Laguna Madre

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Two fisherman stand on a shoal in Laguna Madre

The Laguna Madre is a long, shallow bay along the western coast of the Gulf of Mexico in the United States and Mexico. Meaning "mother lagoon" in Spanish, the Laguna Madre proper is 130 miles (209 km) long, the length of Padre Island; its biological corridor, though, extends well into Mexico, to Rio Soto la Marina in the Mexican State of Tamaulipas.^[1]

In the United States, Laguna Madre is separated from the Gulf of Mexico on the east by Padre Island, and bounded on the west by mainland Texas, and extends from Corpus Christi in the north to Port Isabel in the south. In Mexico, Laguna Madre is separated from the Gulf of Mexico on the east by a number of barrier islands, including Barra Los Americanos, Barra Jesus Maria, and Barra Soto la Marina. It is bounded on the west by mainland Tamaulipas.

The Gulf Intracoastal Waterway runs through the length of the Laguna Madre in the United States.

1 Characteristics
2 Ecology
3 Footnotes:
4 Sources

[edit] Characteristics

The Laguna Madre is very shallow, with an average depth of only 0.9 m.^[2] The lagoon is connected to the ocean by only two narrow inlets, so the tidal range--which is already minor in this part of the Gulf of Mexico--is negligible.^[3] Atmospheric effects are much more important than tides in its circulation; its weak currents generally follow the prevailing winds, and these winds can influence the water level by as much as a meter.^[4]

Oceanographically, the Laguna Madre is considered a hypersaline lagoon; this indicates that it is usually much saltier than the ocean, due to being nearly landlocked in a semiarid environment.^[5] Its salinity generally increases from south to north, with distance from its major inlet near Port Isabel, but it is difficult to determine an average figure.^[6] This is because its salinity can vary wildly depending on rainfall and freshwater inflow, from as high as 120 ppt (12%)--over three times saltier than the ocean--to as low as 2 ppt (2%) after a heavy rain.^[7]

[edit] Ecology

The Laguna Madre is one of the most important wildlife refuges on the U.S. coast, as home to many species of fish, migratory birds, sea turtles, and even wildcats.^[8] In fact, it is one of the most important bird wintering habitats in Mexico.^[9]