Ulrich Freier
Alfred Wegener Institute for Polar and Marine Research
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Featured researches published by Ulrich Freier.
Molecular Ecology Resources | 2015
Bettina Meyer; Paolo Martini; Alberto Biscontin; C. De Pittà; Chiara Romualdi; Mathias Teschke; S. Frickenhaus; L. Harms; Ulrich Freier; Simon N. Jarman; So Kawaguchi
The Antarctic krill, Euphausia superba, has a key position in the Southern Ocean food web by serving as direct link between primary producers and apex predators. The south‐west Atlantic sector of the Southern Ocean, where the majority of the krill population is located, is experiencing one of the most profound environmental changes worldwide. Up to now, we have only cursory information about krills genomic plasticity to cope with the ongoing environmental changes induced by anthropogenic CO2 emission. The genome of krill is not yet available due to its large size (about 48 Gbp). Here, we present two cDNA normalized libraries from whole krill and krill heads sampled in different seasons that were combined with two data sets of krill transcriptome projects, already published, to produce the first knowledgebase krill ‘master’ transcriptome. The new library produced 25% more E. superba transcripts and now includes nearly all the enzymes involved in the primary oxidative metabolism (Glycolysis, Krebs cycle and oxidative phosphorylation) as well as all genes involved in glycogenesis, glycogen breakdown, gluconeogenesis, fatty acid synthesis and fatty acids β‐oxidation. With these features, the ‘master’ transcriptome provides the most complete picture of metabolic pathways in Antarctic krill and will provide a major resource for future physiological and molecular studies. This will be particularly valuable for characterizing the molecular networks that respond to stressors caused by the anthropogenic CO2 emissions and krills capacity to cope with the ongoing environmental changes in the Atlantic sector of the Southern Ocean.
Nature Ecology and Evolution | 2017
Bettina Meyer; Ulrich Freier; Volker Grimm; Jürgen Groeneveld; Brian P. V. Hunt; Sven E. Kerwath; Rob King; Christine Klaas; E. A. Pakhomov; Klaus M. Meiners; Jessica Melbourne-Thomas; Eugene J. Murphy; Sally E. Thorpe; Dieter Wolf-Gladrow; Lutz Auerswald; Albrecht Götz; Laura Halbach; Simon N. Jarman; So Kawaguchi; Thomas Krumpen; Gernot Nehrke; Robert Ricker; Michael D. Sumner; Mathias Teschke; Rowan Trebilco; I. Noyan Yilmaz
A dominant Antarctic ecological paradigm suggests that winter sea ice is generally the main feeding ground for krill larvae. Observations from our winter cruise to the southwest Atlantic sector of the Southern Ocean contradict this view and present the first evidence that the pack-ice zone is a food-poor habitat for larval development. In contrast, the more open marginal ice zone provides a more favourable food environment for high larval krill growth rates. We found that complex under-ice habitats are, however, vital for larval krill when water column productivity is limited by light, by providing structures that offer protection from predators and to collect organic material released from the ice. The larvae feed on this sparse ice-associated food during the day. After sunset, they migrate into the water below the ice (upper 20 m) and drift away from the ice areas where they have previously fed. Model analyses indicate that this behaviour increases both food uptake in a patchy food environment and the likelihood of overwinter transport to areas where feeding conditions are more favourable in spring.Winter sea ice is thought to provide critical grazing habitat for overwintering Antarctic krill. In contrast, here the authors show that the pack-ice zone is a food-poor habitat, but does serve as an important sheltering ground for developing larvae.
Limnology and Oceanography | 2009
Bettina Meyer; Veronica Fuentes; Citlali Guerra; Katrin Schmidt; Angus Atkinson; Susanne Spahic; Boris Cisewski; Ulrich Freier; Alejandro Olariaga; Ulrich Bathmanna
The Journal of Experimental Biology | 2008
Lutz Auerswald; Ulrich Freier; Andreas L. Lopata; Bettina Meyer
Geophysical Research Letters | 2017
Klaus M. Meiners; Stefanie Arndt; Sophie Bestley; Thomas Krumpen; Robert Ricker; M. Milnes; K. Newbery; Ulrich Freier; Simon N. Jarman; Rob King; Roland Proud; So Kawaguchi; Bettina Meyer
Deep-sea Research Part Ii-topical Studies in Oceanography | 2016
Patti Virtue; Bettina Meyer; Ulrich Freier; Peter D. Nichols; Zhongnan Jia; Rob King; Jacob Virtue; Kerrie M. Swadling; Klaus M. Meiners; So Kawaguchi
EPIC3Berichte zur Polar- und Meeresforschung, 400, pp. 171-178, ISSN: 1618-3193 | 2001
Philipp Assmy; Ulrich Freier; Joachim Henjes; Christine Klaas; Victor Smetacek
Supplement to: Meyer, B et al. (2017): The winter pack ice zone provides a sheltered but food-poor habitat for larval Antarctic krill. Nature Ecology & Evolution, https://doi.org/10.1038/s41559-017-0368-3 | 2017
Bettina Meyer; Ulrich Freier; Volker Grimm; Jürgen Groeneveld; Brian P Hunt; Sven E. Kerwath; Rob King; Christine Klaas; E. A. Pakhomov; Jess Melbourne-Thomas; Eugene J. Murphy; Sally E. Thorpe; Dieter A Wolf-Gladrow; Lutz Auerswald; Albrecht Götz; Laura Halbach; Simon Jarman; So Kawaguchi; Thomas Krumpen; Klaus M. Meiners; Gernot Nehrke; Robert Ricker; Michael Summer; Mathias Teschke; Rowan Trebilco; Noyan Yilmaz
In supplement to: Meyer, B et al. (2017): The winter pack ice zone provides a sheltered but food-poor habitat for larval Antarctic krill. Nature Ecology & Evolution, https://doi.org/10.1038/s41559-017-0368-3 | 2017
Bettina Meyer; Ulrich Freier; Volker Grimm; Jürgen Groeneveld; Brian P Hunt; Sven E. Kerwath; Rob King; Christine Klaas; E. A. Pakhomov; Jess Melbourne-Thomas; Eugene J. Murphy; Sally E. Thorpe; Dieter A Wolf-Gladrow; Lutz Auerswald; Albrecht Götz; Laura Halbach; Simon Jarman; So Kawaguchi; Thomas Krumpen; Klaus M. Meiners; Gernot Nehrke; Robert Ricker; Michael Summer; Mathias Teschke; Rowan Trebilco; Noyan Yilmaz
In supplement to: Meyer, B et al. (2017): The winter pack ice zone provides a sheltered but food-poor habitat for larval Antarctic krill. Nature Ecology & Evolution, https://doi.org/10.1038/s41559-017-0368-3 | 2017
Bettina Meyer; Ulrich Freier; Volker Grimm; Jürgen Groeneveld; Brian P Hunt; Sven E. Kerwath; Rob King; Christine Klaas; E. A. Pakhomov; Jess Melbourne-Thomas; Eugene J. Murphy; Sally E. Thorpe; Dieter A Wolf-Gladrow; Lutz Auerswald; Albrecht Götz; Laura Halbach; Simon Jarman; So Kawaguchi; Thomas Krumpen; Klaus M. Meiners; Gernot Nehrke; Robert Ricker; Michael Summer; Mathias Teschke; Rowan Trebilco; Noyan Yilmaz