The Wonder of Small Things

by Maggie Koerth-Baker

From a public perspective, biology in the oceans, like biology on the land, tends to favor the charismatic megafauna. Stop by your local aquarium and you’ll find masses huddled around the seal pool or the shark tank. People will even attempt to interact with the octopodes. Meanwhile, smaller creatures sit on the sidelines. Crabs, starfish, and ray-like skates have some admirers at the touch tanks. But in the world of small things, they’re actually quite large. The ocean is full of even tinier organisms—worms and snails, small shelled animals and even stationary colonies of life that look like rocks or lumps of sand.

The ocean is an amazing place, and Bill Grossman can tell you about the things that live there—large, small, or tiny. Grossman is specimen collector for the Marine Biological Laboratory. Essentially, he’s part of a system of support staff for scientists. When researchers at MBL need sea creatures to study, it’s people like Grossman who go out on the water and find them.

Back in May, I got to take a short trip aboard the R/V Gemma, MBL’s specimen collection boat. The videos I brought back can teach you some amazing things about animals you thought you knew well, and introduce you to creatures you probably never noticed before.

The first video, posted above, focuses on three animals: Skate, crabs, and a strange, colony-dwelling life form known as a sand sponge.

Skates, as you’ll notice, look a lot like rays—and they are closely related. The key difference between the two is actually alluded to in the video. Grossman explains that researchers at MBL are particularly interested in skates because of the eggs that they lay. These are some amazing eggs. You won’t see any in the video, but they’re black, crazy looking, hard packets, bracketed between two long spines. In the packet, which is semi-opaque, you can see a bright orange blob—the embryonic skates. Seriously, it’s like something out of Aliens.

Egg case from a skate

Rays don’t produce those. In fact, they don’t lay eggs at all. Baby rays are born alive, just like human babies.

Sand sponge, from MBL Marine Organism Database

The other thing I want to give you a better look at is the sand sponge. It’s not actually a sponge. Nor is it, as it appears, a blob of sand stuck together. Instead, it’s a colony of creatures called ascidians, or sea squirts. If I’m understanding correctly, that sandy exterior is actually part of their living tissue.

In this second video, Grossman pulls half of a bivalve shell out of the pile shells, and crabs, and urchins on the Gemma’s deck. But it’s not bivalves that we’re learning about. Instead, that shell, abandoned by its deceased original owner, has become an ecosystem in its own right, home to a variety of worms and snails and other small creatures.

In particular, pay attention to the hydroides. These are little worms that live inside tubes made calcium carbonate. The tubes are white or red, and the worms like to build them on hard surfaces. That includes empty shells, but it’s more than that. Hydroides can build their tubes on the undersides of boats. They also build inside intake pipes, meant to bring cooling water to power plants and factories. In those situations, these little worms can become big pests.

Finally, this last video is all about sand collars and starfish. What’s a sand collar? It’s not an animal, itself. Instead, the collar is a gelled-together mass of eggs produced by the moon snail. These animals have a beautiful, frilly name, but are actually ravenous predators. They eat clams. Lots of clams. Moon snails eat clams like drunk frat boys eat buffalo wings. In fact, back in 2010, a veritable phalanx of moon snails nearly put Maine’s human clam diggers out of business.

In all of these little tidbits, there’s a key lesson you ought to learn: Amazing things are happening, all the time, at a scale that we don’t always pay attention to. If your interest in animals begins and ends with creatures larger than the average Collie dog, you’re going to miss out. Here’s a challenge for what’s left of the Summer. Get down on your hands and knees, and spend some time inspecting all of the life forms that are smaller than a breadbox.

For more information on specimen collection, read this interview with Ed Enos. He’s Bill Grossman’s boss, and superintendent of MBL’s Aquatic Resources Department.

Piece originally published at Boing Boing |