A contest sponsored by the University of Miami's Rosenstiel School of Marine and Atmospheric Science has been recognizing the top underwater pictures taken by amateur photographers since 2005, but this year is different: For the first time, Internet users are being asked to select a "fan favorite" from five nominees. The voting runs through Sunday, and the People's Choice will be revealed along with other winners on April 18. Which is your favorite?

Courtesy of UM Underwater Photo Contest

The sun glints behind a jellyfish seen from the waters below.

Courtesy of UM Underwater Photo Contest

A crab and its eggs make a colorful display.

Courtesy of UM Underwater Photo Contest

A single fish is framed by a school of smaller swimmers.

Courtesy of UM Underwater Photo Contest

A penguin peers into the camera as it floats by.

Courtesy of UM Underwater Photo Contest

Colorfully striped fish make their way through an underwater scene.

The arrangement of the pictures reflects the current standings in the "People's Choice" poll. Those rankings could change as the week goes on. For now, the identity of the photographers is being held back, although at least one of the nominees is making a personal plea on the University of Miami website. That's where you can register your vote — or "votes," since you can click for your favorite once a day through Sunday. Stay tuned for the big reveal on April 18.

More about underwater photography:

• Underwater photography contest kicks off
• Bellyflop! Amazing photos of underwater dogs
• 2011: Cameras capture underwater wonders
• Photo exhibit displayed on artificial reef

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.