A Cryptic Sulfur Cycle in Oxygen-Minimum–Zone Waters off the Chilean Coast

By D. Canfield, Frank Stewart, B. Thamdrup, L. de Brabandere, T. Dalsgaard, E. Delong, Niels Peter Revsbech, O. Ulloa. Science, 2010

613 citations recorded by the source corpus.

Cryptic Sulfur Cycling Aerobic bacteria and ocean circulation patterns control the formation and distribution of oxygen-minimum zones at moderate depth in the oceans. These habitats host microorganisms that thrive on other metabolic substrates in the absence of oxygen—most commonly, metabolizing thermodynamically favorable nitrogen compounds like nitrate. Off the coast of Chile, however, Canfield et al. (p. 1375, published online 11 November; see the Perspective by Teske) suggest that bacteria may often reduce sulfate as well. Metagenomic sequencing revealed the presence of both sulfate-reducing and sulfide-oxidizing bacteria. With the coincidence of sulfate and nitrate reduction, the sulfur and nitrogen cycles may be intimately linked; for example, sulfate reduction could provide nitrogen-rich ammonium for bacteria that ultimately transform it into nitrogen gas. Bacterial sulfur reduction and oxidation accompanies nitrogen cycling where oxygen levels at depth are low. Nitrogen cycling is normally thought to dominate the biogeochemistry and microbial ecology of oxygen-minimum zones in marine environments. Through a combination of molecular techniques and process rate measurements, we showed that both sulfate reduction and sulfide oxidation contribute to energy flux and elemental cycling in oxygen-free waters off the coast of northern Chile. These processes may have been overlooked because in nature, the sulfide produced by sulfate reduction immediately oxidizes back to sulfate. This cryptic sulfur cycle is linked to anammox and other nitrogen cycling processes, suggesting that it may influence biogeochemical cycling in the global ocean.

Subfields: Oceanography

View Paper: https://www.semanticscholar.org/paper/6978ecc3afce6732b8c5f6ed6005624b72d4b957

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Oceanography

Citations in the corpus

Widespread functional anoxia in the oxygen minimum zone of the Eastern South Pacific (2012, methodology): “In the deployment off Chile, the detection limit was 30 nmol kg 1 due to a slow response time of the measuring circuit, which prevented the signal from stabilizing during the cycles of front-guard polarization.”
Oxygen distribution and aerobic respiration in the north and south eastern tropical Pacific oxygen minimum zones (2014, background): “There are, however, also indications that the thermodynamically most feasible reactions may coexist with alternative reactions with less energy efficiency such as the occurrence of sulfate reduction in high-nitrate waters (Canfield et al., 2010).”
Anammox and denitrification in the oxygen minimum zone of the eastern South Pacific (2012, background): “While all of these processes have been shown to be active in the ETSP OMZ, their activity was not sufficient to cover the ammonium demand of anammox at the measured rates and stoichiometries (Thamdrup et al. 2006; Lam et al. 2009; Canfield et al. 2010).”
Exploring nucleo-cytoplasmic large DNA viruses in Tara Oceans microbial metagenomes (2013, background): “An example of co-excluding taxa was a relationship between Prochlorococcus, existing in the euphotic zone, and sulfur-oxidizing symbionts, a lineage of g-Proteobacteria known to have an important role in sulfur-oxidizing microbial communities in deeper aphotic OMZs (q¼ 0.011; Canfield et al., 2010; ”