Lake Maracaibo is polluted with oil and excess nutrients

Today’s Image of the Day from NASA Earth Observatory features Lake Maracaibo, where pollution from leaking oil and excess nutrients has transformed the water. 

Lake Maracaibo is located in northwestern Venezuela. It is one of the largest lakes in South America and one of the oldest in the world. Maracaibo is connected to the Gulf of Venezuela and the Caribbean Sea by a narrow strait. According to NASA, the north end of the lake is brackish, while the south end is mostly fresh due to abundant flows from nearby rivers.

A large oil and gas reserve is located beneath Lake Maracaibo, and thousands of wells have been drilled into the lake bed. Media reports suggest that much of this oil-extraction infrastructure is in bad shape, and oil slicks occur often. 

“The oil spills are multiple and continuous, and you can easily spot the sources,” said Eduardo Klein-Salas, a remote sensing scientist at Simón Bolívar University. “Maracaibo Lake has more than 10,000 oil-related installations and a network of thousands of kilometers of underwater pipelines, most of them 50 years old.”

“The oil is spilling from many aging, submerged pipelines that are not maintained, mostly not even mapped,” said Frank Muller-Karger, a marine scientist at the University of South Florida. “Other oil slicks come from leaking above-surface storage tanks and vessels, and still others from drilling platforms.”

The lake is also overloaded with excess nutrients, which cause massive algae blooms.

“The green blooms you see are phytoplankton and cyanobacteria blooms, locally called verdín,” said Klein-Salas. “They are a permanent feature of the lake, dependent on the seasonal cycle of mixing of the already highly eutrophic environment.”

“The NASA satellite data on both problems [duckweed and oil] were amply circulated in Venezuela a decade ago and still are,” said Muller-Karger. “The ecological problems with oil spills are cumulative and affect many local fishermen, not just in Lake Maracaibo but in many places along the Venezuelan coast from Lake Maracaibo to the Gulf of Paria. Yet there is no effort by the government to change things; rather, the oil spills have gotten worse with time.”

Image Credit: NASA Earth Observatory

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By Chrissy Sexton, Earth.com Staff Writer