Transgenerational effects alleviate severe fecundity loss during ocean acidification in a ubiquitous planktonic copepod

• Published in: Global Change Biology
• Main Authors: Thor, Peter, Dupont, Sam
• Other Authors: Fram Centre Flagship ‘Ocean, University of Gothenburg, Swedish Research Councils VR and Formas (Linnaeus grant), the European Community through ASSEMBLE
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2015
• Subjects: General Environmental Science; Ecology; Environmental Chemistry; Global and Planetary Change; Ocean acidification; Copepods
• Online Access: http://dx.doi.org/10.1111/gcb.12815; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fgcb.12815; https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.12815

Abstract Ocean acidification (OA) caused by anthropogenic CO 2 emission is projected for thousands of years to come, and significant effects are predicted for many marine organisms. While significant evolutionary responses are expected during such persistent environmental change, most studies consider only short‐term effects. Little is known about the transgenerational effects of parental environments or natural selection on the capacity of populations to counter detrimental OA effects. In this study, six laboratory populations of the calanoid copepod Pseudocalanus acuspes were established at three different CO 2 partial pressures ( p CO 2 of 400, 900 and 1550 μatm) and grown for two generations at these conditions. Our results show evidence of alleviation of OA effects as a result of transgenerational effects in P. acuspes . Second generation adults showed a 29% decrease in fecundity at 900 μatm CO 2 compared to 400 μatm CO 2 . This was accompanied by a 10% increase in metabolic rate indicative of metabolic stress. Reciprocal transplant tests demonstrated that this effect was reversible and the expression of phenotypic plasticity. Furthermore, these tests showed that at a p CO 2 exceeding the natural range experienced by P. acuspes (1550 μatm), fecundity would have decreased by as much as 67% compared to at 400 μatm CO 2 as a result of this plasticity. However, transgenerational effects partly reduced OA effects so that the loss of fecundity remained at a level comparable to that at 900 μatm CO 2 . This also relieved the copepods from metabolic stress, and respiration rates were lower than at 900 μatm CO 2 . These results highlight the importance of tests for transgenerational effects to avoid overestimation of the effects of OA.