What are the consequences of adaptation to elevated pCO2 in the
polychaete Ophryotrocha labronica?
A. Rodríguez- Romero 1*, M. Jarrold 2, G. Massamba-N’Siala3, J. Spicer 2. P. Calosi 2
1
Departamento de Ecología y Gestión Costera. Instituto de Ciencias Marinas de Andalucía
(CSIC). Campus Río San Pedro. 11510 Puerto Real (Cádiz). Spain.
2
Marine Biology and Ecology Research Centre, Faculty of Science, University of Plymouth,
Drake Circus, Plymouth, Devon PL4 8AA, UK.
3
Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia,
via Campi 213/D - 41125 Modena, Italy.
*
Presenting author contact: araceli.rodriguezromero@icman.csic.es
Current global climate change is occurring at an unprecedented rate due to increasing
anthropogenic carbon dioxide (CO2) emissions. Consequently, significant alterations in
oceanic conditions are predicted over the next century, including a reduction in surface water
pH by 0.3-0.4 units (termed Ocean Acidification ‘OA’).OA represents an unprecedented
hazard to marine ecosystems, having the potential to lower organisms’ performance, fitness
and ultimately impact ecosystem biodiversity and function. One of the major challenges is to
understand the responses of marine ectotherms to such a rapid change; a key question is
whether species can adapt fast enough to prevent local population and species extinctions,
of which currently little is known.
We investigate the developmental, life-history and physiological responses to OA in the F1
generation of the marine polychaete,Ophryotrochalabronica. Individuals were sourced from a
laboratory population kept for over four years under variable and elevated pCO2 conditions,
and exposed to seawater at two different pCO2treatments: ambient -395 μatm (pH 8.03) and
elevated -1068 μatm (pH 7.78). Survival and growth rates were recorded through offspring
development until they reached maturity. In addition, once individuals reached maturity, new
pairs were formed to assess fecundity, time interval between spawns and egg size, as well
as survival rates, metabolic rates and upper thermal tolerance.
Fecundity was significantly greater in the elevated pCO2 treatment, whilst for all other traits
there was no significant effect of pCO2. Greater fecundity in the elevated pCO2but with no
difference either in time interval between spawns, or egg size between treatments, suggests
there was no trade-off in egg quality. Additionally, the fact physiological responses did not
differ between treatments could be interpreted as the lower fecundity in the control treatment
was a result of change in energy partitioning, with more energy invested into general
maintenance.
Overall, these results show evidence of decreased fitness in control conditions and could be
interpreted as the worms used already being adapted to elevated pCO2.Our perhaps
unexpected results have the potential to improve our understanding of the consequences
and implications of adaptation to elevated pCO2 conditions in marine ectotherms.