The Great Lakes are some of the biggest freshwater lakes in the world. They are also famous for their shipwrecks. Most of them are in great shape, even after hundreds of years.
The lakes are very cold, which slows down rotting. This is a bit like how a fridge keeps your food fresh. And unlike the water in oceans or seas, there is no salt. Salt rusts, or breaks down, metal in the ships. There is none of that in the Great Lakes!
But now, the shipwrecks are starting to break down quickly. Experts are trying to record all they can before these wrecks disappear.
There are two reasons why these shipwrecks are in trouble. The first is that climate change is making storms stronger. These storm waves can damage ships.
But the biggest problem is tiny shellfish, called zebra and quagga mussels. They are from Europe. They are not supposed to be in the Great Lakes. We call them " " because they don't live here naturally.
Invasive species cause problems because the other animals and plants are not used to them. An invasive species can eat food that other creatures need. Or sometimes they don’t have any natural predators to eat them. Their numbers can get really big.
Zebra and quagga mussels have done a lot of harm to the Great Lakes. They first came here in the 1980s by accident. Big ships from other countries brought them over without knowing it.
When they got here, these mussels started multiplying fast. They have almost wiped out the local mussel species. They also cover almost everything underwater, including shipwrecks.
These mussels harm both wooden and metal ships. The mussels use tiny threads called filaments to stick to surfaces. These threads dig into the wood, making it crumble. And the mussel poop has an acid that eats through metal.
Experts say there's no good way to save the shipwrecks from being destroyed. This means that we could lose their history forever. That is why some people are working really hard to collect all the information they can about the wrecks.
Ken Merryman is a diver and computer expert from Minnesota. He helped create a website called 3Dshipwrecks. It has 3D models of 160 sunken ships. Divers swim down to take lots of pictures of the wreck. Then a computer puts all the information together into one 3D picture!
Merryman hopes to make a map of the 1,400 shipwrecks we know about in the Great Lakes. Even if the wrecks fall apart, the information will still be safe.
Updated October 19, 2023, 5:02 P.M. (ET)
By John Crossingham
