In Teo Source’s Cambridge salon, a row of empty white salon chairs tells the story: the effect of coronavirus concerns on a small business. On Thursday, Source said she’s had daily cancellations of appointments and they stretch through April.

“I don’t really know what’s going on right now, but it’s crazy,” said Source, owner of Le Petit Salon Curl Concept. “Because my clientele drop [by] at least over half, over 50 percent has been cancelled, and it's a big problem. “

Some clients, like college students, are leaving town. But others, like professors and locals, are just worried about getting the COVID-19 virus. Social distancing is impossible in a salon, so it's a tough sell.

Just downstairs is Black Sheep Bagels, a business that thrives on student traffic. After two years building up what he calls “a community” from the school population, owner Manny Ramirez said students came in to commiserate over the sudden end to their semester on campus on Thursday.

"It's kind of chaotic right now, as a small business owner in Harvard Square. We’re feeling the pressure, we’re scared,” Ramirez said. "I know a lot of my peers, small business owners in the neighborhood, are also scared.”

Ramirez estimated he’ll lose over 40% of his revenue with Harvard students gone. In the meantime, labor costs aren’t going away — he has more than a dozen employees to pay.

And one of the biggest money-makers for area restaurants and small business — commencement — is in doubt.

Bob Slate Stationer on Brattle Street has been a landmark store for the Harvard crowd for decades, but recent foot traffic has been crushed. Owner Laura Donohue said Thursday that Harvard seniors even came in to return their specially purchased thesis binders. Usually, she said, her sales lift in the month of March.

“We don’t know how long this is going to last. If this is a two-month problem, that’s a very big deal for small retailers,” Donohue said. “When revenue is gone, it’s gone. It doesn’t come back. People don’t come back to you two months later and buy again. And you still have the bills, you’re still paying bills, you’re still paying rent and you’re still paying for the product.”

She said she worried about hourly workers — not only at her store and small businesses, but also at the larger chains.

"A normal sort of immediate reaction might be, 'Well, I need fewer hours, I’m going to cut back because I need to keep some funds around,' but then you have the staff who don’t get paid," Donohue said. "Unless they have a huge safety net of savings or access to some funds, then the ripple effect is just enormous."

For many shops, the drop in tourists is an even bigger economic blow than the loss of student business. Harvard Square usually gets between 8 and 10 million visitors a year, according to Denise Jillson, executive director of the Harvard Square Business Association. Jillson said many tourists come from Asia, where Harvard is an icon.

“This is very different,” Jillson said. “You know, we’ve had circumstances around the Boston Marathon bombing and 9-11 that impacted business for a few weeks, but [it’s] the uncertainty of this virus and the global scale of this virus.”

It’s a tough balance. Weighing caution about coronavirus with calls to go out and shop, Jillson said she hopes local shoppers will pick up the slack so businesses can survive.

Just two miles from Harvard is Kendall Square, one of the world’s largest clusters of science and technology. Coronavirus vaccine research is underway in several neighborhood buildings, and some of it’s not the kind of work you can do from home.

But that’s not the case for most of Kendall Square’s workforce. On Thursday, the streets grew quiet as rapidly increasing numbers of employees were told to work from home.

“I’m very concerned for the small stores, or any company that’s manufacturing, like hard goods," said Peter Wallace, a product designer at Pivotal Labs who was on his way home to start working remotely. He said he knows he's lucky.

"Obviously when workers don’t come in, you’re not going to be able to produce as much product, and then that’s going to hurt sales,” Wallace said. "So, I’m definitely concerned for the companies that aren't able to say, 'Hey, you’re on a laptop all day at work, why not just do that from home.'"

Local restaurant Area Four sits on Kendall's Technology Square. It’s famed for its pizza — once ordered by President Barack Obama. Area Four partner Jeffrey Pond said Thursday he felt a real drop in business this week.

“I think this is the beginning of it. I think it's going to get worse, to be quite honest, for a while,” Pond said. “Some of the friends that we have in this area are down already 20-30 percent just this week. That was even with the existing foot traffic. I think a lot of us are bracing for well over 50% loss or potential closing, temporarily anyway. Which I think is definitely a possibility.”

Pond said he would be happy for any government aid, but thought the fastest end to the crisis will come if people stay home.

"You’ve got to talk to your landlords, you've got to talk to your vendors," Pond said. "'Cause we’re all in this together, to be quite honest with you.”