Question

Discuss these benefits by siting three benefits that the estuaries provide for both the terrestrial community and the oceanic communities directly associate with an estuary (3 points). What happens when these estuary communities are removed or destroyed (1pt)?

Answer 1

Estuaries provide us with a suite of resources, benefits and services. Some of these can be measured in dollars and cents, while others cannot. Estuaries provide places for recreational activities, scientific study and aesthetic enjoyment. Estuaries are an irreplaceable natural resource that must be managed carefully for the mutual benefit of all who enjoy and depend on them. Below are additional ways in which estuaries are important

Estuaries are critical natural habitat

Thousands of species of birds, mammals, fish and other wildlife depend on estuarine habitats as places to live, feed and reproduce. And many marine organisms, including most commercially-important species of fish, depend on estuaries at some point during their development.

Because they are biologically productive, estuaries provide ideal areas for migratory birds to rest and refuel during their long journeys. Because many species of fish and wildlife rely on the sheltered waters of estuaries as protected spawning places, estuaries are often called the "nurseries of the sea."

Estuaries have economic value

Estuaries have important commercial value and their resources provide economic benefits for tourism, fisheries and recreational activities. The protected coastal waters of estuaries also support important public infrastructure, serving as harbors and ports vital for shipping and transportation.

The economy of many coastal areas is based primarily on the natural beauty and bounty of estuaries. When those natural resources are imperiled, so too are the livelihoods of those who live and work in estuarine watersheds. Over half the U.S. population lives in coastal areas, including along the shores of estuaries. Coastal watershed counties provided 69 million jobs and contributed $7.9 trillion to the Gross Domestic Product in 2007 (National Ocean

Economics Program, 2009).

Estuaries perform environmental service

Estuaries also perform other valuable services. Water draining from uplands carries sediments, nutrients and other pollutants to estuaries. As the water flows through wetlands such as swamps and salt marshes, much of the sediments and pollutants are filtered out. This filtration process creates cleaner and clearer water, which benefits both people and marine life.

Salt marsh grasses and other estuarine plants also help prevent erosion and stabilize shorelines.

Estuaries act as a protective buffer

Wetland plants and soils also act as natural buffers between the land and ocean, absorbing flood waters and dissipating storm surges. This protects upland habitat as well as valuable real estate from storm and flood damage

Terrestrial community and the oceanic communities directly associate with an estuary

Examples of nearly every type of estuarine habitat exist along the coastline of the United States. In New England, salt-tolerant grasses fill salt marshes along the shores of tidal rivers. As one travels further south, the Atlantic Coast becomes much sandier, and barrier beaches enclose huge bays or sounds. In this region, estuarine habitats cover large areas along tidal rivers, and salt marshes reach far inland. Along the southern coast of Florida and lining the Gulf of Mexico are extensive mazes of mangrove forests, also called mangals.

From northwestern Florida to the Texas coast are long, narrow, sandy barrier islands and shallow estuaries lined with marshes. Along the Texas coast, barrier islands protect estuaries that have formed narrow lagoons with small openings to the Gulf of Mexico. In these areas, estuaries with very little freshwater input often become hypersaline or super salty.

Along the Pacific Coast of the United States, from northern California to Alaska, coastal rivers flow quickly out of the mountains and into very small estuaries. San Francisco Bay is one of the largest estuaries on the U.S. West Coast, and one of only a few that is similar in size to those found on the East Coas

Of the thirty-two largest cities in the world in the early 1990s, twenty-two were located on estuaries.

As ecosystems, estuaries are under threat from human activities such as pollution and overfishing. They are also threatened by sewage, coastal settlement, land clearance and much more. Estuaries are affected by events far upstream, and concentrate materials such as pollutants and sediments.Land run-off and industrial, agricultural, and domestic waste enter rivers and are discharged into estuaries. Contaminants can be introduced which do not disintegrate rapidly in the marine environment, such as plastics, pesticides, furans, dioxins, phenols and heavy metals.

Such toxins can accumulate in the tissues of many species of aquatic life in a process called bioaccumulation. They also accumulate in benthic environments, such as estuaries and bay muds: a geological record of human activities of the last century. The elemental composition of biofilm reflect areas of the estuary impacted by human activities, and over time may shift the basic composition of the ecosystem, and the reversible or irreversible changes in the abiotic and biotic parts of the systems from the bottom up.

For example, Chinese and Russian industrial pollution, such as phenols and heavy metals, has devastated fish stocks in the Amur River and damaged its estuary soil.

Estuaries tend to be naturally eutrophic because land runoff discharges nutrients into estuaries. With human activities, land run-off also now includes the many chemicals used as fertilizers in agriculture as well as waste from livestock and humans. Excess oxygen-depleting chemicals in the water can lead to hypoxia and the creation of dead zones.[This can result in reductions in water quality, fish, and other animal populations. Overfishing also occurs. Chesapeake Bay once had a flourishing oyster population that has been almost wiped out by overfishing. Oysters filter these pollutants, and either eat them or shape them into small packets that are deposited on the bottom where they are harmless. Historically the oysters filtered the estuary's entire water volume of excess nutrients every three or four days. Today that process takes almost a year,and sediment, nutrients, and algae can cause problems in local waters.