Ocean and fishery pollution: Difference between revisions
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==History== | ==History== | ||
'''General Information''' | '''General Information''' | ||
The Chesapeake Bay watershed is 64,000 square miles and has 11,600 miles of tidal shoreline, including tidal wetlands and islands. The watershed encompasses parts of six states. Approximately 17 million people live in the watershed; about 10 million people live along its shores or near them. | The Chesapeake Bay watershed is 64,000 square miles and has 11,600 miles of tidal shoreline, including tidal wetlands and islands. [[Image:Chesapeake Bay.jpg|275px|left|thumb|Chesapeake Bay - Maryland]]The watershed encompasses parts of six states. Approximately 17 million people live in the watershed; about 10 million people live along its shores or near them. | ||
Formed about 12,000 years ago as glaciers melted and flooded the Susquehanna River valley, the Chesapeake Bay is North America's largest estuary and the world's third largest. Chesapeake Bay is approximately 200 miles long and runs north-south from the mouth of the Susquehanna River to the Atlantic Ocean. Chesapeake Bay's headwaters begin at Cooperstown, N.Y., home to the Baseball Hall of Fame. More than 500 million pounds of seafood is harvested from the Bay every year. The Bay supports 3,600 species of plant and animal life, including more than 300 fish species and 2,700 plant types. <ref> Bay Area Facts. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=433></ref> | |||
'''Health of Chesapeake Bay''' | '''Health of Chesapeake Bay''' | ||
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The leading threat to the health of the Chesapeake Bay is excess nitrogen and phosphorus pollution that destroys habitat and causes fish kills. Top sources of these pollutants include agriculture, sewage treatment plants, runoff from urban and suburban areas, and air pollution from automobiles, factories, and power plants. Other threats to the Bay's health include sprawl, toxic pollution, and poor fishery management. | The leading threat to the health of the Chesapeake Bay is excess nitrogen and phosphorus pollution that destroys habitat and causes fish kills. Top sources of these pollutants include agriculture, sewage treatment plants, runoff from urban and suburban areas, and air pollution from automobiles, factories, and power plants. Other threats to the Bay's health include sprawl, toxic pollution, and poor fishery management. | ||
Since colonial times, the Bay has lost half of its forested shorelines, over half of its wetlands, nearly 90 percent of its underwater grasses, and more than 98 percent of its oysters. During the 350 years between 1600 and 1950, approximately 1.7 million acres of the Bay watershed were developed. During the 30 years between 1950 and 1980, the Bay watershed lost an additional 2.7 million acres to development. | Since colonial times, the Bay has lost half of its forested shorelines, over half of its wetlands, nearly 90 percent of its underwater grasses, and more than 98 percent of its oysters. During the 350 years between 1600 and 1950, approximately 1.7 million acres of the Bay watershed were developed. During the 30 years between 1950 and 1980, the Bay watershed lost an additional 2.7 million acres to development. | ||
The landmark Chesapeake Bay Agreement (a voluntary pledge to Save the Bay signed by the governors of Maryland, Virginia, and Pennsylvania as well as the administrator of the Environmental Protection Agency and the mayor of Washington, D.C.) serves as the blueprint for restoring the Bay's health. | The landmark Chesapeake Bay Agreement (a voluntary pledge to Save the Bay signed by the governors of Maryland, Virginia, and Pennsylvania as well as the administrator of the Environmental Protection Agency and the mayor of Washington, D.C.) serves as the blueprint for restoring the Bay's health. <ref> Bay Area Facts. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=433></ref> | ||
'''Geography''' | '''Geography''' | ||
On average, the Chesapeake holds more than 15 trillion gallons of water. Although the Bay’s length and width are dramatic, the average depth is only about 21 feet. The Bay is shaped like a shallow tray, except for a few deep troughs believed to be remnants of the ancient Susquehanna River. The troughs form a deep channel along much of the length of the Bay. The channel allows passage of large commercial vessels. Because it is so shallow, the Chesapeake is far more sensitive to temperature changes and wind than the open ocean. | On average, the Chesapeake holds more than 15 trillion gallons of water. Although the Bay’s length and width are dramatic, the average depth is only about 21 feet. The Bay is shaped like a shallow tray, except for a few deep troughs believed to be remnants of the ancient Susquehanna River. [[Image:ChesBay.jpg|275px|right|thumb|Chesapeake Bay]]The troughs form a deep channel along much of the length of the Bay. The channel allows passage of large commercial vessels. Because it is so shallow, the Chesapeake is far more sensitive to temperature changes and wind than the open ocean. <ref> Geography. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=683></ref> | ||
'''Habitat''' | '''Habitat''' | ||
The Chesapeake Bay provides food, water, cover, and nesting or nursery areas to more than 3,000 migratory and resident wildlife species. Habitat types range from hardwood forests of the Appalachian mountains to saltwater marshes in the Bay. These habitats are influenced by climate, soils, water, plant and animal interactions, and human activities. | The Chesapeake Bay provides food, water, cover, and nesting or nursery areas to more than 3,000 migratory and resident wildlife species. Habitat types range from hardwood forests of the Appalachian mountains to saltwater marshes in the Bay. These habitats are influenced by climate, soils, water, plant and animal interactions, and human activities. <ref> Habitat. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=684></ref> | ||
'''Plants''' | '''Plants''' | ||
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Underwater grasses like wetlands, underwater grasses (known as submerged aquatic vegetation or SAV) serve as habitat for aquatic animals, and as a food source for waterfowl. And like other Bay grasses, they produce much-needed oxygen. But perhaps their most constructive feature is their ability to trap sediment that can cloud the water. As waves roll into grass beds, the movement is slowed and energy is dispelled, protecting shorelines from erosion. During the growing season, Bay grasses take up and retain nitrogen and phosphorus, removing excess levels that could fuel unwanted growth or algae. | Underwater grasses like wetlands, underwater grasses (known as submerged aquatic vegetation or SAV) serve as habitat for aquatic animals, and as a food source for waterfowl. And like other Bay grasses, they produce much-needed oxygen. But perhaps their most constructive feature is their ability to trap sediment that can cloud the water. As waves roll into grass beds, the movement is slowed and energy is dispelled, protecting shorelines from erosion. During the growing season, Bay grasses take up and retain nitrogen and phosphorus, removing excess levels that could fuel unwanted growth or algae. | ||
Survival of Bay grasses is affected by the amount of light that reaches the plants. Poor water quality resulting in less light penetration is the primary cause for declining grasses. Algal blooms, as a result of too much nitrogen and phosphorus, also cloud the water and reduce sunlight to SAV. The absence of SAV translates into a loss of food for many Chesapeake Bay species, but bay grasses have rebounded steadily since their lowest point in 1984. | Survival of Bay grasses is affected by the amount of light that reaches the plants. Poor water quality resulting in less light penetration is the primary cause for declining grasses. Algal blooms, as a result of too much nitrogen and phosphorus, also cloud the water and reduce sunlight to SAV. The absence of SAV translates into a loss of food for many Chesapeake Bay species, but bay grasses have rebounded steadily since their lowest point in 1984. <ref> Plants. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=612></ref> | ||
'''Animals''' | '''Animals''' | ||
Probably the best-known animal in the Bay watershed is the famous blue crab, but many other species call this watershed home. The Chesapeake Bay provides food, water, cover, and nesting or nursery areas to more than 3,000 migratory and resident wildlife species. | Probably the best-known animal in the Bay watershed is the famous blue crab, but many other species call this watershed home. The Chesapeake Bay provides food, water, cover, and nesting or nursery areas to more than 3,000 migratory and resident wildlife species. <ref> Animals. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=613></ref> | ||
''Crabs and Oysters'' | ''Crabs and Oysters'' | ||
Crabs and oysters are famous Bay residents, but sadly their numbers are alarmingly low. From the 1950s to the 1970s, the average annual oyster catch was about 25 million pounds per year, and the blue crab harvest contributed nearly a third of the nation’s catch. Today, the Bay’s oyster population is a mere two percent of its historic level, and reduced amounts of underwater grass habitat, in addition to low summer levels of dissolved oxygen, continue to keep the crab population well-below the average. | Crabs and oysters are famous Bay residents, but sadly their numbers are alarmingly low. From the 1950s to the 1970s, the average annual oyster catch was about 25 million pounds per year, and the blue crab harvest contributed nearly a third of the nation’s catch. Today, the Bay’s oyster population is a mere two percent of its historic level, and reduced amounts of underwater grass habitat, in addition to low summer levels of dissolved oxygen, continue to keep the crab population well-below the average. <ref> Crabs and Oysters. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=613></ref> | ||
'''Water Quality''' | '''Water Quality''' | ||
The Chesapeake Bay and its rivers and streams are in critical condition. They suffer from an overload of pollution from many different sources. Nitrogen and phosphorus pollution are the most serious problems facing the Bay. Too much nitrogen and phosphorus cause algae blooms that block sunlight to underwater grasses. When the blooms decompose, they consume oxygen and create “dead zones,” where dissolved oxygen levels are too low to sustain marine life. | The Chesapeake Bay and its rivers and streams are in critical condition. They suffer from an overload of pollution from many different sources. Nitrogen and phosphorus pollution are the most serious problems facing the Bay. Too much nitrogen and phosphorus cause algae blooms that block sunlight to underwater grasses. When the blooms decompose, they consume oxygen and create “dead zones,” where dissolved oxygen levels are too low to sustain marine life. <ref> Water Quality. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=495></ref> | ||
Excess nitrogen and phosphorus from many human activities degrade our water quality. One major source of excess nitrogen and phosphorus is: | Excess nitrogen and phosphorus from many human activities degrade our water quality. One major source of excess nitrogen and phosphorus is: | ||
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''Agriculture'' | ''Agriculture'' | ||
Farming and a healthy farm economy play a critical role in local communities. Preserving farms and open space is essential, because these lands serve as precious natural filters for our water. But agricultural lands also contribute nitrogen, phosphorus, and sediment pollution to our rivers and streams. Agricultural measures such as limiting polluting runoff: stream buffers, cover crops, rotational grazing, and other “best management practices” are the most cost-effective way to reduce nitrogen and phosphorus pollution to the Bay. In fact, scientists estimate that we could achieve almost two-thirds of the nitrogen and phosphorus reductions necessary to restore the Chesapeake Bay, at only 13 percent of the total cost of Bay restoration, by implementing them. | Farming and a healthy farm economy play a critical role in local communities. Preserving farms and open space is essential, because these lands serve as precious natural filters for our water. [[Image:MCMB analysis.png|325px|right|thumb|MC-MB analysis of "best management practices"]]But agricultural lands also contribute nitrogen, phosphorus, and sediment pollution to our rivers and streams. Agricultural measures such as limiting polluting runoff: stream buffers, cover crops, rotational grazing, and other “best management practices” are the most cost-effective way to reduce nitrogen and phosphorus pollution to the Bay. In fact, scientists estimate that we could achieve almost two-thirds of the nitrogen and phosphorus reductions necessary to restore the Chesapeake Bay, at only 13 percent of the total cost of Bay restoration, by implementing them. | ||
Other sources by human activities include sewage, stormwater, air pollution etc. | Other sources by human activities include sewage, stormwater, air pollution etc. <ref> Agriculture. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=506></ref> | ||
==Algal Blooms== | ==Algal Blooms== | ||
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'''What is Eutrophication?''' | '''What is Eutrophication?''' | ||
“Eutrophication is the enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen, phosphorus, or both.” <ref>“Eutrophication”. Science Daily. 1995-2009 http://www.sciencedaily.com/articles/e/eutrophication.htm</ref> | “Eutrophication is the enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen, phosphorus, or both.” <ref>“Eutrophication”. Science Daily. 1995-2009 <http://www.sciencedaily.com/articles/e/eutrophication.htm></ref> Phosphorus and nitrogen are limiting factors in natural marine and aquatic ecosystems. When quantities of these elements are released into aquatic ecosystems, algal blooms often form in response. Although eutrophication sometimes occurs naturally in marine ecosystems, many problems with eutrophication along coastlines and within smaller bodies of water like bays, lakes and rivers have been attributed human activities. | ||
'''What are Algal Blooms?''' | '''What are Algal Blooms?''' | ||
Algal blooms are the “rapid excessive growth of algae, generally caused by high nutrient levels and favorable conditions. [They can] result in deoxygenation of the water mass when the algae die, leading to the death of aquatic flora and fauna” often known as creating hypoxic zones. | Algal blooms are the “rapid excessive growth of algae, generally caused by high nutrient levels and favorable conditions. [[File:Red_Tide.jpg|275px|left|thumb|A Red Tide]][They can] result in deoxygenation of the water mass when the algae die, leading to the death of aquatic flora and fauna” often known as creating hypoxic zones.<ref>“Algal Bloom”. Green Facts: Facts on Health and the Environment. Sept. 10 2009. <http://www.greenfacts.org/glossary/abc/algal-bloom.htm></ref> Algal blooms can occur in both saltwater and freshwater environments although they may be more prevalent in salt water ecosystems. Because of the variety species of algae that live in these two distinct environments, algal blooms vary in color ranging from green to a yellow-brown to a red (which is more commonly known as a red tide). | ||
'''How are Algal Blooms created?''' | |||
Algal blooms occur in response to an increase in the quantity of a limiting nutrient in the aquatic ecosystem, most often nitrogen or phosphorus. When these chemicals come in contact with the body of water the algae and phytoplankton take advantage of the abundance of these nutrients and grow and multiply sometimes reaching concentrations of hundreds of thousands per millimeter. <ref>“Algal Bloom”. Science Daily. 1995-2009. <http://www.sciencedaily.com/articles/a/algal_bloom.htm></ref> | |||
'''How do Algal Blooms affect the Ecosystems of the Chesapeake Bay?''' | '''How do Algal Blooms affect the Ecosystems of the Chesapeake Bay?''' | ||
For the Chesapeake Bay, many of the sources of nutrient pollution come from: farm fertilizer runoff (both manure and chemical fertilizer), farm pesticide runoff, and air pollution. “Air pollution from vehicles, industries, gas-powered lawn tools and other emitting sources contribute nearly one-third of the total nitrogen load to the Chesapeake's waterways.” In 2008 alone the Chesapeake Bay absorbed 13.8 million pounds of phosphorus and 291 million pounds of nitrogen. | For the Chesapeake Bay, many of the sources of nutrient pollution come from: farm fertilizer runoff (both manure and chemical fertilizer), farm pesticide runoff, and air pollution. “Air pollution from vehicles, industries, gas-powered lawn tools and other emitting sources contribute nearly one-third of the total nitrogen load to the Chesapeake's waterways.” <ref>“Nutrients”. Chesapeake Bay Program: A Watershed Partnership. Sept. 15 2009. <http://www.chesapeakebay.net/nutrients.aspx?menuitem=14690></ref> [[File:Different_Ecosystem_Situations.gif|400px|right|thumb|Healthy vs. Unhealthy Ecosystems]] In 2008 alone the Chesapeake Bay absorbed 13.8 million pounds of phosphorus and 291 million pounds of nitrogen. <ref>“Pollutants”. Chesapeake Bay Program: A Watershed Partnership. March 20 2009. <http://www.chesapeakebay.net/status_pollutants.aspx?menuitem=19795></ref> 38% of the total nitrogen content in the Chesapeake Bay comes from agricultural practices <ref>“Sources of Nitrogen Loads to the Bay.” Chesapeake Bay Program: A Watershed Partnership. 2007. <http://www.chesapeakebay.net/status_nitrogensources.aspx?menuitem=19797></ref> while 45% of the total phosphorus content in the Chesapeake Bay comes from agricultural origins. <ref>“Sources of Phosphorus Loads to the Bay” Chesapeake Bay Program: A Watershed Partnership. 2007. <http://www.chesapeakebay.net/status_phosphorusloads.aspx?menuitem=19801></ref> Algal blooms triggered by these pollutants create problems in the Chesapeake Bay in that they block the sunlight from reaching underwater grasses which provide food for birds and shelter for fish and crabs. Algal blooms also absorb the oxygen in the water, thus creating hypoxic zones where no species can effectively live and degrading the biodiversity of the ecosystem. <ref>“Nutrients”. Chesapeake Bay Program: A Watershed Partnership. Sept. 15 2009.<http://www.chesapeakebay.net/nutrients.aspx?menuitem=14690></ref> | ||
==Hypoxic Zones== | ==Hypoxic Zones== | ||
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==References== | ==References== | ||
<references/> | |||
Latest revision as of 13:35, 24 November 2009
History
General Information
The Chesapeake Bay watershed is 64,000 square miles and has 11,600 miles of tidal shoreline, including tidal wetlands and islands.
The watershed encompasses parts of six states. Approximately 17 million people live in the watershed; about 10 million people live along its shores or near them.
Formed about 12,000 years ago as glaciers melted and flooded the Susquehanna River valley, the Chesapeake Bay is North America's largest estuary and the world's third largest. Chesapeake Bay is approximately 200 miles long and runs north-south from the mouth of the Susquehanna River to the Atlantic Ocean. Chesapeake Bay's headwaters begin at Cooperstown, N.Y., home to the Baseball Hall of Fame. More than 500 million pounds of seafood is harvested from the Bay every year. The Bay supports 3,600 species of plant and animal life, including more than 300 fish species and 2,700 plant types. <ref> Bay Area Facts. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=433></ref>
Health of Chesapeake Bay
According to the CBF's 2008 State of the Bay Report the Bay's health rates a 28 out of 100 (a "pristine" Bay circa. 1600). At its worst in the early 1980s, the Bay would have scored a 23. A "saved Bay" would score a 70. (CBF: Chesapeake Bay Foundation)
The leading threat to the health of the Chesapeake Bay is excess nitrogen and phosphorus pollution that destroys habitat and causes fish kills. Top sources of these pollutants include agriculture, sewage treatment plants, runoff from urban and suburban areas, and air pollution from automobiles, factories, and power plants. Other threats to the Bay's health include sprawl, toxic pollution, and poor fishery management. Since colonial times, the Bay has lost half of its forested shorelines, over half of its wetlands, nearly 90 percent of its underwater grasses, and more than 98 percent of its oysters. During the 350 years between 1600 and 1950, approximately 1.7 million acres of the Bay watershed were developed. During the 30 years between 1950 and 1980, the Bay watershed lost an additional 2.7 million acres to development. The landmark Chesapeake Bay Agreement (a voluntary pledge to Save the Bay signed by the governors of Maryland, Virginia, and Pennsylvania as well as the administrator of the Environmental Protection Agency and the mayor of Washington, D.C.) serves as the blueprint for restoring the Bay's health. <ref> Bay Area Facts. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=433></ref>
Geography
On average, the Chesapeake holds more than 15 trillion gallons of water. Although the Bay’s length and width are dramatic, the average depth is only about 21 feet. The Bay is shaped like a shallow tray, except for a few deep troughs believed to be remnants of the ancient Susquehanna River.
The troughs form a deep channel along much of the length of the Bay. The channel allows passage of large commercial vessels. Because it is so shallow, the Chesapeake is far more sensitive to temperature changes and wind than the open ocean. <ref> Geography. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=683></ref>
Habitat
The Chesapeake Bay provides food, water, cover, and nesting or nursery areas to more than 3,000 migratory and resident wildlife species. Habitat types range from hardwood forests of the Appalachian mountains to saltwater marshes in the Bay. These habitats are influenced by climate, soils, water, plant and animal interactions, and human activities. <ref> Habitat. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=684></ref>
Plants
Underwater grasses like wetlands, underwater grasses (known as submerged aquatic vegetation or SAV) serve as habitat for aquatic animals, and as a food source for waterfowl. And like other Bay grasses, they produce much-needed oxygen. But perhaps their most constructive feature is their ability to trap sediment that can cloud the water. As waves roll into grass beds, the movement is slowed and energy is dispelled, protecting shorelines from erosion. During the growing season, Bay grasses take up and retain nitrogen and phosphorus, removing excess levels that could fuel unwanted growth or algae.
Survival of Bay grasses is affected by the amount of light that reaches the plants. Poor water quality resulting in less light penetration is the primary cause for declining grasses. Algal blooms, as a result of too much nitrogen and phosphorus, also cloud the water and reduce sunlight to SAV. The absence of SAV translates into a loss of food for many Chesapeake Bay species, but bay grasses have rebounded steadily since their lowest point in 1984. <ref> Plants. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=612></ref>
Animals
Probably the best-known animal in the Bay watershed is the famous blue crab, but many other species call this watershed home. The Chesapeake Bay provides food, water, cover, and nesting or nursery areas to more than 3,000 migratory and resident wildlife species. <ref> Animals. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=613></ref>
Crabs and Oysters
Crabs and oysters are famous Bay residents, but sadly their numbers are alarmingly low. From the 1950s to the 1970s, the average annual oyster catch was about 25 million pounds per year, and the blue crab harvest contributed nearly a third of the nation’s catch. Today, the Bay’s oyster population is a mere two percent of its historic level, and reduced amounts of underwater grass habitat, in addition to low summer levels of dissolved oxygen, continue to keep the crab population well-below the average. <ref> Crabs and Oysters. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=613></ref>
Water Quality
The Chesapeake Bay and its rivers and streams are in critical condition. They suffer from an overload of pollution from many different sources. Nitrogen and phosphorus pollution are the most serious problems facing the Bay. Too much nitrogen and phosphorus cause algae blooms that block sunlight to underwater grasses. When the blooms decompose, they consume oxygen and create “dead zones,” where dissolved oxygen levels are too low to sustain marine life. <ref> Water Quality. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=495></ref>
Excess nitrogen and phosphorus from many human activities degrade our water quality. One major source of excess nitrogen and phosphorus is:
Agriculture
Farming and a healthy farm economy play a critical role in local communities. Preserving farms and open space is essential, because these lands serve as precious natural filters for our water.
But agricultural lands also contribute nitrogen, phosphorus, and sediment pollution to our rivers and streams. Agricultural measures such as limiting polluting runoff: stream buffers, cover crops, rotational grazing, and other “best management practices” are the most cost-effective way to reduce nitrogen and phosphorus pollution to the Bay. In fact, scientists estimate that we could achieve almost two-thirds of the nitrogen and phosphorus reductions necessary to restore the Chesapeake Bay, at only 13 percent of the total cost of Bay restoration, by implementing them.
Other sources by human activities include sewage, stormwater, air pollution etc. <ref> Agriculture. Chesapeake Bay Foundation. <http://www.cbf.org/Page.aspx?pid=506></ref>
Algal Blooms
What is Eutrophication?
“Eutrophication is the enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen, phosphorus, or both.” <ref>“Eutrophication”. Science Daily. 1995-2009 <http://www.sciencedaily.com/articles/e/eutrophication.htm></ref> Phosphorus and nitrogen are limiting factors in natural marine and aquatic ecosystems. When quantities of these elements are released into aquatic ecosystems, algal blooms often form in response. Although eutrophication sometimes occurs naturally in marine ecosystems, many problems with eutrophication along coastlines and within smaller bodies of water like bays, lakes and rivers have been attributed human activities.
What are Algal Blooms?
Algal blooms are the “rapid excessive growth of algae, generally caused by high nutrient levels and favorable conditions.
[They can] result in deoxygenation of the water mass when the algae die, leading to the death of aquatic flora and fauna” often known as creating hypoxic zones.<ref>“Algal Bloom”. Green Facts: Facts on Health and the Environment. Sept. 10 2009. <http://www.greenfacts.org/glossary/abc/algal-bloom.htm></ref> Algal blooms can occur in both saltwater and freshwater environments although they may be more prevalent in salt water ecosystems. Because of the variety species of algae that live in these two distinct environments, algal blooms vary in color ranging from green to a yellow-brown to a red (which is more commonly known as a red tide).
How are Algal Blooms created?
Algal blooms occur in response to an increase in the quantity of a limiting nutrient in the aquatic ecosystem, most often nitrogen or phosphorus. When these chemicals come in contact with the body of water the algae and phytoplankton take advantage of the abundance of these nutrients and grow and multiply sometimes reaching concentrations of hundreds of thousands per millimeter. <ref>“Algal Bloom”. Science Daily. 1995-2009. <http://www.sciencedaily.com/articles/a/algal_bloom.htm></ref>
How do Algal Blooms affect the Ecosystems of the Chesapeake Bay?
For the Chesapeake Bay, many of the sources of nutrient pollution come from: farm fertilizer runoff (both manure and chemical fertilizer), farm pesticide runoff, and air pollution. “Air pollution from vehicles, industries, gas-powered lawn tools and other emitting sources contribute nearly one-third of the total nitrogen load to the Chesapeake's waterways.” <ref>“Nutrients”. Chesapeake Bay Program: A Watershed Partnership. Sept. 15 2009. <http://www.chesapeakebay.net/nutrients.aspx?menuitem=14690></ref>
In 2008 alone the Chesapeake Bay absorbed 13.8 million pounds of phosphorus and 291 million pounds of nitrogen. <ref>“Pollutants”. Chesapeake Bay Program: A Watershed Partnership. March 20 2009. <http://www.chesapeakebay.net/status_pollutants.aspx?menuitem=19795></ref> 38% of the total nitrogen content in the Chesapeake Bay comes from agricultural practices <ref>“Sources of Nitrogen Loads to the Bay.” Chesapeake Bay Program: A Watershed Partnership. 2007. <http://www.chesapeakebay.net/status_nitrogensources.aspx?menuitem=19797></ref> while 45% of the total phosphorus content in the Chesapeake Bay comes from agricultural origins. <ref>“Sources of Phosphorus Loads to the Bay” Chesapeake Bay Program: A Watershed Partnership. 2007. <http://www.chesapeakebay.net/status_phosphorusloads.aspx?menuitem=19801></ref> Algal blooms triggered by these pollutants create problems in the Chesapeake Bay in that they block the sunlight from reaching underwater grasses which provide food for birds and shelter for fish and crabs. Algal blooms also absorb the oxygen in the water, thus creating hypoxic zones where no species can effectively live and degrading the biodiversity of the ecosystem. <ref>“Nutrients”. Chesapeake Bay Program: A Watershed Partnership. Sept. 15 2009.<http://www.chesapeakebay.net/nutrients.aspx?menuitem=14690></ref>
Hypoxic Zones
Crabs
Policies
References
<references/>
