Arrecife Alacrán
- ISS004-E-8516
- 11 March 2002
- 17:38 UTC
Located in the southern regions of the Gulf of Mexico, 116 km off the northern coast of Mexico's Yucután Peninsula, Arrecife Alacrán (Scorpion Reef) is the largest of a group of emergent reefs that lie on the outer edge of the Campeche Bank and form a loose arc of reefs and cays that parallel the northern and western coasts of the Yucután Peninsula.
With an appearance reminiscent of an atoll formation, Arrecife Alacrán is a large, emergent, shallow-water platform reef. Oval-shaped in outline, the reef measures 27 km in length and is up to 15 km across. Major structural features include the long arcuate reef on the eastern (windward) side (at top in the above image) and the poorly-developed series of largely-submerged reefs on the western face. The protected interior lagoon contains a profusion of reticulate reef formations, patch reefs and coralline ridges; in the northwest the lagoon contains more open regions.
The western (leeward) rim contains five vegetated cays: Isla Chica, Isla Desterrada, Isla Desertora, Isla Pérez, and Isla Pájaros; there are also areas of shifting sand bank that may become alternatively exposed and removed with wind and wave action as well as being modified by storm activity. The islands are all low-lying and vegetated, rising to no more than 4 m above sea level.
The islands of Arrecife Alacrán are regionally important seabird nesting sites as well providing stopover to species migrating across the Gulf of Mexico. Nesting species include Masked Booby, Red-footed Booby, Brown Booby, Laughing Gull, Brown Noddy, Magnificent Frigatebird, Royal Tern, Sandwich Tern and Sooty Tern.
image: earth sciences and image analysis laboratory, nasa johnson space center.
