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Marine Sources of Halocarbons

Oceanography

  1. Robert M. Moore

Published Online: 15 JUL 2005

DOI: 10.1002/047147844X.oc1708

Water Encyclopedia

Water Encyclopedia

How to Cite

Moore, R. M. 2005. Marine Sources of Halocarbons. Water Encyclopedia. 4:149–151.

Author Information

  1. Dalhousie University, Halifax, Nova Scotia, Canada

Publication History

  1. Published Online: 15 JUL 2005

Abstract

Halogens, particularly chlorine and bromine, are important in the atmosphere as catalysts for destruction of stratospheric ozone. The oceans are a major reservoir of dissolved halogens and act as a supply to the atmosphere through the production of sea salt aerosols and organic trace gases. The latter, having in many cases much longer lifetimes in the atmosphere than sea salt particles, are able to mix to high altitude and, on photolysis, release halogen radicals. Organoiodine compounds, notably methyl iodide, have marine sources but, on account of their short atmospheric lifetime, normally release iodine at lower elevations. Nevertheless, the transport of marine-produced methyl iodide in the atmosphere represents an important source of this biologically essential element to the continents. Marine macrophytes are well established as sources of numerous halogenated gases, and marine phytoplankton are known to be significant sources of bromoform and dibromomethane. While the fluxes of methyl halides between the ocean and atmosphere have been estimated within reasonable limits, the processes that produce them are a subject of active research. Many halocarbons are consumed in seawater by a combination of chemical and biological processes with the result that the direction of flux between ocean and atmosphere can vary temporally and spatially in both magnitude and direction.

Keywords:

  • halogens;
  • chlorine;
  • bromine;
  • iodine;
  • halocarbons;
  • methyl halides;
  • macrophytes;
  • phytoplankton;
  • stratosphere;
  • ozone