NOAA Great Lakes Environmental Research Laboratory

The latest news and information about NOAA research in and around the Great Lakes


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Eight years of Great Lakes underwater glider data now available to the public

CIGLR’s Russ Miller deploying glider in Lake Huron, June 2017

NOAA Great Lakes Environmental Research Laboratory (GLERL) and the Cooperative Institute for Great Lakes Research (CIGLR) recently posted eight years’ worth of Great Lakes autonomous underwater vehicle (AUV), or “glider data ”  on NOAA’s Integrated Ocean Observing System (IOOS) Underwater Glider Data Assembly Center (DAC) map. The map is a collaborative effort and includes current and historical glider missions dating back to 2005 from around the planet. This data is useful to government agencies, researchers, environmental managers, and citizens who use Great Lakes data for better understanding the characteristics of Great Lakes water.

CIGLR glider just before a deployment in Lake Michigan at the NOAA GLERL Lake Michigan Field Station in Muskegon, MI.

The collection and analysis of this data is a close collaboration between NOAA GLERL, CIGLR and partner institutions. CIGLR owns and operates the glider, and it is deployed using NOAA GLERL vessels. Data managers and researchers from both organizations are working together to make this data as useful and accessible as possible. This cooperative project, which has been funded by the Great Lakes Observing System (GLOS; a part of the IOOS program), aims to support science, public safety, and security through the use of unmanned systems (UxS).

Glider Tech Specs

This glider is buoyancy-driven, meaning it controls its depth in the water by inflating and deflating a “bladder” that in turn makes it sink or float. It typically operates at around 30 meters (100 feet) below the lake surface, but can go as deep as 200 meters (650 feet) when needed. While the glider is able to work on it’s own, scientists wirelessly communicate with it regularly throughout its journey when it’s at the surface. It’s programmed to resurface regularly for check-ins, so we always know right where it is and we can even instruct it to change its mission path if necessary. It may only travel an average of 1 kilometer (0.6 miles) per hour, but its missions can last up to 60 days and provide us with amazing data sets to help answer questions about the Great Lakes ecosystem. Check out the video below from NOAA’s Ocean Service and visit this fact page for more on how the glider works.

The importance of data collection

With every deployment, the glider measures the water’s physical properties such as temperature, mineral content, pressure, and salinity. (Yes, even the Great Lakes have a tiny bit of salinity!) It also measures biological properties such as chlorophyll fluorescence and concentrations of dissolved organic matter, which indicate the region’s level of primary biological productivity (the amount of organic matter produced by phytoplankton in the water). Phytoplankton might be tiny, but their productivity is extremely important to the lakes’ ecosystems because it provides nutrients to the rest of the food web.

CIGLR glider floating just below the surface of the water.

When you piece together all these day-to-day measurements, you can use them to study seasonal changes such as movement of the thermocline – or steep temperature gradient in the lake – which can impact the rate of biological activity in the spring and summer. The size and intensity of spring algal blooms and occasional “whiting events” (accumulations of calcium carbonate particles in the water due to increased biological productivity) are other examples of seasonal biological phenomena the glider can observe. The glider collects high-quality data efficiently and cost-effectively, day and night in all weather conditions, ultimately allowing us to collect more data in a shorter amount of time than is possible with traditional ship-based methods. The robust datasets it gives us advance our understanding of Great Lakes processes on short-term, seasonal, and annual timescales — and lay a foundation for observing changes in the lakes over several decades.

This map shows NOAA GLERL/CIGLR underwater glider pathways in southern Lake Michigan, available on NOAA’s Integrated Ocean Observing System (IOOS) Underwater Glider Data Assembly Center map.  A long-term series of Lake Michigan observations in the southern basin of Lake Michigan began in 2012, criss-crossing between Muskegon, Milwaukee. This complements data collected by the NOAA National Data Center Station 45007, as well as temperature string in the southern basin of the lake,  connecting the observations of NOAA GLERL and University of Wisconsin-Madison. 

Glider paths shown on the maps include all deployment from 2012-2019. These paths expand observations collected by Federal and University research vessels in the same regions of the Great Lakes, through the use of other tools, such as NOAA GLERL’s Plankton Survey System (PSS) and Multiple Opening and Closing Net and Environmental Sampling System (MOCNESS). It is important to have a long period of observations from many types of collection across the lakes to better understand how things like water temperature at different depths, inputs from rivers, and seasonal changes to other characteristics of the water affect the ecosystem.This information is useful in understanding the impacts of invasive species, harmful algal blooms, and our changing climate.

This map shows NOAA GLERL/CIGLR underwater glider pathways in the Great Lakes, available on NOAA’s Integrated Ocean Observing System (IOOS) Underwater Glider Data Assembly Center map. In 2013, 2015, 2017, and 2018, glider deployments were chosen to complement ship- and glider-based observations of the Environmental Protection Agency (EPA), NOAA, United States Geological Survey (USGS), and Coordinated Science and Monitoring Initiative (CSMI) in Lakes Michigan, Ontario and Huron.  Lake Erie is too shallow for effective use of this glider, and Lake Superior has been monitored by EPA and University of Minnesota Large Lakes Observatory gliders.

Future deployments and collaboration

Planning is currently underway for future missions in the Great Lakes and potential applications for the glider’s wide variety of data. The glider will also be used this year on Lake Michigan for research and observations during the 2020 Cooperative Science and Monitoring Initiative (CSMI), a binational effort to coordinate science and monitoring activities in one of the five Great Lakes each year. This year’s CSMI research will likely use the glider to gain a better understanding of water quality in the lake’s nearshore regions – the area in the water from where waves begin to break, up to the lowest water point on the beach. With great partners like CIGLR and GLOS, the future is bright for NOAA’s underwater glider explorations.


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Sinkhole Science: Groundwater in the Great Lakes

If you followed our fieldwork last summer, you probably remember hearing about our research on the fascinating sinkholes and microbial communities that lie at the bottom of northern Lake Huron off the coast of Alpena, MI. Now you can experience this research as a short film!

NOAA GLERL has partnered with Great Lakes Outreach Media to create a short film entitled Sinkhole Science: Groundwater in the Great Lakes. It was recently featured on Detroit Public Television’s Great Lakes Now program as well as the Thunder Bay National Marine Sanctuary’s International Film Festival. 

In the film, you’ll learn how NOAA GLERL’s Observation Systems and Advanced Technology (OSAT) branch studies how these sinkholes impact the water levels and ecosystems of the Great Lakes. GLERL’s OSAT Program Leader Steve Ruberg explains the high-tech gadgets involved in this research, including a remotely operated vehicle (ROV), a tilt-based current sensor, and temperature strings to determine vertical movement of groundwater entering the lakes through the sinkholes.

Hit “play” to dive into the exciting world of GLERL’s sinkhole science!

Researchers from NOAA GLERL’s Observation Systems and Advanced Technology team set out on the R/V Storm to study sinkholes on the floor of northern Lake Huron off the coast of Alpena, MI. Photo: Great Lakes Outreach Media
Researchers on NOAA GLERL’s R/V Storm deploy a remotely operated vehicle (ROV) to observe sinkholes at the bottom of Lake Huron off the coast of Alpena, MI. Photo: Great Lakes Outreach Media
NOAA GLERL’s OSAT Program Lead Steve Ruberg and Instrument Specialist Steven Constant observe a sinkhole via live video feed from the ROV. Photo: Great Lakes Outreach Media
NOAA GLERL Marine Engineer Kyle Beadle controls the ROV in order to observe sinkholes from the R/V Storm. Photo: Great Lakes Outreach Media
NOAA GLERL Instrument Specialist Steven Constant and Vessel Captain Travis Smith monitor the ROV as it dives beneath the surface to observe a sinkhole. Photo: Great Lakes Outreach Media


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Great Lakes ice, evaporation, and water levels

Ice conditions in Lake Superior under a clear blue sky near Grand Marais. March 24, 2014. Credit: NOAA

Editor’s Note: This blog post was updated on February 4, 2020 to reflect an updated Seasonal Ice Forecast. Please be sure to read the entire update for more information on this active area of research at NOAA GLERL!

As many of us in the Great Lakes community start to don our parkas and break out the snow shovels, we know the splashing waves on our shorelines will soon be replaced with ice. And, with near-record high water levels in the lakes this year, the question of how ice and water levels will affect coastal communities in the months ahead looms large. 

The role of ice in the Great Lakes water budget

To start, we know that evaporation plays a major role in water levels by withdrawing water that enters the lakes from precipitation and runoff. So, high evaporation contributes to lower water levels, and low evaporation contributes to higher water levels. (For more on the Great Lakes water budget, check out this infographic.)  Traditional thinking is that high ice cover forms a “cap” that leads to decreased evaporation of lake water. However, we now know that the relationship between ice, evaporation, and water levels is more complex than that. 

While this assessment on Great Lakes evaporation from Great Lakes Integrated Sciences & Assessments explains that high ice cover is still associated with less evaporation the following spring, it also reports that evaporation rates before winter have an effect on how much ice forms in the first place. Specifically, it explains that high evaporation rates in the fall correspond with high ice cover the following winter. So just as ice cover can influence evaporation, the reverse is true as well – a much different story than the one-way street it was previously thought to be.

A look at 2020 ice cover: NOAA GLERL’s observations & predictions

On January 1st, 2020, the total Great Lakes ice cover was 1.3%. That’s about a third as much ice as around the same time last year, and barely anything compared to early 2018, when it was already about 20%. You’ll see in the figure below that shallow, protected bays tend to freeze first, especially ones that are located in the northern Great Lakes region. So it makes sense that most of the ice so far is in the bays of Lake Superior, followed by northern bays in Lakes Michigan and Huron like Green Bay and Georgian Bay.

Click here for more comparisons like this on GLERL’s website

GLERL conducts research on ice cover forecasting on two different time scales: short-term (1-5 days) and seasonal. GLERL’s short-term ice forecasting is part of the upgrade to the Great Lakes Operational Forecast System (GLOFS), a set of models currently being transitioned to operations at the National Ocean Service to predict things like currents, water temperature, water levels, and ice. The ice nowcast and forecast products (concentration, thickness, velocity) have been tested for the past several years and will soon become operational (available for the general public). 

GLERL’s ice climatologist, Jia Wang, produces an experimental annual projection for Great Lakes ice cover using a statistical model that predicts maximum Great Lakes ice cover percentages for the entire season. This model’s prediction is based on the predicted behaviors of four global-scale air masses: ENSO (El Nino and Southern Oscillation), NAO (North Atlantic Oscillation), PDO (Pacific Decadal Oscillation), and AMO (Atlantic Multidecadal Oscillation). While they’re all pretty far away from the Great Lakes, past research has shown that these air masses — or global teleconnections — heavily influence the year-to-year variability of Great Lakes ice cover. 

Based on this experimental model’s results, NOAA GLERL projects this Great Lakes ice cover this winter to be around 47%. That’s almost 9% below the long-term average of 55.7%. Here’s the preliminary projection broken down by lake:

Lake Superior: 54%

Lake Michigan: 41%

Lake Huron: 66%

Lake Erie: 80%

Lake Ontario: 32%


Updated Seasonal Ice Forecast

On 1/24/2020, GLERL researchers reran the experimental ice forecast model. The reason for the revised ice projection was due to significant deviation in the actual teleconnection indices from what was predicted in November. Because the model uses these predicted teleconnections to predict ice cover, it is important to use the most accurate values. The experimental ice forecast model is rerun to get updated values. NOAA GLERL’s research towards improving our capabilities for ice forecasting is ongoing. This research product continues to evolve as we gain understanding of the complex climatic drivers for the Great Lakes Region.

Lake Superior = 46-54%
Lake Michigan = 23-42%
Lake Huron = 47-72%
Lake Ontario = 16-36%
Lake Erie = 67-74%

Why did the 2020 Great Lakes ice cover forecast change? / What factors go into this forecast?

The experimental Great Lakes ice forecast is initially calculated in November and is based on a model run based on the forecasted teleconnection patterns for December, January and February. If the teleconnection values diverge from the forecast (that is, the climate did not act as predicted) then the experimental ice forecast model is updated with the latest information on expected teleconnection indices for the remainder of the winter.

What does the ice coverage range mean?

Because there is uncertainty with this experimental forecast, two different versions of the model are used. Version “a ” uses only 4 teleconnection patterns (NAO, AMO, ENSO, PDO) as variables (inputs). Version “b” also includes observed November lake surface temperature (LST) as a variable. November and December LST were shown to be equally well correlated with ice cover but by using November LST, it enables the forecast to be made a month earlier.

Ice cover is low right now, what could happen that would increase ice coverage?

A lot can still happen as there are many weeks of winter left. Historically, much of the major freezing happens in February. However, if temperature continues to remain abnormally warm, it is unlikely ice cover would reach these values.

Why is it important to continue this research?

NOAA GLERL continues to refine the ice forecast model, active research designed to improve the Great Lakes ice forecast. We plan to improve the forecast skill by adding the cumulative freezing degree days since December 1, and update the forecast every two weeks throughout the ice season.


Predicting Great Lakes water levels

Forecasts of Great Lakes monthly-average water levels are based on computer models, including some from NOAA GLERL, along with more than 150 years of data from past weather and water level conditions. The official 6-month forecast is produced each month through a binational partnership between the U.S. Army Corps of Engineers and Environment and Climate Change Canada.

Want to know more about GLERL’s ice research? Visit our ice cover webpage for current conditions, forecasts, historical data, and more!

Great Lakes ice cover facts since 1973

94.7% ice coverage in 1979 is the maximum on record.

9.5% ice coverage in 2002 is the lowest on record.

11.5% ice coverage in 1998, a strong El Niño year.

The extreme ice cover in 2014 (92.5%) and 2015 (88.8%) were the first consecutive high ice cover years since the late 1970’s.

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On March 6, 2014, Great Lakes ice cover was 92.5%, putting winter 2014 into 2nd place in the record books for maximum ice cover. Satellite photo credit: NOAA Great Lakes CoastWatch and NASA.


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Millions of Microbes: The Unexpected Inhabitants of Lake Huron’s Underwater Sinkholes

When most people think of sinkholes, a massive cavity in the ground opening up and swallowing a car is what usually comes to mind. But when scientists at the NOAA Great Lakes Environmental Research Laboratory (GLERL) hear “sinkholes,” their minds jump to an unusual place — the bottom of a Great Lake.

Aerial view of research boat on green water
Researchers on GLERL’s R/V Storm study sinkholes in northern Lake Huron off the coast of Alpena, Michigan. (Credit: David J Ruck/Great Lakes Outreach Media)

Thousands of years ago, off the coast of Alpena, Michigan, patches of ground beneath Lake Huron collapsed to form a series of underwater sinkholes — some measuring hundreds of feet across and up to 60 feet deep. You may have read this NOAA.gov article about how these sinkholes are contributing water to Lake Huron, but did you know they also support a huge kingdom of microorganisms?

Microbes might be tiny, but they’re one of the biggest research topics in the Great Lakes. They thrive near the sinkholes because the groundwater seeping in has the perfect chemistry for their survival: low oxygen levels and lots of chloride and sulfate, which come from the dissolved limestone underlying the lake. These factors make the sinkholes inhospitable for fish and other wildlife normally found in the Great Lakes, which means these microbes have a much easier time surviving there than other creatures. With perfect living conditions and little competition, they’re so abundant that they form purple, green, and white microbial mats that cover the lake floor like a colorful carpet.

Floor of Lake Huron covered by purple and white microbial mats with bubbles in them.
Purple microbial mats in the Middle Island Sinkhole in Lake Huron, June 2019. Small hills and “fingers” like this one in the mats are caused by gases like methane and hydrogen sulfide bubbling up beneath them. (Credit: Phil Hartmeyer, NOAA Thunder Bay National Marine Sanctuary)

Scientists at GLERL are collaborating with partners from the University of Michigan and Grand Valley State University to see just what these microscopic lake dwellers can teach us. This video by Great Lakes Outreach Media highlights how they can even give us a deeper insight into the history of Earth itself.

Associate Professor Greg Dick from the University of Michigan discusses cyanobacteria’s important role in Earth science. This clip is from Great Lakes Outreach Media’s upcoming documentary, “The Erie Situation.”

Some sinkholes are so deep that sunlight can’t reach them, but that doesn’t stop some microbes from calling them home. They’re able to live their entire lives in complete darkness, because they get their energy from the added minerals in the water rather than from sunlight — a process called chemosynthesis. But whether they need sunlight or not, several of the microbial species present have proven to be full of surprises.

“In the near-shore systems, the cyanobacteria we found have DNA signatures that come closest to comparing to the cyanobacteria found at the bottom of a lake in Antarctica. So that’s a strange coincidence,” said Steve Ruberg, the scientist in charge of sinkhole research at GLERL. “Some of the other bacteria we’ve found in the deeper systems have only been found off the coast of Africa.”

Fish sitting on a rock, which is covered by purple and white microbes
A burbot resting on rocks covered in purple and white microbial mats inside the Middle Island sinkhole in Lake Huron. (Credit: Phil Hartmeyer, NOAA Thunder Bay National Marine Sanctuary)

The particular sinkholes we’re studying are located within NOAA’s Thunder Bay National Marine Sanctuary, an area of Lake Huron that’s federally protected for the purpose of preserving nearly 200 shipwrecks. In fact, the only reason we know about these sinkholes is because they were discovered by accident only 18 years ago, on a research cruise documenting the shipwrecks.

Close up of rocks covered in  purple, white and green microbes on the bottom of Lake Huron, with a diver in the background.
A diver observes the purple, white and green microbes covering rocks in Lake Huron’s Middle Island Sinkhole (Credit: Phil Hartmeyer, NOAA Thunder Bay National Marine Sanctuary)

So why did this microbial paradise come into existence in the first place? The story goes back much further than the sinkholes’ discovery in 2001. About 400 million years ago, before the Great Lakes even existed, a layer of limestone bedrock formed beneath what is now Lake Huron. Then around 10,000 years ago, underground caves were created when a chemical reaction between the limestone and acidic groundwater dissolved away holes in the bedrock. All that was left were weakly supported “ceilings” that eventually collapsed into the sinkholes we — and the microbes — know and love today.

Close up of rocks covered in purple, white and green microbes on the floor of Lake Huron
Purple cyanobacteria and white chemosynthetic mats on the floor of Lake Huron with Lowell Instruments current meter. (Credit: Phil Hartmeyer, NOAA Thunder Bay National Marine Sanctuary)

Since Lakes Michigan and Erie have the same limestone bedrock as Lake Huron, GLERL scientists think these lakes could be home to more of these fascinating underwater features. So while the excitement of this fieldwork has died down for the year, our research on Great Lakes sinkholes and their tiny inhabitants is far from over.