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Effects of produced water on reproduction and early life stages of the purple sea urchin (Strongylocentrotus purpuratus): Field and laboratory tests

Thesis/Dissertation ·
OSTI ID:7149017

This dissertation focuses on the effects of produced water (an oil-production effluent) on reproduction in the purple sea urchin (Strongy-locentrotus purpuratus) using both field and laboratory experiments. The author investigated the effects of chronic exposure to produced water on the gametogenesis and gamete performance using an in-situ caging experiment. He found a significant negative relationship between gonad mass and cage distance for both sexes, indicating that urchins living closer to the outfall produced significantly larger gonads. He also found significant differences in the fertilizability of eggs between cages and this showed a positive relationship with distance from the outfall. These findings indicate that while urchins exposed to a produced water outfall produce large gonads, they suffer a marked decrease in gamete performance. In a subsequent study the author explored whether and how brief exposure to a range of concentrations of produced water affected gametes and early larval stages of the purple sea urchin. Specifically, he exposed separately and together, eggs, sperm, and zygotes to ascertain the relative sensitivities of these life stages to produced water at durations and concentrations realistic to each state. He also explored the nature of the biological responses, and the potential for delayed expression. I found that both apparent fertilization and embryonic developmental success showed decreased performance with increasing produced water concentrations. Produced water exposure effectively slowed embryological developmental rates, but did not affect embryo survivorship. The spatial and temporal variability in toxicity of receiving waters was addressed using a fertilization bioassay. Receiving waters were collected along a transect down-field from the discharge on three dates while the outfall was actively discharging, and on one date while the plant was not discharging.

Research Organization:
California Univ., Santa Barbara, CA (United States)
OSTI ID:
7149017
Country of Publication:
United States
Language:
English