Discipline: Ecology, Environmental & Earth Sciences
Subcategory: STEM Research
Andrij Horodysky - Hampton University
Co-Author(s): Richard W. Brill, Virginia Institute of Marine Science; Sierra Williams-McLeod, Hampton University; Caroline Turner, James Madison University
The rapid uptake of carbon dioxide (CO2) by the world’s oceans since the Industrial Revolution is causing a rapid decline in ocean pH. There is thus an exigent need to explore the mechanisms at the organism-environment interface through which fishes respond to ocean acidification. The OANeuro Project therefore used the auditory brainstem response technique and morphological analyses to examine the effects of projected CO2 concentrations over the next two centuries on the form and function of the red drum (Sciaenops ocellatus) auditory system. This project examined the effects of both acute (two-week) and chronic (eight week) aqueous CO2 exposure on the: (1) morphological development of otoliths, (2) ecophysiological performance of the auditory system, and (c) capability of a GABAA receptor antagonist to alter potential sensory deficits during acute and chronic acidification. Both acute and chronic exposures to CO2 conditions projected over the next two centuries significantly increased auditory threshold, reducing response to low intensity sounds at the specific frequencies red drum use to communicate. For acute exposures, intramuscular administration of gabazine (4 ug g-1) restored some, but not all, auditory function to levels demonstrated by red drum subjected to current CO2 conditions. By contrast, gabazine administration was ineffective at restoring auditory function in chronically exposed red drum due to increased otolith dysmorphia, mass, and asymmetry relative to fish exposed to current CO2 levels. Collectively, these results demonstrate that acute exposure to CO2 causes significant but reversible neurotransmitter disruption, chronic exposures cause morphological changes to sensory endorgans and disruptions to auditory function that cannot be compensated by neurotransmitter function, with implications for communication and reproductive signaling in this soniferous coastal species.
Funder Acknowledgement(s): NSF-HBCU-UP-RIA
Faculty Advisor: None Listed,