The atmospheric and deep sea reservoirs of carbon dioxide are linked via physical, chemical, and biological processes. The last of these include photosynthesis, particle settling, and organic matter remineralization, and are collectively termed the “biological carbon pump.” Herein, we present results from a 13-y (1992–2004) sediment trap experiment conducted in the permanently oligotrophic North Pacific Subtropical Gyre that document a large, rapid, and predictable summertime pulse in particulate matter export to the deep sea (4,000 m).

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.