Dissolved organic carbon

Dissolved organic carbon (DOC) is a broad classification for organic molecules of varied origin and composition within aquatic systems. The "dissolved" fraction of organic carbon is an operational classification. Many researchers use the term "dissolved" for compounds below 0.45 micrometers, but 0.22 micrometers is also common, saving colloidal for higher concentrations. A practical definition of dissolved typically used in marine chemistry is all substances that pass through a GF/F filter. The recommended measure technique is the HTCO technique after filtration on precombusted glass fiber filters, typically GF/F filters.[1]

DOC in marine and freshwater systems is one of the greatest cycled reservoirs of organic matter on Earth. The source of DOC depends on the body of water. In general, organic carbon compounds are a result of decomposition processes from dead organic matter such as plants. When water contacts highly organic soils, these components can drain into rivers and lakes as DOC.

DOC is also extremely important in the transport of metals in aquatic systems. Metals form extremely strong complexes with DOC, enhancing metal solubility while also reducing metal bioavailability.

Contents

Significance

DOC is a food supplement, supporting growth of microorganisms and plays an important role in the global carbon cycle through the microbial loop.[2] Moreover it is an indicator of organic loadings in streams, as well as supporting terrestrial processing (e.g., within soil, forests, and wetlands) of organic matter. Dissolved organic carbon has a high proportion of biodegradable dissolved organic carbon (BDOC) in first order streams compared to higher order streams. In the absence of extensive wetlands, bogs, or swamps, baseflow concentrations of DOC in undisturbed watersheds generally range from approximately 1 to 20 mg/L carbon. Carbon concentrations considerably vary across ecosystems. For example, the Everglades may be near the top of the range and the middle of oceans may be near the bottom. Occasionally, high concentrations of organic carbon indicate anthropogenic influences, but most DOC originates naturally.

The BDOC fraction consists of organic molecules that heterotrophic bacteria can use as a source of energy and carbon. Some subset of DOC constitutes the precursors of disinfection byproducts for drinking water. BDOC can contribute to undesirable biological regrowth within water distribution systems.

See also

External links

References



Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Dissolved Organic Carbon — Der Begriff Gelöster organischer Kohlenstoff bzw. engl. dissolved organic carbon (DOC) gehört als Teil des Gesamten organischen Kohlenstoffs zu den Kohlenstoff Summenparametern und bezeichnet die gelösten Formen. Derartige Teilchen sind kleiner… …   Deutsch Wikipedia

  • Total organic carbon — (TOC) is the amount of carbon bound in an organic compound and is often used as a non specific indicator of water quality or cleanliness of pharmaceutical manufacturing equipment. A typical analysis for TOC measures both the total carbon present… …   Wikipedia

  • Colored dissolved organic matter — (CDOM) is the optically measurable component of the dissolved organic matter in water. Also known as chromophoric dissolved organic matter, yellow substance, and gelbstoff, CDOM occurs naturally in aquatic environments primarily as a result of… …   Wikipedia

  • Carbon sequestration — is the capture of carbon dioxide (CO2) and may refer specifically to: The process of removing carbon from the atmosphere and depositing it in a reservoir. [1] When carried out deliberately, this may also be referred to as carbon dioxide removal,… …   Wikipedia

  • Carbon cycle — The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth.The cycle is usually thought of as four major reservoirs of carbon interconnected by… …   Wikipedia

  • Carbon sink — A carbon sink is reservoir of carbon that accumulates and stores carbon for an indefinite period. The main natural sinks are: # Absorption of carbon dioxide by the oceans # Photosynthesis by plants and algae The process by which carbon sinks… …   Wikipedia

  • carbon cycle — 1. Ecol. the circulation of carbon atoms in the biosphere as a result of photosynthetic conversion of carbon dioxide into complex organic compounds by plants, which are consumed by other organisms: the carbon returns to the atmosphere in the form …   Universalium

  • Carbon dioxide — Carbon dioxide …   Wikipedia

  • Carbon filtering — is a method of filtering that uses a piece of activated carbon to remove contaminants and impurities, utilizing chemical adsorption. Each piece of carbon is designed to provide a large section of surface area, in order to allow contaminants the… …   Wikipedia

  • Carbon–hydrogen bond activation — or C−H activation may be defined as a reaction that cleaves a carbon–hydrogen bond. Often the term is restricted to reactions involving organometallic complexes and proceeding by coordination of a hydrocarbon to the inner sphere of metal, either… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.