Guests gathered for the fifth annual Walter Cronkite awards ceremony and reception on Tuesday, beneath an ivory tent on the front lawn of Karen and David Brush’s Edgartown home. The house, once belonging to the late CBS news anchorman, was a particularly special venue, but it was not the only trace of Mr. Cronkite’s legacy present on Tuesday night. His grandson, Walter Cronkite 4th, now an associate producer for CBS News, was in attendance to present the awards to two distinguished guests: Sylvia Earle and Sam Low.

Walter Cronkite 4th presents award to Dr. Sylvia Earle. — Ray Ewing

The Cronkite awards are presented each year to people who have shown a commitment to using the media to create positive social change. This year’s theme was the oceans, a topic Mr. Cronkite cared deeply about as both a sailor and environmental advocate. The event benefitted the Martha’s Vineyard Youth Leadership Initiative, a project of the Stone Soup Leadership Institute of which Mr. Cronkite was chairman for over a decade.

Ms. Earle is a National Geographic Society explorer in residence. Aside from spending thousands of hours underwater in her lifetime and setting the record for solo diving at a depth of 1,000 metres, she also led the first team of female aquanauts during the Tekite Project in 1970. Now, she is the subject of Vineyard filmmaker Bob Nixon’s documentary Mission Blue, which premieres on Netflix on August 15. A prescreening of the film was held on Tuesday evening at the public beach in Menemsha.

Mr. Low, an Oak Bluffs anthropologist, author, filmmaker and photographer, has won acclaim for his 2013 book Hawaiki Rising—Hokule’a, Nainoa Thompson and the Hawaiian Renaissance, about a group of Hawaiians who sailed the world in a replica of an ancient Polynesian voyaging canoe to connect with their culture and ancestry. Mr. Low was also the maker of 1983 film The Navigators — Pathfinders of the Pacific, about the Polynesian settlement of the Pacific.

Mr. Cronkite 4th presented Ms. Earle and Mr. Low with their awards, which included a biography of his grandfather. Commendations from Hawaii Gov. Neil Abercrombie were read aloud, thanking Ms. Earle and Mr. Low for their commitment to the environment.

Bob Schieffer, moderator of Face the Nation, spoke at the ceremony — Ray Ewing

On stage, the award recipients shared their gratitude for the honors they were given.

“I am so deeply honored to receive this award in the name of an individual for whom I have tremendous respect,” said Ms. Earle. “I mean, I grew up just thinking about Walter Cronkite almost as the voice of God . . . for me being here with you and looking out at Walter Cronkite’s boat and realizing that his presence is very much still alive and well here in Martha’s Vineyard, it’s like a dream.”

Mr. Low expressed similar gratitude as he reflected on the experiences that earned him the accolade.

“To be voyaging in the path that our ancestors took to discover and settle one third of the world’s surface was an astonishing experience for anyone with Hawaiian blood,” he said. “In a deep sense Hokule’a has enabled us to recover our past, our ancient wisdom and then to think of ways to bring that wisdom forward, to present it to the world, as a way of being bono, or just, or living in balance with our family.”

Bob Schieffer, moderator of Face the Nation, and Christopher Callahan, founding dean of the Walter Cronkite School of Journalism and Mass Communication at Arizona State University, were keynote speakers.

Mr. Schieffer shared anecdotes about working with Mr. Cronkite as a young journalist at CBS.

The event benefited Martha's Vineyard Youth Leadership Initiative. — Ray Ewing

“The question I always get asked about Walter Cronkite was, what was Walter really like?” Mr. Schieffer said. “Well, the answer is he was exactly the way you would want him to be. He was exactly in private life as he was on camera. He was a wonderful friend, I would probably not be standing up here today had it not been for Walter Cronkite, but you know he set a great example for all of us, what he stood for, his principles. He was a wonderful guy and I know, knowing him as I did, he would have loved to have been here today.”

Adding his notes, Mr. Callahan said: “If you want to see part of Walter’s legacy, tune in on Sunday mornings to Face the Nation and you watch Bob Schieffer do interviews. That is a major part of Walter Cronkite’s legacy.”

To wrap up the night, several of the eight members of the youth leadership initiative went on stage to speak about their experience in the program.

“It’s really empowering,” said Mary Ollen, who has been involved in the program for three years. “I think everyone talks about young people as being the leaders of tomorrow and through MVYLI I think we’ve all learned that we can really be the leaders of today and actually make a difference in our community, in our Island, and in our world.”

Marianne Larned, who leads the programs as executive director, and Marsha Reeves-Jews, president of the Stone Soup Leadership Institute board of directors, also spoke.

The ceremony was followed by a reception on the lawn of the Brush residence overlooking the Edgartown harbor.