Long-Range Geomagnetic Navigation in Sea Turtles An Interdisciplinary Approach to Localizing Magnetite-Based Biological Magnetoreceptors
Abstract
This research involved a three-pronged multidisciplinary approach. In the first, we developed a new magnetomotive optical coherence tomography (MMOCT) system with unprecedented sensitivity. This system can detect small concentrations of magnetic particles in biological tissue and may thus prove useful in the search for magnetite-based magnetoreceptors. The second approach involved identifying candidate genes involved in assembling magnetoreceptors. Specifically, we investigated gene expression after administering a magnetic pulse, a procedure known to disrupt magnetic orientation in several animals and considered to be a diagnostic test for magnetite-based magnetoreception. In trout, 181 genes were differentially expressed after application of a magnetic pulse, including increased expression in six copies of the frim gene, which encodes a subunit of the universal iron-binding and trafficking protein ferritin. In lobsters, a large number of genes (more than 2,500) had differential expression, including many potentially related to iron homeostasis. Results in both animals are consistent with magnetite-based magnetoreception, inasmuch as many of the genes with altered expression might plausibly be linked to repair or replacement of magnetic receptors disrupted by the pulse. Finally, we conducted behavioral and modeling studies including:(1) analyses providing evidence that sea turtles imprint on the magnetic field of their home areas and use this information to navigate back years later; (2) development of a novel behavioral assay for investigating the ability of sea turtles to recognize and learn specific magnetic fields; (3) experiments investigating behavioral effects of pulsed magnetic fields on fish and lobsters; and (4) investigation of strategies and algorithms for magnetic navigation that might be useful in engineered navigation systems.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 14, 2021
- Accession Number
- AD1142611
Entities
People
- Amy L. Oldenburg
- Kenneth J Lohmann
- Sönke Johnsen
Organizations
- Duke University
- University of North Carolina at Chapel Hill