Production of refractory dissolved organic matter by bacteria.
Most of the oceanic reservoir of dissolved organic matter (DOM) is of marine origin and is resistant to microbial oxidation, but little is known about the mechanisms of its formation. In a laboratory study, natural assemblages of marine bacteria rapidly (in <48 hours) utilized labile compounds (glucose, glutamate) and produced refractory DOM that persisted for more than a year. Only 10 to 15% of the bacterially derived DOM was identified as hydrolyzable amino acids and sugars, a feature consistent with marine DOM. These results suggest that microbial processes alter the molecular structure of DOM, making it resistant to further degradation and thereby preserving fixed carbon in the ocean.
Ogawa
H
H
Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo 164-8639, Japan. hogawa@ori.u-tokyo.ac.jp
Amagai
Y
Y
Koike
I
I
Kaiser
K
K
Benner
R
R
D000596:Amino Acids / Q000378:metabolism*; D000606:Amino Sugars / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism*; D003470:Culture Media; D005947:Glucose / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D009112:Muramic Acids / Q000378:metabolism; D009930:Organic Chemicals / Q000378:metabolism*; D010457:Peptidoglycan / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012623:Seawater / Q000382:microbiology*; D013997:Time Factors
D000596:Amino Acids; D000606:Amino Sugars; D003470:Culture Media; D009112:Muramic Acids; D009930:Organic Chemicals; D010457:Peptidoglycan; D000644:Quaternary Ammonium Compounds; D018698:Glutamic Acid; D002244:Carbon; D005947:Glucose