Focus |

Marine iron cycling

Iron is a vital micronutrient in the marine environment, and variations in the supply and transformation of this element can alter ocean productivity. In this web focus, we present a collection of articles that examine the modern marine iron cycle and assess how iron cycling has varied through time.

Content

Iron is an essential fuel for life in the oceans. The influence of this element on biogeochemistry — and nitrogen cycling in particular — varies across environments and time.

Editorial | | Nature Geoscience

The recent expansion of observational data has changed our understanding of the ocean iron cycle and its linkages with nutrients such as carbon and nitrogen.

Review Article | | Nature

Dust-borne nutrients can enhance productivity in the surface ocean. Two years of sediment trap data reveal that dust enhances carbon export to depth by increasing surface nitrogen fixation, productivity and carbon sinking rates in the North Atlantic.

Article | | Nature Geoscience

Atmospheric oxygen was maintained at low levels throughout huge swathes of Earth's early history. Estimates of phosphorus availability through time suggest that scavenging from anoxic, iron-rich oceans stabilized this low-oxygen world.

News & Views | | Nature Geoscience

Dissolved iron is mysteriously pervasive in deep ocean hydrothermal plumes. An analysis of gas, metals and particles from a 4,000 km plume transect suggests that dissolved iron is maintained by rapid and reversible exchanges with sinking particles.

News & Views | | Nature Geoscience

From the archives

Volcanic eruptions at ocean ridges produce large volumes of glass that is rapidly leached by seawater. Geochemical calculations suggest that this process helps to explain the deposition of carbonates at the end of extreme ice ages.

News & Views | | Nature Geoscience

Bioavailable iron is released from anoxic sediments, such as those that underlie the Peruvian upwelling zone. Analyses of iron levels in sediments from this region suggest that iron release occurs in a relatively narrow range of redox conditions, and that the amount of iron released to the upwelling waters has varied over the past 140,000 years.

Letter | | Nature Geoscience

Marine sediments deposited beneath the eastern Pacific upwelling margin are a substantial sink for silica. The geochemistry of these sediments suggests that periods of intense upwelling result in iron limitation, which enhances the export of silica from the surface to the deep ocean and sediments.

Article | | Nature Geoscience