Panta Rhei

Organic Carbon in Natural Waters


I read a book named Organic geochemistry of natural waters. I enjoyed reading this book very much. The following are some notes originally from the book.

  • Ground waters have 100 times more inorganic matter, while lakes and rivers have about 10 times more inorganic matter. Swamps, marshes, and bogs represent the other extreme, where organic matter is greater in concentration than inorganic matter.
  • Dissolved organic carbon varies with the type of water from approximately 0.5 mg/l for ground water and seawater to over 30 mg/l for colored water from swamps. Seawater has the lowest DOC with a median concentration of 0.5 mg/l, and ground water has a median concentration of 0.7 mg/l. Some pristine streams have low concentrations of DOC from 1 to 3 mg/l. Rivers and lakes contain more organic carbon and range in DOC from 2 to 10 mg/l. Finally, swamps, marshes, and bogs have concentrations of DOC from 10 to 60 mg/l and are cases where organic compounds dominate the water chemistry.
  • Large rivers carry substantial amounts of POC, and commonly POC is about one half the concentration of DOC. POC may equal DOC in the largest rivers and during times of high discharge. As the concentration of suspended sediment increases, so does the POC. Generally, POC makes up 2 to 3 percent of the sediment as coatings on mineral grains and as discrete organic detritus.
  • POC increase dramatically with increasing discharge, while DOC varies less.
  • DOC decreased with forest soil depth, O horizon 22 to 36 mg/l, A horizon 23 mg/l, B horizon 10 mg/1, the ground waters below the site had a DOC of 7 mg/l. Reason: biological decay and adsorption.
  • Generally, the combination of primary production of plant matter and decomposition rates control the amount of DOC in water. In general the transport of total organic carbon is approximately one percent of the net primary production, and this is reflected in a climatic effect on DOC.

Reference: Thurman E (1985). Amount of organic carbon in natural waters. Organic geochemistry of natural waters: Springer; p. 7–65.

Posted on
categories: CARBON  tags: organic carbon  natural water