San Francisco Chronicle

Out of the blue: biolumines­cence

- Tom Stienstra is The San Francisco Chronicle’s outdoors writer. Email: tstienstra@sfchronicl­e.com Twitter: @StienstraT­om

On a night made for sorcerers and wizards, the tidal surge glowed neon blue at the south end of Rodeo Beach. A marine phenomenon called biolumines­cence radiated through the sea near three inshore stacks.

The dark coastal sky seemed filled with diamonds. The lights from a few ships out to sea sparkled on the horizon.

Photograph­er Tony Rowell, not quite believing the scene in front of him, gazed through his tripod-mounted Nikon and then exposed an image for 15 seconds. Within that span, a meteor had streaked across the sky.

“I think I got it,” Rowell remembered saying. Then the full scope of the rare scene hit him like a bass drum booming in his chest: He might have captured the image of a lifetime.

“It was pure luck, just pure luck,” Rowell said. “I was just at the right place at the right time. Serendipit­ous. A complete accident.”

The biolumines­cence lasted 3 to 4 hours on back-to-back nights last weekend at Rodeo Beach, a landmark on the Marin Headlands in the Golden Gate National Recreation Area.

In past years, verified episodes of biolumines­cence have occurred in Tomales Bay, Pacifica, the northern Santa Cruz County coast and Big Sur. Late February and March seem to be the most likely time for it, when a synergy of marine and atmospheri­c conditions can merge.

When biolumines­cence occurs, the ocean appears to glow — often blue or green, something like the aurora borealis of the sea. The light is produced by organisms, dinoflagel­lates (such as plankton) in a bloom, timed just right with disturbed water, which can produce a phosphores­cent glow.

In Tomales Bay, for instance, you can camp on the western shore of Point Reyes National Seashore and never see the phenomenon. But paddle on a calm, cold night in late winter, and the glow — most often green here — can appear around your kayak. During World War II, there are tales of sailors watching the sea glow behind their ship’s propellers. On the coast, it occurs in the tidal surf zone.

The problem is that you never know when or where the conditions will be right.

Rowell’s chance came after a photo workshop — he teaches at Looking Glass Photo in Berkeley — when he invited students to join him on an impromptu photo shoot at Rodeo Beach. Rowell is a renowned night-sky photograph­er (his book, “Sierra Starlight,” was published in 2015) always willing to share his techniques. He also works with Celestron Telescopes.

“It’s the dark skies at Rodeo Beach that make it ideal for night photograph­y,” Rowell said. “It’s one of the darkest places in the region to photograph the night skies. On the beach, with the Marin Headlands blocking San Francisco, you get below the lights of the city.”

When he arrived at 7:30 on Saturday evening, nobody else was on the beach.

“I was heading out there with several students to the beach to take nighttime, longexposu­re photograph­y,” Rowell said. “The biolumines­cence appeared right in front of us, and at one point, the setting moon with stars all around us, the moonlight refracted right through the blue waves.”

Rapturous with his luck, Rowell returned Sunday night with a pal, Sean Harnden. They quickly saw the phenomenon had shifted to the southern part of the beach, about a quarter-mile away, near the three landmark sea stacks.

The ocean glowed phosphores­cent blue in the surf zone as he set up his equipment: A Nikon D850 body matched with a 24mm Nikon lens, mounted on a Manfrotto tripod.

“After a few hundred photos, the tide started coming in, and we were getting ready to leave,” Rowell said. “It was about 10 p.m. I had set up an exposure for 15 seconds, looked up and saw a bright meteor.”

Rowell, who once took an iconic photo of a Geminid meteor over the Mount Whitney summit, called that event a similar piece of luck. But for photograph­ers, luck often comes for those who spend the longest days and nights afield.

“If somebody wants to see something like this, there is no way to plan for it or to predict it,” Rowell said. “It’s a natural phenomenon, a special event. Who knows, it might happen again tonight. And who knows where?”

 ?? Photos courtesy Tony Rowell ??
Photos courtesy Tony Rowell
 ??  ?? A meteor streaks across the night sky as a rare marine phenomenon known as biolumines­cence lights the waters a phosphores­cent blue near Rodeo Beach at the Marin Headlands in a scene captured by photograph­er Tony Rowell, below.
A meteor streaks across the night sky as a rare marine phenomenon known as biolumines­cence lights the waters a phosphores­cent blue near Rodeo Beach at the Marin Headlands in a scene captured by photograph­er Tony Rowell, below.
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