Organism/System Summary of findings Reference
Calcifying Algae
Crustose coralline algae (unidentified species)

Manipulation: Acid addition
Duration: 7 weeks
Design: Outdoor continuous-flow mesocosms: control at ambient reef pCO2 (average 380 ppm), others manipulated to ambient + 365 ppm. Recruitment and growth of crustose coralline algae were measured on clear acrylic cylinders after 7 weeks in control and manipulated flumes.
Results: Under high CO2 conditions, CCA recruitment rate decreased by 78% and percentage cover decreased 92% relative to ambient; non-calcifying algae percent cover increased by 52% relative to ambient.

Kuffner et al., 2008
 
Rhodoliths of mixed crustose coralline algae including Lithophyllum cf. pallescens, Hydrolithon sp. and Porolithon sp. Manipulation: Acid addition
Duration: 9 months
Design: Outdoor continuous-flow mesocosms: control at ambient reef pCO2 (average 380 ppm), others manipulated to ambient + 365 ppm. Rhodolith growth was measured with buoyant weighing. Results: Rhodolith growth in control mesocosms was 250% lower than those in acidified mesocosms; that is, they experienced net dissolution.
Jokiel et al., 2008
 
Porolithon onkodes Manipulation: Bubbled CO2
Duration: 8 weeks
Design: Algae placed in flow-through aquaria: 2 temperatures: 25–26°C and 28–29°C; 3 pH levels: 8. 0–8.4 (control) 7.85–7.95 and 7.60–7.70.
Results: P. onkodes calcification rate in low pH treatment was 130% less (25–26°C) and 190% less (28–29°C) than in control (i.e., net dissolution).
Anthony et al., 2008


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