Phosphorous, Farming, and Fish. Cool mornings, fresh breezes, and glinting sunlight invigorated those of us on Gibraltar Island, and we (literally) jumped aboard an opportunity to go out on the water on small research vessels to learn about the ecology of Lake Erie. On this day in this year, the story was a good one: while the water clarity measured by a secchi disk was much less than I saw a few weeks ago on a ferry in northern Lake Huron, the sampling we made of the plankton and algae that clouds the water revealed to us the base of the food web that makes the fisheries of western Lake Erie so phenomenal. The quick trawling run we made returned a plethora of fish: walleye, yellow perch, and non-native white perch, but no invasive gobies. One statistic can say much, and the data point of the day was this: while Lake Erie contains only 2 percent of the total water in the Great Lakes, 50 percent of the fish live here.
The biological productivity of Lake Erie extends beyond its shoreline, or really vice-versa. The watershed, which at its western end encompasses northeastern Ohio, southwestern Michigan, and parts of Indiana, contains rich farmland and supports a vital agricultural economy. The Maumee River, the largest single tributary to the Great Lakes, drains this land and its mouth is the active port of Toledo. The organic matter from this watershed transferred into the sun-warmed, shallow waters of western Lake Erie creates a perfect breeding ground for algae, plankton, and other plants that support the insect larvae, small fish, and other creatures that feed the gamefish that end up on the plates of anglers.
|Extent of algae bloom in 2011 in Western Lake Erie (the Detroit River is in upper left)|
But while humans have long benefitted from this natural land-water ecosystem, something has gotten out of whack in the last few years. In 2011, warm weather and high levels of dissolved phosphorous (P) spawned a bloom of algae that Lake Erie had not experienced for decades. In addition to fouling beaches, reducing oxygen levels, and driving fish (and fishermen) out of coastal areas, the rich soup of nutrients supported the growth of several species of blue-green algae including microcystin, a toxic cyanobacteria that can kill fish, birds, and mammals. While the full chain of scientific connections has not yet been made, it is clear that a rise in recent years of phosphorous in Lake Erie plays a key role. This past summer, the near drought conditions have reduced run-off, and algae growth has been much lower. However, another wet and warm year could easily spawn another algae bloom.
We Have Been Here Before. In 1971, that keen cultural observer Dr. Seuss wrote about the mythical Humming Fish’s search for a new clean-water home: “They’ll walk on their fins and get woefully weary in search of some water that isn’t so smeary. I hear things are just as bad up in Lake Erie.” In the 1960s, Lake Erie was declared dead as a result of algae blooms, the Cuyahoga River in Cleveland caught fire, and concern for the smallest of Great Lakes helped spur the passage of the Clean Water Act in 1972. The resulting investments in upgraded sewage treatment systems, bans on some detergents and fertilizers, and positive changes in agricultural practices resulted in major declines in phosphorous levels, cleaner water, and a restored Lake Erie. In the 1980s, Dr. Seuss republished “The Lorax,” source of the Humming Fish, deleting the above reference. Now, people are quoting the original version again.
The shallow depth of Lake Erie makes it an ideal environment to grow algae, of both good and bad varieties. The shallow depth also means that the total volume of water in the Lake is less than any other of the Great Lakes, and thus the water in the Lake, which is ever-flowing in from the Detroit River and out over Niagara Falls, turns over in just a few years. The water in low-flow, deep Lake Superior takes several hundred years to be replace. Thus, in the 1970s, the reduction in phosphorous inflows quickly resulted in a clean Lake Erie.
With the hope that reductions in phosphorous and rapid turnover can again help the Lake recover, scientists are looking into the sources and pathways that bring “Big P” into the Lake. What we use to wash our clothes, how we get our lawns green, and how we make our crops grow all effect the amount of phosphorous in the ecosystem. Lots of attention is being paid to agricultural practices: what kinds, and when and how, fertilizer is applied to fields; when plowing does or does not occur; how we drain farmland and design ditches; and the types of crops grown in and out of season; all of these may play a role.
The Nature Conservancy has for several years worked in the upper watershed of the Maumee River to promote agricultural practices that reduce the run-off of fertilizer and sediment; now those efforts are being redoubled and expanded (read more here). Many partners–from local conservation districts and agricultural supply companies to university researchers and advocacy groups on both sides of the border–are all seeking ways to reduce the amount of phosphorous in Lake Erie and thus reduce the algae blooms that threaten to kill the Lake again.
The Nature Conservancy has set, and moved on, several ambitious goals to restore the coastline of Lake Erie. Already, 2,500 acres of wetlands have been re-established along the western end of the Lake, thanks in part to funding from the Great Lakes Restoration Initiative and other public and private sources. Partnerships with Ducks Unlimited has helped fix and open dike systems so that wetlands have become connected with the flow of the Lake and waterfowl sites created. Working with both public and private landowners, the Conservancy is halfway towards its goal of having 40 percent of the area within one mile of the shore in natural habitat. Finally, land stewards appear to have found ways to get the upper hand on phragmites, the invasive marsh grass that crowds out native plants and animals and retards water flow.
|Scheeff Nature Preserve|
Place Matters. In Western Lake Erie, The Nature Conservancy is successfully moving from its traditional focus on specific preserves to managing the whole ecosystem that is Lake Erie. But with the move from sites to system, place still matters; it’s just a matter of scale. To mentally comprehend a whole Great Lake as a place requires an informed observer, but several things help. First, getting out on the water gave me a true appreciation for the liquid, moveable nature of the place. Secondly, standing on points of land and ascending the Peace Memorial above Put-In-Bay allowed me to see the full sweep of the ecosystem. And finally, moving around–by car across the coastland of northeast Ohio, by ferry from and to the mainland, and by bike around South Bass Island–provided me with an appreciation of Lake Erie, and the people, who define this place.
After an intellectually challenging meeting, I was fortunate to be able to spend a little extra time exploring the place I was in. I started my trip with a bike, and then walk, around the nine-acre Scheeff East Point Nature Preserve at the northern tip of South Bass Island. On an island, small spots can take on a significance well beyond their size, and this is true with this coastal point that provides an important migratory landing pad for both birds and monarch butterflies. As well, the endangered Lake Erie water snake comes ashore here. Saving the property was a hard fought effort by locals, who acquired the site after old homes and vegetation had been cleared by a prospective developer. On the day I visited, new sycamores were being planted to restore the site. This is where it begins, with individual people caring enough to save a place.
The task before us is twofold. First, we need to transfer the love of place from the specific to the whole landscape. Lake Erie can be saved if we can change policies in two countries, if we can find the will to make large public investments in land and infrastructure, and if we can modify the cultural practices in how we use the land. Second, if we can think about the whole ecosystem that is Lake Erie and celebrate what makes it special, then people from many walks of life will be inspired to take the individual actions necessary to save it.
Thank you to the talented and committed Great Lakes staff of The Nature Conservancy for making this visit to Lake Erie possible. Photo on the left is of TNC’s Ohio State Director Josh Knights helping with fish sampling. Thanks too to the Stone Lab staff for their hospittality.
Thank you to Lana Pollack, co-chair of the International Joint Commission, for the Dr. Seuss reference and for her leadership on Lake Erie (read more here).