Divers can view historic shipwrecks at the bottom of the Great Lakes with increasing clarity, but the clear water is a cause for concern.
There are likely more than 6,000 shipwrecks in the Great Lakes, with many of the shipwrecks’ histories showcased at the Great Lakes Shipwreck Museum. For some, the shipwrecks are best viewed in person, and divers often plunge to the lake’s bottom in hopes of exploring the wrecks and conducting research. The wreckage is growing more visible as an invasive species clears algae from the murky lake water, but divers are concerned that the species will reduce the shipwrecks to rubble.
The species, zebra mussels, act as filter feeders. The fingernail-sized mollusk attaches itself to solid surfaces and then feeds on particles by sucking in water and discharging what it doesn’t use. This activity cleans the water around the shipwrecks, but the mussels are destroying the historic sites over time.
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“Our dilemma is that yes, the visibility is great for scuba divers and we now can enjoy and see wrecks more, but they are disintegrating at a faster rate than we have ever seen previously,” said Durrell Martin, the president of Save Ontario Shipwrecks, according to a Canadian Broadcasting Corp. (CBC) report.
“We can’t stop this,” Martin continued. “Shipwrecks we thought would be here another 200 years from now and we could enjoy, we realized probably within the next 10 to 20 years, they’ll all be gone. They’ll be piles of lumber on the bottom.”
Newsweek reached out to Save Ontario Shipwrecks through an online form for further comment.
When the zebra mussels affix themselves to the ship’s wooden structures, the increased pressure and burrowing nature of the mussels’ attachment eventually collapses the boat. In addition to their damaging the wood, steel and iron structures are impaired by an acid produced in the mussels’ feces, according to the CBC’s report.
Divers are desperate for a solution because data is limited on the shipwrecks, meaning that the full extent of historical significance is unknown for the items on the shipwreck or the boats themselves.
The zebra mussels pose a host of other problems. The U.S. Geological Survey (USGS) estimates the mollusks likely arrived in the Great Lakes in the 1980s when ships from Europe discharged ballast water into American lakes. The mussels have been feeding on algae in the water ever since.
The clear water can make for picturesque scuba dives, but the lack of algae means that native species aren’t getting the food they need. Zebra mussels also clog water intakes, causing power plants to spend millions of dollars to remove them, according to a USGS report.
Since their arrival, the mussels have spread throughout the Great Lakes and have entered large rivers throughout the nation. They have also been found in Texas, Colorado, Utah, Nevada and California, according to the USGS.