Every spring, snowmelt and fertilizer runoff from half a continent funnel down the Mississippi and empty into the Gulf of Mexico — and every spring, the Gulf pays for it. In the latest episode of Rising Tide: The Ocean Podcast, hosts David and Vicki sit down again with Dr. Nancy Rabalais, the LSU marine ecologist who has spent decades mapping the Gulf's infamous "Dead Zone," a stretch of oxygen-starved water created when algae blooms — fueled by that same runoff — die, sink, and suffocate everything below.

This year's zone, by Rabalais's latest count, sprawls across roughly the size of Rhode Island. In past years, it's swelled to the footprint of New Jersey.

Rabalais walks through the chemistry behind the bloom-and-crash cycle, but the conversation doesn't stop at nutrients. She and the hosts also dig into the long tail of the 2010 BP oil spill and what a decade and a half of aftermath has revealed about the Gulf's resilience — and its limits.

It's a clear-eyed look at a disaster that unfolds every year, mostly out of sight, at the bottom of America's most productive fishery. Tune in for the full conversation with one of the Gulf's most dogged chroniclers.

Forty miles off Honduras, where the Meso-American Reef meets the Caribbean, Roatan has long drawn divers chasing coral walls and whale sharks. On this episode of Rising Tide, David and Vicki dive into island life and reef conservation with Natalie Shuman, owner of Sun Divers Roatan and co-founder of Roa Girls Dive. From cooking invasive lionfish to choosing coral-safe sunblock—and settling the age-old debate over burning in a new dive mask—Natalie brings a working dive-shop owner's view of what it takes to protect a reef while keeping divers safe and stoked.