TABLE 3.

Comparison of sulfide oxidation rates for 2013 and 2014

Yr and pathway for sulfide oxidation	[H2S] (μM)	Concn of oxidant	k	Rate (nM/min)
2013
Iron oxides	4	1.5 μMa	148 M−1 min−1	0.89
Manganese oxide	4	6 μMb	436 M−1 min−1	11
Phototrophic sulfide bacteria	4	0.1 μmol m−2 s−1 PAR fluxc	0.10 min−1	400
2014
Iron oxides	10	1.5 μMa	148 M−1 min−1	2.2
Manganese oxide	10	2 μMb	436 M−1 min−1	8.72
Phototrophic sulfide bacteria	10	0.1 μmol m−2 s−1 PAR fluxc	0.075 min−1	750

^aMaximum measured concentration of Fe³⁺ at the interface.

^bMaximum measured concentration of manganese oxide at the interface.

^cLowest light intensity for which measurements of H₂S loss rates were made (Fig. 3), which is representative of light intensities measured at the interface in 2011.