What is a defining characteristic of submersed plants in aquatic ecosystems?

Submersed plants are adapted to live fully underwater in aquatic ecosystems, and one defining characteristic is their reliance on water buoyancy for support. This buoyancy allows these plants to maintain their structure and grow in deeper water channels where light penetration can vary. The flexible and often lightweight design of their leaves and stems enables them to thrive without the need for substantial rigidity, which would be more necessary in terrestrial plants that face gravity's full force.

Submersed plants typically do not extend above the water surface, as that characteristic would apply more to emergent plants. They are not restricted to shallow waters; many submersed species can be found at various depths, often thriving in environments that may be unsuitable for emergent or floating types. Additionally, most submersed plants are not adapted to survive in terrestrial conditions, as they rely on aquatic environments for their metabolic processes and gas exchange, making them ill-suited for land habitats.