Development of embryonic market squid, Doryteuthis opalescens, under chronic exposure to low environmental pH and O-2

TitleDevelopment of embryonic market squid, Doryteuthis opalescens, under chronic exposure to low environmental pH and O-2
Publication TypeJournal Article
Year of Publication2016
AuthorsNavarro M.O, Kwan G.T, Batalov O., Choi C.Y, Pierce N.T, Levin L.A
JournalPlos One
Date Published2016/12
Type of ArticleArticle
ISBN Number1932-6203
Accession NumberWOS:000389587100102
Keywordsacidification; calamary sepioteuthis-australis; california coast; carbonate chemistry; cephalopod sepia-officinalis; co2 tolerance; egg masses; loligo-vulgaris; ocean; oxygen; temperature

The market squid, Doryteuthis opalescens, is an important forage species for the inshore ecosystems of the California Current System. Due to increased upwelling and expansion of the oxygen minimum zone in the California Current Ecosystem, the inshore environment is expected to experience lower pH and [O-2] conditions in the future, potentially impacting the development of seafloor-attached encapsulated embryos. To understand the consequences of this co-occurring environmental pH and [O-2] stress for D. opalescens encapsulated embryos, we performed two laboratory experiments. In Experiment 1, embryo capsules were chronically exposed to a treatment of higher (normal) pH (7.93) and [O-2] (242 mu M) or a treatment of low pH (7.57) and [O-2] (80 mu M), characteristic of upwelling events and/or La Nina conditions. The low pH and low [O-2] treatment extended embryo development duration by 5-7 days; embryos remained at less developed stages more often and had 54.7% smaller statolith area at a given embryo size. Importantly, the embryos that did develop to mature embryonic stages grew to sizes that were similar (non-distinct) to those exposed to the high pH and high [O-2] treatment. In Experiment 2, we exposed encapsulated embryos to a single stressor, low pH (7.56) or low [O-2] (85 mu M), to understand the importance of environmental pH and [O-2] rising and falling together for squid embryogenesis. Embryos in the low pH only treatment had smaller yolk reserves and bigger statoliths compared to those in low [O-2] only treatment. These results suggest that D. opalescens developmental duration and statolith size are impacted by exposure to environmental [O-2] and pH (pCO(2)) and provide insight into embryo resilience to these effects.

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