Photochemical degradation of dissolved organic carbon and its impact on the oceanic carbon cycle

  title={Photochemical degradation of dissolved organic carbon and its impact on the oceanic carbon cycle},
  author={K William Mopper and Xianliang Zhou and Robert J. Kieber and David J. Kieber and Richard J. Sikorski and Ronald D. Jones},
THE processes that regulate the cycling of oceanic dissolved organic carbon (DOC), one of the largest carbon reservoirs on the Earth's surface1, are largely unknown. DOC residues in the deep sea, below 500 m, seem to be composed mainly of biologically refractory compounds2–10 such as humic substances11. The average apparent 14C age of this refractory DOC is >6,000 yr in the deep Pacific2, suggesting that its rate of turnover is slow, but the pathways and rates responsible for this apparent slow… 

Photochemical reactivity of ancient marine dissolved organic carbon

Marine dissolved organic carbon (DOC) is the largest reservoir of reduced carbon in seawater and persists up to 4,000–6,000 conventional radiocarbon (14C) years on average. Photochemical degradation

Mixing it up in the ocean carbon cycle and the removal of refractory dissolved organic carbon

The results suggest that while refractory molecules can persist in the ocean for millennia, removal is rapid when they encounter their fate, and the observed and projected climate-induced slowdown of global overturning circulation could reduce the exposure of refraction molecules to disparate removal processes.

Extraordinary slow degradation of dissolved organic carbon (DOC) in a cold marginal sea

It is shown that high concentrations of DOC are maintained almost constantly over 100 years in the entire deep East/Japan Sea (EJS), suggesting that the storage capacity of DOC in the world ocean is very sensitive to global warming and slowdown of global deep-water overturning.

Formation of carbon monoxide by photolysis of dissolved marine organic material and its significance in the carbon cycling of the oceans

The importance of carbon monoxide (CO) as a major sink for the OH radical in the atmosphere is well established [1]. However, comparatively little is known about its role in the world oceans. In

Revisiting the disappearance of terrestrial dissolved organic matter in the ocean: a δ 13 C study

Organic carbon (OC) depleted in 13 C is a widely used tracer for terrestrial organic matter (OM) in aquatic systems. Photochemical reactions can, however, change δ 13 C of dissolved organic carbon

Efficient export of carbon to the deep ocean through dissolved organic matter

This work finds that DOM is remineralized and produced with a C:N:P stoichiometry of 199:20:1 that is substantially lower than for bulk pools, but greater than for particulate organic matter, which may contribute to the excess respiration estimated to occur in the interior ocean.

Removal of Refractory Dissolved Organic Carbon in the Amundsen Sea, Antarctica

It is shown that deep-DOC is consumed along with fresh-DOC in the Amundsen Sea Polynya, implying that water circulation through the surface layer, where fresh- DOC is produced, may play an important role in global DOC cycling.

Natural abundance radiocarbon studies of dissolved organic carbon (DOC) in the marine environment

Marine dissolved organic carbon (DOC), an active reservoir in the global carbon cycle, has an average age of 6000 years and is comprised of biochemicals which may or may not cycle on different time



Photochemical source of biological substrates in sea water: implications for carbon cycling

DISSOLVED organic carbon (DOC) in sea water represents one of the largest reservoirs of carbon on the earth1. The main fraction of this DOC is generally believed to be composed of old2, biologi-cally

Radiocarbon in dissolved organic matter in the central North Pacific Ocean

The origin of dissolved organic carbon (DOC) in the ocean has been long debated. Whereas Mantoura and Woodward1 have used the conservative nature of DOC in a British estuary to conclude that ≥50% of

Concentrations and radiocarbon signatures of dissolved organic matter in the Pacific Ocean

We present evidence suggesting that only a portion of the dissolved organic carbon (DOC) in the seawater analyzed previously by Williams and Druffel (1987) was oxidized by the UV-radiation method.

Dissolved Organic Carbon from Deep Waters resists Microbial Oxidation

It is shown that the dissolved organic carbon (DOC) content of deep water is relatively constant over a wide range of depths and throughout many regions of the world's oceans.

Bacterial utilisation of organic matter in the deep sea

The aim of the work reported here was to determine the growth rate of a heterotrophic, low nutrient bacterium isolated from seawater collected at a depth of 2,000 m in the north-central Pacific Ocean, and to equate this growth rate with O2 consumption and utilisation of DOC.

Molecular evidence for a terrestrial component of organic matter dissolved in ocean water

Dissolved organic matter (DOM) in seawater represents one of the largest active carbon reservoirs on Earth1. Although mass-balance calculations suggest a substantial riverine input to the marine DOM

Hydroxyl radical photoproduction in the sea and its potential impact on marine processes.

Photochemical production rates and steady-state concentrations of hydroxyl radicals (.OH) were measured in sunlight-irradiated seawater, finding that DOM in the deep sea is degraded more readily by .OH (and its daughter radicals), than is DOM in open-ocean surface water.