1. Estuaries By Dan Lawson

2. What is an estuary? An estuary is a coastal body of water which is openly connecting a freshwater stream with a saltwater environment such as the ocean. An estuary is a coastal body of water which is openly connecting a freshwater stream with a saltwater environment such as the ocean.

3. Location Estuaries are found all over the world in coastal areas. They can also be called bays, lagoons, harbors, or sounds. They are only true estuaries, however, when there is both salt and fresh water present. Estuaries are found all over the world in coastal areas. They can also be called bays, lagoons, harbors, or sounds. They are only true estuaries, however, when there is both salt and fresh water present.

4. Types of Estuaries Drowned River Valleys- Drowned River Valleys- Many estuaries of this type were formed between 15,000-6,000 years ago. Many estuaries of this type were formed between 15,000-6,000 years ago. They were formed when the end of the last glaciation period caused sea level to rise 100- 130m. They were formed when the end of the last glaciation period caused sea level to rise 100- 130m. Drowned river valleys are typically wide and shallow, rarely exceeding 30m in depth. Drowned river valleys are typically wide and shallow, rarely exceeding 30m in depth. Examples include Chesapeake Bay (the largest estuary in the United States) and Delaware Bay. Examples include Chesapeake Bay (the largest estuary in the United States) and Delaware Bay. Chesapeake Bay from Satellite

5. Types of Estuaries Lagoon-Type- Lagoon-Type- Semi isolated from the ocean by barrier islands, which are narrow strips of land that only allow water to flow through small inlets. Semi isolated from the ocean by barrier islands, which are narrow strips of land that only allow water to flow through small inlets. A good example is Pamlico Sound, the largest lagoon on the US east coast. Located in North Carolina, it is separated from the Atlantic by the Outer Banks. A good example is Pamlico Sound, the largest lagoon on the US east coast. Located in North Carolina, it is separated from the Atlantic by the Outer Banks.

6. Types of Estuaries Fjord Type – Fjord Type – Found in valleys that are deeply eroded from glacial activity. Found in valleys that are deeply eroded from glacial activity. Very narrow and deep Very narrow and deep Can exceed 300m in depth Can exceed 300m in depth Examples include Alaskan coast, Puget Sound region of Washington, areas in Norway, and New Zealand. Examples include Alaskan coast, Puget Sound region of Washington, areas in Norway, and New Zealand.

7. Organisms Found in Estuaries Estuaries are among the most heavily populated areas in the world, with almost 60% of species being found in estuaries and coastal areas. In order to survive in the water found in an estuary, organisms must be euryhaline (able to adapt to a wide range of salinity) Estuaries are among the most heavily populated areas in the world, with almost 60% of species being found in estuaries and coastal areas. In order to survive in the water found in an estuary, organisms must be euryhaline (able to adapt to a wide range of salinity) Some examples of organisms found in estuaries are eels, horseshoe crabs, oysters, seahorses, blue crabs, bull sharks, salmon, striped bass, and sturgeon. Some examples of organisms found in estuaries are eels, horseshoe crabs, oysters, seahorses, blue crabs, bull sharks, salmon, striped bass, and sturgeon.

8. Threats to Estuaries Estuaries are threatened by both human and non-human environmental impacts. Estuaries are threatened by both human and non-human environmental impacts. Some of the main natural threats include sediment deposition which can clog feeding and breathing holes of certain species. Sediment also works to fill in estuaries, decreasing space for organisms to live. Some of the main natural threats include sediment deposition which can clog feeding and breathing holes of certain species. Sediment also works to fill in estuaries, decreasing space for organisms to live. Another problem is rapidly changing salinity levels, which create a harsh environment for organisms in the estuary. Another problem is rapidly changing salinity levels, which create a harsh environment for organisms in the estuary.

9. Threats to Estuaries Human Impacts – Human Impacts – Of the 32 largest cities in the world, 22 are located on estuaries. Of the 32 largest cities in the world, 22 are located on estuaries. Pollution from upstream travels down the river and affects the estuary environment. Pollution from upstream travels down the river and affects the estuary environment. Bioaccumulation can occur which is when pollutants such as Mercury or pesticides build up in the tissues of marine animals, making them unsafe for consumption. Bioaccumulation can occur which is when pollutants such as Mercury or pesticides build up in the tissues of marine animals, making them unsafe for consumption. Another threat to estuary life is overfishing. The Chesapeake Bay oyster population used to be huge, but has almost been wiped out due to overfishing. This greatly reduces the ability of oysters to help filter the water. Another threat to estuary life is overfishing. The Chesapeake Bay oyster population used to be huge, but has almost been wiped out due to overfishing. This greatly reduces the ability of oysters to help filter the water. It has been said that the oysters used to filter excess nutrients from all of the water in the estuary in 3-4 days. Now the process takes almost a year. It has been said that the oysters used to filter excess nutrients from all of the water in the estuary in 3-4 days. Now the process takes almost a year.

10. In Conclusion Estuaries are a vital part of the ecosystem. The huge amount of organisms living in this environment are essential to the well being of other environments such as the ocean and rivers. Estuaries are a vital part of the ecosystem. The huge amount of organisms living in this environment are essential to the well being of other environments such as the ocean and rivers. Estuaries are essential to anadromous animals that travel up stream to spawn. Estuaries are essential to anadromous animals that travel up stream to spawn. They also act as the filters of the water travelling downstream towards the ocean. They also act as the filters of the water travelling downstream towards the ocean. Without estuaries, many species of plants and animals would not be able to survive. Without estuaries, many species of plants and animals would not be able to survive.