Estuaries are some of the most unique and diversified ecosystems in the world. Found along coastal regions where salt water coming in from the sea during tides mixes with freshwater entering the ocean. The result is a unique system that is a critical habitat for plants, animals, and fish. There are few places on land that possess the diversity of life that can be found in estuaries. These are often some of the most fertile regions on the Earth as well. Constant nutrients flowing through sediments in the rivers combine with those carried in by the tides.
It is estimated that 75 percent of all commercially caught fish spent a portion of their life in an estuary environment. This makes them critical for the life cycle of fish, as well as having tremendous commercial benefit. Millions of birds flock to these areas annually during migration to feed on the abundance of food. Fish lay eggs in these regions spawning millions of fish. Shrimp, reptiles, small mammals, and frogs all call these areas home as well.
This critical habitat is endangered from development as well as pollution. As human populations encroach upon estuaries they are commonly drained to make them more suitable for development. Draining and filling in wetlands eliminates the habitat and forces populations to locate elsewhere to survive. In many instances this disrupts the entire ecosystem in the region. Unfortunately, many species of plants and animals need estuaries to survive so if their habitats are destroyed then the species is gone forever.
Upriver farming which often relies heavily on pesticides and fertilizers to maximize yield end up polluting the rivers and streams through run off. These pollutants are carried downstream where they end up killing fish, birds, and other animals that depend on the estuaries to survive. Pollutants can also be absorbed by the fish and can pose a health risk to whatever eats those including humans. Bacteria from animal waste also find its way into the water and ends up downstream. There they can impact populations that have no natural resistance to them. Increased erosion from runoff adds extra sediment to the water which leads to excessive buildup reducing water surface available.
As these bodies of water become popular to recreational users new challenges are added. Pollutions from boats as well as trash left behind builds up in the system. The boats themselves can change the dynamics of the environment killing fish as well as disrupting vital spawning grounds. Often marinas are built leading to both clearing and increased human traffic. In many regions of the world factories and towns add both pollution and sewage to water supplies. Since estuaries are semi-contained it is easy for this waste to build up to dangerous levels for both people and animals.
A change in climate leading to sea water rises would directly threaten these low lying areas. As more sea water is added the delicate balance would be upset causing these areas to be overrun. Many times there is not much of a barrier between the estuary and the sea. Even a rise of a few feet could be all it takes to destroy the local ecosystem. Estuaries are extremely delicate and often upstream activities are just as harmful as direct changes to the environment itself. These vital waters are critical for millions of plants and animals and need protection as well as awareness if they are to survive. All ecosystems are connected and losing one can disrupt the entire system.