Strontium randomly substituting for calcium in fish otolith aragonite

Area of Science:

• * Otolith chemistry
• * Fish ecology
• * Fisheries science

Background:

• * Fish ear bones (otoliths) are crucial for understanding fish ecology and fisheries.
• * The incorporation of strontium (Sr) into otoliths is a fundamental assumption, but its precise mechanism has been unverified.
• * Misinterpretation of Sr incorporation could impact fish and fisheries management.

Purpose of the Study:

• * To investigate and explicitly determine the mode of strontium (Sr) incorporation into fish otoliths.
• * To test the long-held assumption of Sr's random replacement of calcium (Ca) within the aragonite lattice.
• * To validate the chemical basis of otolith chemistry for reliable fisheries research.

Main Methods:

• * Utilized X-ray absorption spectroscopy (XAS), specifically extended X-ray absorption fine structure (EXAFS) analysis.
• * Analyzed otoliths from seven fish species across diverse aquatic environments.
• * Included comparative analysis of aragonitic structures from cephalopods and corals.

Main Results:

• * Consistent evidence across all analyzed samples demonstrated that Sr randomly replaces Ca within the aragonite lattice.
• * The study provides explicit confirmation of the binding mechanism for Sr in fish otoliths.
• * The findings validate the prevailing assumption regarding Sr incorporation in otolith chemistry.

Conclusions:

• * This research validates the fundamental assumption that strontium is randomly incorporated into the calcium carbonate lattice of fish otoliths.
• * The confirmed mechanism of Sr incorporation ensures the accuracy of otolith chemistry data.
• * Reliable otolith chemistry data supports improved understanding and management of fish populations and fisheries.