New Perspectives on the Marine Carbon Cycle-The Marine Dissolved Organic Matter Reactivity Continuum

Environ Sci Technol. 2022 May 3;56(9):5371-5380. doi: 10.1021/acs.est.1c08871. Epub 2022 Apr 20.

Abstract

This perspective challenges our current understanding of the marine carbon cycle, including an alternative explanation of bulk 14C-DOM measurements. We propose the adoption of the carbon reactivity continuum concept previously established for lakes and sediments for the oceans using kinetic data and term this the marine DOM reactivity continuum. We need to gain a fundamental understanding of the biogeochemical drivers of surface water DOM concentrations and reactivity, biological carbon pump efficiency, and the autotrophic communities that are the ultimate but variable sources of marine DOM. This perspective is intended to shift our focus to a more inclusive kinetic model and may lead us to a more accurate assessment of the active and dynamic role marine DOM plays in the global carbon cycle. Currently, the kinetic data to establish and validate such a marine DOM reactivity continuum model are still lacking, and their resolution depends on the discovery of new organic tracers that span large differences in reactivity and microbial degradation rates. We may need to refocus our efforts in deciphering the structure and reactivity of marine organic molecules in a kinetic context, including the microbial and physicochemical constraints on molecular reactivity that are present in the deep ocean.

Keywords: kinetic model; marine DOM; organic tracers; reactivity continuum.

Publication types

  • Review

MeSH terms

  • Carbon
  • Carbon Cycle*
  • Dissolved Organic Matter*
  • Kinetics
  • Membrane Transport Proteins

Substances

  • Dissolved Organic Matter
  • Membrane Transport Proteins
  • Carbon