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Sarlin PJ, Morris S, Geethambika SB, Gopi L, Muraleedharan M, Thomas JA, Savitha G, Joseph P. Halocercus lagenorhynchi infection in a stranded striped dolphin Stenella coeruleoalba (Meyen, 1833) on the Southwest coastline of India. J Parasit Dis 2024; 48:168-179. [PMID: 38440750 PMCID: PMC10908710 DOI: 10.1007/s12639-024-01646-6] [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: 07/02/2023] [Accepted: 12/29/2023] [Indexed: 03/06/2024] Open
Abstract
Necropsy on a striped dolphin Stenella coeruleoalba (Meyen, 1833) entangled in ghost fishing net and dead while rescuing yielded some helminth parasites, later identified as Halocercus lagenorhynchi. DNA barcoding of the host and parasite and the phylogenetic analysis of the parasite was conducted. This study provides valuable information towards establishing basal data of marine mammal parasite diversity and distribution in the Indian waters. We believe this is the first report of the occurrence of Halocercus lagenorhynchi in marine mammals in India.
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Affiliation(s)
- Pathissery John Sarlin
- PG and Research Department of Zoology, Fatima Mata National College (Autonomous), University of Kerala, Kollam, India
| | - Sancia Morris
- Institute of Chemical Technology Mumbai, IOC Bhuvneshwar Odisha, Bhubaneswar, India
| | | | - Lijin Gopi
- School of Medicine and Public Health, Department of Medicine, University of Wisconsin, Madison, USA
| | - Megha Muraleedharan
- PG and Research Department of Zoology, Fatima Mata National College (Autonomous), University of Kerala, Kollam, India
| | - Jeniffer Ann Thomas
- PG and Research Department of Zoology, Fatima Mata National College (Autonomous), University of Kerala, Kollam, India
| | - Gayathry Savitha
- PG and Research Department of Zoology, Fatima Mata National College (Autonomous), University of Kerala, Kollam, India
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Gulson-Castillo ER, Van Doren BM, Bui MX, Horton KG, Li J, Moldwin MB, Shedden K, Welling DT, Winger BM. Space weather disrupts nocturnal bird migration. Proc Natl Acad Sci U S A 2023; 120:e2306317120. [PMID: 37812699 PMCID: PMC10589677 DOI: 10.1073/pnas.2306317120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 08/22/2023] [Indexed: 10/11/2023] Open
Abstract
Space weather, including solar storms, can impact Earth by disturbing the geomagnetic field. Despite the known dependence of birds and other animals on geomagnetic cues for successful seasonal migrations, the potential effects of space weather on organisms that use Earth's magnetic field for navigation have received little study. We tested whether space weather geomagnetic disturbances are associated with disruptions to bird migration at a macroecological scale. We leveraged long-term radar data to characterize the nightly migration dynamics of the nocturnally migrating North American avifauna over 22 y. We then used concurrent magnetometer data to develop a local magnetic disturbance index associated with each radar station (ΔBmax), facilitating spatiotemporally explicit analyses of the relationship between migration and geomagnetic disturbance. After controlling for effects of atmospheric weather and spatiotemporal patterns, we found a 9 to 17% decrease in migration intensity in both spring and fall during severe space weather events. During fall migration, we also found evidence for decreases in effort flying against the wind, which may represent a depression of active navigation such that birds drift more with the wind during geomagnetic disturbances. Effort flying against the wind in the fall was most reduced under both overcast conditions and high geomagnetic disturbance, suggesting that a combination of obscured celestial cues and magnetic disturbance may disrupt navigation. Collectively, our results provide evidence for community-wide avifaunal responses to geomagnetic disturbances driven by space weather during nocturnal migration.
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Affiliation(s)
- Eric R. Gulson-Castillo
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI48109
- Museum of Zoology, University of Michigan, Ann Arbor, MI48109
| | | | - Michelle X. Bui
- Department of Physics, University of Texas, Arlington, TX76019
| | - Kyle G. Horton
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO80523
| | - Jing Li
- Department of Statistics, University of Michigan, Ann Arbor, MI48109
| | - Mark B. Moldwin
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI48109
| | - Kerby Shedden
- Department of Statistics, University of Michigan, Ann Arbor, MI48109
| | - Daniel T. Welling
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI48109
| | - Benjamin M. Winger
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI48109
- Museum of Zoology, University of Michigan, Ann Arbor, MI48109
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3
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Geomagnetic disturbance associated with increased vagrancy in migratory landbirds. Sci Rep 2023; 13:414. [PMID: 36624156 PMCID: PMC9829733 DOI: 10.1038/s41598-022-26586-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/16/2022] [Indexed: 01/11/2023] Open
Abstract
Rare birds known as "accidentals" or "vagrants" have long captivated birdwatchers and puzzled biologists, but the drivers of these rare occurrences remain elusive. Errors in orientation or navigation are considered one potential driver: migratory birds use the Earth's magnetic field-sensed using specialized magnetoreceptor structures-to traverse long distances over often unfamiliar terrain. Disruption to these magnetoreceptors or to the magnetic field itself could potentially cause errors leading to vagrancy. Using data from 2 million captures of 152 landbird species in North America over 60 years, we demonstrate a strong association between disruption to the Earth's magnetic field and avian vagrancy during fall migration. Furthermore, we find that increased solar activity-a disruptor of the avian magnetoreceptor-generally counteracts this effect, potentially mitigating misorientation by disabling the ability for birds to use the magnetic field to orient. Our results link a hypothesized cause of misorientation to the phenomenon of avian vagrancy, further demonstrating the importance of magnetoreception among the orientation mechanisms of migratory birds. Geomagnetic disturbance may have important downstream ecological consequences, as vagrants may experience increased mortality rates or facilitate range expansions of avian populations and the organisms they disperse.
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Pophof B, Henschenmacher B, Kattnig DR, Kuhne J, Vian A, Ziegelberger G. Biological Effects of Electric, Magnetic, and Electromagnetic Fields from 0 to 100 MHz on Fauna and Flora: Workshop Report. HEALTH PHYSICS 2023; 124:39-52. [PMID: 36480584 PMCID: PMC9722389 DOI: 10.1097/hp.0000000000001624] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
This report summarizes effects of anthropogenic electric, magnetic, and electromagnetic fields in the frequency range from 0 to 100 MHz on flora and fauna, as presented at an international workshop held on 5-7 November in 2019 in Munich, Germany. Such fields may originate from overhead powerlines, earth or sea cables, and from wireless charging systems. Animals and plants react differentially to anthropogenic fields; the mechanisms underlying these responses are still researched actively. Radical pairs and magnetite are discussed mechanisms of magnetoreception in insects, birds, and mammals. Moreover, several insects as well as marine species possess specialized electroreceptors, and behavioral reactions to anthropogenic fields have been reported. Plants react to experimental modifications of their magnetic environment by growth changes. Strong adverse effects of anthropogenic fields have not been described, but knowledge gaps were identified; further studies, aiming at the identification of the interaction mechanisms and the ecological consequences, are recommended.
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Affiliation(s)
- Blanka Pophof
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
| | - Bernd Henschenmacher
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
| | - Daniel R. Kattnig
- Department of Physics and Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Jens Kuhne
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
| | - Alain Vian
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, F-49000 Angers, France
| | - Gunde Ziegelberger
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
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Brown TM, Wilhelm SI, Mastromonaco GF, Burness G. A path forward in the investigation of seabird strandings attributed to light attraction. CONSERVATION SCIENCE AND PRACTICE 2022. [DOI: 10.1111/csp2.12852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Affiliation(s)
- Taylor Marie Brown
- Environmental and Life Sciences Graduate Program Trent University Peterborough Ontario Canada
| | - Sabina I. Wilhelm
- Environment and Climate Change Canada Mount Pearl Newfoundland Canada
| | | | - Gary Burness
- Department of Biology Trent University Peterborough Ontario Canada
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6
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Levitt BB, Lai HC, Manville AM. Effects of non-ionizing electromagnetic fields on flora and fauna, Part 2 impacts: how species interact with natural and man-made EMF. REVIEWS ON ENVIRONMENTAL HEALTH 2022; 37:327-406. [PMID: 34243228 DOI: 10.1515/reveh-2021-0050] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 05/26/2021] [Indexed: 06/13/2023]
Abstract
Ambient levels of nonionizing electromagnetic fields (EMF) have risen sharply in the last five decades to become a ubiquitous, continuous, biologically active environmental pollutant, even in rural and remote areas. Many species of flora and fauna, because of unique physiologies and habitats, are sensitive to exogenous EMF in ways that surpass human reactivity. This can lead to complex endogenous reactions that are highly variable, largely unseen, and a possible contributing factor in species extinctions, sometimes localized. Non-human magnetoreception mechanisms are explored. Numerous studies across all frequencies and taxa indicate that current low-level anthropogenic EMF can have myriad adverse and synergistic effects, including on orientation and migration, food finding, reproduction, mating, nest and den building, territorial maintenance and defense, and on vitality, longevity and survivorship itself. Effects have been observed in mammals such as bats, cervids, cetaceans, and pinnipeds among others, and on birds, insects, amphibians, reptiles, microbes and many species of flora. Cyto- and geno-toxic effects have long been observed in laboratory research on animal models that can be extrapolated to wildlife. Unusual multi-system mechanisms can come into play with non-human species - including in aquatic environments - that rely on the Earth's natural geomagnetic fields for critical life-sustaining information. Part 2 of this 3-part series includes four online supplement tables of effects seen in animals from both ELF and RFR at vanishingly low intensities. Taken as a whole, this indicates enough information to raise concerns about ambient exposures to nonionizing radiation at ecosystem levels. Wildlife loss is often unseen and undocumented until tipping points are reached. It is time to recognize ambient EMF as a novel form of pollution and develop rules at regulatory agencies that designate air as 'habitat' so EMF can be regulated like other pollutants. Long-term chronic low-level EMF exposure standards, which do not now exist, should be set accordingly for wildlife, and environmental laws should be strictly enforced - a subject explored in Part 3.
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Affiliation(s)
| | - Henry C Lai
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Albert M Manville
- Advanced Academic Programs, Krieger School of Arts and Sciences, Environmental Sciences and Policy, Johns Hopkins University, Washington DC Campus, USA
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7
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Pollard-Wright H. Feelings of Knowing - Fundamental Interoceptive Patterns (FoK-FIP): a magnetic monopole-like "pure mental" process fundamental to subjective feelings and self-awareness. Commun Integr Biol 2022; 15:1-54. [PMID: 35186178 PMCID: PMC8855850 DOI: 10.1080/19420889.2021.2023280] [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] [Indexed: 10/28/2022] Open
Abstract
The Feelings of Knowing - Fundamental Interoceptive Patterns (FoK-FIP) is a transdisciplinary theory developed to explain elusive phenomena suspected to exist that do not easily lend themselves to empirical measurement. The FoK-FIP theory posits that specialized self-generated biomagnetism and "pure mental" process share similarities with the hypothetical elementary particle described in particle physics, magnetic monopoles with a magnetic charge. Feelings of Knowing (FoK) are "awareness charge" that are self-generated events. Fundamental Interoceptive Patterns (FIP) are restricted oscillatory magnetic fields that are FoK caused phenomena. Further, FoK produces "cognitive force," an observing ego representing specialized interoceptive awareness. Through embodied states, FoK-FIP acts as a "biological node," an informational processing unit in which physiological signals and an observing ego's sensations or feelings are centered. An observing ego cognitively broadcasts using specialized small magnetic signals and four phases of a narrowed range of interoceptive signals. By defining interoceptive signals (i.e., signals of the body's internal state) using FoK-FIP through cognitive broadcasting, an observing ego creates a world it projects around itself. This process is understood through the components map with interoceptive markers (IMs), a novel algorithm based on biological evolution. FoK-FIP-related predictions are described as are empirical studies to test aspects of the theory. The FoK-FIP theory details a path to wellbeing based on a sense of control and capacity for self-care. Mental stability is thought to change as a function of an observing ego's volitional reactions.
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Affiliation(s)
- Holly Pollard-Wright
- Institute of Electrical and Electronics Engineers (IEEE), The National Coalition of Independent Scholars (NCIS)
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8
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Wynn J, Padget O, Morford J, Jaggers P, Davies K, Borsier E, Guilford T. How might magnetic secular variation impact avian philopatry? J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:145-154. [PMID: 35152316 PMCID: PMC8918480 DOI: 10.1007/s00359-021-01533-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 11/28/2022]
Abstract
A tendency to return to the natal/breeding site, 'philopatry', is widespread amongst migratory birds. It has been suggested that a magnetic 'map' could underpin such movements, though it is unclear how a magnetic map might be impacted by gradual drift in the Earth's magnetic field ('secular variation'). Here, using the International Geomagnetic Reference Field, we quantified how secular variation translates to movement in the implied positions at which combinations of different magnetic cues (inclination, declination and intensity) intersect, noting that the magnitude of such movements is determined by the magnitude of the movements of each of the two isolines, and the angle between their movement vectors. We propose that magnetic parameters varying in a near-parallel arrangement are unlikely to be used as a bi-coordinate map during philopatry, but that birds could use near-orthogonal magnetic gradient cues as a bi-coordinate map if augmented with navigation using more local cues. We further suggest that uni-coordinate magnetic information could also provide a philopatry mechanism that is substantially less impacted by secular variation than a bi-coordinate 'map'. We propose that between-year shifts in the position of magnetic coordinates might provide a priori predictions for changes in the breeding sites of migratory birds.
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Affiliation(s)
- Joe Wynn
- Department of Zoology, Oxford Navigation Group, 11a Mansfield Road, Oxford, OX1 3SZ, Oxfordshire, UK.
| | - Oliver Padget
- Department of Zoology, Oxford Navigation Group, 11a Mansfield Road, Oxford, OX1 3SZ, Oxfordshire, UK
| | - Joe Morford
- Department of Zoology, Oxford Navigation Group, 11a Mansfield Road, Oxford, OX1 3SZ, Oxfordshire, UK
| | - Paris Jaggers
- Department of Zoology, Oxford Navigation Group, 11a Mansfield Road, Oxford, OX1 3SZ, Oxfordshire, UK
| | - Katrina Davies
- Department of Zoology, Oxford Navigation Group, 11a Mansfield Road, Oxford, OX1 3SZ, Oxfordshire, UK
| | - Emma Borsier
- Department of Zoology, Oxford Navigation Group, 11a Mansfield Road, Oxford, OX1 3SZ, Oxfordshire, UK
| | - Tim Guilford
- Department of Zoology, Oxford Navigation Group, 11a Mansfield Road, Oxford, OX1 3SZ, Oxfordshire, UK.
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9
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Putman NF. Magnetosensation. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:1-7. [PMID: 35098367 DOI: 10.1007/s00359-021-01538-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 10/19/2022]
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Granger J, Cummer SA, Lohmann KJ, Johnsen S. Environmental sources of radio frequency noise: potential impacts on magnetoreception. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:83-95. [DOI: 10.1007/s00359-021-01516-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 11/27/2022]
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11
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Benitez-Paez F, Brum-Bastos VDS, Beggan CD, Long JA, Demšar U. Fusion of wildlife tracking and satellite geomagnetic data for the study of animal migration. MOVEMENT ECOLOGY 2021; 9:31. [PMID: 34116722 PMCID: PMC8196450 DOI: 10.1186/s40462-021-00268-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 05/30/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Migratory animals use information from the Earth's magnetic field on their journeys. Geomagnetic navigation has been observed across many taxa, but how animals use geomagnetic information to find their way is still relatively unknown. Most migration studies use a static representation of geomagnetic field and do not consider its temporal variation. However, short-term temporal perturbations may affect how animals respond - to understand this phenomenon, we need to obtain fine resolution accurate geomagnetic measurements at the location and time of the animal. Satellite geomagnetic measurements provide a potential to create such accurate measurements, yet have not been used yet for exploration of animal migration. METHODS We develop a new tool for data fusion of satellite geomagnetic data (from the European Space Agency's Swarm constellation) with animal tracking data using a spatio-temporal interpolation approach. We assess accuracy of the fusion through a comparison with calibrated terrestrial measurements from the International Real-time Magnetic Observatory Network (INTERMAGNET). We fit a generalized linear model (GLM) to assess how the absolute error of annotated geomagnetic intensity varies with interpolation parameters and with the local geomagnetic disturbance. RESULTS We find that the average absolute error of intensity is - 21.6 nT (95% CI [- 22.26555, - 20.96664]), which is at the lower range of the intensity that animals can sense. The main predictor of error is the level of geomagnetic disturbance, given by the Kp index (indicating the presence of a geomagnetic storm). Since storm level disturbances are rare, this means that our tool is suitable for studies of animal geomagnetic navigation. Caution should be taken with data obtained during geomagnetically disturbed days due to rapid and localised changes of the field which may not be adequately captured. CONCLUSIONS By using our new tool, ecologists will be able to, for the first time, access accurate real-time satellite geomagnetic data at the location and time of each tracked animal, without having to start new tracking studies with specialised magnetic sensors. This opens a new and exciting possibility for large multi-species studies that will search for general migratory responses to geomagnetic cues. The tool therefore has a potential to uncover new knowledge about geomagnetic navigation and help resolve long-standing debates.
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Affiliation(s)
- Fernando Benitez-Paez
- School of Geography and Sustainable Development, Irvine Building, University of St Andrews, North Street, St Andrews, KY16 9AL, Scotland, UK
- The Alan Turing Institute British Library, England, London, UK
| | - Vanessa da Silva Brum-Bastos
- School of Geography and Sustainable Development, Irvine Building, University of St Andrews, North Street, St Andrews, KY16 9AL, Scotland, UK
| | - Ciarán D Beggan
- British Geological Survey, Research Ave South, Riccarton, Edinburgh, Scotland, UK
| | - Jed A Long
- School of Geography and Sustainable Development, Irvine Building, University of St Andrews, North Street, St Andrews, KY16 9AL, Scotland, UK
- Department of Geography and Environment, Western University, London, Ontario, Canada
| | - Urška Demšar
- School of Geography and Sustainable Development, Irvine Building, University of St Andrews, North Street, St Andrews, KY16 9AL, Scotland, UK.
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Klimley AP, Putman NF, Keller BA, Noakes D. A call to assess the impacts of
electromagnetic fields
from subsea cables on the movement ecology of marine migrants. CONSERVATION SCIENCE AND PRACTICE 2021. [DOI: 10.1111/csp2.436] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
| | | | - Bryan, A. Keller
- Florida State University Coastal and Marine Laboratory St. Teresa Florida USA
| | - David Noakes
- Oregon Hatchery Research Center, Fisheries and Wildlife Department Oregon State University Corvallis Oregon USA
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13
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Smith MA, Waugh DA, McBurney DL, George JC, Suydam RS, Thewissen JGM, Crish SD. A comparative analysis of cone photoreceptor morphology in bowhead and beluga whales. J Comp Neurol 2020; 529:2376-2390. [PMID: 33377221 DOI: 10.1002/cne.25101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/30/2022]
Abstract
The cetacean visual system is a product of selection pressures favoring underwater vision, yet relatively little is known about it across taxa. Previous studies report several mutations in the opsin genetic sequence in cetaceans, suggesting the evolutionary complete or partial loss of retinal cone photoreceptor function in mysticete and odontocete lineages, respectively. Despite this, limited anatomical evidence suggests cone structures are partially maintained but with absent outer and inner segments in the bowhead retina. The functional consequence and anatomical distributions associated with these unique cone morphologies remain unclear. The current study further investigates the morphology and distribution of cone photoreceptors in the bowhead whale and beluga retina and evaluates the potential functional capacity of these cells' alternative to photoreception. Refined histological and advanced microscopic techniques revealed two additional cone morphologies in the bowhead and beluga retina that have not been previously described. Two proteins involved in magnetosensation were present in these cone structures suggesting the possibility for an alternative functional role in responding to changes in geomagnetic fields. These findings highlight a revised understanding of the unique evolution of cone and gross retinal anatomy in cetaceans, and provide prefatory evidence of potential functional reassignment of these cells.
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Affiliation(s)
- Matthew A Smith
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, Ohio, USA.,Rebecca D. Considine Research Institute, Akron Children's Hospital, Akron, Ohio, USA
| | - David A Waugh
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - Denise L McBurney
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - John C George
- Department of Wildlife Management, North Slope Borough, Utqiagvik, Alaska, USA
| | - Robert S Suydam
- Department of Wildlife Management, North Slope Borough, Utqiagvik, Alaska, USA
| | - Johannes G M Thewissen
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, USA
| | - Samuel D Crish
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, Ohio, USA
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14
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Johnsen S, Lohmann KJ, Warrant EJ. Animal navigation: a noisy magnetic sense? ACTA ACUST UNITED AC 2020; 223:223/18/jeb164921. [PMID: 32967977 DOI: 10.1242/jeb.164921] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Diverse organisms use Earth's magnetic field as a cue in orientation and navigation. Nevertheless, eliciting magnetic orientation responses reliably, either in laboratory or natural settings, is often difficult. Many species appear to preferentially exploit non-magnetic cues if they are available, suggesting that the magnetic sense often serves as a redundant or 'backup' source of information. This raises an interesting paradox: Earth's magnetic field appears to be more pervasive and reliable than almost any other navigational cue. Why then do animals not rely almost exclusively on the geomagnetic field, while ignoring or downplaying other cues? Here, we explore a possible explanation: that the magnetic sense of animals is 'noisy', in that the magnetic signal is small relative to thermal and receptor noise. Magnetic receptors are thus unable to instantaneously acquire magnetic information that is highly precise or accurate. We speculate that extensive time-averaging and/or other higher-order neural processing of magnetic information is required, rendering the magnetic sense inefficient relative to alternative cues that can be detected faster and with less effort. This interpretation is consistent with experimental results suggesting a long time course for magnetic compass and map responses in some animals. Despite possible limitations, magnetoreception may be maintained by natural selection because the geomagnetic field is sometimes the only source of directional and/or positional information available.
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Affiliation(s)
- Sönke Johnsen
- Biology Department, Duke University, Durham, NC 27708, USA
| | - Kenneth J Lohmann
- Biology Department, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Eric J Warrant
- Lund Vision Group, Biology Department, Lund University, 223 62 Lund, Sweden
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