Picture of paddlers on the bioluminescent kayak tour of Merritt Island National Wildlife Refuge

In the summer and early fall, the Indian River Lagoon is full of luminous organisms.

Photograph by Douglas R. Clifford, Alamy

By Maryellen Kennedy Duckett

The darker the night skies, the more stunning the aquatic light shows in the Merritt Island National Wildlife Refuge's Indian River Lagoon. The lagoon is the site of two distinct and dazzling performances of bioluminescence (the emission of light produced by a chemical reaction within a living organism). A Day Away Kayak Tours leads guided tours into the darkness to witness both.

Dinoflagellate Tour, Indian River Lagoon, Merritt Island National Wildlife Refuge

When you enter the lagoon on the north end of the refuge, your paddle becomes a paintbrush and the water a canvas. Each stroke creates streaks and puffs of blue-green neon light under the surface and sends glittery droplets into the dark night sky. The living laser show is created by one-celled, light-emitting organisms called dinoflagellates. And from June through early October, the Indian River Lagoon is packed with the luminous organisms, often numbering more than 100,000 per liter of water. "These little life-forms create cold light within themselves like fireflies do," says Elisabeth Mahan, A Day Away Kayak Tours co-owner and guide. The glowing effect illuminates tiny fish, sea grass, water droplets, and kayaker hands dipped beneath the surface. Adds Mahan: "Bioluminescence is something you have to experience for yourself. It will leave you awestruck." Tours last about two hours, and reservations are required.

Comb Jellies Tour, Indian River Lagoon, Merritt Island National Wildlife Refuge

Mid-October through May, gelatinous comb jellies take over the starring role in the Indian River Lagoon light show. While commonly mistaken for jellyfish, comb jellies are distinct animals named for the giant, comblike rows of cilia running up and down their bodies. They also generate colors in two ways: through bioluminescence, emitting a flashing blue-green light when disturbed; and by refracting light through the motion of their cilia. The cilia combs act like paddles, propelling the jellies and scattering light, which creates a pulsing, rainbow-like pattern. The resulting underwater color display is similar to what you'd see on a dinoflagellates tour of the lagoon in summer or early fall, yet the experiences are distinct and worth separate visits.


When to Go: Bioluminescence is most easily observed on the darkest nights, when the moon isn't clearly visible. Use a lunar calendar to help choose the best night for your tour.

What to Wear: Bring and wear insect repellent (particularly after a heavy rainfall), long pants, and a long-sleeved shirt to protect against mosquitoes (particularly if there's little to no wind).

What to Bring: Pack bottled water, snacks, and a change of clothes (since you'll likely get wet).

Practical Tip: Tours last about two hours. There's no restroom at the launch site, so use the facilities at A Day Away Kayak Tours in Titusville before boarding the shuttle for the 20-minute drive to the refuge.


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