Читать книгу Encyclopedia of Renewable Energy - James Speight G., James G. Speight - Страница 102

Aquatic plants (also known as hydrophytic plants, hydrophytes) are plants that have adapted to living in aquatic environments and are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that grows in or near water and is emergent, submergent, or floating. The three types of aquatic plants are (i) submerged aquatic weeds. submerged plants are rooted in the pond bottom and grow up through the water column, (ii) emergent aquatic weeds, and (iii) free floating aquatic weeds.

Aquatic plants include kelp from the ocean, and freshwater plants such as algae, water hyacinth, and duckweed. Aquatic plants are considered to be a sub-category of biomass and the plants, like wood products, dried vegetation, and crop residues, have the potential to produce biomass fuels.

Aquatic plants have adapted to living in or on aquatic environments and, because living on or under water surface requires numerous special adaptations, aquatic plants can only grow in water or permanently saturated soil. As opposed to typical plant types, aquatic plants do not have a problem in retaining water due to the abundance of water in its environment. This means that the plant has less need to regulate transpiration which requires less energy and increases the possible benefits.

Enhancing the growth rate of these plants by increased nutrient supply, for example, from carbon dioxide in flue gases, or growing suitable plants in conjunction with municipal wastewater treatment facilities, has received some attention. While quantitative data and costs for this resource are limited, full development of the aquatic biomass energy potential is not expected to approach 1% of total US energy requirements.

Algae are tiny aquatic plants have the potential to grow extremely fast in the hot, shallow, saline water found in some lakes in the desert Southwestern United States. Forms of algae thrive on carbon dioxide, and emissions from power plants have been used to feed the plants, which are then used in biofuels.

See also: Algae, Aquasphere, Biomass.