Terrigenous or benthic inputs refer to materials that originate from land (terrestrial sources) or the seafloor (benthic sources) and are transported into aquatic systems, particularly oceans and lakes. These inputs can have significant impacts on the physical, chemical, and biological characteristics of aquatic environments.
Here’s a breakdown of each term:
1. Terrigenous Inputs
- Definition: These are materials that come from land-based sources, such as soil, dust, and organic matter, that are transported into aquatic environments by rivers, wind, glaciers, or runoff.
- Types of Terrigenous Inputs:
- Sediments: Soil particles, sands, and clays that are eroded from the land and carried into bodies of water by rivers, streams, and wind.
- Nutrients: Fertilizers, nitrogen, phosphorus, and other chemicals from agricultural runoff that can affect water quality.
- Pollutants: Pesticides, heavy metals, and industrial chemicals that are washed off the land into water bodies.
- Organic Matter: Plant materials, animal remains, and other organic materials from terrestrial ecosystems.
- Dust: Wind-blown dust and ash that can carry both minerals and microorganisms from land to oceans.
- Impact on Aquatic Systems: Terrigenous inputs can alter the nutrient balance, cause water turbidity (cloudiness), affect photosynthesis by blocking sunlight, and contribute to eutrophication (nutrient overload) and pollution.
2. Benthic Inputs
- Definition: These refer to materials or substances that originate from the seafloor (benthic zone) and enter the water column, either due to natural processes or human activity. These inputs can come from the ocean floor or lake bed.
- Types of Benthic Inputs:
- Organic Matter: Decomposing plant and animal material, such as detritus and benthic organisms.
- Nutrients: Release of nutrients like nitrogen, phosphorus, and silica from sediments, particularly in areas of high biological activity on the seafloor.
- Sediments: Fine sediments that are resuspended from the benthic environment, either by currents, wave action, or biological activities like burrowing organisms.
- Metals and Pollutants: Accumulation of heavy metals or pollutants that have settled on the seafloor and may be remobilized into the water column.
- Impact on Aquatic Systems: Benthic inputs can contribute to nutrient cycling in aquatic ecosystems, alter the chemical composition of the water, and influence benthic communities and productivity. They can also contribute to the release of pollutants and impact water quality.
Distinguishing Features:
- Terrigenous Inputs: Primarily from land-based sources, usually transported by rivers, streams, or atmospheric processes like wind.
- Benthic Inputs: Primarily from the seafloor or lakebed, often associated with processes that resuspend or release materials from the sediment into the water column.
Examples:
- Terrigenous Inputs: Fertilizer runoff from agricultural fields, sediment from river erosion, dust from deserts, and pollutants from urban runoff.
- Benthic Inputs: Nutrients released from ocean sediments in estuaries, organic matter from decomposing benthic organisms, or pollutants such as heavy metals from contaminated sediments.
Environmental Impact:
Both terrigenous and benthic inputs can significantly affect water quality and ecosystem health:
- Terrigenous inputs often lead to eutrophication, sedimentation, and increased turbidity, which can harm aquatic life.
- Benthic inputs can influence the availability of nutrients, alter the water’s chemical properties, and affect benthic organisms and ecosystems.