CAREER: Investigating environmental acidification and temperature as drivers of morphological alteration and physiological deficits in auditory systems of soniferous fishes

Hampton University, Hampton VA

Investigators

Abstract

Since the Industrial Revolution, the ocean has become 30% more acidic due to its uptake of carbon dioxide, and coastal areas and freshwaters are frequently more acidic still due to inputs from natural and agricultural land and human activities in adjacent watersheds. The goal of this CAREER project is to examine the effects of temperature and carbon dioxide exposure on the structure and function of the auditory (hearing) systems of closely-related sound-producing fishes of the croaker/drum family Sciaenidae. These fishes are model organisms for the study of fish hearing and communication, most support valuable recreational fisheries in habitats ranging from fresh through salt water, and nearly all produce sounds to aid in reproduction and/or to raise alarm when disturbed or threatened. While auditory sense is of great importance to these sound producing fishes, little is known about the effects of changing environmental conditions on fish hearing and communication. This project's interdisciplinary approach will make significant impacts in this rapidly emerging field that will be of broad interest to both the ocean science and recreational fishing stakeholder communities. The award supports recruitment and professional development of postdoctoral, graduate, and undergraduate researchers from underrepresented groups in STEM disciplines. Student training includes mastery of quantitative reasoning, critical thinking, and communication skills regarding environmental impacts on aquatic ecosystems and sustainable stewardship of future ecosystems. This CAREER Award will expand the interdisciplinary neurosensory laboratory developed at Hampton University under the PI's earlier Research Initiation Award to examine how changing environmental conditions over the next century may affect the form and function of auditory systems of phylogenetically-related soniferous fishes that rely on auditory communication during aggregate spawning. This project will apply electrophysiological techniques and morphological analyses to assay the effects of increased temperature and CO2 concentrations representative of projected changes over the next century on auditory morphology and neurosensory function in representative freshwater, estuarine, and fully marine sciaenid fishes. Using related fishes from a common phylogeny but differing habitats and life histories, this project will examine the effects of chronic aqueous CO2 exposure (i.e. acidification) and increased temperature on the: (1) morphological development of sensory structures via digital microscopy and computerized tomography (CT), (2) neurosensory performance of auditory systems via Auditory Brainstem Response, and (3) manipulation of the GABA neurotransmitter to alter sensory deficits during CO2 exposure. This CAREER project will enhance research capacity and provide critical infrastructure that will support continued research by the PI, a postdoctoral associate, and both graduate and undergraduate students from underrepresented backgrounds in STEM beyond the award's lifetime. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.