Blue ice is in the headlines of various news stories about Great Lakes winters over the past 5 years or so. While it is often referred to as “rare,” I haven’t found any substantiating studies explaining why that is other than articles trying to gain attention in headlines. It is indeed the result of particular conditions of the ice, but why recently is it garnering attention vs. any other Michigan winter?
What makes ice appear blue?
Blue ice in the Great Lakes region forms when the ice is particularly dense and clear, free of air bubbles and internal edges, allowing light to penetrate deeper without scattering. As a result, the longer wavelengths of light get absorbed (towards red spectrum) while shorter wavelengths (towards the blue end) bounce back – making the ice appear blue.
Are clearer lakes a contributor to blue ice?
While I am not aware of any study correlating the frequency of appearance of blue ice to studies of water clarity, it would be an interesting hypothesis to explore. Scientists have already been involved in tracking the changes in water clarity in the Great Lakes for decades. One study in the Journal of Great Lakes Research examined satellite data between 1998 and 2012 and found the light was able to penetrate 20 percent deeper over that time period in Lake Michigan and Lake Huron. That’s enough to dethrone Lake Superior as being the clearest!
The changes in water clarity may seem like a good thing, but indicate a dramatic change in the ecosystem driven primarily by explosions of mussel populations. Great Lakes divers are all too familiar with the population growth of zebra and quagga mussels over the past 20-30 years. They practically cover every inch of shipwrecks and found in abundance at the bottom of the St. Clair River. The mussels are filter feeders, and dramatically reduce the plankton counts in these freshwater lakes. They are also raising concerns about their contributions to algae blooms because they eat the good algae and tend to spit out the more toxic kind creating imbalances.
How large is the population? One of the co-authors of the satellite study on water clarity, Gary Fahnenstiel, told Great Lakes Today that “It’s estimated in Lake Michigan right now the mussels can filter the entire volume of water in six days.”
Blue ice on Lake St. Clair
This winter is off to a pretty slow start for Great Lakes ice cover for 2021, and Lake St. Clair is no exception. It was only a few weeks ago I took a scouting trip to see what conditions were like. No ice at all on St. Clair.
NOAA ice cover tracking only showed 12% coverage as of Feb 2. January 2021 was a near-record low and NOAA estimates we may only see 30% total Great Lakes ice cover this year if the trend continues. But a recent lengthy cold snap triggered at least some Lake St. Clair ice to begin building up, which tends to freeze up much faster than its larger “great” relatives.
This makes my first trip out to photograph ice on Lake St. Clair this year – something I skipped last year altogether due to very haphazard conditions. The morning light was likely to be hit or miss with 97% cloud cover predicted. And it was certainly a miss for anything dramatic, but the overcast light happened to be just right to bring out the blues in some of the ice sheets stacked along the shore when the light hit them just right.
Does more blue predict more green?
I think this is an interesting question to ponder. If blue ice is truly on the rise (unknown), and partly related to the increases in clarity of the lakes (hypothesis), which is caused greatly by mussels … is blue ice correlated at all with growing algae blooms? As such – more blue could mean more green – which is not a good thing, as alluring as the ice is.
Wow! Glad I follow your blog because it’s like taking a class on the environment. Glad there are no quizzes, just lessons to learn. I have no previous knowledge of blue ice until I read you post. I’ve seen images before but knew nothing about it. I also am astounded by statement that “mussels can filter the entire volume of water in six days.” Hard for this mind to get wrapped around that. Finally I’m glad you made the trip and shared these images. Beautiful!
It’s hard for anyone to get their mind around that one about the mussels Monte. Glad you find some information here useful, I try.
Your thoughts just go to show how complex these systems are – mostly beyond our understanding, not that we don’t need to keep trying. It’s like glass, isn’t it? Thanks for getting out there and photographing it – very cool, Mark.
Only wish I understood more Lynn. It did look like someone swept up a bunch of broken glass.
Well, that’s what your photo conveys, so you did it justice. 🙂
Beautiful photos, Mark, and an interesting subject regarding the possible relationship of blue ice to other lake conditions. This statement floored me, “It’s estimated in Lake Michigan right now the mussels can filter the entire volume of water in six days.” That’s almost unbelievable.
Even given less than dramatic lighting, you made some great photos. Worth the trip, I’d say.
That is a pretty amazing stat eh? I knew there were a lot of them, but to filter out that much water is pretty amazing. They do indeed cover most every surface, cause problems with water intakes, etc. I actually read another stat that mussels now make up about 90% of the total biomass of the lakes! And there is really nothing to do about it it seems.
Very nice photograph. I had never heard of blue ice…
Thank you Alessandra!
Looks like something from the planet Krypton, scientific explanation notwithstanding.
I can see it being part of Superman’s ice cave
Interesting…..and beautiful. I had never heard of blue ice before. I mean I’ve seen it in Antarctica photos but that’s about it.
I think it maybe the same concept with the light absorption with the big icebergs. These are pretty small scale compared to some other buildups around Michigan that garnered headlines.