Effect of Elevated Carbon Dioxide on Two Scleractinian Corals: Porites cylindrica (Dana, 1846) and Galaxea fascicularis (Linnaeus, 1767)

Table 2

Chlorophyll pigments, zooxanthellae cell density, and mitotic index of P. cylindrica and G. fascicularis (mean ± standard deviation) under control and elevated pCO₂. Each reading was based on six coral nubbins analysed at the end of the experiment. Pair 𝑡-test was conducted to compare the parameters under control and elevated pCO₂. Bolded figures indicate a significant different and vice versa.

	P. cylindrica			G. fascicularis
	Control	Elevated pCO2	𝑃	Control	Elevated pCO2	𝑃
Chlorophyll-a (𝜇g 10^6 cell^-1)	8.25 ± 2.37	12.47 ± 6.28	.088	6.75 ± 1.61	12.51 ± 0.59	.016
Chlorophyll-b (𝜇g 10^6 cell^-1)	10.65 ± 4.25	11.58 ± 5.95	.386	3.50 ± 1.11	13.08 ± 0.63	.004
Chlorophyll-c (𝜇g 10^6 cell^-1)	9.70 ± 3.96	14.25 ± 7.77	.109	1.64 ± 0.62	18.79 ± 8.89	.006
Zooxanthellae cell density (× 10^6 cells cm^-2)	1.58 ± 0.18	1.09 ± 0.56	.043	2.90 ± 1.08	0.87 ± 0.21	.002
Mitotic index (%)	2.69 ± 1.30	0.95 ± 0.68	.010	5.18 ± 1.46	6.47 ± 3.01	.322