Meeting Abstract
The copepod Tigriopus californicus inhabits dynamic tidepools where multiple environmental factors vary in both a predictable and unpredictable fashion. Our objective was to quantify interactions between salinity and acute thermal tolerance. Copepods collected from Hopkins Marine Station were acclimated in 60ppt or 30ppt salinity for two weeks and then acutely transferred to a range of salinities before exposure to a controlled heat stress. These preliminary data revealed up to a 10°C difference in LT50 between the two acclimation salinities when tested at high acute salinities. Opportunistic field sampling of thermal tolerance of mature females corroborated the lab observations. Specifically, initial LT50 in egg-bearing females was high when the tide pool salinity exceeded 80ppt; LT50 decreased after the salinity stochastically decreased to 37ppt following a wave event. The LT50subsequently increased after the salinity naturally reverted to higher levels over several weeks of evaporative concentration. In a third experiment, mature females were placed in salt water ranging from normal seawater (30ppt) to 60ppt. As the females’ offspring hatched and matured, both offspring and parental generation females were subjected to acute heat stress. Both parent females and offspring reared in higher salinities exhibited higher thermal tolerance, substantiating our previous findings. Altogether, copepods exposed to a higher salinity – both chronically and acutely – exhibit compensatory physiological responses that enhance survivability of other acute stressors such as temperature. Such interactions between covarying environmental parameters add complexity to biological forecasts.
