![]() The hope is the new ballast discharge regulations will shut the door to new invasions. They are among the culprits responsible for toxic algae blooms on Lake Erie that threaten public water supplies. The foreign organisms are implicated in botulism outbreaks that have suffocated tens of thousands of birds on the eastern shore of Lake Michigan. These invaders have decimated native fish populations and rewired the way energy flows through the world's largest freshwater system, sparking an explosion in seaweed growth that rots in reeking pockets along thousands of miles of shoreline. Small boats had access to the lakes since the 1800s thanks to relatively tiny man-made navigation channels stretching in from the East Coast and a canal at Chicago that artificially linked Lake Michigan to the Mississippi River basin.īut the consequences of opening a nautical freeway into the Great Lakes for globe-roaming freighters proved disastrous - at least 56 non-native organisms have since been discovered in the lakes, and the majority arrived as stowaways in freighter ballast tanks. Lawrence River, around Niagara Falls and into the heart of the continent. ![]() Lawrence Seaway, a system of channels, locks and dams that opened the door for ocean freighters to sail up the once-wild St. and Canadian governments obliterated the lake's natural barrier to invasive fish, plants, viruses and mollusks with the construction of the St. Environmental Protection Agency to begin requiring overseas ships to decontaminate their ballast water before discharging it into the five lakes that together span a surface area the size of the United Kingdom.ĭespite their vastness, for thousands of years the inland seas above Niagara Falls were as isolated from the outside world as a Northwoods Wisconsin pond. Then she realized that one of them was alive.Ī watershed moment has arrived for the Great Lakes.Īfter decades of regulatory paralysis, a federal judge has forced the U.S. She tried to muscle them apart but she couldn't. Up came a wormless scoop of stones, the smallest of which were pebbles not much bigger than her fingertips.īut there was something odd about two of these tinier stones. "I thought - if we get nothing, we get nothing, and I'll just mark it off that this is not an area to sample." "I can't even explain why it popped into my head," Santavy says. She was hunting for muck-loving worms but figured she'd take a poke into the rocks because, well, to this day, she still doesn't know. Clair on that steamy Wednesday morning, Santavy decided to drop her sampling scoop into the cobble below. That means dumping water from ship-steadying ballast tanks - water taken onboard outside the Great Lakes, water that too often and for too long swarmed with exotic life from ports around the globe.Īs the three young researchers were drifting over a rocky-bottomed portion of Lake St. ![]() When water levels are low or sediment is high, the channel isn't deep enough and sometimes ships have to lighten their loads to squeeze through. The government carved that pathway long ago to allow freighters to sail as far inland as Milwaukee and Duluth. Clair because the lake is as shallow as a swimming pool in most places, except for an approximately 30-foot-deep navigation channel down its middle. Water pools in it and then churns through as the outflows from Lakes Superior, Michigan and Huron swirl down into Erie, then continue flowing east over Niagara Falls into Lake Ontario, and finally out the St. Clair looks like a 24-mile-wide aneurysm in the river system east of Detroit that connects Lake Huron to Lake Erie. Sonya Santavy was a freshly graduated biologist aboard the research boat as its whining outboard pushed it toward the middle of the lake that straddles the U.S. Researcher Sonya Santavy, who discovered Zebra Mussels during a survey in Lake St Clair in 1988.
0 Comments
Leave a Reply. |