Watermarks

Welcome to Watermarks

In this issue of your exclusive multimedia National Aquarium member magazine, we are taking a look at the unique species and places that make our region—and the Aquarium itself—such a special place.

Amazing Alcids

The National Aquarium's amazing alcids—puffins, black guillemots and razorbills—display fascinating and significant seasonal molting patterns. With the help of our gifted staff photographers, we're ruffling some feathers and taking a closer look.

Reading the Reef: Sharks, Climate Change and You

Biodiversity—like the numerous species teeming around our Blacktip Reef exhibit—is an important indicator of ocean ecosystem health. See what sharks mean to a reef system and how their presence or absence relate to climate change, and how our choices can make all the difference within these fragile blue spaces.

Internationally Renowned Oceanographer Sylvia Earle

"I consider aquariums to be an essential part of educating the public at large. I hope this place is like a halfway house to get to the BIG Aquarium—the ocean itself—to let people see what they otherwise would not see. I thank you for being ambassadors for the ocean."

Sylvia Earle addressing our staff and volunteers during her visit on December 1, 2021.

Ask the Expert

Lizzie S. Asked:

"Sometimes when we visit the National Aquarium, the water in the Inner Harbor is a cloudy green color. Other times, it looks normal. What causes this?"

We Answered:

Sulfur bacteria live happily on the bottom of the harbor where there's a tiny bit of sunlight and no oxygen. When we experience a really hot day followed by a cold night, like we often see in September and October, the sharp temperature change affects the density of brackish salt water. This causes surface water to sink rapidly, displacing the water at the bottom, which is then brought to the surface. When the sun rises the next day, the bacteria harvest sunlight to perform anoxygenic photosynthesis—or photosynthesis without the production of oxygen. The waste product of this process is hydrogen sulfide, which has a characteristic smell of rotten eggs. The chemical reaction between the sulfur bacteria and sunlight also results in a bright green color, which is why this bloom is often referred to as a "pistachio tide."

-Charmaine Dahlenburg, National Aquarium Director of Field Conservation

Do you have a science, animal or conservation question for National Aquarium experts? Email us at geninfo@aqua.org, use the subject line "Ask the Experts" and you might see your question in our next issue of Watermarks.

Interactive 3D Aquarium Tour

Whether you’d like to relive your most beloved National Aquarium moments, plan your next visit or just explore from the comfort of your couch, check out our interactive 3D tour. Click-by-click, you can navigate your way from our front door to your favorite exhibits and everyplace in between. What are you waiting for? Hop in and take a look around!