Growing Up Salty: The Effects of Transient Salinity on Tadpole Growth, Behavior, and Development

Student: Gabi Tutelo and Isabella Rupert

Major: Marine Biology

Mentors: Dr. Allison Welch

Department: Biology

Growing Up Salty: The Effects of Transient Salinity on Tadpole Growth, Behavior, and Development

Freshwater ecosystems are undergoing significant degradation due to human activity. Road deicing, agricultural practices, and rising sea levels have been linked to the salinization of freshwater environments. Elevated salinity levels can have lethal and sublethal effects on freshwater organisms. Amphibians are exceptionally vulnerable to these conditions because of their semi-permeable skin, low salinity tolerance, and complex life cycle. Tadpoles exposed to elevated salinity have an increased mortality rate and, in milder cases, suppressed growth and development. These effects increase chances of predation and can ultimately have a negative impact on reproduction. When exposed to these stressors, amphibians may experience a phenomenon known as developmental plasticity which causes them to alter the trajectory of their development in the presence of a stressor, for example by accelerating development when conditions in the larval environment are stressful. After a stressor is alleviated, the tadpole may experience a period of compensatory growth allowing them to accelerate their growth in order to "catch-up" in size. Such a rapid period of growth is likely to come at some cost to the tadpoles, specifically involving the link between tadpole behavior and their ability to experience compensatory growth. Both compensatory growth, developmental plasticity, and behavior, as well as their links to one another, are poorly understood in amphibians, particularly in relation to salinity stress. In this study, we will expose tadpoles to elevated salinity for different portions of development in order to monitor the effects on size, developmental stage, and behavior before, during, and after the exposure. This experiment will lead to a better understanding of compensatory growth and developmental plasticity in amphibians as well as the consequences of salinity stress on amphibian development and behavior and the risks of freshwater salinization.