Trans-Generational Plasticity in the New Zealand Sea Star Patiriella regularis in Response to Combined ocean acidification and Warming: The Effects of Adult Exposure on Offspring Performance

Chair: Philip Munday

Kate Sparks (1) and Miles Lamare (1)
1 Department of Marine Science, University of Otago, 310 Castle Street, Dunedin 9016 New Zealand

Background
Sea stars have been identified as particularly vulnerable to the effects of ocean acidification and warming. The rate of climate change may be too rapid for genetic evolution to ‘keep up’ and therefore non-genetic inheritance, such as trans-generational plasticity and maternal effects, may become increasingly important in deciding species’ survival.

Methods
This study quantified the natural variation within wild populations of P.regularis in response to combined ocean acidification and warming using a Quantitative Genetics protocol and a modified North Carolina II breeding design. A sub-set of adults from the same population were then exposed to predicted near-future climate change predictions for the Southern Ocean (based on IPCC scenarios) for a period of 12 months. The Quantitative Genetics breeding design will then be replicated (February 2016) and the offspring raised in combinations of the same conditions as parental exposure. Offspring performance will be analysed in context of parental exposure. Multivariate analyses will be used to estimate variance components and calculate genetic correlations across environmental gradients. Narrow-sense heritability and Anticipatory Parental Effects (APEs) including maternal effects will be calculated as a measure of trans-generational plasticity.

Findings
This study expects to find that adult exposure to combined ocean acidification and warming over long time-scales significantly affects both physiological health and reproductive fitness, and therefore influences offspring performance. Within the adult populations exposed to each combination of stressors, it is expected that acclimation potential between individuals will vary. Larvae from parents exposed to environmental stressors may perform worse, regardless of their environment, than those larvae from parents kept in ‘ambient’ conditions.

Conclusions
P.regularis is expected to possess sufficient variation within each population to allow a sub-set of individuals to adapt to climate change, and it is expected that non-Darwinian (i.e. non-genetic) inheritance from ‘tolerant’ parents will influence performance in successive generations.