Meeting Abstract
As sea levels rise from global climate change, animals inhabiting coastal wetlands will be increasingly exposed to elevated and more variable salinities. While it is presumed that anurans are poor osmoregulators and therefore will be extirpated from salt-intruded wetlands, mounting evidence suggests that some species are not only capable of tolerating elevated salinities but actually thrive in wetlands with chronic saltwater exposure. Indeed, we have found that coastal amphibian populations with a history of exposure to increased salinities persist in abundance in high salinity habitats. Interestingly, few studies have investigated how these species cope with salt stress and little is known about how amphibians maintain water balance in hypertonic environments. We are investigating how the localization, regulation, and abundance of ion pumps (i.e., NKA/NKCC) and water channel surface proteins (i.e., aquaporins) in different tissues vary in response to elevated salinities, species identity, and population location (salt protected inland populations vs. salt exposed coastal populations). Specifically, in this study we quantify changes in mass, blood osmolality and expression and localization of key osmoregulatory proteins in a putatively salt-tolerant species (Hyla cinerea) and a putatively intolerant species (Hyla chrysoscelis) after exposure to a salinity gradient. We found differences among species in both change in mass and in blood osmolality. H. chrysoscelis lost mass at a faster rate with increasing salinity above isotonic and had a concomitant faster increase in blood osmolality than H. cinerea. Finally, we show differences in the abundance and localization of key osmoregulatory proteins (e.g. aquaporins).
