A parameter for detecting estrogenic exposure in the copepod Acartia tonsa

Area of Science:

• Marine Biology
• Endocrinology
• Ecotoxicology

Background:

• Estrogens, like 17beta-estradiol, are known to stimulate female sexual maturation and egg production in crustaceans.
• The copepod Acartia tonsa exhibits continuous egg production, making it a suitable model for studying reproductive maturation.
• Egg production rate can serve as a reliable indicator of female reproductive organ maturation.

Purpose of the Study:

• To investigate the effects of estrogen exposure on the maturation profile of Acartia tonsa.
• To establish egg production rate as a quantifiable endpoint for assessing estrogenic effects in crustaceans.
• To differentiate between specific estrogenic effects and general toxic stress responses.

Main Methods:

• Acartia tonsa were exposed to 17beta-estradiol and bisphenol A (BPA).
• Egg production rates were monitored over time to create maturation profiles.
• A nonestrogenic compound, 2,3-dichlorophenol, was used to test for non-specific toxic effects.

Main Results:

• Exposure to 17beta-estradiol (23 microg/L) and bisphenol A (20 microg/L) significantly increased egg production rates.
• The observed increase in egg production indicates accelerated maturation of reproductive organs.
• 2,3-dichlorophenol exposure did not affect egg production, ruling out general toxic stress as the cause.

Conclusions:

• Estrogen exposure, including from the endocrine disruptor bisphenol A, accelerates sexual maturation and egg production in Acartia tonsa.
• Egg production profiling is a valid method for assessing estrogenic impacts on crustacean reproduction.
• This research highlights the potential of environmental estrogens to disrupt marine invertebrate reproductive processes.