-3_2] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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23
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24
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Introducing Antarctic Krill Euphausia superba Dana, 1850. BIOLOGY AND ECOLOGY OF ANTARCTIC KRILL 2016. [DOI: 10.1007/978-3-319-29279-3_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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25
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Meyer B, Teschke M. Physiology of Euphausia superba. BIOLOGY AND ECOLOGY OF ANTARCTIC KRILL 2016. [DOI: 10.1007/978-3-319-29279-3_4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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