Algal Blooms and Microcystins: The Fouling of Lake Erie

Algal Blooms and Microcystins: The Fouling of Lake Erie

A Colorful History : Often called blue-green algae, cyanobacteria are neither restricted to blue and green hues nor are they true algae. They bring a carmine tinge to the Red Sea and make the Spirulina-eating African flamingos blush pink. When these simple bacteria appeared some 3.5 billion years ago*, they produced oxygen by photosynthesis, changing the fate of the earth forever. Then in the Precambrian era, according to the theory of endosymbiosis, they were co-opted as chloroplasts into the cells of green plants. They also form nitrogen-fixing nodules in the roots of plants and partner with fungi to colonize barren new lands as lichen. Little wonder that scientists consider them the most successful group of microbes ever. But as Shakespeare mused: Why then, can one desire too much of a good thing?

Toxic Blooms: Ever opportunistic, cyanobacteria can rapidly increase in biomass to form thick green scum euphemistically known as blooms on the surface of shallow lakes. Over-fed with nutrient run-off from fertilized farmlands, sewage disposal or industrial waste, the blooms in turn feed bacteria, which then consume dissolved oxygen, killing off fish and creating dead zones. That’s not all: the blooms produce potent toxins that target the liver, brain and skin. The worst offenders are microcystins: cyclic compounds that fit snugly into the pocket of a class of enzymes known as protein phosphatases (image) and block their tumor-suppressing activity. In 1996, 76 dialysis patients at a clinic in Caruaru, Brazil, died from acute liver failure after water contaminated with microcystins was used in renal dialysis treatment. Their cyclic structure makes microcystins resistant to most water treatment processes, and boiling only concentrates the toxin. The building blocks that make up the toxin are unusual (non-protein amino acids) , and cannot be broken down by enzymes found in our cells. Recently, algal blooms in Lake Erie forced the shut-down of the entire water system in the city of Toledo, leaving half a million residents with no water. Given that this is becoming “the new normal” ( in many freshwater supplies around the world, what is the solution?

Bioremediation: There are no short term solutions to the blooming problem! We can cut back on fertilizer use, although faster acting, more efficiently utilized phosphate formulations actually encourage algal growth. Fortunately, we can exploit the chemical warfare in the battleground of the blooms themselves. It’s thought that cyanoblooms produce these toxins to protect themselves from heat and oxidation stress. But competing bacteria like Sphingomonas secrete enzymes that can degrade microcystins. Research on natural bioremediation by culturing beneficial bacteria and studying their genetic and biochemical pathways could help nip future blooms in the bud.   

Ref (image inset):

Ref ( #openaccess ): Cyanobacterial Toxin Degrading Bacteria: Who Are They?

#ScienceEveryday  when it’s not #ScienceSunday  

*Edit: Corrected from 3.5 mya , thanks Martin Vogel ! It turns out that cyanobacteria are the oldest known fossils, from Archaean rocks of Western Australia. This is very cool, since the oldest rocks are only a little older: 3.8 billion years old!


This entry was posted in Rajini Rao and tagged , , . Bookmark the permalink.

46 Responses to Algal Blooms and Microcystins: The Fouling of Lake Erie

  1. Pam Adger says:

    Fantastic Rajini Rao! I was just reading about this to make a post. Now I don’t have to. I can share yours. I wouldn’t have come up with all of this on my own. You rock!

  2. Rajini Rao says:

    Pam Adger do go ahead and write up something too! I would love to read it. There are so many angles that need to be covered by this problem that I only picked a few. For example, we grow too much corn (for ethanol subsidies) and that requires a lot of phosphate fertilizer. There’s the issue of warmer spring weather in the next few years. Etc.  🙂

  3. Pam Adger says:

    Rajini Rao The cause angle sure is contentious. Some of the stuff I have been reading comes close to playground name calling. It sure does evoke the emotional response. 

  4. Rajini Rao says:

    Yes, indeed! Notice I did not use a certain term meaning big changes in atmospheric patterns 😉

  5. Rajini Rao says:

    There’s a great #ScienceCaturday  post by Aida Hazlan on why cats love catnip!

    Besides, Shaker Cherukuri , I’m traveling tomorrow 🙂

  6. I’m rather ashamed to admit I finally poured a large bottle of bleach in my own outdoor water feature (no fish or animals in it) to get rid of all the horrible green scummy algae. Yes, I had tried lots of natural eco-friendly remedies, but to no avail. 

  7. Rajini Rao says:

    Eileen O’Duffy these are also the same bacteria that form a pink scum inside sinks and tubs indoors. Drat them! 

  8. Paul M says:

    Rajini Rao, have you ever looked into phycobilisomes, the light-harvesting antenna complexes of cyanobacteria? I think they’re one of the coolest molecular machines (except that they have no moving parts, like most solar panels) ever, from both a structural and biophysical standpoint. Because of the spectral properties and arrangements of their different light-harvesting proteins (phycobiliproteins), they are among the most efficient energy collectors known, which is why cyanobacteria are so successful in low light habitats. 

  9. Rajini Rao says:

    Paul M thanks for the introduction. I just looked them up and found this sentence: “The geometrical arrangement of a phycobilisome is very elegant and results in 95% efficiency of energy transfer”. What can be better than elegance and efficiency in nature? 

  10. Alan Kotok says:

    Thanks Rajini Rao … I’m originally from Buffalo, at the other end of Lake Erie from Toledo, so this is potentially an issue for friends and family in my home town. Ironically, the states and provinces bordering Lake Erie have over the years done a good job at cleaning up industrial pollution. And now this.

  11. Rajini Rao says:

    Alan Kotok I was just reading up on the history of Lake Erie’s pollution problems. As you point out, things were bad, got much better and now are bad again. To quote: “Lake Erie has a long, troubled history. A common refrain in 1960 was “Lake Erie is Dead.” The lake and its tributaries have been polluted enough to catch on fire multiple times; the 1969 Cuyohoga fire is just the most famous one. Lake Erie is even mentioned in Dr. Seuss’ 1971 book The Lorax.

    Lake Erie’s mess helped inspire the formation of the EPA in 1970, and the Clean Water Act of 1972. Things got better; Lake Erie became a hub for fishing and recreation, and is considered the “Walleye Capitol of the World.” To be able to consume fish from the lake at all, much less swim in the water, is a major achievement in just a few decades.

    How did Lake Erie go from polluted, flaming disaster to environmental success story…and then back again to environmental disaster, in just 45 years?”


  12. Paul M says:

    Phycobilisomes are so efficient because the light emission spectrum of each phycobiliprotein has very high overlap with the absorption spectrum of the next phycobiliprotein it’s attached to. If you think about it like a bucket brigade, in a phycobilisome, the people passing the buckets are all standing very close to each other. That way, they don’t spill much water as they pass the bucket up the line.

  13. Rajini Rao says:

    Paul M sounds like the fluorescence resonance energy transfer (FRET) technique we use in research, but with more than two molecules!

  14. vinay jain says:

    Good work Rajini Rao to find out and save from a problem.Proud to be your friend.

  15. Paul M says:

    It IS FRET, precisely!

  16. Jim Carver says:

    Rajini Rao  Well I can tell you quite simply without having to look anything up: In the period from the post war to the 60s the majority of the pollution was industrial in nature. Lake Erie was a toxic waste dump for industry. When that was cleaned up through tough legislation an underlying problem remained but was harder to see, agricultural runoff, at the surface, but also in groundwater. The current problem will take much longer to deal with because these ag chemicals have permeated the soils and aquifers throughout the entire region. There is no simple fix.

    This issue was the main driving force that made me want to get into the environmental movement and I passed out brochures about it in grade school…and got beat up by bullies a few times also.

  17. Martin Vogel says:

    This is a fascinating story. Can it be that these little fellows live here for 3500 million years, not 3.5?

  18. Rajini Rao says:

    Thanks for that excellent summary, Jim Carver .

  19. It’s ironic Rajini Rao that we have this major problem and the scientific solution, the creation of GMOs that make their own fertilizer, is being held up by anti-GMO sentiments in the areas affected. The primary problem with Ag runoff is the copious use of chemical fertilizers to enrich the soil because most agricultural plants don’t possess either the enzymes or the nitrogen-fixing bacteria to make their own amino acids. And most major fertilizers are made from components of oil using oil’s energy to create them. Living on Lake Ontario and an almost stones throw from Lake Erie, seeing the blooms is kind of frightening. But the lack of education about their causes is also something that makes me scratch my head.

  20. Rajini Rao says:

    Martin Vogel yikes, yes! Thanks for catching that. I will edit the post now. Actually, it is 3.5 billion years ago 😛

  21. Rajini Rao says:

    Joshua Baecker I agree: anything that can reduce inorganic fertilizer use is terrific- whether it is by old fashioned crop rotations (with nitrogen fixing plants like legumes) and reduction of monoculturing, or modern techniques of genetic engineering. 

  22. theory of the …chemist lavoisier ………

  23. Jim Carver says:

    Rajini Rao I think the first thing that needs to happen is to pass strict laws that govern the rate of fertilizer application. The EPA has guidelines, but they have no teeth.

    Studies have been done and they found that it’s not uncommon for farmers to use 2-3 times the recommended rate. If you couple that with urban runoff from lawns and such, which are basically not regulated at all…well, you have a free-for-all.

    So we need strict laws and public education before we can begin to tackle the problem. Even if you stopped using P today, it would be some time before you could see major reductions, although any reduction would be welcome.

    This is quite similar to (or exactly similar) to the rate of carbon going into the atmosphere, and to mention that many of these compounds result in increased greenhouse gases as well. (Mostly NOX in that case)

  24. So blue-green algae are the guinea pigs (neither pigs nor from Guinea) of micro fauna ( neither exclusively blue-green nor actually algae)!

  25. Rajini Rao says:

    That was inflorescent, thanks Rashid Moore 🙂

  26. Rajini Rao says:

    Panah Rad thanks 🙂

  27. Very, very interesting, thanks, so informative, learnt a lot.

  28. psher grant says:

    Thanks, this was informative.

  29. I always find something in your posts to learn, learn, learn…

    Thank you, Rajini Rao, that’s why I joined G+!

  30. Rajini Rao says:

    That’s great to know, thanks D. Freistädter 🙂

  31. Filtering the fertilized water through wetlands would help very much to prevent these Algea blooms and subsequent Dead zones…… “As murky water snakes through a man-made wetland between Dallas and Houston, its shallow ponds of lush vegetation slowly filter out phosphorous and nitrates until, a week later, the water runs clear as a creek into the area drinking supply.

    The 2,000-acre wetland system in Fairfield converts what is mainly treated wastewater that would otherwise flow into the Gulf of Mexico into an additional 65,000 gallons per day feeding the Richland-Chambers Reservoir — a significant contribution in a state enduring prolonged drought.”

  32. Rajini Rao says:

    Building (or rebuilding) wetlands to slow down water drainage is an excellent solution, thanks for linking to the article John Despujols. The Lake Erie blooms were blamed on sudden, heavy rains that drained nutrient rich water from farmlands too quickly into the lake. Although, as the article notes in closing, “But with corn and soybean crops fetching record prices, it has been difficult to find others willing to take land out of production.” More farmers have to be willing to give up farmland to be turned into wetlands, and the incentives for intensive farming have to be reduced.  

  33. The Dead Zones that form each year in the Gulf of Mexico are a great example.  After diverting the Mississippi river from its natural course through wetlands deltas with levees that funnel it straight into the Gulf of Mexico Louisiana is also losing over an acre an hour to erosion. The natural sedimentation process from the river kept it growing for the last 5000 years are so until it abruptly reversed… It makes no sense not to re-divert the river back through the wetlands…   “They said the new land, more than 18 square miles formed since the early 1970s, is providing hope that man-made sediment diversions along the Mississippi River could produce similar results by 2035, as predicted by the state’s coastal Master Plan. It’s also helping scientists design diversions to try to rebuild land elsewhere in the state. ”

  34. Rajini Rao says:

    Excellent, thanks. Meg Tufano was asking me about ways to ameliorate the eutrophication on another share and I’m tagging her to direct her to your links, John Despujols .

  35. Great here is more:  “Wetlands on agricultural land have got much better at trapping nutrients which would otherwise be conveyed to lakes or the sea. Constructing wetlands is also cheaper than many other environmental measures, but they could be even more effective. This is the conclusion of a new report from Halmstad University commissioned by the Swedish Board of Agriculture.”

  36. Mary T says:

    Thanks for another fascinating post Rajini Rao ~ I somehow missed this yesterday.

  37. Rajini Rao says:

    Mara Rose you’re welcome, thanks for stopping by.

  38. “Acid mine drainage effectively remediated by 

    natural wetlands

    Natural wetlands can provide effective long-term remediation of contamination 

    from abandoned mines, new research suggests. The study examined a natural 

    wetland receiving water from a copper mine in the UK, and showed that the 

    water’s acidity and levels of toxic metals were significantly reduced once it had 

    passed through the wetland.”

  39. Beautiful garden and the girls are the best only one

  40. Gary Klafta says:

    That is because of all the trash people are throwing into that lake.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s