Allochthonous organic carbon

McCart, E., A. M. Gordon, N. K. Kaushik, B. Lazerte, E. Mallory, R. W. Bachmann, J. R. Jones, R. H. Peters, and D. M. Soballe. 1995. Characterization of selected allochthonous organic carbon inputs within a terrestrial-aquatic ecotone in Algonquin Park, Ontario. Lake Reserve Management 11 168. 

Jansson, M., A. K. Bergstrom, P. Blomqvist, A. Isaksson, and A. Jonsson. 1999. Impact of allochthonous organic carbon on microbial food web carbon dynamics and structure in Lake Ortrasket. Archive fur Hydrobiologia 144 409—428. 

Wetzel, R. G., and A. Otsuki. 1974. Allochthonous organic carbon of a marl lake. Archiv fiir Hydrobiologie 73 31-56. 

Marce R, Moreno-Ostos E, Lopez P, Armengol J (2008) The role of allochthonous inputs of dissolved organic carbon on the hypolimnetic oxygen content of reservoirs. Ecosystems 11 1035-1053... 

Figure 1. Allochthonous and autochthonous sources of dissolved organic carbon in natural waters. (Reproduced with permission from reference 1. Copyright 1985 Kluwer Academic Publishers.)...

III. Regulation of Allochthonous Dissolved Organic Carbon and Dissolved Organic Nitrogen 51... 

III. REGULATION OF ALLOCHTHONOUS DISSOLVED ORGANIC CARBON AND DISSOLVED ORGANIC NITROGEN... 

The maximum value of HON/AON increases in systems with allochthonous carbon inputs. The maximum potential is related directly to the allochthonous organic matter input that is respired in the system (Alloch. Resp.). Additionally, the increased HON will depend on the relative growth efficiency of heterotrophic bacteria on allochthonous material (BGEa och) and the C N ratio of allochthonous material (C Nalloc]l), such that... 

The formula for BCD in Eq. (2) was derived under the assumption that the bacterial growth rate was mineral nutrient limited. If the supply rate of labile organic carbon from allochthonous and autochthonous sources is insufficient to meet this demand, the pool of labile dissolved organic carbon (DOC) will eventually be depleted and the bacteria will become carbon... 

Stable carbon isotopes have been commonly used to distinguish between allochthonous versus autochthonous organic carbon inputs to estuaries. One of the most important pieces of information that can be gathered from this information is the delineation between C3 and C4 plant inputs. 

Allochthonous inputs from the Amazon River and local drainage thus contribute 4.3 Tg yr of organic carbon to floodplain. This represents approximately 4% of total plant production within the floodplain. However, the majority of the allochthonous inputs are refractory carbon, while most of the aquatic plant production is available to other trophic levels. 

In lakes, the pool of dissolved organic carbon (DOC) is dominated by dissolved humic substances (up to 80% of the DOC). Lake humic substances are similar to soil humic substances in that carboxyl, hydroxyl, phenol, and probably methoxyl groups are of major significance. Fluorescence spectra of DOC may be interpreted in terms of the different geochemical origins of DOC (e.g., allochthonous versus algal derived). One or more moieties of dissolved humic substances are produced autochthonously mechanisms may include polymerization of phenols (promoted by transition metals), Maillard condensations, or oxidation via phenolase systems. Aliphatic structural units in dissolved humic substances provide a flexible conformation to the humic substance molecule. ... 

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