What is the primary purpose of a benthic barrier?

The primary purpose of a benthic barrier is to smother and prevent aquatic plants from rooting. Benthic barriers are typically constructed from materials such as geotextiles or other impermeable fabrics that are placed on the substrate of a water body. By covering the bottom, these barriers block sunlight from reaching the plants below, which hinders their ability to photosynthesize and grow. Additionally, by preventing their roots from contacting the substrate, the barrier effectively stops new plants from establishing themselves, controlling the growth of invasive or undesirable aquatic vegetation in managed water bodies. This technique is often employed in aquatic pest control to manage problematic species and promote a healthier aquatic ecosystem.

The other options, while relevant to aquatic environments, do not align with the primary function of a benthic barrier. Enhancing fish growth involves different management strategies like habitat improvement or food source management. Controlling water temperature relates more to physical or chemical interventions rather than blocking sunlight as a benthic barrier does. Lastly, filtering water pollutants typically requires the use of absorbent materials or bioremediation practices, not a barrier that primarily impacts plant growth.