Slithering slugs that look like Day-Glo jewelry, paper-thin
flatworms floating and billowing like silk scarves, swarms of
jellyfish, crocodile fish, scorpion fish — these are the tiny
creatures of the sea that depend on coral reefs for survival. In
the new nature documentary “The Last Reef 3D,” they squiggle and
swim in front of your face, daring you to grasp at them. But the
film wants to do more than impress with its underwater
photography and 3-D effects. It’s a cautionary tale about the
fragility of the reefs, but the film could use a little more
urgency in making its case.  It begins with a bang — literally:
footage of a nuclear blast on the Marshall Islands’ Bikini
Atoll, where the United States tested nuclear weapons from 1946
to ’58. The fallout destroyed the undersea reefs. But, left
alone for years, those reefs came back, we’re told by the
narrator, in a testament to their resiliency.  The film then
goes on to describe other threats to coral reefs, which are an
essential part of the sea’s ecology. P