Can trans‐generational experiments be used to enhance species resilience to ocean warming and acidification?

Abstract

Human‐assisted, trans‐generational exposure to ocean warming and acidification has been proposed as a conservation and/or restoration tool to produce resilient offspring. To improve our understanding of the need for and the efficacy of this approach, we characterized life‐history and physiological responses in offspring of the marine polychaete Ophryotrocha labronica exposed to predicted ocean warming (OW: + 3°C), ocean acidification (OA: pH −0.5) and their combination (OWA: + 3°C, pH −0.5), following the exposure of their parents to either control conditions (within‐generational exposure) or the same conditions (trans‐generational exposure). Trans‐generational exposure to OW fully alleviated the negative effects of within‐generational exposure to OW on fecundity and egg volume and was accompanied by increased metabolic activity. While within‐generational exposure to OA reduced juvenile growth rates and egg volume, trans‐generational exposure alleviated the former but could not restore the latter. Surprisingly, exposure to OWA had no negative impacts within‐ or trans‐generationally. Our results highlight the potential for trans‐generational laboratory experiments in producing offspring that are resilient to OW and OA. However, trans‐generational exposure does not always appear to improve traits and therefore may not be a universally useful tool for all species in the face of global change.

Can multi-generational exposure to ocean warming and acidification lead to the adaptation of life-history and physiology in a marine metazoan?

“…The effects of parental conditioning are not confined to vertebrates; parental exposure to acidification (+1150 µatm P CO2 ) halved the reduction in fecundity caused by acute exposure to the same conditions in offspring of the copepod Pseudocalanus acuspes (Thor and Dupont, 2015), while parental exposure to ocean warming and acidification (+2°C and +400 µatm P CO2 ) reduced the negative effects of acute exposure on larval size in the coral Pocillopora damicornis . However, parental and acute exposure to combined global change drivers does not always affect the progeny, despite the negative effects of singlestressor exposure, as shown recently in the marine polychaete Ophryotroca labronica (Chakravarti et al, 2016).…”

“…100 worms) was collected from a single site in Porto Empedocle harbor (Sicily, Italy: 37°17′N, 13°3 1′E) in January 2014 (Chakravarti et al, 2016). The culture was transferred to the Marine Evolutionary Physiology (MEP) laboratory at the Université du Québec à Rimouski (Canada), where it was kept for eight generations under control conditions (temperature 27°C, pH 8, salinity 35, 12 h light:12 h dark), selected to maximize reproductive output (Åkesson, 1970).…”

“…Here, we describe the effects of multi-generational exposure to ocean warming and acidification on the life-history and physiological response of an emerging model organism for evolutionary studies in the marine realm, O. labronica (Massamba N'Siala et al, 2014;Rodríguez-Romero et al, 2016;Chakravarti et al, 2016). This study is an extension of the transgenerational experiment conducted by Chakravarti et al (2016), who exposed O. labronica to control (27°C, pH 8), ocean warming (+3°C) and ocean acidification (−0.4 pH units) scenarios in isolation and in combination over two generations.…”

“…This study is an extension of the transgenerational experiment conducted by Chakravarti et al (2016), who exposed O. labronica to control (27°C, pH 8), ocean warming (+3°C) and ocean acidification (−0.4 pH units) scenarios in isolation and in combination over two generations. We followed these individuals for a further five generations, measuring a suite of life-history ( juvenile developmental rate, juvenile survival to sexual maturity, average reproductive body size and fecundity) and physiological (cellular reactive oxygen species content, mitochondrial density and capacity) traits in each generation.…”

Warm-preconditioning protects against acute heat-induced respiratory dysfunction and delays bleaching in a symbiotic sea anemone

“…Thermal preconditioning in marine ectotherms often involves altered carbohydrate metabolism and aerobic respiration (Sokolova and Pörtner, 2003;Sommer and Pörtner, 2004;Kraffe et al, 2007;Pörtner et al, 2007;Oellermann et al, 2012;Chung and Schulte, 2015), notably through the regulation of mitochondrial function (Somero and Hochachka, 2002). For example, increasing mitochondrial density and aerobic capacity is a common adaptive response to cold conditions ( polychaetes: Sommer and Pörtner, 1999;polar marine invertebrates: Pörtner, 2001;Peck, 2002;Pörtner et al, 2007), while warm acclimation often correlates with decreased mitochondrial density/aerobic capacity (rainbow trout: Kraffe et al, 2007; polychaetes: Chakravarti et al, 2016) and reduced sensitivity to short-term heating (killifish: Chung and Schulte, 2015). Warm preconditioning in corals may occur through similar processes.…”