Courtesy Mark RyanLast October, I attended the Geological Society of America’s annual meeting held here in Minneapolis. The convention presented plenty of opportunities to hear the latest ideas in geology, paleontology, and planetary science but the highlight for me was being able to join a GSA field trip on Lake Superior aboard the research vessel, the Blue Heron.
Courtesy Mark RyanThe 86-foot vessel is owned by the University of Minnesota-Duluth (UMD) and operated by the Large Lakes Observatory (LLO), an organization created in 1994 for investigating the geochemical and geophysical properties of large lakes, and their global impact. To accomplish this research, the LLO required a worthy vessel for limnological research, and the Blue Heron was purchased just three years later.
The vessel docks at the Corps of Engineers Vessel Yard on Park Point (aka Minnesota Point), a natural sand bar separating Duluth’s harbor basin from Lake Superior. The ten-mile spit was created by the lake’s wave action on material deposited by the St. Louis river, and is supposedly the largest freshwater sand bar in the world. Field trip leaders Doug Ricketts, the marine superintendent at LLO, and Charlie Matsch, professor emeritus of geology at UMD, greeted arriving participants and divided us into two groups. While one group spent the morning on Lake Superior, the other visited geological highlights in the Duluth area with professor Matsch. In the afternoon the groups switched places.
I joined the morning shift on the lake with a dozen geologists made up of GSA attendees from Minnesota, Wisconsin, and City University of New York. Besides Doug Ricketts and the ship’s five crew members, regents professor Tom Johnson, and the director of the LLO, professor Steve Colman, were also on hand to help demonstrate and explain the Blue Heron’s research capabilities.
Courtesy Mark Ryan
Courtesy Mark RyanWe shoved off right on schedule, heading across the harbor toward the Superior entrance on the Wisconsin end of the sand bar. The crew spent this time going over the ship’s safety rules - how to descend ladders, which alarms meant what, how to communicate with the bridge - that sort of thing. We then made a quick tour of the facilities. The Blue Heron is equipped with a wet lab on the open deck and two dry labs inside, and all sorts of data gathering equipment for geophysical, geochemical, and biological sampling. These include multibeam sonar for profiling the lake bottom and sub-bottom, several coring instruments for collecting sediment samples, and water samplers able to collect at various depth levels in the water column while also measuring such things as temperature, depth, pH levels, and conductivity. There’s gear for tracking lake currents, and plankton nets and a trawl for gathering biological data. Inside, both above and below deck, computers record, display and analyze the gathered data. Many of the off-ship instruments can be monitored and controlled on-board from computer consoles.
Courtesy Mark RyanThe R/V Blue Heron is outfitted to carry five crew members and six researchers and can stay on the lake, around the clock, for 21 days between port calls. It’s used mainly on Lake Superior, the largest and least studied of the Great Lakes. Shipboard amenities are sparse (there’s no television or DVD) but include eleven bunks, a full galley for food preparation, dining table, shower, and of course, the "head", or as you landlubbers like to call it, the toilet. Internet service is sometimes available when the vessel is near shore.
Courtesy Mark RyanUpon entering Lake Superior, the crew set to work demonstrating some of the vessel’s science gear, which is pretty much the same kind of instrumentation used in oceanographic research. Just beyond the Superior entrance, the EchoTech CHIRP/sidescan sonar tow fish was lowered from the Blue Heron’s stern. This bright yellow instrument is towed underwater behind the vessel as it makes several passes over the lake bed, and able to gather hydrographic and bathymetric data. One function is to send out an intermittent, low frequency “chirp” pulse that can penetrate the sub-bottom and record changes in its geophysical properties. The sonar data is processed using on-deck computers.The first demonstration was a scan of the underwater channel of the Nemadji River, a Wisconsin tributary to the lake. The mouth of the Nemadji has been drowned by a process called post-glacial rebound or more scientifically, differential isostatic rebound. During the last ice age, a mile thick sheet of ice covered the region and placed enormous pressure on the earth’s crust, depressing it downward. As the glaciers retreated, that enormous weight was gradually removed, and the lake basin began to rebound (a process still going on today). But the northern and eastern ends of Lake Superior basin are rebounding at a faster rate, tilting the water southward and to the west and subsequently flooding those areas of the shoreline.
Courtesy Mark RyanAs the submerged tow fish was doing its stuff, we all gathered at a couple workstations in the lower deck dry lab to watch as images appeared on the computer screens. In one, you could plainly see the distinct profile of the Nemadji’s drowned riverbanks.
Courtesy Mark RyanThe other monitor displayed bathymetric information being picked up by the duel frequency sidescan sonar. Printouts of the lakebed topography, created from a mosaic of stitched-together scans, were laid out on a worktable with several charts and maps.
Courtesy Mark RyanFor the next demonstrations, the Blue Heron moved out several miles onto the big lake. We’d all been warned of the lake’s fickle weather, and told to bring proper attire, just in case. Having been raised in Duluth, I was well acquainted with Superior’s moodiness, especially in autumn, so I brought along rain gear, a jacket, and an extra sweatshirt, expecting the worst. But I was most comfortable in jeans and a t-shirt. Cloud cover was sporadic, and while the water temperature was only around 49 degrees, the air temperature hovered in the mid to upper 70s during the entire excursion. We couldn’t have hoped for a nicer day; a perfect Duluth day, as we used to call them.
While some of the group watched the crew prepare for the next presentation, others enjoyed lunch (sandwich, chips, fruit and a cookie) at the galley dining table. During my lunch break Tom Johnson told me the story of how the university came to own the research vessel. In her previous life, the Blue Heron was known as the Fairtry a commercial fishing trawler that fished the Grand Banks in the northwest Atlantic (like the Andrea Gail in The Perfect Storm). UMD purchased it in 1997 and Tom sailed it from Portland, Maine, through the St. Lawrence Seaway and across the Great Lakes to Duluth. Despite some minor engine problems at the start, he said it was a fantastic two-and-a-half week trip. Over the next winter, the Fairtry was converted into a limnological research vessel and re-christened the Blue Heron.
Courtesy Mark RyanMeanwhile, out on the back deck, the crew was ready to launch the next instrument, a carousel of canisters called Niskin bottles used for sampling the water column.
Courtesy Mark RyanThis device is lowered into the lake and controlled remotely from the deck, and can collect samples at various depths into any one of its dozen canisters. It can also measure temperature, conductivity, pH balance, transparency, dissolved oxygen levels and other tests. After deployment, marine technician, Jason Agnich, sat at a computer workstation just inside the hatch, and easily controlled the carousel with a joystick while monitoring its progress on a couple electronic displays.
Courtesy Mark RyanWe moved a little farther down lake where two coring instruments, a spider-framed multi-corer, and an arrow-like gravity corer were put into action. The first can collect several shallow core samples by lowering it by winch to the lakebed, while the latter is dropped like a giant dart deep into the sub-bottom sediment for one large core.
Courtesy Mark RyanAfter each was raised back to the surface, the collected core samples were removed from their tubing and laid out on the wet lab table for study. We all huddled around the workbench as each core was cut open with a knife so participants could take a closer look. The sediment cores were composed of a densely packed fine-grained mucky silt as brown as milk chocolate, and appeared more appropriate for a scatological study than a geological one, to me anyway. But that didn’t stop some of us from taking home a small plastic bag of it as a souvenir.
Courtesy Mark Ryan
Courtesy Mark RyanAs we made our way back toward the harbor, I stood at the starboard rail and took in the beautiful autumn colors lighting up the lake’s distant North Shore. We were three, maybe four miles offshore but I was able to pick out my old stomping grounds in Duluth’s east end. The old neighborhood – like much of the city - was built up on terraces formed by past shoreline configurations of prehistoric Lake Superior. Duluth’s Skyline Parkway, a boulevard that skirts the hilltop across the length of the city was built on an old gravel beach line of Glacial Lake Duluth when the water surface was nearly five hundred feet above its present level. The bridge over the mouth of the Lester River was just barely discernible from where I stood but it was easy to spot the large swath of dark pine forest that encompassed Lester Park and Amity creek (the western branch of Lester river) where my friends and I used to hang out. It’s also where Charlie Matsch would guide our group later in the afternoon. He brought us there to examine the Deeps, my favorite old swimming hole carved out of the massive basalt flows that extruded from what’s now the center of Lake Superior during the Mid-continental rifting event that took place nearly a billion years ago.
Courtesy Mark RyanWe returned to port through the Duluth entrance, and as we entered the canal captain Mike King announced our arrival with a blast of the Blue Heron’s air horn. Duluth’s landmark Aerial-Lift Bridge, already raised for our return entry, responded in kind with a shrill loud blast of its own. Tourists lining the pier called out and waved as we passed the old lighthouse and rolled toward the harbor. We all waved back and I have to say it was kind of a thrill, for me anyway, after having participated in the same ritual, oh probably a hundred times in the past but always from the pier not from a vessel.
Courtesy Mark RyanThe Blue Heron swung in through the harbor, and soon we were back at port where we started at the Corps of Engineers Vessel Yard. Charlie Matsch was there to greet us and take for the second leg of the field trip.
Charlie took us first up the hillside to the rocky knob near the landmark memorial Enger Tower where he showed us some interesting exposures of gabbro, an intrusive rock common to the geological formation known as the Duluth Complex. Much of the bluffs west of downtown Duluth are composed of this dark, course-grained mafic rock. Now, I admit I enjoy a geological outcrop as much as the next guy (especially when a real geologist is explaining it), but it was the sweeping view from the hilltop that drew my attention.
Courtesy Mark RyanThe lake and harbor and much of the St. Louis river bay stretched out below us in an array of vivid blues contrasting with the bright reds and golds of autumn. On one side of the harbor, bridges, railroads, and structures of industry jutted out on Rice's Point toward Wisconsin, paralleled on the other side by the slender ribbon of Park Point. As I took in this grand vista, a small, barely discernible bluish blur of movement caught my eye. There, cutting through the harbor, the Blue Heron headed southward toward the Superior entrance for another run on the great lake.
Courtesy Mark RyanLast week, Lake Superior, which is bordered by Minnesota, Wisconsin, Michigan, and Ontario, Canada, recorded its highest average surface temperature ever, a balmy 68.3°F. People seeking relief from a very hot summer have been flocking to the shores and beaches and actually swimming in the lake! That is so unlike the Lake Superior I remember growing up in Duluth. Sure, we liked to spend a day on the sand beaches of Park Point or lounging on the rocky outcrops along the North Shore but swimming was usually not an option. On average, Lake Superior’s overall temperature is barely above freezing (39 °F), and back then it seemed you couldn’t even wade in ankle-deep without having your breath sucked out of your lungs and thinking your feet had fallen off. Standing knee-deep in the water for even a short time was unbearable and a true test of endurance. And for guys, going any further was just plain crazy, unless you wanted verifiable (and excruciating) proof of Costanza’sTheory of Shrinkage.
Those hell-bent among us would sometimes make a mad suicide dash across the burning sands and actually dive into the frigid waters only to set off the mammalian diving reflex and cause their vital organs to start to shut down. Their only hope was if the lifeguards were watching and were properly certified in CPR.
Temperature ranges on Superior have been recorded for more than three decades. In recent years, the normal average surface temperature for Lake Superior during the month of August has been only 55°, so this dramatic rise in the average is unusual. As expected, many people are quick to point a finger at global warming as the cause for the rise. That’s not a bad guess considering the National Oceanic and Atmospheric Administration (NOAA) just proclaimed the year 2010 as the hottest on record, globally.
But physicist Jay Austin at the University of Minnesota-Duluth’s Large Lake Observatory has been closely tracking the lake’s surface temperatures, and predicted the record high back in July. He says the warm water this summer is at least partially due to a recent El Niño event that had an unusual effect on the lake this past winter.
“2009 was a very strong El Niño year,” Austin said. “And that El Niño year led to a year at least on Superior where there was very little ice.”
That lack of ice led to a quicker and earlier warm up of Lake Superior’s surface waters. The other Great Lakes showed similar increases in their average warm temperatures as well. Although ice usually forms on the lake surface during the winter months, Lake Superior rarely freezes over completely. The last time was in 1979.
The following video illustrates the contrast between last winter and the one prior to that. Each day on their Coast Watch website, NOAA posts 3 or 4 photographs taken by a satellite in geosynchronous orbit above Lake Superior. Early in 2009 I began collecting the images regularly thinking they could come in handy for a future Buzz story such as this. From March 2009 to May 2010 I collected something like 1100 satellite photos. Edited together, they make for an interesting time-lapse video that illustrates the weather patterns over the big lake from one winter to the next. At the start of the video (March 2009) ice-cover is apparent over much of the lake and can be seen building then melting away as the spring thaw brings warmer temperatures. But later in the video, as summer passes into fall and fall into winter, no ice appears at all over the expanse of the lake’s surface. Other than that I don’t know how informative the time-lapse ended up being but it’s certainly interesting to watch, particularly the wind and cloud patterns seen flowing off the lake starting in late January 2010.
"This year is just tremendously anomalous," Austin said. "This year ranks up there with the warmest water we have ever seen, and the warming trend appears to be going on in all of the Great Lakes."
The big question is what effect these warmer temperatures have on the lake’s ecology? Austin admits it’s hard to say.
"Fish have a specific range of temperatures in which they like to spawn," he said. "It may be that for some fish this very warm year is going to be great for them, but for others, like trout which are a very cold-adapted fish, it's not going to be great."
One problem for the trout could be that scourge of the Great Lakes, the jawless sea lamprey. Lampreys are invasive parasites and attach themselves to lake trout and live off their blood. It’s unknown what changes, if any, the warmer waters will have on their life-cycle. They may lay eggs faster and in larger quantities, increasing their populations, and their impact on the trout species.
Lake Superior has probably passed through its peak time for temperature this summer so more than likely the 68.3°F record will stand for the rest of the year. If you want to keep track you can go to the Michigan Sea Grant website where you can follow all the Great Lakes’ daily surface temperatures. But who knows? This summer may not be the height of the 30-year warming trend. Let’s see what next year has in store.
Personally, I’m concerned these warm water temperatures will spoil us. Being able to endure extremely cold temperatures is a Minnesota tradition, and helps build character. It makes you tough and able to withstand all sorts of adversity as well as the harshest of elements. Which brings to mind the time when my wife (then girlfriend) and I were in Glacier National Park and decided to go for a swim in St. Mary’s Lake. There were only a few other people goofy enough to be swimming in the glacial lake at the same time. It didn’t surprise us to learn they were all from Minnesota.
We were so proud of ourselves.
Just when you thought it couldn't get worse, now there's an oil spill in the Kalamazoo River in Michigan. Enbridge, the company responsible, is trying to keep the spill from reaching Lake Michigan.
Courtesy kate.gardiner ScienceBuzz is covering the danger Asian carp present to the Great Lakes. Last week a 19.6-pound, 34.6-inch bighead carp became entangled in a fishing net about six miles from Lake Michigan.
“Asian carp are like cockroaches; when you see one, you know it’s accompanied by many more you don’t see,” said Henry Henderson, of the Natural Resources Defense Council.
You can learn more in The New York Times
Courtesy Less Salty
LEEDCo is leading efforts to build, install, and deploy an offshore wind farm on Lake Erie. An initial five wind generators (20-megawatts, enough to power 16,000 homes) are to be located near Cleveland, Ohio, with a 2012 completion target. The expected cost is projected to be $100 million.
The 20 MW venture is just the initial phase. If the test phase is successful, LEEDCo would like to see the Lake Erie wind farm generating up to 1000 MW of energy by 2020. ConsumerEnergyReport
LEEDCo recently announced a long-term partnership with GE who will provide the 5 direct-drive wind turbines for LEEDCo’s 20-megawatt offshore wind project.
Many hoops and hurdles need to be traversed before obtaining major financial commitments. (learn more at Cleveland.com
Approval from at least 16 federal and state agencies, including the U.S. Army Corp of Engineers, the Ohio Department of Natural Resources and the Public Utilities Commission of Ohio. LEEDCo has yet to file any permit applications but does meet weekly with an interagency task force, the Lake Erie Offshore Wind Team, that Strickland created 18 months ago. Concerns that the turbines will harm birds and bats. A $350,000 study is under way, including radar, laser and acoustic identification of bird and bat flight paths. The proposed site will need a four-mile radius of air space in which few if any birds have been detected. How to anchor the towers in Lake Erie. Engineers must determine whether to sink steel piles down to bedrock, typically some 60 to 80 feet below the "glacial till" on the lake bottom. If pilings are needed, officials are uncertain whether the region still has the capacity to produce enough of the heavy steel that would be required. A way to get the power to shore. Underwater cables from the turbines to shore would need right-of-way approval from the state. The impact of winter ice. Plans call for an ice cream-cone shaped foundation at the water's level, which forces the ice down and breaks it, hopefully saving on cost, LEEDCo's Wagner said. A means of paying for the project. Financing details are still tenuous -- and could be more complicated than the engineering, said Wagner.
Courtesy Dr. Mohamed FaisalNo… not a rock bass (even though it has a red iris). Nor any normal walleye you might be lucky enough to snag. This fish you might not even need to actually catch. It could be floating next to the boat along with most of the other fish in your favorite river, lake, or reservoir. That is if the dreaded VHS continues to spread and strike us deep in the land of 10,000 lakes. Move over zebra mussel, Eurasian milfoil, and the Asian carp, VHS is viral hemorrhagic septicemia and the latest migrant in the spread of invasive species.
Viral hemorrhagic septicemia (VHS) is a virus. It is a small invading critter that can be quite infectious. Not all fish will show obvious signs. Those that do can exhibit hemorrhaging in the eyes, around the fins, or on the gills. Bloating, erratic behavior, bulging eyes, or even lesions could also be present. On the inside, the disease will attack the liver, kidneys, spleen or swim bladder. Those fish that do survive can still be infected and spread the disease. Blood, urine and even the reproductive fluids of infected fish can pass on the virus. Larger fish can get it from eating smaller infected fish.
The disease can be wide spread and is known to affect up to 28 different species of fish. Some of the fish kills have numbered in the tens of thousands. Many of our popular game fish are susceptible. Walleye, Northern Pike, Muskellunge, Smallmouth Bass, Perch, Crappies, Bluegills, Sheepshead and many others are on the list. Even some species of shiner bait fish have been found to carry the disease. While deadly for many fish, the disease is of no harm to humans. The warmth of our bodies is too hot for the virus to survive.
The virus has been known for many decades, but until recently was mainly a scourge of European fish farms. Viral hemorrhagic septicemia was first detected in American coastal waters in 1988, among the salmon populations of the Pacific Northwest. Then in 2005, tested fish showed up positive between Lake Huron and Lake Erie, and were confirmed in samples harvested two years earlier. Now, local news just recently reported on a Cornell study that found VHS diseased fish in the bay waters of the Duluth-Superior harbor on the western edges of Lake Superior. Make no mistake… the ‘bleeding fish’ disease is here at our doorstep.
Guests of the inland waterways will be reminded to be vigilant in safe boating and fishing practices by local resource managers. Be mindful not to transport fish, plants, or bait from one water body to another. Keep those live-wells empty, and dry or rinse that boat! It will fall upon all of us to remain vigilant. Let’s not allow this disease to become a crippling blow to our native fisheries. If we do, it is possible that we’ll witness many seasons of massive fish kills.
More good VHS information:
Wisconsin Dept. of Natural Resources
Courtesy kate.gardiner The commercial fishing industry in the Great Lakes, worth more than $7 billion a year, is threatened by Asian carp. Asian bighead (Hypophthalmichthys nobilis) and silver (H. molitrix) carp imported in 1970 to remove algae from catfish farms escaped into the Mississippi River during a flood. Since then they have outcompeted other fish. Along some stretches of the Illinois River, the carp make up 95 percent of the biomass. In December, the State of Michigan filed a lawsuit against the State of Illinois to close of locks between Chicago-area waterways and Lake Michigan.
"We cannot allow carp into the Great Lakes. It will destroy our Great Lakes fisheries, the economy," Michigan Gov. Jennifer Granholm said in a prepared statement." New York Times
On Jan 19, 2010, the U.S. Supreme Court turned down Michigan's request to block Asian carp invasion of Great Lakes (Scientific American). The Supreme Court didn't reveal any of the reasoning behind its ruling, which simply read: "The motion for preliminary injunction is denied."
Governor of Michigan, Jennifer Granholm, is "asking for an immediate summit at the White House with the administration to shut down these locks, at least temporarily, until a permanent solution can be found.”
The AP reported the White House response to be:
“The Obama administration clearly understands the urgency of this critical issue, and we look forward to meeting with them on the threat the Asian carp poses to the Great Lakes.” Dayton Daily News
Courtesy Wongx ATIn a collision of Beatles and Gordon Lightfoot song topics, an unmanned, small yellow submarine is puttering about the depths of Lake Superior, providing lake quality data to researchers back on shore. Launched earlier this week, the seven-foot-long, $74,000 device is on a two-week test run to see if it can prove to be a more cost-effective way of monitoring the lake's water quality than by using people on boats.
Is the sub's color a tribute to The Beatles? Not really. Creator Jay Austin of the University of Minnesota-Duluth told the Star-Tribune: "Yellow's the international color of research. It's an easy color to see in the water, so it's very typical to paint your equipment yellow. I've got a research buoy that's the same color."
And so far into the mission's run, no sign of any Blue Meanies in the great waters of Gitchigumi.
Courtesy Mark RyanPublic beaches along the North Shore of Lake Superior in Minnesota are the cleanest beaches of all the Great Lakes states. The National Resources Defense Council did their annual "Testing the Waters" survey and found that only 5 percent of Superior's north shore beaches in Minnesota showed worse levels of pollution than the national standards. Wisconsin had more than double the amount with 13 percent. Read more here.