Effects of Ocean Warming and Acidification on the Embryonic Development of Doryteuthis Opalescens and Doryteuthis Pealeii

Committee Members

• Dr. Chun-Ta Lai (Chair), Biology
• Dr. Kevin Hovel, Biology 
• Dr. Arielle Levine, Geography

Abstract

Projected increases in ocean temperature and partial pressure of carbon dioxide (pCO₂) due to anthropogenic carbon emissions are expected to significantly alter coastal marine ecosystems, particularly within the Southern California Bight and Northwest Atlantic Ecoregion. These changes may disrupt food web stability through alterations in abiotic conditions. I investigated the impacts of elevated temperature and pCO₂ on embryonic development in two mid-trophic squid species, Doryteuthis opalescens and D. pealeii, both in the superorder Decapodiformes.

Specifically, I examined metabolic and morphological responses in squid paralarvae reared in four seawater treatments consisting of combinations of present-day and end-of-century projected levels of temperature and pCO₂ . I reared egg capsules for both species in the laboratory, exposing them to differing levels of pCO₂ and temperature for a maximum of 28 days until hatching. On the day of hatching, O₂ consumption, head area, head width, eye area, statolith area, body area, mantle length, and full body length were measured. The effects of elevated temperature and pCO₂ differed between the two species. D. opalescens paralarvae exhibited generally smaller morphological sizes, under elevated temperature and pCO₂ conditions. In contrast, D. pealeii paralarvae demonstrated increased morphological dimensions under the same conditions.

Additionally, D. pealeii paralarvae showed elevated O₂ consumption rates, while D. opalescens paralarvae exhibited a more subdued metabolic response to temperature increases. These findings highlight significant interspecific variability in responses to future ocean conditions, despite the similarity in life history traits between the two species. My study underscores the complexity of climate change impacts on Decapodiformes and emphasizes the necessity of species-specific assessments to predict ecological consequences for marine organisms.