In California's Yosemite National Park, the main sound coming from headquarters is the constant buzzing of unanswered phones.
"There's normally 25 to 30 people in the building," said Park Ranger Scott Gediman, public affairs officer. "There are four of us now."
Gediman is one of those still working since Tuesday, when the federal government shut down, all national parks closed, phones at many offices stopped being answered and official U.S. websites went blank.
That makes him "essential," or, for agencies that prefer a less judgmental label, "excepted." And that means he and thousands of others in government operations across the country are working through the shutdown and handling the jobs of the 800,000-plus federal workers who have been furloughed.
They're doing the work of many and not getting paid until after a budget agreement allows the government to reopen.
"People are taking it in stride," said Gediman. "There's no animosity."
The National Institutes of Health (NIH) website is down, but John Burklow, associate director of communications, and his assistant are the only two answering the phones in a division that normally has 38 people.
Almost half the 14,700 employees have been furloughed.
"People have skeletal crews all over," said Burklow, who had handled more than 50 calls by midafternoon Wednesday.
"There are thousands of experiments going on, everyone is trying to protect their experiments, and some of the people who have been asked to stay are taking care of patients and (test) animals," he said.
The shutdown is dashing hopes of treatment for some. The NIH runs the largest research hospital in the world, and there are 1,400 studies ongoing, including 500 clinical trials. Every week, 200 patients enroll in the trials.
That has stopped. Any patient — some critical — who enrolls now will be told to wait.
"It's more of a delay," Burklow said. "We will get to them."
If a doctor decides a patient's life is threatened by a delay, the patient may be accepted, Burklow said.
In the meantime, "people are working and not getting paid."
National park rangers are trying to avert emergencies. At Grand Canyon National Park in Arizona, law enforcement rangers, electrical crews and other safety crews are still working, but almost 80 percent of the 558 employees were furloughed. That doesn't include 1,400 concession employees who work in the park for private firms contracted by the government.
The majestic tourist attraction brings in $467 million a year from tourists and supports 7,300 jobs in surrounding communities.
Maureen Oltrogge, a 27-year Park Service veteran, is handling the hundreds of calls with one other person. All reservations for campgrounds, rafting trips and weddings on the South Rim are canceled.
"On average, we have one to three weddings a day at this time of the year," Oltrogge said. "We had some people who had planned on getting married here who are pretty upset."
So are commercial companies that had planned on filming in the park this week and schools that had planned field trips. The park usually attracts an average of 18,000 visitors a day in October.
Everyone will be out of the park by Thursday. The only ones avoiding cancellations are the adventurous who are camping in areas too remote to reach or those who have already embarked on a rafting trip.
"I'm here to do a job and I'll continue to do my job," said Oltrogge, whose birthday fell on the first day of the shutdown. "They may decide they don't need two people in information … We don't know if we'll get paid. I try not to think about that right now."