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Three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin

The largest habitat by volume on Earth is the oceanic midwater, which is also one of the least understood in terms of animal ecology. The organisms here exhibit a spectacular array of optical adaptations for living in a visual void that have only barely begun to be described. We describe a complex p...

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Autores principales: Rosenthal, Eric I., Holt, Amanda L., Sweeney, Alison M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5454286/
https://www.ncbi.nlm.nih.gov/pubmed/28468923
http://dx.doi.org/10.1098/rsif.2016.1034
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author Rosenthal, Eric I.
Holt, Amanda L.
Sweeney, Alison M.
author_facet Rosenthal, Eric I.
Holt, Amanda L.
Sweeney, Alison M.
author_sort Rosenthal, Eric I.
collection PubMed
description The largest habitat by volume on Earth is the oceanic midwater, which is also one of the least understood in terms of animal ecology. The organisms here exhibit a spectacular array of optical adaptations for living in a visual void that have only barely begun to be described. We describe a complex pattern of broadband scattering from the skin of Argyropelecus sp., a hatchetfish found in the mesopelagic zone of the world's oceans. Hatchetfish skin superficially resembles the unpolished side of aluminium foil, but on closer inspection contains a complex composite array of subwavelength-scale dielectric structures. The superficial layer of this array contains dielectric stacks that are rectangular in cross-section, while the deeper layer contains dielectric bundles that are elliptical in cross-section; the cells in both layers have their longest dimension running parallel to the dorsal–ventral axis of the fish. Using the finite-difference time-domain approach and photographic radiometry, we explored the structural origins of this scattering behaviour and its environmental consequences. When the fish's flank is illuminated from an arbitrary incident angle, a portion of the scattered light exits in an arc parallel to the fish's anterior–posterior axis. Simultaneously, some incident light is also scattered downwards through the complex birefringent skin structure and exits from the ventral photophores. We show that this complex scattering pattern will provide camouflage simultaneously against the horizontal radially symmetric solar radiance in this habitat, and the predatory bioluminescent searchlights that are common here. The structure also directs light incident on the flank of the fish into the downwelling, silhouette-hiding counter-illumination of the ventral photophores.
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spelling pubmed-54542862017-06-05 Three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin Rosenthal, Eric I. Holt, Amanda L. Sweeney, Alison M. J R Soc Interface Life Sciences–Physics interface The largest habitat by volume on Earth is the oceanic midwater, which is also one of the least understood in terms of animal ecology. The organisms here exhibit a spectacular array of optical adaptations for living in a visual void that have only barely begun to be described. We describe a complex pattern of broadband scattering from the skin of Argyropelecus sp., a hatchetfish found in the mesopelagic zone of the world's oceans. Hatchetfish skin superficially resembles the unpolished side of aluminium foil, but on closer inspection contains a complex composite array of subwavelength-scale dielectric structures. The superficial layer of this array contains dielectric stacks that are rectangular in cross-section, while the deeper layer contains dielectric bundles that are elliptical in cross-section; the cells in both layers have their longest dimension running parallel to the dorsal–ventral axis of the fish. Using the finite-difference time-domain approach and photographic radiometry, we explored the structural origins of this scattering behaviour and its environmental consequences. When the fish's flank is illuminated from an arbitrary incident angle, a portion of the scattered light exits in an arc parallel to the fish's anterior–posterior axis. Simultaneously, some incident light is also scattered downwards through the complex birefringent skin structure and exits from the ventral photophores. We show that this complex scattering pattern will provide camouflage simultaneously against the horizontal radially symmetric solar radiance in this habitat, and the predatory bioluminescent searchlights that are common here. The structure also directs light incident on the flank of the fish into the downwelling, silhouette-hiding counter-illumination of the ventral photophores. The Royal Society 2017-05 2017-05-03 /pmc/articles/PMC5454286/ /pubmed/28468923 http://dx.doi.org/10.1098/rsif.2016.1034 Text en © 2017 The Authors. http://creativecommons.org/licenses/by/4.0/ Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
spellingShingle Life Sciences–Physics interface
Rosenthal, Eric I.
Holt, Amanda L.
Sweeney, Alison M.
Three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin
title Three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin
title_full Three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin
title_fullStr Three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin
title_full_unstemmed Three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin
title_short Three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin
title_sort three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin
topic Life Sciences–Physics interface
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5454286/
https://www.ncbi.nlm.nih.gov/pubmed/28468923
http://dx.doi.org/10.1098/rsif.2016.1034
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