today
8:30 a.m. Audubon Society Field Trip See Event Description
read >9 a.m. Arcata Farmers' Market Arcata Plaza
read >9:30 a.m. Discovery Walk: Unknown Waterfront See Event Description
read >9:30 a.m. Manila Dunes Restoration Manila Community Center
read >10 a.m. Manila Dunes Guided Walk Manila Community Center
read >10 a.m. Library Book Sale Humboldt County Library
read >10 a.m. Dia de los Muertos and Mexican Folk Art Sale Private Eureka home
read >10 a.m. Final Arcata Farmer's Market Arcata Farmers' Market (off the plaza)
read >11 a.m. Donlin Foreman Dance Workshop Dell'Arte
read >2 p.m. Humboldt Coastal Nature Center Draft Trails Plan Walk Stamps House
read >5 p.m. Bati Zado and Show Redwood Raks World Dance Studio
read >6 p.m. The Tumbleweeds Chapala Cafe
read >6 p.m. Ali Chaudhary (jazz duo) Libation
read >6:30 p.m. Not Evil, Just Wrong Humboldt Area Foundation
read >7 p.m. Guitar Stan (country) Old Town Coffee & Chocolates
read >8 p.m. Guitar Orchestra of Barcelona Arkley Center for the Performing Arts
read >8 p.m. Stones in His Pockets Arcata Playhouse
read >8 p.m. A Christmas Carol North Coast Repertory Theater
read >8 p.m. Donna Landry Swing Dance Moose Lodge
read >8 p.m. North Coast Wind Ensemble Fulkerson Recital Hall at HSU
read >8:30 p.m. The Last Minute Men (international) Cafe Mokka
read >9 p.m. Ian McFeron Band (folk rock) Six Rivers Brewery
read >9 p.m. The Michael Paul Band WAVE @ blue lake casino
read >9 p.m. The Generatorz (classic rock) Central Station Cocktail Lounge
read >9 p.m. Taxi Bear River Casino
read >9 p.m. VJ Itchie Fingaz Pearl Lounge
read >9 p.m. Jack Ruby Presents + Blue Street + Acufunkture (DIY rock) Jambalaya
read >9 p.m. 2nd Annual Scorpio Bash The Red Fox Tavern
read >10 p.m. Music by DJ Sidelines
read >10 p.m. DJ Icy Hot Aunty Mo's Lounge
read >10 p.m. Jemimah Puddleduck (rock) Humboldt Brews
read >10 p.m. White Manna + Midday Veil + The King Salmon Duo (rock) Jambalaya
read >11 p.m. Radio Moscow (psychadelic blues) + Mosquito Bandito (one-man surf/garage) The Alibi Lounge and Restaurant
read >previous columns
March 27, 2008
Hunting Worms
I recently went big-game hunting in the bay for a ...
read >March 20, 2008
Tsunami Terrors
Understanding the nature of tsunamis could save your life. They ...
read >March 13, 2008
In Formation
The V-formations of honking Aleutian Cackling Geese that decorate our ...
read >
Photos
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The jellyfish Velella. Photo courtesy of Curt Beebe.
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Diagram of Velella anatomy by Don Garlick.
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Diagram of Velella's sail by Don Garlick
Ancient Mariners
By Don Garlick
Sailing is an ancient enterprise. Humans used the wind to cross the oceans thousands of years ago. Sails, however, existed 350 million years before humans hoisted theirs. The jellyfish Velella, several centimeters long, sails warm oceans to feed upon pelagic organisms which it captures with stinging tentacles a few centimeters long. Fortunately, their nematocysts (see "Garlick's Notebook," Nov. 15, 2007) are usually too short to penetrate human skin. Strong winds from the north often strand millions of these purple mariners on local beaches.
Velella's anatomy is depicted in the cross-section. The photo, courtesy of Curt Beebe, reveals its unique two-fold symmetry (180 degree rotations leave it unchanged). The absence of mirror symmetry means that the animal tends to sail at an angle to the wind because the sail tends to orient perpendicular to the wind. I floated a wood and plastic model, which I defined as left-handed, on a large puddle. It consistently sailed to the left of the down-wind direction. For winds from the south, left-handed Velella would safely move away from our coast. I have read that Velellas appearing on Chile's beaches are generally right-handed. This may be the only organism whose chiral anatomy (handedness) is influenced by the Coriolis Effect (see "Garlick's Notebook," Oct. 18, 2008).
For your appreciation, countless Velellas will be showing up soon on a beach near you. Will they all be left-handed?
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