Effects of elevated CO2 partial pressure and temperature on the coccolithophore Syracosphaera pulchra

Abstract

The effects of elevated partial pressure of CO 2 (pCO 2 ) and temperature on the coccolithophore Syracosphaera pulchra were investigated in isolation and in combination. Both the diploid and the haploid life stages were studied. Batch cultures were grown under 4 conditions: 400 µatm and 19°C; 400 µatm and 22°C; 740 µatm and 19°C; and 740 µatm and 22°C. The growth rate (μ) significantly increased under elevated pCO 2 only in the haploid stage and showed a different pattern with respect to temperature: it was higher at an elevated temperature in the haploid stage at 400 µatm whereas it decreased in the diploid stage at 740 µatm. Increasing both parameters together increased the growth rate by 11% in the haploid stage only. Elevated pCO 2 had a negative impact on the content of particulate organic carbon (POC), production and cell size in both life stages at 19°C, while no significant effect was observed at 22°C. Increasing temperature significantly increased the content of POC and production in the diploid stage at 740 µatm, while at 400 µatm it significantly decreased both the content of POC and production in the haploid stage. A simultaneous increase in pCO 2 and temperature had a negative effect on the content of POC and production in the haploid stage only. Neither the rate of calcification (production of particulate inorganic carbon, PIC) nor the PIC:POC ratio were significantly affected by elevated pCO 2 , temperature or their interaction. These results showed a strong interactive effect between pCO 2 and temperature in affecting the physiology of S. pulchra, an effect that was often more pronounced in the haploid life stage. Elevated pCO 2 had a stronger effect than temperature.

High levels of solar radiation offset impacts of ocean acidification on calcifying and non-calcifying strains of Emiliania huxleyi

“…1, Table 2), in agreement with previous work on this species (e.g. Langer et al 2009, Shi et al 2009, Fiorini et al 2011, although it should be borne in mind that only constant light was employed in previous studies. Furthermore, the enhancements of elevated CO 2 on POC and PON production were higher under high solar radiation compared with low solar radiation conditions (Figs.…”

Environmental controls on coccolithophore calcification

“…Neither high temperature nor CO 2 concentration alone affected PIC, but despite a much higher abundance of coccolithophores in the high CO 2 concentration and temperature treatment, overall PIC was significantly reduced. Fiorini et al (2011b) grew Syracosphaera pulchra at 19 and 22°C and with 400 and 740 ppm CO 2 ; no significant differences in the PIC:POC ratio were found among the treatments. These experiments used realistic temperature and CO 2 values for today and later this century, and generally showed no effect of increased temperature on PIC:POC, or a decrease with increasing temperature in present, but not future, CO 2 .…”

“…The effect of the interaction of temperature and pCO 2 on calcification has been investigated by a number of authors (Feng et al 2008, De Bodt et al 2010, Borchard et al 2011, Fiorini et al 2011b, Xu et al 2011). Xu et al (2011 found that elevated temperature, within the range studied, increased photosynthesis and calcification of Emiliania huxleyi strain CS-369 at present-day seawater [Ca 2+ ], but reduced both if [Ca 2+ ] was reduced to 0.1 mM.…”

Ocean Acidification Affects Redox-Balance and Ion-Homeostasis in the Life-Cycle Stages of Emiliania huxleyi

“…In recent studies, so-called matrix approaches were used, in which the effects of OA were investigated in combination with other, independently varied parameters like light, temperature, or nutrients [18]–[21]. These studies revealed that the effects of OA on different physiological parameters vary significantly, depending on the constellation of framing environmental parameters, which directly or indirectly relate to cellular energy state (Fig.…”