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Julia Parrish quoted in Scientific American on bizarre blue "jellyfish" signaling spring

Wednesday, May 3, 2023 - 15:15

Julia Parrish, UW Biology Professor, is quoted in a Scientific American article about blue "jellyfish" washing up on California beaches. Along the U.S. Pacific coast, droves of alien creatures about the size of a doughnut are washing up on beaches and leaving a mat of briefly blue debris that soon fades to a crackly white -- hiding just how bizarre these tiny animals are. 

Along the U.S. Pacific coast, droves of alien creatures about the size of a doughnut are washing up on beaches and leaving a mat of briefly blue debris that soon fades to a crackly white—hiding just how bizarre these animals are.

“Most people experience them as some kind of weird, off-white, old-toenail-color crunchiness that you walk on on the beach,” says Julia Parrish, a marine ecologist at the University of Washington. “They have no idea that they’re actually walking across billions and billions of organisms.”

The invasion may be a sign of warmer temperatures in the oceans or even of the large-scale climate pattern known as El Niño, although scientists say these connections are more hypothesis than proved fact.

Countless creatures, each one a blob reaching up to about 80 millimeters wide, can wash up on a single beach within days—because these predatory animals, called velellas (Velella velella), or by-the-wind sailors, are linked together. Such hydrozoans form a subgroup of Cnidaria, a phylum whose members also include jellyfish and coral. For velellas, each apparent “jellyfish” is a colony of many individual polyps hitched to a “float” they build together: a blue-rimmed, tentacled disk topped by a clear “sail.” Members of a colony use their stingers to capture the plankton that feeds their shared digestive system.

Read the full article in Scientific American.

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