BioEd Online

Small can be beautiful, as these pictures of tiny marine animals testify. Marine biologists took the stunning snaps on a research cruise to survey the small creatures of the deep that support the ocean's food chains.

The cruise, part of a research effort called the Census of Marine Zooplankton, captured and catalogued thousands of samples, representing some 500 different species, from depths of up to 5 kilometres. They were caught using a special device that systematically opens nets at depth intervals of a kilometre.

The scientists hoped to discover more about the diversity of these tiny creatures at such extreme depths, where they have never been trawled for before.

The 28-strong crew of researchers sorted the samples into species groups and distinguished similar-looking species using an on-board DNA sequencer. "We believe this is the first team ever to sequence DNA of zooplankton on a rocking, rolling ship," says the cruise's scientific leader, Peter Wiebe of the Woods Hole Oceanographic Institution in Massachusetts. The results revealed a greater diversity of species than expected, including some that are new to science.

Among the haul were tiny shrimp, swimming worms, 'flying' snails, pulsing jellyfish and some fish. All but the fish fall into the vast category of marine life called zooplankton.

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