Effects of Salinity on the Survival, Growth, Development, and Metamorphosis ofFejervarya limnocharisTadpoles Living in Brackish Water

Abstract

We studied salinity tolerance and the effects of salinity on growth, development, and metamorphosis in Fejervarya limnocharis tadpoles living in brackish water. Specifically, we examined whether tadpoles exhibit adaptive plasticity in development when exposed to different salinities. Tadpoles collected on Green and Orchid Islands off Southeastern Taiwan were assigned to salinities of 0, 3, 5, 7, 9, 11, and 13 parts per thousand (ppt). The daily survival, weekly growth, and development of tadpoles were recorded until metamorphosis. More than 50% of tadpoles survived in 9 ppt for over a month, and a few individuals survived in 11 ppt for 20 days, suggesting that F. limnocharis tadpoles tolerate salinity better than the tadpoles of most species studied to date. Tadpoles at 9 ppt had lower survivorship, and retarded growth and development (from Gosner stage 26 to 35) compared to the other treatments. Tadpoles metamorphosed early at a smaller size as salinity increased, suggesting the existence of adaptive developmental plasticity in F. limnocharis in response to osmotic stress. Phenotypic plasticity in the age and size at metamorphosis in response to salinity may provide a means for tadpoles to adapt to the unpredictable salinity variation in coastal rock pools.

Increasing the illumination slowly over several weeks protects against light damage in the eyes of the crustacean Mysis relicta

“…Thermal and photic stress has been found to change fatty acid composition and the ultrastructure of photoreceptive membranes in crayfish eyes (Kashiwagi et al, 1997). Under salinity acclimation, reported responses range from changes in epithelial Na + /K + -ATPase activity (shrimp: McNamara and Torres, 1999;frog: Wu et al, 2014) to whole-organism effects on development (frog tadpoles: Wu and Kam, 2009). In fact, it appears as remarkable that acclimation of eyes and visual function to variations in light levels on the time scale of seasonal changes has not been reported before.…”

Spectroscopic Determination of Water Salinity in Brackish Surface Water in Nandoni Dam, at Vhembe District, Limpopo Province, South Africa

“…It also impacts on various social, economic and environmental related uses by both rural and urban communities [14][15][16][17][18]. The high levels of salt deposits cause an unfavourable hydrological environment in water that restricts its domestic use such as for drinking and normal production of crops [16,19]. Scale build-up due to water salinity also necessitates increased frequency and cost of repair and maintenance of the public infrastructure [20].…”

“…It also impacts on various social, economic and environmental related uses by both rural and urban communities [15][16][17][18][19]. The high levels of salt deposits cause an unfavourable hydrological environment in water that restricts its domestic use such as for drinking and normal production of crops [17,20].…”

Irreversibility of a bad start: early exposure to osmotic stress limits growth and adaptive developmental plasticity

“…The environments experienced by amphibian larvae are usually heterogeneous and unpredictable, as they are often at risk from pond drying, food shortages, extreme temperatures, predator attacks, water acidity or salinity (Newman 1992;Alford 1999;Rose 2005;Wu and Kam 2009). Development of amphibian larvae is very plastic, varying their time to and size at metamorphosis either adaptively in response to specific environmental cues or non-adaptively due to environmental fluctuations themselves (Newman 1992;Rose 2005;Rudolf and Rödel 2007).…”

“…All tadpoles are sensitive to salinity, and moderate salinity (2-9 parts per thousand; ppt) decreases tadpole survival, growth, and development (Christy and Dickman 2002;Gomez-Mestre et al 2004;Chinathamby et al 2006;Wu and Kam 2009). In most systems, pond salinity is lowest at the beginning of the amphibian reproductive period, as ponds fill up, and gradually increases over time as ponds evaporate and are maximal just prior to pond desiccation.…”