On the central coast of California, environmental toxicologist Peter Weiss-Penzias and his team of researchers find dangerously high levels of mercury in mountain lions. Tracking the pollutant down the food web, they discover that mercury is coming from the fog—a beloved icon of California.

Across the sweeping rift-valley plains of northern Tanzania, two guardians keep the balance: endangered Masai giraffes and the Maasai pastoralists who share their land. Sentinels of Engaruka offers a rare, ground-level view of this fragile alliance at a time when invasive shrubs, shrinking pasture, and climate change threaten to tip the scales.

A documentary shining a light on the community of owl box keepers and preservationists in the San Francisco Bay Area and surrounding areas.

The San Francisco Bay is a hub for imports, tankers, sailboats, rowing and swimming. It is also an estuary where marine species hunt, feed, visit and live. Yet few scientists have studied the local sharks in the SF Bay in recent decades, until now. Dr. Meghan Holst founded OSEA (Ocean Science Expedition Academy) and leads citizen science expeditions to monitor shark species and teach a new generation of scientists.