TY - JOUR

T1 - Resilience to temperature and pH changes in a future climate change scenario in six strains of the polar diatom Fragilariopsis cylindrus

AU - Pančić, Marina

AU - Hansen, Per Juel

AU - Tammilehto, Anna

AU - Lundholm, Nina

PY - 2015

Y1 - 2015

N2 - Abstract. The effects of ocean acidification and increasedtemperature on physiology of six strains of the polar diatomFragilariopsis cylindrus from Greenland were investigated.Experiments were performed under manipulated pH levels(8.0, 7.7, 7.4, and 7.1) and different temperatures (1, 5, and8 C) to simulate changes from present to plausible futurelevels. Each of the 12 scenarios was run for 7 days, and a significantinteraction between temperature and pH on growthwas detected. By combining increased temperature and acidification,the two factors counterbalanced each other, andtherefore no effect on the growth rates was found. However,the growth rates increased with elevated temperaturesby 20–50% depending on the strain. In addition, a generalnegative effect of increasing acidification on growth was observed.At pH 7.7 and 7.4, the growth response varied considerablyamong strains. However, a more uniform response wasdetected at pH 7.1 with most of the strains exhibiting reducedgrowth rates by 20–37% compared to pH 8.0. It should beemphasized that a significant interaction between temperatureand pH was found, meaning that the combination of thetwo parameters affected growth differently than when consideringone at a time. Based on these results, we anticipatethat the polar diatom F. cylindrus will be unaffected bychanges in temperature and pH within the range expected bythe end of the century. In each simulated scenario, the variationin growth rates among the strains was larger than thevariation observed due to the whole range of changes in eitherpH or temperature. Climate change may therefore notaffect the species as such, but may lead to changes in thepopulation structure of the species, with the strains exhibitinghigh phenotypic plasticity, in terms of temperature andpH tolerance towards future conditions, dominating the population.

AB - Abstract. The effects of ocean acidification and increasedtemperature on physiology of six strains of the polar diatomFragilariopsis cylindrus from Greenland were investigated.Experiments were performed under manipulated pH levels(8.0, 7.7, 7.4, and 7.1) and different temperatures (1, 5, and8 C) to simulate changes from present to plausible futurelevels. Each of the 12 scenarios was run for 7 days, and a significantinteraction between temperature and pH on growthwas detected. By combining increased temperature and acidification,the two factors counterbalanced each other, andtherefore no effect on the growth rates was found. However,the growth rates increased with elevated temperaturesby 20–50% depending on the strain. In addition, a generalnegative effect of increasing acidification on growth was observed.At pH 7.7 and 7.4, the growth response varied considerablyamong strains. However, a more uniform response wasdetected at pH 7.1 with most of the strains exhibiting reducedgrowth rates by 20–37% compared to pH 8.0. It should beemphasized that a significant interaction between temperatureand pH was found, meaning that the combination of thetwo parameters affected growth differently than when consideringone at a time. Based on these results, we anticipatethat the polar diatom F. cylindrus will be unaffected bychanges in temperature and pH within the range expected bythe end of the century. In each simulated scenario, the variationin growth rates among the strains was larger than thevariation observed due to the whole range of changes in eitherpH or temperature. Climate change may therefore notaffect the species as such, but may lead to changes in thepopulation structure of the species, with the strains exhibitinghigh phenotypic plasticity, in terms of temperature andpH tolerance towards future conditions, dominating the population.

U2 - 10.5194/bg-12-4235-2015

DO - 10.5194/bg-12-4235-2015

M3 - Journal article

VL - 12

SP - 4235

EP - 4244

JO - Biogeosciences

JF - Biogeosciences

SN - 1726-4170

M1 - 12

ER -