Organic matter gets into water through two main pathways: from outside the water body and from within the water body itself.
Allochthonous Organic Matter
- Definition: This type of organic matter originates from terrestrial sources, meaning it comes from outside the water body. This is also referred to as allochthonous NOM.
- Sources:
- Decomposition of plant matter like leaves, twigs, and grasses.
- Breakdown of animal remains, including dead insects and other organisms.
- Soil erosion carrying organic particles into water sources.
- Transportation: This material reaches water bodies through drainage within watersheds, often after rainfall washes it from the land (Fabris et al., 2008).
- Surface runoff during heavy precipitation.
- Leaching through soil into groundwater, eventually reaching rivers and lakes.
Autochthonous Organic Matter
- Definition: This type of organic matter is produced within the water body itself. This is also referred to as autochthonous NOM.
- Sources:
- Microbial Activity: Bacteria and fungi break down other organic matter in the water, releasing dissolved organic compounds.
- Algal Activity: Photosynthetic algae produce organic matter as a byproduct of their metabolism. When algae die, their remains contribute to the organic matter pool.
- Processes: These processes occur directly within the water ecosystem.
Summary Table
| Category | Origin | Sources |
|---|---|---|
| Allochthonous Organic Matter | Outside the water body (terrestrial) | Breakdown of terrestrial organisms, plant material, soil erosion |
| Autochthonous Organic Matter | Inside the water body (aquatic) | Microbial and algal activities, decomposition of aquatic organisms. |
Practical Insights
- Water Quality: The presence of organic matter impacts water quality. While some organic matter is necessary for aquatic life, excessive amounts can cause problems such as:
- Reduced oxygen levels as organic matter decomposes, potentially harming fish and other aquatic organisms.
- Discoloration of water.
- Promotion of algal blooms if there are excessive nutrients, and this also can be impacted by the type of organic matter present.
- Water Treatment: Organic matter can also cause problems in water treatment plants. It can react with disinfectants to form harmful byproducts and also lead to the formation of biofilms within the plant.
