Lake Maracaibo
Encyclopedia
Lake Maracaibo is a large brackish bay
in Venezuela
at 09°48′57"N 71°33′24"W. It is connected to the Gulf of Venezuela
by Tablazo Strait (55km) at the northern end, and fed by numerous rivers, the largest being the Catatumbo
. It is commonly considered a lake
rather than a bay
or lagoon
, and at 13,210 km² it would be the largest lake in South America. The geological record shows that it has been a true lake in the past, and as such is one of the oldest lakes on Earth at 20-36 million years old.
Lake Maracaibo acts as a major shipping route to the ports of Maracaibo
and Cabimas
. The surrounding Maracaibo Basin
contains large reserves of crude oil, making the lake a major profit center for Venezuela. A dredged channel gives oceangoing vessels access to the bay. The General Rafael Urdaneta Bridge
(8.7 km long; completed 1962), spanning the bay's outlet, is one of the longest bridges in the world.
The lake is also the location of Catatumbo lightning
.
The first known settlements on the bay were those of the Goajiros, who still are present in large numbers, but have re-settled in the western boundary area with Colombia. The first Europe
an to discover the bay was Alonso de Ojeda
on August 24, 1499, on a voyage with Amerigo Vespucci
(the same one for which the American continents were named).
Legend has it that upon entering the lake, Ojeda's expedition found groups of indigenous huts, built over stilts on water ("palafitos" in Spanish), and interconnected by boardwalks on stilts, with each other and with the lake shore. The stilt houses reminded Vespucci of the city of Venice
, , so he named the region "Venezuela," meaning "little Venice" in Italian. The word has the same meaning in Spanish, where the suffix
-uela is used as a diminutive
term (e.g., plaza / plazuela, cazo / cazuela); thus, the term's original sense would have been that of a "little Venice". (Examples of palafitos can still be found in "Santa Rosa", an area in the city of Maracaibo.)
Although the Vespucci story remains the most popular and accepted version of the origin of the country's name, a different reason for the name comes up in the account of Martín Fernández de Enciso
, a member of the Vespucci and Ojeda crew. In his work Summa de Geografía, he states that they found an indigenous population who called themselves the "Veneciuela," which suggests that the name "Venezuela" may have evolved from the native word.
The port town of Maracaibo
was founded in 1529 on the western side. In July 1821, the bay was the site of the Battle of Lake Maracaibo
, an important battle in the Venezuelan War of Independence
. Oil production began in the surrounding basin in 1914, with wells drilled by Bataafsche Petroleum Maatschappij, a predecessor of Royal Dutch Shell
.
On April 6, 1964, at 11:45 pm, the supertanker Esso Maracaibo, loaded with 236000 barrels (37,521,001.6 l) of crude oil, suffered a major electrical failure, so that control of steering was lost. Thus it collided with pier #31 of the two-year-old General Rafael Urdaneta Bridge across the mouth of the lake. A 259 metre section of the bridge roadway fell into the water with a portion coming to rest across the tanker just a few feet from the ship's superstructure. Fortunately, no oil spill
occurred, and there were no deaths or serious injuries on the tanker, but seven motorists and passengers in vehicles crossing the bridge were killed.
The majority of this islands are located in the Almirante Padilla municipality, including:
and submerging a large population. A program of mitigative measures to address the seismic risk was begun in 1988. Ongoing maintenance and improvements to the dike will be needed, as it continues to subside by as much as 7 cm per year.
As of June 18, 2004, a large portion (18%) of the surface of Lake Maracaibo is covered by duckweed specifically Lemna
. Although efforts to remove the plant have been underway, the plant – which can double its size every 48 hours – covers over 130 million cubic metres of the lake. The only way to remove the weed is to pull it out of the lake physically – no chemical or biological method has been found to treat the weed. The government has been spending $2 million monthly to clean the lake, and the state-run oil company Petroleos de Venezuela S.A.
has created a $750 million cleanup fund. Current efforts are barely keeping up with the growth of the plant. The removal process has proven to be particularly difficult in the center of the lake where a specially equipped ship may be needed to pull the weed off the lake.
There is some mystery as to how the plant came to reside in the waters of Lake Maracaibo. According to scientists from the Institute for the Conservation of Lake Maracaibo (ICLAM), one of the government organizations charged with the care of Lake Maracaibo, the weed is probably native to the lake, but few studies have been conducted to confirm that suspicion. The prodigious growth of the freshwater marine plant is likely a self-purification mechanism. Others disagree, believing the type of duckweed to be native to Florida and Texas and thus the infestation is a result of its having been transported by ship.
Another point of uncertainty is why the scale of the outbreak is so great. Maracaibo is fed by both salt water from the Caribbean and fresh water from numerous rivers. The lighter fresh water floats on top of the heavier salt water, which forms a dense layer on the bottom. This set-up traps nutrients that have settled on the floor of the lake. In the spring of 2004, heavy rains disrupted the usual pattern. The sudden influx of fresh water stirred the layers, allowing nutrients to float to the top, where duckweed and other plants reside. These nutrients may have triggered the duckweed's rapid expansion. Additional sources of nutrients include untreated sewage
discharge and fertilizer
s and other industrial waste
flowing into the lake through rivers (97 percent of the country's raw sewage is discharged without treatment into the environment). Furthermore, chemicals used to clean up oil spill
s may have contributed to the duckweed problem. The lake basin hosts Venezuela's largest oil field
s, and high concentrations of biodegradable dispersant
s that contain phosphates and polyaspartic acid – a chemical used to increase nutrient uptake in crops – have been found, a veritable feast for the plants. Scientists at ICLAM disagree, saying that dispersants have been banned from the lake for years and, even if they were present, could not contain enough nutrients to support the current duckweed population.
Duckweed is not toxic to fish, but some scientists are concerned that it could suck oxygen
out of the lake as it decays, asphyxiating large numbers of fish. Though officials say the weed hasn't harmed fish yet, it is putting a dent in the local fishing
industry. The plant clogs the motor
s of small boats, making it impossible for fishers to launch their vessels. Duckweed further threatens the local ecosystem
by choking out other plants as it shades large portions of the lake. In certain conditions, the weed may concentrate heavy metals
and bacteria
such as salmonella
and Vibrio cholerae
, the bacterium that causes cholera
. Despite these problems, the weed may yet have some positive use; duckweed can be treated to be fed to poultry
or to make paper
.
As of 2007 the duckweed problem continues. http://www.intute.ac.uk/sciences/worldguide/html/image_1924.html
Bay
A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...
in Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
at 09°48′57"N 71°33′24"W. It is connected to the Gulf of Venezuela
Gulf of Venezuela
The Gulf of Venezuela is a gulf of the Caribbean Sea bounded by the Venezuelan states of Zulia and Falcón and by Guajira Department, Colombia...
by Tablazo Strait (55km) at the northern end, and fed by numerous rivers, the largest being the Catatumbo
Catatumbo River
The Catatumbo River is a river rising in northern Colombia, flowing into Lake Maracaibo in Venezuela. The Catatumbo River is approximately 210 miles long...
. It is commonly considered a lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
rather than a bay
Bay
A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...
or lagoon
Lagoon
A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...
, and at 13,210 km² it would be the largest lake in South America. The geological record shows that it has been a true lake in the past, and as such is one of the oldest lakes on Earth at 20-36 million years old.
Lake Maracaibo acts as a major shipping route to the ports of Maracaibo
Maracaibo
Maracaibo is a city and municipality located in northwestern Venezuela off the western coast of the Lake Maracaibo. It is the second-largest city in the country after the national capital Caracas and the capital of Zulia state...
and Cabimas
Cabimas
Cabimas is a town on the shore of Maracaibo Lake in Zulia State in northwestern Venezuela. Its current population is around 200,859 .Before 1900, Venezuela was known to possess commercial quantities of petroleum. One major find was the 'Zumaque 1' well in 1914, in the area of Mene Grande, about 50...
. The surrounding Maracaibo Basin
Maracaibo Basin
The Maracaibo Basin in Western Venezuela is a prolific, oil-producing sedimentary basin. The basin is bounded on the north by the Oca Fault which separates it from the Caribbean Sea. The remaining sides of the basin are bounded by a branching in the northern Andes Mountains termed the Sierra de...
contains large reserves of crude oil, making the lake a major profit center for Venezuela. A dredged channel gives oceangoing vessels access to the bay. The General Rafael Urdaneta Bridge
General Rafael Urdaneta Bridge
The General Rafael Urdaneta Bridge is located at the outlet of Lake Maracaibo, in western Venezuela. The bridge connects Maracaibo with much of the rest of the country...
(8.7 km long; completed 1962), spanning the bay's outlet, is one of the longest bridges in the world.
The lake is also the location of Catatumbo lightning
Catatumbo lightning
The Catatumbo Lightning is an atmospheric phenomenon in Venezuela. It occurs strictly in an area located over the mouth of the Catatumbo River where it empties into Lake Maracaibo...
.
History
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an to discover the bay was Alonso de Ojeda
Alonso de Ojeda
Alonso de Ojeda was a Spanish navigator, governor and conquistador. His name is sometimes spelled Alonzo and Oxeda.-Early life:...
on August 24, 1499, on a voyage with Amerigo Vespucci
Amerigo Vespucci
Amerigo Vespucci was an Italian explorer, financier, navigator and cartographer. The Americas are generally believed to have derived their name from the feminized Latin version of his first name.-Expeditions:...
(the same one for which the American continents were named).
Legend has it that upon entering the lake, Ojeda's expedition found groups of indigenous huts, built over stilts on water ("palafitos" in Spanish), and interconnected by boardwalks on stilts, with each other and with the lake shore. The stilt houses reminded Vespucci of the city of Venice
Venice
Venice is a city in northern Italy which is renowned for the beauty of its setting, its architecture and its artworks. It is the capital of the Veneto region...
, , so he named the region "Venezuela," meaning "little Venice" in Italian. The word has the same meaning in Spanish, where the suffix
Suffix
In linguistics, a suffix is an affix which is placed after the stem of a word. Common examples are case endings, which indicate the grammatical case of nouns or adjectives, and verb endings, which form the conjugation of verbs...
-uela is used as a diminutive
Diminutive
In language structure, a diminutive, or diminutive form , is a formation of a word used to convey a slight degree of the root meaning, smallness of the object or quality named, encapsulation, intimacy, or endearment...
term (e.g., plaza / plazuela, cazo / cazuela); thus, the term's original sense would have been that of a "little Venice". (Examples of palafitos can still be found in "Santa Rosa", an area in the city of Maracaibo.)
Although the Vespucci story remains the most popular and accepted version of the origin of the country's name, a different reason for the name comes up in the account of Martín Fernández de Enciso
Martín Fernández de Enciso
Martín Fernández de Enciso was a navigator and geographer from Seville, Spain. He was instrumental in colonising the Isthmus of Darien. Fernandez de Enciso founded a village near the Cabo de la Vela with the name Nuestra Señora Santa María de los Remedios del Cabo de la Vela, the first settlement...
, a member of the Vespucci and Ojeda crew. In his work Summa de Geografía, he states that they found an indigenous population who called themselves the "Veneciuela," which suggests that the name "Venezuela" may have evolved from the native word.
The port town of Maracaibo
Maracaibo
Maracaibo is a city and municipality located in northwestern Venezuela off the western coast of the Lake Maracaibo. It is the second-largest city in the country after the national capital Caracas and the capital of Zulia state...
was founded in 1529 on the western side. In July 1821, the bay was the site of the Battle of Lake Maracaibo
Battle of Lake Maracaibo
The Battle of Lake Maracaibo also known as the "Naval Battle of the Lake" was fought on 24 July 1823 in Venezuela's Lake Maracaibo between Admiral José Prudencio Padilla and royalist Captain Ángel Laborde....
, an important battle in the Venezuelan War of Independence
Venezuelan War of Independence
-The First Republic:Criollos resented the mercantilist policies of Spain. Trade was only allowed in Pacific ports which was a terrible burden for Argentina, Paraguay and the Caribbean colonies. This is significant as Cuba and Puerto Rico were forced to allow free trade in 1763 by Britain and...
. Oil production began in the surrounding basin in 1914, with wells drilled by Bataafsche Petroleum Maatschappij, a predecessor of Royal Dutch Shell
Royal Dutch Shell
Royal Dutch Shell plc , commonly known as Shell, is a global oil and gas company headquartered in The Hague, Netherlands and with its registered office in London, United Kingdom. It is the fifth-largest company in the world according to a composite measure by Forbes magazine and one of the six...
.
On April 6, 1964, at 11:45 pm, the supertanker Esso Maracaibo, loaded with 236000 barrels (37,521,001.6 l) of crude oil, suffered a major electrical failure, so that control of steering was lost. Thus it collided with pier #31 of the two-year-old General Rafael Urdaneta Bridge across the mouth of the lake. A 259 metre section of the bridge roadway fell into the water with a portion coming to rest across the tanker just a few feet from the ship's superstructure. Fortunately, no oil spill
Oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is mostly used to describe marine oil spills, where oil is released into the ocean or coastal waters...
occurred, and there were no deaths or serious injuries on the tanker, but seven motorists and passengers in vehicles crossing the bridge were killed.
Islands
Due to its large extension and its geological conformation some Islands are of considerable size and populated with fisherman, commercial and recreational purposes.The majority of this islands are located in the Almirante Padilla municipality, including:
- Zapara Island
- Toas IslandToas islandToas Island is a small limestone island belonging to Venezuela. It is in the north-west of the country, north of Maracaibo Lake, just southwest of Zapara Island and to the south of San Carlos peninsula, forming part of the "Barra del Lago de Maracaibo"...
- San Carlos Island
- Isla de Providencia
- Isla de Pescadores
- Los Pájaros Island
- Maraca Island
- San Bernardo Island
- Sabaneta de Montiel Island
Fishing
As recently as 2000, Lake Maracaibo supported 20,000 fishermen. http://www.businessweek.com/2000/00_51/c3712238.htmSettlements
Several settlements built out on stilts over the lake – palafitos – still exist in the south and south-west, notably at Lagunetas.Subsiding ground
Due to the massive volume of oil removed in the Maracaibo Basin, some oil-producing areas adjacent to Lake Maracaibo have sunk, changing the geography of the region. The original concessions to oil companies purposefully assigned swamps and wetlands along the East border of the lakes for facilities. This required the oil companies to build dikes and drain the land in order to build their facilities, Dutch Shell takes credit for some of the most enduring dike systems. Since the nationalization maintenance of the dike systems has fallen upon the Venezuelan government to sub-sea-level areas like Tía Juana, Lagunillas, and Bachaquero from encroachment by the waters. Cumulative subsidence is as much as 5 meters, and it continues at a rate of up to 20 cm/yr at some locations inland and typically 5 cm/yr along the coast. Many consider the dike to be a disaster in waiting, with the potential of an earthquake causing soil liquefactionSoil liquefaction
Soil liquefaction describes a phenomenon whereby a saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid....
and submerging a large population. A program of mitigative measures to address the seismic risk was begun in 1988. Ongoing maintenance and improvements to the dike will be needed, as it continues to subside by as much as 7 cm per year.
Duckweed infestation
Lemna
Lemna is a genus of free-floating aquatic plants from the duckweed family. These rapidly-growing plants have found uses as a model system for studies in community ecology, basic plant biology, in ecotoxicology, in production of biopharmaceuticals, and as a source of animal feeds for agriculture...
. Although efforts to remove the plant have been underway, the plant – which can double its size every 48 hours – covers over 130 million cubic metres of the lake. The only way to remove the weed is to pull it out of the lake physically – no chemical or biological method has been found to treat the weed. The government has been spending $2 million monthly to clean the lake, and the state-run oil company Petroleos de Venezuela S.A.
Petróleos de Venezuela S.A.
Petróleos de Venezuela, S.A. is the Venezuelan state-owned petroleum company. It has activities in exploration, production, refining and exporting oil, as well as exploration and production of natural gas...
has created a $750 million cleanup fund. Current efforts are barely keeping up with the growth of the plant. The removal process has proven to be particularly difficult in the center of the lake where a specially equipped ship may be needed to pull the weed off the lake.
There is some mystery as to how the plant came to reside in the waters of Lake Maracaibo. According to scientists from the Institute for the Conservation of Lake Maracaibo (ICLAM), one of the government organizations charged with the care of Lake Maracaibo, the weed is probably native to the lake, but few studies have been conducted to confirm that suspicion. The prodigious growth of the freshwater marine plant is likely a self-purification mechanism. Others disagree, believing the type of duckweed to be native to Florida and Texas and thus the infestation is a result of its having been transported by ship.
Another point of uncertainty is why the scale of the outbreak is so great. Maracaibo is fed by both salt water from the Caribbean and fresh water from numerous rivers. The lighter fresh water floats on top of the heavier salt water, which forms a dense layer on the bottom. This set-up traps nutrients that have settled on the floor of the lake. In the spring of 2004, heavy rains disrupted the usual pattern. The sudden influx of fresh water stirred the layers, allowing nutrients to float to the top, where duckweed and other plants reside. These nutrients may have triggered the duckweed's rapid expansion. Additional sources of nutrients include untreated sewage
Sewage
Sewage is water-carried waste, in solution or suspension, that is intended to be removed from a community. Also known as wastewater, it is more than 99% water and is characterized by volume or rate of flow, physical condition, chemical constituents and the bacteriological organisms that it contains...
discharge and fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
s and other industrial waste
Industrial waste
Industrial waste is a type of waste produced by industrial activity, such as that of factories, mills and mines. It has existed since the outset of the industrial revolution....
flowing into the lake through rivers (97 percent of the country's raw sewage is discharged without treatment into the environment). Furthermore, chemicals used to clean up oil spill
Oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is mostly used to describe marine oil spills, where oil is released into the ocean or coastal waters...
s may have contributed to the duckweed problem. The lake basin hosts Venezuela's largest oil field
Oil field
An oil field is a region with an abundance of oil wells extracting petroleum from below ground. Because the oil reservoirs typically extend over a large area, possibly several hundred kilometres across, full exploitation entails multiple wells scattered across the area...
s, and high concentrations of biodegradable dispersant
Dispersant
A dispersant or a dispersing agent or a plasticizer or a superplasticizer is either a non-surface active polymer or a surface-active substance added to a suspension, usually a colloid, to improve the separation of particles and to prevent settling or clumping...
s that contain phosphates and polyaspartic acid – a chemical used to increase nutrient uptake in crops – have been found, a veritable feast for the plants. Scientists at ICLAM disagree, saying that dispersants have been banned from the lake for years and, even if they were present, could not contain enough nutrients to support the current duckweed population.
Duckweed is not toxic to fish, but some scientists are concerned that it could suck oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
out of the lake as it decays, asphyxiating large numbers of fish. Though officials say the weed hasn't harmed fish yet, it is putting a dent in the local fishing
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....
industry. The plant clogs the motor
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
s of small boats, making it impossible for fishers to launch their vessels. Duckweed further threatens the local ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
by choking out other plants as it shades large portions of the lake. In certain conditions, the weed may concentrate heavy metals
Heavy metals
A heavy metal is a member of a loosely-defined subset of elements that exhibit metallic properties. It mainly includes the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight,...
and bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
such as salmonella
Salmonella
Salmonella is a genus of rod-shaped, Gram-negative, non-spore-forming, predominantly motile enterobacteria with diameters around 0.7 to 1.5 µm, lengths from 2 to 5 µm, and flagella which grade in all directions . They are chemoorganotrophs, obtaining their energy from oxidation and reduction...
and Vibrio cholerae
Vibrio cholerae
Vibrio cholerae is a Gram-negative, comma-shaped bacterium. Some strains of V. cholerae cause the disease cholera. V. cholerae is facultatively anaerobic and has a flagella at one cell pole. V...
, the bacterium that causes cholera
Cholera
Cholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae. The main symptoms are profuse watery diarrhea and vomiting. Transmission occurs primarily by drinking or eating water or food that has been contaminated by the diarrhea of an infected person or the feces...
. Despite these problems, the weed may yet have some positive use; duckweed can be treated to be fed to poultry
Poultry
Poultry are domesticated birds kept by humans for the purpose of producing eggs, meat, and/or feathers. These most typically are members of the superorder Galloanserae , especially the order Galliformes and the family Anatidae , commonly known as "waterfowl"...
or to make paper
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
.
As of 2007 the duckweed problem continues. http://www.intute.ac.uk/sciences/worldguide/html/image_1924.html