Sulfate (SO42-) reduction is a major SO42- output flux from Earth’s
oceans, but an imbalance between recent estimates of this flux and
corresponding input fluxes suggests inaccuracy in our understanding.
Here, we combine global geographic trends in aqueous and dissolved-phase
sedimentary data to resolve this inaccuracy. [SO42-] profiles from
700+ sites partition into geographically-distinct k-means clusters based
on net sulfate reduction rate (nSRR). Pairing nSRRs with
literature-derived pyrite accumulation rates confirms that shelf and
slope pyrite burial dominate burial globally. Our results also suggest
that sampling and measurement biases have led to erroneously high prior
global output estimates and can account for the flux imbalance.
Disparate mean d34S values for shelf versus deeper ocean pyrite indicate
that sea level change may be an overlooked mechanism for forcing past
changes in seawater d34S.