Editor's Summary

24 June 2010

Ocean nitrates on the up


Seasonal (spring and summer) depletion of dissolved inorganic carbon occurs in the surface mixed layers of most of the unproductive or oligotrophic regions of the world's oceans. The missing dissolved inorganic carbon is thought to be converted to particulate carbon by photosynthesis, yet there are seemingly insufficient dissolved nutrients present to support the required amount of plant growth. A possible nutrient supply mechanism has now been identified in a study in the North Pacific. Short-lived transport events — lasting less than 10 days — connect the nutrient-poor surface waters with deep-water stocks of dissolved nitrates. When the water column from the surface to a depth of 250 metres is considered as a whole, there is near equivalence in nutrient supply and demand.

LetterNitrate supply from deep to near-surface waters of the North Pacific subtropical gyre

Kenneth S. Johnson, Stephen C. Riser & David M. Karl

doi:10.1038/nature09170