Degradation of Terrigenous Dissolved Organic Carbon in the Western Arctic Ocean
Dennis A. Hansell,1*
David Kadko,1
Nicholas R. Bates2
The largest flux of terrigenous organic carbon into the ocean
occurs in dissolved form by way of rivers. The fate of this
material is enigmatic; there are numerous reports of conservative
behavior over continental shelves, but the only knowledge we
have about removal is that it occurs on long unknown time scales
in the deep ocean. To investigate the removal process, we evaluated
terrigenous dissolved organic carbon concentration gradients
in the Beaufort Gyre of the western Arctic Ocean, which allowed
us to observe the carbon's slow degradation. Using isotopic
tracers of water-mass age, we determined that terrigenous dissolved
organic carbon is mineralized with a half-life of 7.1 ±
3.0 years, thus allowing only 21 to 32% of it to be exported
to the North Atlantic Ocean.
2 Bermuda Biological Station for Research, 17 Biological Lane, Ferry Reach, St. George's GE-01, Bermuda.
* To whom correspondence should be addressed. E-mail: dhansell{at}rsmas.miami.edu
