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Ocean Acidification Has Multiple Modes of Action on Bivalve Larvae.

Waldbusser GG, Hales B, Langdon CJ, Haley BA, Schrader P, Brunner EL, Gray MW, Miller CA, Gimenez I, Hutchinson G - PLoS ONE (2015)

Bottom Line: We found, as documented in other bivalve larvae, that shell development and growth were affected by aragonite saturation state, and not by pH or PCO2.Although different components of physiology responded to different carbonate system variables, the inability to normally develop a shell due to lower saturation state precludes pH or PCO2 effects later in the life history.However, saturation state effects during early shell development will carry-over to later stages, where pH or PCO2 effects can compound OA effects on bivalve larvae.

View Article: PubMed Central - PubMed

Affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States of America.

ABSTRACT
Ocean acidification (OA) is altering the chemistry of the world's oceans at rates unparalleled in the past roughly 1 million years. Understanding the impacts of this rapid change in baseline carbonate chemistry on marine organisms needs a precise, mechanistic understanding of physiological responses to carbonate chemistry. Recent experimental work has shown shell development and growth in some bivalve larvae, have direct sensitivities to calcium carbonate saturation state that is not modulated through organismal acid-base chemistry. To understand different modes of action of OA on bivalve larvae, we experimentally tested how pH, PCO2, and saturation state independently affect shell growth and development, respiration rate, and initiation of feeding in Mytilus californianus embryos and larvae. We found, as documented in other bivalve larvae, that shell development and growth were affected by aragonite saturation state, and not by pH or PCO2. Respiration rate was elevated under very low pH (~7.4) with no change between pH of ~ 8.3 to ~7.8. Initiation of feeding appeared to be most sensitive to PCO2, and possibly minor response to pH under elevated PCO2. Although different components of physiology responded to different carbonate system variables, the inability to normally develop a shell due to lower saturation state precludes pH or PCO2 effects later in the life history. However, saturation state effects during early shell development will carry-over to later stages, where pH or PCO2 effects can compound OA effects on bivalve larvae. Our findings suggest OA may be a multi-stressor unto itself. Shell development and growth of the native mussel, M. californianus, was indistinguishable from the Mediterranean mussel, Mytilus galloprovincialis, collected from the southern U.S. Pacific coast, an area not subjected to seasonal upwelling. The concordance in responses suggests a fundamental OA bottleneck during development of the first shell material affected only by saturation state.

No MeSH data available.


Related in: MedlinePlus

Experimental Carbonate Chemistry Treatments.Carbonate chemistry treatments of Ωar and PCO2 (μatm), with pH (total) isopleths to illustrate the relationship among the three variables in the experiments. Grey circles are the actual treatment values, and star indicates the treatment chemistry of the control (freshly collected seawater bubbled with CO2-reduced air for 24 hours).
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pone.0128376.g001: Experimental Carbonate Chemistry Treatments.Carbonate chemistry treatments of Ωar and PCO2 (μatm), with pH (total) isopleths to illustrate the relationship among the three variables in the experiments. Grey circles are the actual treatment values, and star indicates the treatment chemistry of the control (freshly collected seawater bubbled with CO2-reduced air for 24 hours).

Mentions: We examined shell development, growth, respiration rate, approximately 48 hours post-fertilization in the California mussel, Mytilus californianus, in response to different carbonate chemistry system variables. We also examined initiation of feeding approximately 44 hours post fertilization. Employing a unique seawater chemistry manipulation framework we were able to completely separate effects of PCO2 and Ωar, however pH was only pseudo-independent of the these two variables. The combinations of DIC and alkalinity that would be required to generate pH orthogonality within our current experimental range of PCO2 and Ωar are nearly impossible to obtain (see Fig 1 and isopleths of pH).


Ocean Acidification Has Multiple Modes of Action on Bivalve Larvae.

Waldbusser GG, Hales B, Langdon CJ, Haley BA, Schrader P, Brunner EL, Gray MW, Miller CA, Gimenez I, Hutchinson G - PLoS ONE (2015)

Experimental Carbonate Chemistry Treatments.Carbonate chemistry treatments of Ωar and PCO2 (μatm), with pH (total) isopleths to illustrate the relationship among the three variables in the experiments. Grey circles are the actual treatment values, and star indicates the treatment chemistry of the control (freshly collected seawater bubbled with CO2-reduced air for 24 hours).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465621&req=5

pone.0128376.g001: Experimental Carbonate Chemistry Treatments.Carbonate chemistry treatments of Ωar and PCO2 (μatm), with pH (total) isopleths to illustrate the relationship among the three variables in the experiments. Grey circles are the actual treatment values, and star indicates the treatment chemistry of the control (freshly collected seawater bubbled with CO2-reduced air for 24 hours).
Mentions: We examined shell development, growth, respiration rate, approximately 48 hours post-fertilization in the California mussel, Mytilus californianus, in response to different carbonate chemistry system variables. We also examined initiation of feeding approximately 44 hours post fertilization. Employing a unique seawater chemistry manipulation framework we were able to completely separate effects of PCO2 and Ωar, however pH was only pseudo-independent of the these two variables. The combinations of DIC and alkalinity that would be required to generate pH orthogonality within our current experimental range of PCO2 and Ωar are nearly impossible to obtain (see Fig 1 and isopleths of pH).

Bottom Line: We found, as documented in other bivalve larvae, that shell development and growth were affected by aragonite saturation state, and not by pH or PCO2.Although different components of physiology responded to different carbonate system variables, the inability to normally develop a shell due to lower saturation state precludes pH or PCO2 effects later in the life history.However, saturation state effects during early shell development will carry-over to later stages, where pH or PCO2 effects can compound OA effects on bivalve larvae.

View Article: PubMed Central - PubMed

Affiliation: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States of America.

ABSTRACT
Ocean acidification (OA) is altering the chemistry of the world's oceans at rates unparalleled in the past roughly 1 million years. Understanding the impacts of this rapid change in baseline carbonate chemistry on marine organisms needs a precise, mechanistic understanding of physiological responses to carbonate chemistry. Recent experimental work has shown shell development and growth in some bivalve larvae, have direct sensitivities to calcium carbonate saturation state that is not modulated through organismal acid-base chemistry. To understand different modes of action of OA on bivalve larvae, we experimentally tested how pH, PCO2, and saturation state independently affect shell growth and development, respiration rate, and initiation of feeding in Mytilus californianus embryos and larvae. We found, as documented in other bivalve larvae, that shell development and growth were affected by aragonite saturation state, and not by pH or PCO2. Respiration rate was elevated under very low pH (~7.4) with no change between pH of ~ 8.3 to ~7.8. Initiation of feeding appeared to be most sensitive to PCO2, and possibly minor response to pH under elevated PCO2. Although different components of physiology responded to different carbonate system variables, the inability to normally develop a shell due to lower saturation state precludes pH or PCO2 effects later in the life history. However, saturation state effects during early shell development will carry-over to later stages, where pH or PCO2 effects can compound OA effects on bivalve larvae. Our findings suggest OA may be a multi-stressor unto itself. Shell development and growth of the native mussel, M. californianus, was indistinguishable from the Mediterranean mussel, Mytilus galloprovincialis, collected from the southern U.S. Pacific coast, an area not subjected to seasonal upwelling. The concordance in responses suggests a fundamental OA bottleneck during development of the first shell material affected only by saturation state.

No MeSH data available.


Related in: MedlinePlus