As scientists have noticed the negative effects that humans can have on estuaries, people have also decided to protect the estuarine wildlife and the habitats, by creating parks or reserves where estuaries can remain natural. Often, however, humans contribute to the degradation of estuaries by ignoring their value to society, and by doing things that contribute to the destruction of estuaries, like infilling or draining, or by building urban areas, roads, and ports.
Global climate change and sea-level rise are affecting estuaries worldwide [ 5 ]. Ocean circulation and rainfall patterns are changing, land is sinking, and floods and droughts are more common in and around estuaries. Temperatures in many places are getting warmer over time, and normal weather is being replaced by unusually strong storms or changes in their frequency.
All of these things imperil the habitats and ecosystem services provided by estuaries all over the world. In the San Francisco Estuary for example, many wetlands are getting squeezed between the rising ocean and the cities we have built right up to the edges of the estuary Figure 3. The upper edges of estuaries are at risk because the natural upward movement of estuaries is commonly blocked by manmade structures such as paved areas, buildings, roads, or railways.
If these estuary habitats disappear, birds, fish, and crabs will have fewer places to live and they might be exposed to more pollution. If our cities get flooded more often, many businesses and people may have to move to places that are higher and drier, or they may have to pay more to repair damage caused by rising ocean tides.
This is also true for other estuaries all over the world. How governments decide to regulate and protect estuarine environments will have ripple effects on fisheries and wildlife habitats far into the future. The health of our estuaries—and human health and wealth—lies in the balance we achieve between industry and commerce and the need to preserve natural open spaces, like estuaries.
What we decide we want estuaries to look like in the future will be one legacy of our human history. You can choose to be part of building that legacy by learning about and talking with your friends about what makes estuaries so special and useful. Freshwater has low salinity, and sea water has high salinity.
The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Basic Information About Estuaries. Research Program on Water, Land, and Ecosystems. Census Bureau. Bay Area Population Growth.
Historical reconstruction of human-induced changes in U. ClimateWatch Magazine. Share on Facebook. Ecological value. Economic value. Cultural value. Ecological value Estuaries are one of the most productive ecosystems on earth.
They maintain water quality through natural filtration as microbes break down organic matter and sediments bind pollutants. Wetlands that fringe many estuaries also have other valuable functions.
Water draining from the land carries sediments, nutrients, and other pollutants. Much of the sediments and pollutants are filtered out as the water flows through these fringing marshes. This creates cleaner and clearer water, which benefits both people and marine life. Wetland soils and plants like mangroves, sea grasses and reeds also act as a natural buffer between the land and ocean, absorbing floodwaters from land and storm surges from the ocean.
They help maintain biodiversity by providing a diverse range of unique habitats that are critical for the survival of many species. Thousands of birds, mammals, fish and other wildlife use estuaries as places to live, feed and reproduce. Migratory birds use estuaries to rest and gain food during their journeys. Many species of fish and shellfish use estuaries as nurseries to spawn and allow juveniles to grow. Economic value They are tourist attractions. Used for transport and industry.
They have ecological importance to commercial fisheries. Maintain water quality which benefits both people and marine life Natural buffer between the land and ocean, absorbing floodwaters and storm surges. Many species of commercially important fish and shellfish use estuaries as nurseries to spawn and allow juveniles to grow. Cultural value People value estuaries for recreation, scientific knowledge, education, aesthetic and traditional practices. Boating, fishing, swimming, surfing, and bird watching are just a few of the numerous recreational activities people enjoy in estuaries.
Unique estuarine habitats makes them valuable laboratories for scientists and students. Estuaries also provide a great deal of aesthetic enjoyment for the people who live, work, or use them for recreation. Estuaries were a resource sought after by Maori. Timber for building materials, rongoa medicine , harakeke flax for weaving, kai food which included birds, fish, rats, eels, shellfish, humans.
To make full advantage of this plentiful resource, Kainga, which were unfortified villages were established near estuaries. Eels were an important part of the Maori diet. They were caught by hand with a bob or eel pot. The bob was a huhu grub or worm attaches to a string or flax.
The eels teeth were tangled in the fibres and the eel would then be landed. Camps were set up in favourable spots during the autumn spawning migration. The large number of eels caught were filleted and dried in the sun. Estuaries provide us with numerous resources upon which a dollar value cannot easily be placed. They offer benefits and services which greatly improve our lifestyle.
Estuaries are an irreplaceable natural resource that must be managed carefully for the mutual benefit of all who enjoy and depend on them. Why protect estuaries? Estuaries are the preferred site for human settlement. Estuaries receive the final impact of human activities throughout the catchment. This means the use of the surrounding land and the rivers draining into them.
Rubbish dumping, pollution, reclamation, trampling by stock, urban and industrial development and recreational pressures are some of the immediate impacts. Indirect threats — human induced erosion may cause accelerated siltation affecting plant and animal communities. Infilling can be accelerated by poorly managed urban development or forest clearance which increases the runoff. This can increase the turbidity of the water, accelerate sedimentation and spread of silts, muds and clay throughout the estuary.
Sediments trap pollutants like fertilizer run off, petroleum by-products, persistent pesticides and heavy metals. Where fertilizer runoff is trapped in the sediment the process of organic decomposition by microbes speeds up depleting oxygen to dangerously low levels.
Toxic compounds like ammonia and hydrogen sulphide accumulate and can be harmful to other estuarine organisms. All this may decrease the health and diversity of habitats. Estuary monitoring by communities. Over half the U. 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.
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. Coastal counties are growing three times faster than counties elsewhere in the nation. Unfortunately, this increasing concentration of people:.
What happens on the land affects the quality of the water and health of the organisms that live in an estuary. For example, if a river or stream flows through an agricultural area, it picks up fertilizer, manure and pesticides from farming operations that run off the land after a rainstorm.
As it passes urbanized and suburbanized areas, it gathers substances such as:.
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