When a child gives a gift for Mother's Day, the mother always says she loves it, whether that gift is a lumpy clay cup or a macaroni picture that sheds glitter on the freshly mopped kitchen floor. But Jan Cousteau can’t suppress a tender smile, remembering when she told her young daughter Alexandra, “Never throw anything into the street. Trash goes in mommy’s purse.” The little girl dutifully deposited not only her own litter into the purse, but picked up other trash to add to her bemused mother's handbag. Perhaps it shouldn’t have been a surprise — environmentalism runs in the family.

Decades later, Alexandra doesn’t put trash into her mother’s purse anymore, but through her work, she does try to educate the world about better ways to manage garbage and pollution. The importance of conservation and stewardship of the environment are ideas that Alexandra inherited, and using film to share these themes is in her blood. As the granddaughter of legendary explorer and filmmaker Jacques Cousteau, Alexandra grew up in a family of explorers who passed on their love for nature as she journeyed with them on expeditions before she could even crawl.

From a journey to Easter Island when she was just 4 months old to a trip along the Nile as a toddler — where she eagerly helped out around the camp — this was just the beginning for this precocious globetrotter, and a gift she appreciates to this day. “It was a privilege growing up as a Cousteau,” Alexandra said of her youthful adventures.

As she sits comfortably on a couch next to her mother in her Washington, D.C., home, it's hard to imagine Alexandra as the lifelong explorer of seas, jungles and deserts. The films and writings from her travels tell the story as she carries on her grandfather’s tradition of educating people about the natural world. Describing the amazing undersea discoveries that her grandfather made, she said she sees what she does as part of the evolution of the idea of exploration.

“It’s not just for the few and intrepid anymore,” she said. Instead of only going places no one has been before, Alexandra reexamines ideas and places people may think they already know, examining crucial environmental concerns and fragile ecosystems along the way and leading people to “see a place through new eyes.”

In 2008, she founded Blue Legacy, a nonprofit organization designed to tell stories and generate discussion about critical water issues ranging from local watersheds and water quality to oceanic pollution and climate change. Alexandra put together a 138-day trip around North America to explore vital water issues, from places like the Colorado River and the Gulf Coast. The tour, which finished in November, came about after Alexandra did a similar expedition around the world and realized that many people in North America didn’t see how water issues could affected them like water issues affect places like Botswana and India. “People thought this issue didn’t apply to them here, but it does,” she said.

On her journey, Alexandra revisited places where she traveled as a younger woman, but noted that many of them aren’t the same — if they exist at all. “Places I went to as a child are starting to disappear,” she said. Many creeks, ponds and rivers she visited were horribly polluted, affecting the health of communities that were unaware of dangerous chemicals in the water. Alexandra hopes that the work she and her crew did on the trip and the resulting films will help to save these areas from further harm. “After our generation, it will be too late for these treasures,” she said.

Alexandra’s concern for generations to come is more than abstract. She and her husband, Fritz, are expecting their first child, a girl, very soon, and Alexandra wants her daughter to see as many of the same natural wonders in years to come.

“That kind of continuity is important,” she said. Alexandra ascribes a lot of her passion and zeal for environmental advocacy to her mother, Jan. “My mom made sure I had access to wild places,” she said.

Jan Cousteau’s own impressive contributions as a conservationist mesh neatly with the family story. A former fashion model, she married Philippe Cousteau Sr. in 1967 and joined the Cousteau team on several expeditions, serving as cook, photographer and paramedic among other roles. After Philippe Sr. died in a plane accident in 1979, she raised Alexandra and Alexandra’s younger brother Philippe Pierre, working as a wildlife rehabilitator. She and her children helped raise beavers, dolphins, deer and walrus that wouldn’t have survived on their own, and she worked to instill in her children a respect for the natural world. “The responsibility was keen on them from the time they were little,” Jan said.

Because extended travel is so much a part of their lives, Jan and Alexandra said their family often celebrates holidays based more on availability than the calendar. Gifts are usually a product of the latest journey, although Alexandra wouldn’t reveal what she brought for Jan for Mother's Day.

Jan still works to protect wildlife today both on the board of directors of the Washington Humane Society and through her work as a co-founder, with her children, of EarthEcho International, a nonprofit organization that develops programs to engage young people in learning about and protecting the ocean. She still enjoys the occasional expedition, like joining Alexandra for a month during her North American water tour.

She will come along in a few months when Alexandra begins her next adventure, this time to Belize to examine the delicate ecosystem between the country's coast and the coral reefs nearby. “It will be a huge support and comfort to have Mom on expedition,” Alexandra said. The trip will also mark the inaugural adventure of Alexandra’s new daughter, who will join her mother and grandmother — much as Alexandra once did with her parents and carrying on the family tradition that Jacques Cousteau started.

“It’s all inspired by my grandfather,” Alexandra said of her work.

Alexandra and Jan both look forward to the trip — not simply the adventure of it, but the chance once again to share the Cousteau family quest to preserve and educate others about the natural treasures of the world.

“We’re inspiring people to protect the places we love,” Alexandra said.

Also on MNN: Watch videos of Alexandra Cousteau's Blue Legacy expeditions