Aquatic plants can live in saltwater or freshwater; they grow in or near water. They are also sometimes known as macrophytes—large plants—to distinguish them from the microphytes that are common in aquatic environments. Being an essential component of life in seas and rivers, native aquatic plants play a vital role in maintaining balanced aquatic ecosystems. They are an essential source of oxygen, which they produce during photosynthesis, for the respiration of marine organisms. They also form the bases of aquatic food chains.
Moreover, they perform major tasks serving humans and wildlife, including resisting beach erosion. They also help keep sediments on the bottom, keeping the water clearer. Aquatic plants absorb pollutants from water and compete with harmful algae for nutrients; thus, reducing their reproduction. They are also a food source for creatures other than fish, such as turtles, frogs, ducks, and birds. Last but not least, the best fishing spots are usually near aquatic plant beds. The fish eat the insect larvae, snails, and other organisms living on the plants. Some fish also consider them hiding spots from predators or for spawning.
Aquatic Plant Types
There are great differences among aquatic plants; some are quite similar to terrestrial plants, while others are totally different. Aquatic plants can be divided into four types, according to the position of their roots and leaves in water: algae, floating plants, submerged plants, and emerged plants.
- Algae are the oldest and most common type of aquatic plant; they have no roots, stems, or leaves. Although algae are tiny, they are the basis of the ocean food chain; musk grass is an example of freshwater algae.
- The leaves of floating plants float on the water surface; their roots absorb water, and they live in freshwater or saltwater. The leaves of these plants are hard and flat, which helps them absorb more sunlight. Water lilies are an example of floating freshwater plant.
- Submerged plants are completely submerged under the water's surface and their leaves are thin; hydrilla is an example.
- Emerged plants are rooted on the water's bottom, but most of their leaves are above the water surface. They need constant exposure to sunlight; an example is the knotweed herb.
When can aquatic plants become a foe?
Overgrowth of aquatic plants can cause problems in the aquatic environment, especially when they die and decompose. Invasive plants—Eurasian watermilfoil algae is a well-known example—are a major problem in aquatic environments. They are not indigenous, or native, to the ecosystem; their introduction may cause harm. Invasive species include microalgae or microphytes, and macrophytes; they may invade both freshwater and saltwater environments, as well as wetlands, lakes, rivers, estuaries, coastal areas, and even extend into irrigation systems, hydroelectric systems, and aquaculture facilities.
Unlike native plants that are an essential part of their aquatic environment, invasive aquatic plants pose a serious threat. They spread so quickly, forming dense mats of plants that harm fish and the aquatic environment, and hinder navigation, swimming, and other human activities. The widespread also enables it to replace other useful plant species indigenous to the area; even more dangerous is the extreme difficulty—perhaps impossibility—of controlling it.
One of the most famous invasive floating aquatic plants in Egypt is the water hyacinth (Eichhornia crassipes), commonly known as the “Nile rose”, which consume 10 million cubic meters of the Nile river annually due to transpiration. In one square meter, water loss from water hyacinths is about a hundred times that from the sunheat. Apart from the huge loss of water, air will have higher relative humidity.
References
aquaplant.tamu.edu
aspdkw.com
britannica.com
floweraura.com
invasivespeciesinfo.gov
nyis.info
oceanservice.noaa.gov
sciencing.com
snohomishcountywa.gov
Cover Photo by Freepik.