Puerto Rico probes darkening of bioluminescent bay in Vieques

Authorities in Puerto Rico are investigating why a glowing bay that attracts thousands of tourists a year has been growing dark in recent weeks.

The popular Mosquito Bay in the sister island of Vieques is considered one of Puerto Rico's main attractions, and government officials say they are worried about the bay's loss of bioluminescence.

Department of Natural Resources Secretary Carmen Guerrero said Wednesday that she is contacting local and international scientists to launch an investigation.

The bay's waters glow thanks to microscopic plankton known as dinoflagellates that emit light through a chemical reaction when disturbed. The bay last grew dark in early January because of rough seas, but Guerrero said it is unclear why the glow has diminished again in recent weeks.