By Ava D. Kocher, Dr. Juliet Wong

Duke University

https://doi.org/10.55894/dv4.13

Abstract

Rising global surface and ocean temperatures threaten to drastically alter the environmental conditions for marine organisms, via ambient changes and heatwave events. To understand the impact of marine heatwaves on invertebrate physiology, this study investigated how exposure to thermal and hypersaline stress affects the physiology of Lytechinus variegatus, as measured by respiration rate and righting response. Urchins were collected and held in seawater tables at four heat and salinity treatments, with five replicates per treatment. The respiration rate and righting response variables were measured over the course of six days of treatment exposure. 100% mortality occurred in the high heat treatment within three days. Both the intermediate heat and hypersaline treatments exhibited significant decreases in respiration rates on day five, while the controltreatment stayed steady. Righting response times showed no significant differences between treatments or between days of exposure. These results suggest L.variegatus tolerance to heat and saline stress events is physiologically complex and duration-dependent.