We (the Nature and Environment book group) learned so much from this book! Few of us had any idea about ballast water bringing in invasives and bacteria; about the dangers of connecting watersheds at Chicago; that there have been many very rapid and recent changes in the species composition of the Great Lakes; how important phosphorus is. I enjoyed reading about lampreys, which I love seeing at the Barrett Fishway in Holyoke. It was fascinating that the introduced alewife was then declared in need of protection when the balance of species changed, crashing the native perch populations again. Also in this book I learned about:
- “giant trout that can grow to a wolf-sized 70 pounds”
- James Strang, “a fiery rival of Brigham Young” who proclaimed himself king of Beaver Island but also carefully studied the different kinds of lake trout
- veliger, almost microsopic mollusc larvae – “What ensued in the next few years was a veliger blizzard down the canal and into Mississippi River tributaries that nobody could have predicted. Biologists in the early 1990s calculated that the microscopic mussel veligers were tumbling down the Mississippi-bound Illinois River at a rate of 70 million per second.”
- the Cuyahoga River catching on fire is very old – first reported in 1868
- “Biologically contaminated ballast water is the worst kind of pollution because it cannot be fixed by plugging a pipe or capping a smokestack. It does not decay and it does not disperse. It breeds.”
- the Great Black Swamp
- “Lake Erie, which holds only 2 percent of the overall volume of Great Lakes water, is home to about 50 percent of Great Lakes fish” because it is warmer and shallower than the others, so supports more algae
- ‘“The intuition is that a very large lake like this would be slow to respond somehow to climate change,” [Jay Austin] said. “But in fact we’re finding that it’s particularly sensitive.”’
It’s hard to fault Nicolet if he really did believe his journey had taken him to Asia, because there were no Old World analogues for the scope of the lakes he was trying to navigate. The biggest lake in France, after all, is 11 miles long and about 2 miles wide; the sailing distance between Duluth, Minnesota, on the Great Lakes’ western end and Kingston, Ontario, on their eastern end is more than 1,100 miles. No, the bodies of water formally known as the Laurentian Great Lakes are not mere lakes, not in the normal sense of the word. Nobody staring across Huron, Ontario, Michigan, Erie or Superior would consider the interconnected watery expanse that sprawls across 94,000 square miles just a lake, any more than a visitor waking up in London is likely to think of himself as stranded on just an island (the United Kingdom, in fact, also happens to span some 94,000 square miles).
A normal lake sends ashore ripples and, occasionally, waves a foot or two high. A Great Lake wave can swell to a tsunami-like 25 feet. A normal lake, if things get really rough, might tip a boat. A Great Lake can swallow freighters almost three times the length of a football field; the lakes’ bottoms are littered with an estimated 6,000 shipwrecks, many of which have never been found. This would never happen on a normal lake, because a normal lake is knowable. A Great Lake can hold all the mysteries of an ocean, and then some.
This left the four lakes above Niagara Falls largely separated from the rest of the aquatic world. The lakes might have sprawled across an area half the size of California, but in a sense they were as isolated as a one-acre pond in the middle of a forest until the early 19th century, when construction of the Welland and Erie Canal bypassed the falls and linked the lakes to the Atlantic Ocean. Pulling the Niagara plug that had protected the lakes for millennia triggered an ecological calamity best illustrated by the rise and fall of three species of fish—lake trout, sea lampreys and alewives. Their story shows how a delicate ecological tapestry that had been thousands of years in the making unraveled in just a couple of decades.
The decision to push aside lamprey-killer Vernon Applegate’s goal to restore lake trout and instead focus on grafting an exotic predator [salmon] onto the Great Lakes was a bit like rehabbing an ailing Great Plains by laying down sod strips of Kentucky bluegrass and turning the place into one giant golf course—one that would require constant tending—rather than reseeding the expanse with native grasses uniquely evolved over thousands of years to provide stability in the face of droughts, fires and roving herds of grazers.
Briney can catch 15,000 pounds of [bighead carp] in his nets. Not in one day. In 25 minutes. Here is a little perspective on that number: Wisconsin’s quota for commercial perch fishing on all the state waters of Lake Michigan in some past years has been about 20,000 pounds. That’s not a per-day limit. That’s the limit for an entire year.
Scientists have identified 39 invasive species poised to ride the Chicago canal into or out of the Great Lakes, including a fish-killing virus in Lake Michigan today that could ravage the South’s catfish farming industry as well as five species of nuisance fish, including the sea lamprey. Threatening from the other direction, beyond the Asian carp, is the razor-toothed snakehead, which can breathe air and slither short distances over land and is now swimming loose in the Mississippi basin.
Later, rocks rich in phosphates, which is a form of salt containing phosphorus, would be mined and processed for the mineral that doctors came to believe could cure everything from impotence (it couldn’t) to tuberculosis (it couldn’t) to depression (it couldn’t) to alcoholism (it couldn’t) to epilepsy (it couldn’t) to cholera (it couldn’t) to toothaches (it couldn’t).