Natures wonders: sharks detect prey's electricity (Introduction)

by David Turell @, Saturday, May 14, 2016, 18:45 (1225 days ago) @ David Turell

Sharks can pick up electric signals from prey. Still working out how:

http://phys.org/news/2016-05-proton-conducting-material-electrosensory-sharks.html

"Sharks, skates, and rays can detect very weak electric fields produced by prey and other animals using an array of unusual organs known as the ampullae of Lorenzini. Exactly how these electrosensory organs work has remained a mystery, but a new study has revealed an important clue that may have implications for other fields of research.

"The ampullae of Lorenzini are visible as small pores in the skin around the head and on the underside of sharks, skates, and rays (known as elasmobranchs, a subclass of cartilaginous fish). Each pore is open to the environment and is connected to a set of electrosensory cells by a long canal filled with a clear, viscous jelly.

"In the new study, published May 13 in Science Advances, a team of researchers from UC Santa Cruz, University of Washington, and the Benaroya Research Institute at Virginia Mason investigated the properties of this jelly. They found that the jelly is a remarkable proton-conducting material, with the highest proton conductivity ever reported for a biological material.

***

"The integration of signals from several ampullae allows sharks, skates, and rays to detect changes in the electric field as small as 5 nanovolts per centimeter. But how such weak signals are transmitted from the pore to the sensory cells has long been a matter of debate. The researchers speculate that sulfated polyglycans in the jelly may contribute to its high proton conductivity.

"Proton conductivity is the ability of a material or solution to conduct protons (positive hydrogen ions). In a system with very many ordered hydrogen bonds, such as a hydrated hydrophilic polymer, proton conduction can occur along chains of these bonds, Rolandi explained. In technological applications, proton conductors such as Nafion can be used as proton exchange membranes in fuel cells.

"'The first time I measured the proton conductivity of the jelly, I was really surprised," said first author Erik Josberger, an electrical engineering doctoral student in Rolandi's group at UW."

Comment: Split off hydrogen from water and the sharks have positive protons as signals to use to alert their brain to act. Self invented or helped by God?


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