Wednesday, May 17, 2017

The new normal arrives about twice per generation

kw: book reviews, nonfiction, ecology, limnology, great lakes

My family moved to a suburb of Cleveland, Ohio in 1961. One of the first things we did was ride a tour boat up the Cuyahoga River. The tour operator proudly showed how the thoroughly channeled, and very twisty, river had been scooped out here (and cemented in) and patched there (and cemented in) so that ore boats could just barely be eased around corners and bends that sometimes exceeded 180 degrees. He showed off more than 100 bridges across the Cuyahoga that had various ways of turning, tilting and lifting out of the way when a ship came through.

He also, almost casually, mentioned that the oily sludge atop the river was about four inches thick. We could smell it; it was the backdrop to the whole cruise. I remember Dad leaning over to us, sotto voce, "This could burn!" Eight years later it did burn. What none of us learned until much later was that the June,1969 Cuyahoga River fire, which motivated the legislation that became the Clean Water Act, was only the latest of thirteen fires over 101 years. Yes, the Cuyahoga River first caught fire in 1868.

The Great Lakes, Superior, Michigan, Huron, Erie, and Ontario, are really a sort of "northern ocean". When I tell people I have lived on all four coasts of the U.S., it takes most of them a while to realize that the "third coast" is the Gulf Coast. Only one has thought it through and asked which of the Great Lakes I'd resided at.

In The Death and Life of the Great Lakes, Dan Egan chronicles the repeated environmental insults that these "unassailable" lakes have endured. The century-long "fire season" was not the first. Canals linking the lakes to the sea were first constructed in 1783, 85 years before the first fire on the Cuyahoga. The most famous, the Erie Canal, links the Hudson River to the Niagara River above the falls, near Buffalo, New York. It allows barge traffic to bypass the rapid-strewn St. Lawrence River and Niagara Falls, to get to Lake Erie.

Prior to 1825, when the Erie Canal opened, the great lakes were ecologically isolated, mainly by gravity. The rapids along the St. Lawrence River prevent even mighty salmon from reaching Lake Ontario, and Niagara Falls effectively blockades upstream motion by downstream species. Once canal and lock systems were completed, allowing large ships to be lifted as much as 600 feet to reach Lake Superior, they could bring cargo in and out. Their unintended cargo was devastating to the lakes. Some creatures such as the sea lamprey could swim up the canals and through the locks on their own. Others, such as shellfish, traveled as larvae in the ballast water that all ships carry to keep their balance.

Take a close look at these museum specimens. The small shells are about 12-15 mm long, smaller than one of my thumbnails. They are Zebra Mussels, Dreissena polymorpha (Pallas, 1771). They are native to the Ukraine and southern Russia. Looking carefully you can see the stripes and zigzag lines that give them their name. The specimen on the right is attached to the shell of another, native freshwater bivalve.

In 1988, two zebra mussel shells were found in Lake St. Clair, between Lake Erie and Lake Huron. Soon, they were to be found throughout the great lakes. At first, it was thought that they would not infest the deepest part of the lakes because they are not found deeper than about 30 meters. Then a second, related species the Quagga Mussel, Dreissena bugensis Andrusov, 1897, was found. They live deeper down, all the way to the bottom of the deepest part of Lake Superior, 406 m (1,332 ft). (A quagga is an extinct relative of the zebra.)

The portion of this museum tray outlined in blue shows the specimens of zebra mussel in the collection of the Delaware Museum of Natural History. The few older specimens are from Crimea. All the newer ones are from Europe and the U.S., primarily the great lakes.

The list of insults to the great lakes' ecology is long, and it is likely that Dan Egan hasn't covered each and every one. But he has covered all the critical ones:

  • After lampreys came, most of the lake trout died out. An effective poison was developed to "control" lamprey populations, but it was too late for the trout. An east coast herring had also sneaked in, and here they were called alewives. They had boom-bust cycles that left millions or billions dead on the beaches.
  • Two species of salmon were introduced purposely to prey on alewives and also to provide sport fishermen some excitement. Nothing fights like a salmon.
  • Zebra and quagga mussels are just two of the invasive shellfish. Others are less troublesome, but there are dozens of them. A fish from Russia, the roundhead goby, also made its way over, and they prey on these mussels.
  • Another species related to lake trout can prey on gobies. It has become established and, while it doesn't have the fight of a salmon, is a fun catch and good eating.
  • The aforementioned fires, and not only on the Cuyahoga River.
  • Prior to the introduction of second- and third-level sewage treatment, when we lived there, Cleveland's "sewage treatment system" consisted of a big pipe five miles long that discharged right into the lake. Cleveland was not alone. Only when there was an offshore breeze was it sort of safe to swim off the beaches of Cedar Point. Onshore breezes could bring undigested turds ashore.
  • The Chicago Ship Canal siphons some of Lake Michigan into the Mississippi River watershed, also carrying away Chicago's sewage. St. Louis fought several lawsuits before Chicago was forced to quite literally clean up its act.
  • Envious eyes are frequently cast on "all that water", particularly during droughts, which by definition, happen about half the time in any particular place! A city, county or state gets used to fully using the available water in good years, then goes crying for alternatives to fill the gap when things are more "normal". Climate change may make the great lakes even wetter, but the extremes from driest to wettest are likely to be greater than now, and it will just establish a new baseline.
  • Dredging and blasting for ship channels between Huron and Erie has led the level of Lake Huron to decrease by a couple of feet. The "new" channel bottom is softer than the old, and eroding fast. The drawdown will certainly increase.

As long as the stewardship of such resources is in the hands of people who have to run for election every two to four to six years, things can't get much better. Political decision makers have a short memory.

This book is as fascinating as any novel. Sometimes I found myself saying, "What??" Each generation finds a new way to make things worse. The lakes are resilient. They can recover, slowly, to a new ecological balance, if allowed to do so. But we don't have much capacity to leave things alone.

No comments: