Combined effects of increased temperature and endocrine disrupting pollutants on sex determination, survival, and development across generations

Abstract

Understanding the combined effects of anthropogenic impacts such as climate change and pollution on aquatic ecosystems is critical. However, little is known about how predicted temperature increases may affect the activity of endocrine disrupting compounds (EDCs), particularly in species with plasticity in sex determination. We investigated the effects of a concomitant increase in temperature and exposure to estrogenic EDCs on reproduction and development in an estuarine model organism (Menidia beryllina) across multiple generations. Parents (P) were exposed to environmental levels of the estrogenic insecticide bifenthrin or ethinylestradiol (EE2) at 22 °C and 28 °C for 14 days prior to the initiation of spawning trials. Embryos in the F1 generation were exposed to EDCs until 21 days post hatch (dph), reared to adulthood in clean water at elevated temperatures, and spawned. F1 sex ratios were significantly influenced by elevated temperature and EDCs, potentially altering adaptive development. We also observed fewer viable offspring and increased developmental deformities in the F1 and F2 generations, with a greater impact on F2 juveniles. These findings enhance our understanding of responses to EDCs in the context of climate change and may demonstrate heritable effects. Our study represents the first multigenerational assessment of elevated temperatures in combination with environmentally relevant concentrations of commonly detected endocrine disruptors in a model vertebrate species.

The effects of bifenthrin and temperature on the endocrinology of juvenile Chinook salmon

“…Altered reproduction, viability, and growth were several of the adverse transgenerational effects observed from low (1 ng/L) bifenthrin and increased temperature exposures in Menidia beryllina (Decourten and Brander 2017). Increasing temperature and bifenthrin concentrations may have negative impacts to juvenile salmon.…”

Developmental exposure to environmentally relevant concentrations of bifenthrin alters transcription of mTOR and ryanodine receptor-dependent signaling molecules and impairs predator avoidance behavior across early life stages in inland silversides (Menidia beryllina)

“…Previous work has demonstrated that environmentally relevant levels of bifenthrin cause endocrine disruption and interfere with reproduction in inland silversides (Brander et al, 2012a, 2016; DeCourten and Brander, 2017; DeCourten et al, 2018). Here, we expand on these studies to demonstrate that bifenthrin levels in the picomolar (pM) concentration range have the potential to alter neurodevelopment, potentially impacting locomotion and behavior, thereby posing ecological consequences, such as increased risk of predation or impaired reproductive behavior and ability to obtain food.…”

“…Water temperature was maintained at 23 ± 1 °C, with a salinity of 15 ± 1 ppt. Bleached and rinsed cotton yarn was used as spawning substrate (DeCourten and Brander, 2017). The yarn was kept in the spawning tanks for 2 h, after which eggs were carefully separated from the substrate with fine scissors.…”

“…Bioaccumulation of bifenthrin in tissues has also been demonstrated (Munaretto et al, 2013) potentially leading to long-term, or delayed effects resulting from developmental exposure. Endocrine disruption in response to bifenthrin (ng/L) has been repeatedly determined in inland silversides ( Menidia beryllina ), with significant impacts at concentrations ranging from 0.5 to 50 ng/L (Brander et al, 2012b; DeGroot and Brander, 2014; Brander et al, 2016; DeCourten and Brander, 2017). Interestingly, bifenthrin metabolites appear to contribute most to the estrogenic effects (DeGroot and Brander, 2014), and responses can be greater at lower concentrations.…”

“…Studies investigating reproductive output with adult inland silversides determined a significant reduction when they were exposed to 0.5 ng/L for 21 days (Brander et al, 2016). The influences of 1 ng/L bifenthrin were further evaluated in a generation overlapping assay at both ambient and warmer temperatures, showing influences on sex ratios in the F1 generation and decreased viable offspring and deformities in F1 and F2 generation (DeCourten and Brander, 2017). …”