Fig 1.
Median pHT and saturation state of aragonite (ΩAr) from the 88 settlement tiles.
Median n = 8 pH and 5 ΩAr measures per tile. White points are from Upa-Upasina, grey are from Dobu. Error bars are standard errors.
Fig 2.
Settlement tiles from control sites (a, b and c) and volcanic CO2 seep sites (d, e and f) in Papua New Guinea after 13 months deployment. Tiles in situ (a and d), upper sides (b and e), and lower sides (c and f).
Table 1.
Changes in percent cover of the main benthic taxonomic and functional categories, in response to pHT (median per tile), Reef (contrasting Dobu against Upa-Upasina) and Time (contrasting 13 against five months of deployment).
Fig 3.
Shifts in settlement tile community composition along the pH gradients.
Percent cover of non-calcifying algae on the upper (a) and lower (b) settlement tile sides, Peyssonnelia spp. from the upper (c) and lower (d) sides, and crustose coralline algae (CCA) from the upper (e) and lower (f) sides in relation to pHT. Left and right panels per plot represent the five and 13 month old communities, respectively. White points are tiles from Upa-Upasina and grey are from Dobu. The black lines represent the modelled means, while the grey lines are confidence intervals.
Fig 4.
Redundancy analysis ordination of the settlement tile benthic communities at the seep and control sites.
Red points represent tiles from the seeps, and blue from the controls, of Dobu and Upa-Upasina Reefs. Points in the upper polygon are five month (mths) old communities, while those in the lower polygon are at 13 months.
Fig 5.
Metabolic rates from benthic communities on settlement tiles across the seawater carbon chemistry gradients.
Rates of gross photosynthesis (a), respiration (b) and net daily production (c) in 13 month old communities are plotted against the median pHT from the tiles. Gross photosynthesis and respiration are displayed in μg O2 cm-2 hr-1, and daily net production in μg O2 cm-2 day-1. Rates of light (d), dark (e) and net daily calcification (f) are plotted against tile median aragonite saturation state (ΩAr) from the tiles. Light and dark calcification rates are displayed in μg CaCO3 cm-2 hr-1, and daily net calcification in μg CaCO3 cm-2 day-1. White points are from Upa-Upasina and grey are from Dobu. The black lines represent the modelled mean, while the grey lines are confidence intervals.
Table 2.
Changes in community metabolism in response to median pH (gross photosynthesis; respiration) or the saturation state of aragonite (ΩAr: Calcification) and Reef (contrasting Dobu against Upa-Upasina).