Figure 1
From: Biogeochemical feedbacks to ocean acidification in a cohesive photosynthetic sediment
Photographs showing surfaces of intact cores of the subtidal silt sediment submerged in natural, recirculating seawater. The dark areas at the surface of the cores in (a) indicate the presence of pinnate diatoms. The three replicate Fourier Transform Infrared (FTIR) spectra of ground oyster shell granules in (b) indicate absorption peaks around 877 and 713 cm−1. These are due to vibrations of the carbon–oxygen double bond in the carbonate ion of calcite, confirming that the ground oyster shells are primarily composed of calcite. The cores in (c, d) received a 1-mm surface layers of (c) sterile carbonate free sand (Control) or (d) calcite (ground oyster shells; +Calcite).
