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Baille LMR, Zitterbart DP. Effectiveness of surface-based detection methods for vessel strike mitigation of North Atlantic right whales. ENDANGER SPECIES RES 2022. [DOI: 10.3354/esr01202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Lonati GL, Zitterbart DP, Miller CA, Corkeron P, Murphy CT, Moore MJ. Investigating the thermal physiology of critically endangered North Atlantic right whales Eubalaena glacialis via aerial infrared thermography. ENDANGER SPECIES RES 2022. [DOI: 10.3354/esr01193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Richter S, Gerum R, Winterl A, Houstin A, Seifert M, Peschel J, Fabry B, Le Bohec C, Zitterbart DP. Phase transitions in huddling emperor penguins. J Phys D Appl Phys 2018; 51:214002. [PMID: 30416209 PMCID: PMC6221190 DOI: 10.1088/1361-6463/aabb8e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Emperor penguins (Aptenodytes forsteri) are highly adapted to the harsh conditions of the Antarctic winter: they are able to fast for up to 134 days during breeding. To conserve energy, emperor penguins form tight groups (huddles), which is key for their reproductive success. The effect of different meteorological factors on the huddling behaviour, however, is not well understood. Using time-lapse image recordings of an emperor penguin colony, we show that huddling can be described as a phase transition from a fluid to a solid state. We use the colony density as order parameter, and an apparent temperature that is perceived by the penguins as the thermodynamic variable. We approximate the apparent temperature as a linear combination of four meteorological parameters: ambient temperature, wind speed, global radiation and relative humidity. We find a wind chill factor of -2.9 °C/(ms -1), a humidity chill factor of -0.5°C/% rel. humidity, and a solar radiation heating factor of 0.3 °C//(Wm 2). In the absence of wind, humidity and solar radiation, the phase transition temperature (50% huddling probability) is -48.2°C for the investigated time period (May 2014). We propose that higher phase transition temperatures indicate a shrinking thermal insulation and thus can serve as a proxy for lower energy reserves of the colony, integrating pre-breeding foraging success at sea and energy expenditure at land due to environmental conditions. As current global change is predicted to have strong detrimental effects on emperor penguins within the next decades, our approach may thus contribute towards an urgently needed long-term monitoring system for assessing colony health.
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Affiliation(s)
- S Richter
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - R Gerum
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - A Winterl
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - A Houstin
- Centre Scientifique de Monaco, Département de Biologie Polaire, Monaco, Principality of Monaco
- Université de Strasbourg, CNRS, IPHC, UMR 7178, Strasbourg, France
| | - M Seifert
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - J Peschel
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - B Fabry
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
| | - C Le Bohec
- Centre Scientifique de Monaco, Département de Biologie Polaire, Monaco, Principality of Monaco
- Université de Strasbourg, CNRS, IPHC, UMR 7178, Strasbourg, France
| | - D P Zitterbart
- Biophysics Group, Friedrich-Alexander University, Erlangen, Germany
- Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, USA
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Thomisch K, Boebel O, Clark CW, Hagen W, Spiesecke S, Zitterbart DP, Van Opzeeland I. Spatio-temporal patterns in acoustic presence and distribution of Antarctic blue whales Balaenoptera musculus intermedia in the Weddell Sea. ENDANGER SPECIES RES 2016. [DOI: 10.3354/esr00739] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Metzner C, Raupach C, Zitterbart DP, Fabry B. Simple model of cytoskeletal fluctuations. Phys Rev E Stat Nonlin Soft Matter Phys 2007; 76:021925. [PMID: 17930083 DOI: 10.1103/physreve.76.021925] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 05/01/2007] [Indexed: 05/25/2023]
Abstract
The spontaneous motion of microbeads bound to the cytoskeleton of living cells is not an ordinary random walk. Unlike Brownian motion, the mean-square displacement undergoes a transition from subdiffusive to superdiffusive behavior with time. This transition is associated with characteristic changes of the turning angle distribution. Recent experimental data demonstrated that force fluctuations measured in an elastic hydrogel matrix beneath the cell correlate with the bead motion [C. Raupach, Phys. Rev. E 76, 011918 (2007)]. These data indicate that the bead trajectory is driven by motor forces originating from the actomyosin network and that cytoskeletal remodeling processes with short- and long-time dynamics are mainly responsible for the non-Brownian behavior. We show that the essential statistical properties of the spontaneous bead motion can be reproduced by a particle diffusing in a potential well with a slowly drifting minimum position. Based on this simple model, which can be solved analytically, we develop a biologically plausible numerical model of a tensed and continuously remodeling actomyosin network that accounts quantitatively for the measured data.
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Affiliation(s)
- C Metzner
- Biophysics Group, Department of Physics, University of Erlangen-Nuremberg, Henkestrasse 91, 91052 Erlangen, Germany
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