It’s a happy 37th Earth Day for thousands of celebrants in L.A.

They showed up in tie-dyed shirts in Topanga Canyon. In jeans and work shoes in Chatsworth. In a pink “Super Girl” dress, pink tights and pink cowboy boots in Santa Monica.

Thousands marked Earth Day with their own sense of style and urgency Sunday across Los Angeles as environmental awareness was displayed from the ocean to the mountains.

In Culver City, 11-year-old Bentley Duke drew a colorful crayon image of the Earth next to the words “keep it clean” on paper shopping bags that will be used at a nearby Ralphs market.

“My message is to stop polluting. If we keep polluting it will be dirty for our own children,” Bentley said. “It’s like we’re going back to the prehistoric age again.”

Bentley was among 20,000 children and parents who visited a daylong Earth Day celebration at Star Eco Station, an environmental education program for youngsters.

The first Earth Day in 1970 was a life-changing event for Eco Station founder Katya Bozzi, who runs the program with her two adult children. “I thought we’d done it -- we’d taken care of the Earth’s problems. But then in the ‘80s we started seeing for ourselves there was still so much to be done,” she said Sunday.

In Chatsworth, realty appraisal office manager Jody Gallette didn’t remember the first Earth Day. That’s because she was only 2 at the time.

But she and daughter Alyssa Gallette, 9, and son Tyler, 6, visited Chatsworth Park North to paint out graffiti for the 37th annual event. About 100 others also showed up for the cleanup, which was organized by L.A. City Councilman Greig Smith.

The work was eye-opening for Alyssa. “If it gets too polluted it could cause humanity to leave Earth,” she said.

Topanga Canyon’s self-styled Earth Days commemoration included a display of converted diesel automobiles such as the 1986 Mercedes that West Hills resident Christina Walsh converted to run on soybean oil and recycled sushi restaurant tempura oil. “I was 8 at the first Earth Day,” she said. “I wasn’t as concerned then as I am now.”

Nearby, Delmar Lathers, who was 10 in 1970, was pedaling an old exercise bike connected to a military-surplus M-1 tank turret motor. It was powering an electric blender that was making organic blackberry smoothies.

“You still see people tearing around in big gas-guzzling cars,” said Lathers, a ceramics teacher who lives in Topanga. “I don’t know if people are getting it yet that we have a problem.”

Jim Crawford, a Topanga audio engineer, was showing sons Delaney and Dalton, 14 and 13, how hot a solar stove was, even as storm clouds overhead blocked the sun. “Any time you don’t have to pay water and power bills it’s a step forward,” he counseled them.

It was cold and overcast at Santa Monica Beach, where 6-year-old Katie Raphaelson, dressed totally in pink, was heading with her father, TV marketing executive Josh Raphaelson of Santa Monica, to pick up trash for Heal the Bay.

Tom Vitzelio, a history and political science professor from Riverside, was helping son Nicholas, 3, paint a decorative whale on the Santa Monica Pier’s Aquarium wall for Earth Day.

Vitzelio suggested that people still have much to learn.

“One day 100 scientists will say one thing about global warming. The next day another 100 will say something else,” he said. “I honestly don’t think we know enough about this planet.”

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bob.pool@latimes.com