Indiana’s Aquatic Research Institute… on Great Lakes Aquatic Habitats
By Tim Early, Aquatic Research Institute
Were you to attend a class on aquatic habitats offered by the aquatic research institute (ARI) you would first be asked if you knew what a shark, a whale, or a dolphin are. You may be asked to describe a starfish or an octopus, or possibly what you think a coral reef looks like. If you are like most people you would typically answer every question accurately. The next series of questions, however, may throw you: what is the fresh water counterpart of a coral reef? Can you name ten plants or animals, besides fish, that commonly live in lakes? Are sponges and jellyfish found in fresh water? Or how about a carnivorous aquatic plant—where would you find one? And so would begin your introduction to, and education about, habitats within the world’s largest freshwater system … the Laurentian Great Lakes.
“Contemporary thought typically classifies lakes, themselves, as a type of aquatic habitat,” says ARI director, Tim Early. “In the case of the Great Lakes this is far from accurate. Rather, the Great Lakes represent a vast submerged region containing a great number and variety of habitats—analogous to terrestrial regions that contain forests, prairies, or dunes—it’s all a matter of familiarity and perception. Understanding exactly what they are, where they are, how they function within the system are all vital to our understanding and management of aquatic resources.”
That understanding, according to Early, is sometimes problematic, not because it is difficult, but simply because the aquatic environment is so different from our own. We tend to identify terrestrial systems according to their long-lived, dominant species … plants. Hence we derive such terms as “forest,” “prairie,” or “meadow.” In such systems, plant populations control short-lived animal populations. Not so underwater where we name communities after dominant animal species, i.e., coral reefs, fish shoals, oyster beds, etc. In aquatic systems it is the plants that are ephemeral, some species living only a matter of days or even hours. ‘Down there’ it is the animals who “live long and prosper,” as a visiting Vulcan might phrase it. Add to this things such as “plankton,” that have no counterpart in our terrestrial world (there are no organisms that live out unending generations requisite on continually floating in the air), and familiarity suffers even more.
For the past seven years ARI scientific divers have been engaged in locating, identifying, and classifying habitats within the near shore area of southern Lake Michigan. Their efforts have resulted in a list that includes: coastal lagoons, weed beds, sand flats, incidental/artificial habitats, shoals, and clay banks.
“Coastal lagoons are to the lakes as coral reefs are to the ocean or wetlands to a river,” says Early. “These are the biologically richest and most diverse of aquatic habitats.” The ARI defines a coastal lagoon as “… a calm water embayment, separate from the lake, but connected to it by an open channel through which water and aquatic life can pass freely.” Within this type of system one can typically find several other types of habitats normally existing as distinct units in the open waters of lakes. This characteristic classifies the habitat as an ecotone—a component system exhibiting the features of several systems, e.g., an inland lake and mega-limnetic open water. Coastal lagoons also function as spawning sites and nursery grounds for many species, including varieties of sport fish, both territorial (centrarchids) and pelagic (perch, salmon, trout, etc.).
It was their study of coastal lagoons that led ARI researchers to investigate a unique biochemical process involving two seemingly unrelated species, sponges and zebra mussels. In a paper recently published in Environmental Science and Technology (a journal of the American Chemical Society) the researchers proved that a native species of sponge, Eunapias fragilis, actually feeds on the exotic mollusks by encapsulating and digesting them.
Carnivorous sponges are not the only surprise encountered by the ARI in studies of aquatic habitats. While classifying a clay bank habitat the dive team was intrigued by the large number of “pits” occurring throughout the glacial clay structures. Careful observation revealed that each one “erupted” in what appeared to be regular intervals. Samples of the substrate showed the “pits” to actually be the entrance to tunnel systems … each tunnel occupied by a chironomid (midge) larva. The sheer number of pits showed the clay to be home to virtually millions of the tiny insects that metamorphose into winged creatures that fly.
As any fisherman will tell you, midges are an important food source (and sometimes bait) for many species of sport fish. Normally, however, these animals are found in river or stream environments, not deep in the open waters of Lake Michigan. This discovery led to conclusions, such as the reason perch lay eggs at these habitats, or the fact that the midges actually weaken the otherwise solid clay matrix—the first case of “bio-erosion” cited by the group.
“We are only now beginning to see and understand how aquatic habitats function in the lakes,” says Early. “Until now they have been out of sight and, subsequently, out of mind. That is all about to change.” The “change” he is referring to is, perhaps, one of the most unique and innovative ideas to come from the ARI—live and interactive virtual dives, or, “LVDs” as the group calls them.
An LVD virtually puts you underwater. You see the aquascape and everything in it, and you can see, hear, and speak with the divers, underwater, who are conducting the dive—all live and in real-time. “It’s the closest thing to diving you can do without actually getting wet,” according to Jim Gentile, ARI’s dive operations manager.
Using a system pioneered by the ARI in partnership with Ameritech, video and audio signals from underwater are integrated within Indiana’s fiber-optic telecommunication system and, from there, can be channeled anywhere in the world. Recently, the ARI conducted an underwater session, from East Chicago, Indiana, in which thousands of students from around the world participated live and interactively in a dive.
“The concept, itself, is not new,” says Gentile. “You saw it in action during the Gulf War where reporters came to you, live on TV, from the Middle East. Unfortunately, the cost of such production is astronomical … something only major news agencies are capable of funding. What we have done is to design a system whereby we can do the same thing … only at the cost of a long distance telephone call rather than millions of dollars.” Later this year the ARI will offer LVDs to the public, from either its video teleconferencing center in East Chicago, Indiana, or by “sending the dive” to a any distance learning center in any U.S. city.
“This will provide everyone with the opportunity to see and experience aquatic habitats first hand, from the comfort of a room,” says ARI’s director. “You will be able to visit any one of several types of habitats and learn about it through direct interaction—you can ask questions, take a closer look, even follow a fish—you are, for all intents and purposes, ‘down there’ with the other divers.”
The expected result? Increased awareness, knowledge, and understanding of the aquatic environment—not thousands of miles away in the oceans—but right here in our own back yard …
For more information contact:
Aquatic Research Institute
2001 E. 135th St.
E. Chicago, IN 46312