Table 1. Most parsimonious GAM models for intracellular DMSP (DMSPi) for Padina sp., Amphiroa sp. and Turbinaria sp. and water column DMSP on the reef crest and flat at Suleman Reef, Egypt.

Location	Sample	GAM formula	Est. df	GCV score	Adj. R2	Dev. exp. (%)
Crest	Padina	DMSPi ∼ s(TA)+s(DO)	6.92	0.084	0.64	66.4
	Amphiroa	DMSPi ∼ s(TA)+s(Temp:TA)	5.16	0.074	0.278	31.3
	Turbinaria	DMSPi ∼ s(DO)+s(DO:DIC)	4.00	0.150	0.536	56.2
	Water column	DMSPt ∼ s(ΩCa)	2.57	0.009	0.169	27
Flat	Padina	DMSPi ∼ s(TA)+s(TA:ΩCa)	5.02	0.100	0.408	43.7
	Amphiroa	DMSPi ∼ s(Temp)+s(ΩCa)+s(pCO2)	5.99	0.034	0.739	75.4
	Water column	DMSPt ∼ s(DO)+s(pH)	3.98	0.005	0.745	80.9

Statistics presented: estimated degrees of freedom (Est. df), GCV score, Adjusted R² (Adj. R²), % deviance explained (Dev. exp.).

TA: Total alkalinity, DO: dissolved oxygen, Temp: water temperature, DIC: dissolved inorganic carbon, ΩCa: calcite saturation state, pCO₂: partial pressure of CO₂.