LAKE MICHIGAN -- Ever wonder what goes on underneath the surface of Lake Michigan? If so, you're not alone. Scientists wonder, too.

In an effort to unravel some bedeviling mysteries of the Great Lakes ecosystem, a team from the University of Wisconsin-Milwaukee sunk a camera in Lake Michigan off Shorewood, Wis., last summer to record a season on the lakebed.

The camera shot one frame every hour between early June and late September, with automatic exposure adjustments in place to account for changing light conditions on the bottom, about 30 feet underneath the surface.

The result? A 3-minute timelapse video that condenses four months of change in a hidden environment that few people ever see.

But don't think the camera is just there to take pretty pictures.

"It definitely has a scientific purpose," said Harvey Bootsma, a professor at the university's School of Freshwater Sciences.

Bootsma's lab team is studying the growth of a gooey nuisance algae on the lakebed called cladophora. The native algae, once a major problem throughout the lakes, has returned with a vengeance in the last decade and the team research hopes to inform future management.

As evidenced in the video, the algae grows throughout the summer and then slough's off the rocky substrate in the fall. Afterwards, it tends to make its way into drinking water intakes and wash up on beaches, creating an unsightly mess. With a better understanding of the growth and death cycle, Bootsma hopes to give beach managers a heads-up when globs of dead algae are en route.

The camera off Shorewood's Atwater Park is one of a few Bootsma's team has squirreled around the lake. On the Michigan side, there are two cameras located off the Sleeping Bear Dunes National Lakeshore which are helping solve the mystery of escalating Type E avian botulism outbreaks on the lake.

Round gobies, quagga mussel shells and algae on the bottom of Good Harbor Bay in Lake Michigan. University of Wisconsin-Milwaukee School of Freshwater Sciences and the National Park Service research suggests that interactions among these three organisms may ultimately determine when and where outbreaks of avian botulism occur.

Botulism is paralytic condition brought on by ingesting a naturally-occurring toxin produced by bacteria found in sediments. Botulism is causing an escalating number of bird die-offs in northern Lake Michigan. More than 6.500 birds have died in the Sleeping Bear Dunes area in the past decade.

Coincidentally, cladophora is found in abundance off Sleeping Bear.

One of Bootsma's cameras in Good Harbor Bay has been capturing round gobies, an invasive bottom-feeding fish, eating invertebrates in mats of the dead cladophora algae; which collects in parts of the lake and provides a perfect breeding ground for the toxic botulism bacteria as it decomposes and creates oxygen-depleted areas of the lake.

The gobies populate shallow, rocky areas during the summer. In Good Harbor Bay, where cladophora accumulates and decomposes, they make brief daily forays in September into deeper water where the dead algae piles up.

"We still don't have a smoking gun" to explain when botulism spores in the lake become active and toxic, but "almost all of the birds that have been confirmed dead from botulism had round gobies in their guts," Bootsma said.

Are the gobies spreading the toxin that's killing birds around Lake Michigan? Bootsma said they haven't proven it, but that's the hypothesis.

In the timelapse video, there's also an unseen, but important presence. Under the algae mats are huge numbers of invasive zebra and quagga mussels.

Those mussels, which litter the lakebed in densities of 35,000 per-square-meter in some places, filter plankton from the water column and allow more sunlight to reach the bottom. The mussels excrete nutrients which, combined with the extra sunlight, help fuel cladophora algae growth at deeper depths and also provide a hard surface on which the algae can attach.

The loss of plankton throughout the water column is being felt acutely by the sport fishing industry, which is watching chinook salmon numbers drop lake-wide as the baitfish they rely on, plankton-eating alewives, are declining.

About 10 seconds into the video, schools of alewives make an appearance. But their relative absence from the rest of the video -- and therefore the rest of the summer -- is something that Bootsma said is helping lake managers understand the alewife presence in nearshore areas during certain parts of the year.

The mussels "may be underlying all these things we're observing."