Physiological responses of three temperate coralline algae from contrasting habitats to near-future ocean acidification

Abstract

International audienceCoralline algae are major calcifiers of significant ecological importance in marine habitats but are among the most sensitive calcifying organisms to ocean acidification. The elevated pCO(2) effects were examined in three coralline algal species living in contrasting habitats from intertidal to subtidal zones on the north-western coast of Brittany, France: (i) Corallina elongata, a branched alga found in tidal rock pools, (ii) Lithophyllum incrustans, a crustose coralline alga from the low intertidal zone, and (iii) Lithothamnion corallioides (maerl), a free-living form inhabiting the subtidal zone. Metabolic rates were assessed on specimens grown for one month at varying pCO(2): 380 (current pCO(2)), 550, 750 and 1000 mu atm (elevated pCO(2)). There was no pCO(2) effect on gross production in C. elongata and L. incrustans but L. incrustans respiration strongly increased with elevated pCO(2). L corallioides gross production slightly increased at 1000 mu atm, while respiration remained unaffected. Calcification rates decreased with pCO(2) in L. incrustans (both in the light and dark) and L. corallioides (only in the light), while C. elongata calcification was unaffected. This was consistent with the lower skeletal mMg/Ca ratio of C. elongata (0.17) relative to the two other species (0.20). L. incrustans had a higher occurrence of bleaching that increased with increasing pCO(2). pCO(2) could indirectly impact this coralline species physiology making them more sensitive to other stresses such as diseases or pathogens. These results underlined that the physiological response of coralline algae to near-future ocean acidification is species-specific and that species experiencing naturally strong pH variations were not necessarily more resistant to elevated pCO(2) than species from more stable environment. (C) 2013 Elsevier B.V. All rights reserved

Pacific-wide contrast highlights resistance of reef calcifiers to ocean acidification

“…At local scale, coralline algae experiencing naturally diel pH variations are acclimatized to variable pH [29], and some temperate species found in habitats exposed to large pH changes (i.e. tidal pools) are more resistant to OA than species living in habitats characterized by more stable pH [28]. However, more pronounced negative effects of OA were found on the temperate coralline alga Arthrocardia corymbosa exposed to fluctuating pH [53], which suggests a limit to the capacity of coralline algae to acclimatize to OA.…”

There is more to maerl than meets the eye: DNA barcoding reveals a new species in Britain,Lithothamnion erinaceumsp. nov. (Hapalidiales, Rhodophyta)

“…This has led to predictions that calcified macroalgae will be impacted by future global change (Brodie et al, 2014). However, the effect of climate change is species-specific (Ries et al, 2009, ;Noisette et al, 2013) and some species have shown evidence of acclimation to future CO2 conditions (Ragazzola et al, 2013).…”

Rhodoliths in Brazil: Current knowledge and potential impacts of climate change

“…KUFFNER et al, 2008;SEMESI et al, 2009;NOISETTE et al, 2013;JOHNSON et al, 2014), but also in photosynthesis (e.g. ANTHONY et al, 2008;CARPENTER, 2012;COMEAU et al, 2012;JOHNSON et al, 2014;KATO et al, 2014;TAIT, 2014), cell wall thickness (RAGAZZOLA et al, 2012;RAGAZZOLA, 2014b), reproduction (CUMANI et al, 2010), recruitment , and survivorship (DIAZ-PULIDO et al, 2012).…”

“…CARPENTER, 2012;MARTIN et al, 2013;NOISETTE et al, 2013;COMEAU et al, 2014) and light conditions (GAO;ZHENG, 2010;COMEAU et al, 2014), or local factors, such as nutrient concentration (RUSSELL et al, 2009;STENGEL et al, 2014). Besides a variety of studies investigating the OA response in coralline algae, only a few studies have been performed on the effect of the increase in seawater temperature and possible synergistic effects of ocean warming and acidification (see Figure 6B).…”