Reference
Pahlow, M. and Riebesell, U. 2000. Temporal trends in deep ocean Redfield ratios. Science 287: 831-833.
What was done
The authors analyzed open-ocean deep-water nutrient and oxygen data for differences between measurements taken at approximately the same places but at different times. Data were obtained for 1173 stations at 447 locations, covering the years 1947 to 1994. Mean results were determined for the North and South Atlantic and the North and South Pacific.
What was learned
Little differences were noted in either the South Atlantic or the South Pacific over the five decades for which data were analyzed. In the North Atlantic and North Pacific, however, there were significant temporal trends indicative of increasing biological production in their surface waters and its subsequent exportation to the deep-water basins of those oceans.
What it means
In the words of the authors, "the biological part of the marine carbon cycle currently is not in steady state." Indeed, according to their results, the biological productivities of the North Atlantic and North Pacific have been steadily increasing over the past half-century, as increasingly greater amounts of carbon have been exported to the deep waters of their basins. Hence, as ever more carbon is being injected into the atmosphere by anthropogenic activities on land, ever more carbon is being sequestered by biological activities in the oceans.
Reviewed 1 March 2000