Organic Carbon Cycling

Dissolved Organic Matter (DOM)

The component of organic matter which is dissolved in water.

Particulate Organic Matter (POM)

The component of organic matter that exists in particulate form.

Total Organic Matter (OM)

Encompasses both DOM and POM.

Total Organic Carbon (TOC)

Refers to the total amount of carbon in organic compounds, comprising dissolved organic carbon (DOC) and particulate organic carbon (POC).

Other Elements in Organic Matter (OM)

Includes nitrogen (N), phosphorus (P), oxygen (O), sulfur (S), and hydrogen (H).

DOC Concentration Range (Moise River)

2 to 50 mg C L^{-1}.

Oligotrophic Lakes DOC:POC Ratio

10:1 (with DOC at 2.0 mg L^{-1} and POC at 0.2 mg L^{-1}).

Eutrophic Lakes DOC:POC Ratio

6:1 (with DOC at 10.3 mg L^{-1} and POC at 1.7 mg L^{-1}).

Rivers DOC:POC Ratio

3:1 (with DOC at 5.0 mg L^{-1} and POC at 2.0 mg L^{-1}).

Ground Water DOC:POC Ratio

13:1 (with DOC at 0.65 mg L^{-1} and POC at 0.05 mg L^{-1}).

Open Ocean DOC:POC Ratio

9:1 (with DOC at 0.45 mg L^{-1} and POC at 0.05 mg L^{-1}).

Precipitation DOC:POC Ratio

10:1 (with DOC at 1.0 mg L^{-1} and POC at 0.1 mg L^{-1}).

Wetlands-Marshes DOC:POC Ratio

9:1 (with DOC at 15.3 mg L^{-1} and POC at 1.7 mg L^{-1}).

Bog Water DOC:POC Ratio

11:1 (with DOC at 30.3 mg L^{-1} and POC at 2.7 mg L^{-1}).

World Average Surface Waters TOC

6.5 mg L^{-1} (with DOC at 0.6 mg L^{-1} and a DOC:TOC ratio of 10:1).

Net Ecosystem Production (NEP)

Describes the cycling and fates of both autochthonous and allochthonous carbon, including gross primary production (GPP), net primary production (NPP), and various forms of ecosystem respiration.

Autochthonous Carbon

Carbon produced within the ecosystem itself.

Allochthonous Carbon

Carbon imported into the ecosystem from external sources.

Gross Primary Production (GPP)

The total amount of organic matter produced by photosynthesis in an ecosystem over a given period.

Ecosystem Respiration (ER)

The total carbon dioxide released from an ecosystem due to the respiration of all living organisms (producers, consumers, and decomposers).

Labile Dissolved Organic Carbon (LDOC)

Organic carbon sources characterized by faster rates of mineralization.

Recalcitrant Dissolved Organic Carbon (RDOC)

Organic carbon sources characterized by slower rates of mineralization.

Humic Substances

Formed during the decomposition of higher plant tissues, their pathways involve interactions with enzymes and UV light, influencing the stability and utilization of humic compounds.

Lignocellulose

A key contributor to recalcitrant dissolved organic matter, linking metabolic processes across terrestrial and aquatic ecosystems.

Dissolved Organic Matter (DOM)

The component of organic matter which is dissolved in water.

Particulate Organic Matter (POM)

The component of organic matter that exists in particulate form.

Total Organic Matter (OM)

Encompasses both DOM and POM.

Total Organic Carbon (TOC)

Refers to the total amount of carbon in organic compounds, comprising dissolved organic carbon (DOC) and particulate organic carbon (POC).

Other Elements in OM

Includes nitrogen (N), phosphorus (P), oxygen (O), sulfur (S), and hydrogen (H) found in organic matter.

Dissolved Organic Carbon (DOC)

The total amount of carbon present in dissolved organic compounds in water.

Particulate Organic Carbon (POC)

The total amount of carbon present in particulate organic compounds in water.

Humic Acids (HAC)

Large molecular weight organic matter components found in aquatic ecosystems.

Fulvic Acids (FA)

Smaller molecular weight organic matter components found in aquatic ecosystems, often derived from humic substances.

Hydrocarbons (HC)

Organic compounds composed entirely of hydrogen and carbon, found in aquatic ecosystems.

Carbohydrates (CHO)

Organic compounds composed of carbon, hydrogen, and oxygen, found in aquatic ecosystems.

Fatty Acids (FA)

Carboxylic acids with long aliphatic chains, found in aquatic ecosystems.

Amino Acids (AA)

Organic compounds that are the building blocks of proteins, found in aquatic ecosystems.

Autochthonous Carbon

Carbon produced within the ecosystem itself.

Allochthonous Carbon

Carbon imported into the ecosystem from external sources.

Gross Primary Production (GPP)

The total amount of organic matter produced by primary producers in an ecosystem before respiration.

Net Primary Production (NPP)

The net amount of organic matter produced by primary producers after accounting for their own respiration.

Ecosystem Respiration (ER)

The total respiration of all organisms (producers and consumers) within an ecosystem.

Net Ecosystem Production (NEP)

The balance between gross primary production (GPP) and ecosystem respiration (ER).

Labile Dissolved Organic Carbon (LDOC)

Organic carbon sources characterized by high rates of mineralization and rapid decomposition.

Recalcitrant Dissolved Organic Carbon (RDOC)

Organic carbon sources characterized by low rates of mineralization and slow decomposition, resistant to breakdown.

Humic Substances

Complex organic compounds resulting from the decomposition of higher plant tissues, influencing the stability and utilization of organic compounds.

Lignocellulose

A key contributor to recalcitrant dissolved organic matter, often linked to terrestrial and aquatic metabolic processes.