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Boats going through an algae bloom on Lake Erie near Toledo, Ohio.

A massive algae bloom in 2011 turned Lake Erie into pea soup.

Photograph by Peter Essick, National Geographic

Jane J. Lee

National Geographic

Published August 4, 2014

The toxic algae bloom in Lake Erie that provoked last weekend's tap water ban in Toledo, Ohio—where nearly half a million people were told not to use water for drinking, cooking, or bathing—is a preview of similar problems to come around the world, scientists say, thanks in part to climate change.

Northwest Ohio's water ban was lifted Monday morning, but experts say harmful algal blooms that can turn tap water toxic and kill wildlife are becoming more common in coastal oceans and in freshwater across the United States and around the globe.

A toxic algae bloom killed record numbers of manatees in Florida early last year. Another bloom put a record number of marine mammals into California rehabilitation centers earlier this year. (See "Record Number of Seals and Sea Lions Rescued in California.") They can also result in massive fish kills.

The blooms produce toxins that can cause neurological problems like paralysis and seizures in people, though such effects have been best documented in marine mammals and birds.

"Some of [the increase in blooms] can be attributed to global climate change," said Timothy Davis, a research ecologist specializing in harmful algal blooms with the National Oceanic and Atmospheric Administration's (NOAA) Great Lakes Environmental Research Laboratory in Ann Arbor, Michigan. (See "Pictures: Extreme Algae Blooms Expanding Worldwide.")

Volunteers unload drinking water from a truck outside Waite High School in Toledo, Ohio August 3, 2014.
People unload drinking water outside Waite High School in Toledo, Ohio, on August 3.
Photograph by Joshua Lott, Reuters

The algae and bacteria responsible for blooms, including the one that created Toledo's tap water mess—a type of bacteria known as Microcystis—need warm temperatures and the nutrients phosphorus and nitrogen to grow. Microcystis is a kind of cyanobacteria, often mistakenly referred to as blue-green algae.

Climate change is creating warming waters in many parts of the world, including the Great Lakes. Global warming is also boosting storm intensities in some parts of the world, which can increase the terrestrial runoff that supplies the nutrients that feed algae blooms. (Read about our "fertilized world" in National Geographic magazine.)

The nitrogen and phosphorous in the runoff come from leaky septic tanks and from fertilizers used on farms and lawns.

Lake Erie's shallow depths—it's the shallowest of the Great Lakes, with an average depth of 62 feet (19 meters)—also contributed to this year's algae blooms, said Eric Anderson, a physical oceanographer with NOAA's Great Lakes Environmental Research Laboratory. The western basin, the location of the current algae bloom, is even shallower, with an average depth of less than 26 feet (8 meters).

The Great Lakes ice extent last winter was the second largest on record, Anderson said, with ice covering Lake Erie well into April. But because Lake Erie is so shallow, water temperatures were able to recover quickly. " Average surface water temperature in the lake has rebounded to within 1.68 degrees of the average of the last ten years," he said.

Toxins from algal blooms are of particular concern to water managers around Lake Erie, said Anderson.

Strong winds can drive blooms at the water's surface down into the depths of the lake, where water intake pipes can draw contaminated water into systems serving municipalities, he said.

It's unclear whether that happened in Toledo. Samples from other plants that also draw their water from Lake Erie lacked the microcystin toxin that prompted Toledo's tap water ban, raising questions about how the toxins got into the city's water.

The City of Toledo water intake crib is surrounded by algae, Sunday, Aug. 3, 2014, in Lake Erie, about 2.5 miles off the shore of Curtice, Ohio.
Algae surrounds Toledo's intake facility on Lake Erie on August 3.
Photograph by Haraz N. Ghanbari, Associated Press

A Matter of Circumstance

Not every algae bloom produces toxins. Some kinds of Microcystis blooms—like the one in Lake Erie—produce toxins, while others don't.

About half of the Microcystis blooms around the world aren't toxic, said Davis, but "it looks like climate change might be driving these blooms to more toxic strains." Researchers are still trying to figure out why that may be happening.

Toxic algal blooms can seriously impact the health and economies of coastal and lakeside communities. The microcystin that was found in Toledo's water can cause vomiting, nausea, dizziness, diarrhea, or numbness.

This satellite image provided by NOAA shows the algae bloom on Lake Erie in 2011 which according to NOAA was the worst in decades.
A satellite image from NOAA shows an aerial view of Lake Erie's massive 2011 algae bloom.
Photograph by NASA/Earth Observatory

When these blooms run out of steam and die, bacteria feasting on the decaying matter can suck almost all the oxygen out of the water. This can result in another ecological problem: "dead zones," or areas of the ocean devoid of life.

Increases in algae blooms are also expanding dead zones around the world. The Gulf of Mexico hosted one last summer about the size of Connecticut. (See "World's Largest Dead Zone Suffocating Sea.")

It doesn't take very long for aquatic systems like Lake Erie to get thrown off balance, Davis said. But it will take patience and long-term management to get the lake healthy again.

"The biggest thing that people need to be aware of is that there's no short-term solution," he said. "Our lakes and coastal systems are out of balance."

Follow Jane J. Lee on Twitter.

30 comments
Bubba Jones
Bubba Jones

 I wonder If the National Geographic's, would be willing to cough up $2 Billion Dollars in Cash, in a court of law, to settle a Major Lawsuit of fraudulent reporting.The Current Water temperature of Lake Erie, is well below Normal for the Ten year Avg Mean. I think it's time we start firing MAJOR Multi-Billion dollar lawsuits against anyone reporting falsehoods, because they only want to promote this serious fallacy of AGW...

Hrabina Krystyna
Hrabina Krystyna

I have two mini-ponds: one with goldfish and one with mosquito fish. The one with the goldfish has normal green algae in it which provides food for the fish. The one with the mosquito fish usually does the same, except after a rainfall when it gets sticky, plasticy blue-green algae. It doesn't seem to harm the fish although it's hard to tell, as there are numerous fish in the pond. Even the babies are surviving.  I have attempted to clean it out totally and refill it, and the blue-green algae has returned. It's frustrating, and I believe that the rain causes it to start to form. This algae forms floating clumps which if touched can easily be dispersed into the water. I don't add chemicals to the ponds as they have flourished for 15 years on their own. It's only recently that I'm finding this blue-green algae to be problematic and overbearing. Any suggestions for cures? I have to link the formation of this algae with the rainfall in Phoenix, which is very rare to begin with. Can it be caused by the spraying of mosquito killer in the air by planes? We have so much chlorine pumped into our water at night, thinking so the residents don't notice it. Comments?

Guy Dude
Guy Dude

Here's a couple of emails from the Climategate scandal of 2009. First, IPCC chief ho bag at East Anglia U., Phil Jones: "The scientific community would come down on me in no uncertain terms if I said the world had cooled from 1998. OK it has but it is only seven years of data and it isn't statistically significant.'

Kevin Trenberth, head of climate analysis at the National Center for Atmospheric Research (and a lead author of the IPCC's 2001 and 2007 Scientific Assessment of Climate Change), writes on 12 October 2009 that "We can't account for the lack of warming at the moment and it is a travesty that we can't."

pat Moffitt
pat Moffitt

 I'm not sure how these blooms can be linked to climate change. NOAA's Lake Erie data http://www.erh.noaa.gov/buf/laketemps/lktemp.html shows that the temperatures for this July were well within the expected range of temperatures. The highests July temperature since 1927 was 75.1F in 1987 and the low was 64.3F in 1992. This year's July average was 71.8F.


Microcystis dominates under low nitrate conditions (relative to phosphorus) and the anabanea blooms of the earlier decades only proliferate when all forms of nitrogen are very low. Blue greens such as anabena can utlize the "limitless" atmsopheric nitrogen so restricting nitrogen can actually promote blooms of cyanobacteria.


Also be aware that restricting lawn fertilizer results in low turf density and as such more exposed bare ground. Since phosphus is bound to soil particles poor turf resulting from insufficient fertilizer can lead to increased phosphorus loads. 


The danger here is that this complex science is being forced to conform to standard narratives- narratives that can create real harm. 

Jeffrey Raia
Jeffrey Raia

Remember not so long ago when "experts" would blame everything on El Nino?

V Mitchell
V Mitchell

This type of thing has been happening for years.  In Michigan the sewage and road drainage is connected.  When a large storm comes thru the raw sewage is dumped in the lakes and streams.  This is upstream of Lake Erie.  Nothing like drinking out of the toilet and all else that is dumped down the drain.  You would think they would fix the problem. You guys is gov are to be serving the public.  Come on, you can do the right thing if you want to.

Jonathan Strauss
Jonathan Strauss

agricultural runoff (heavy use of fertilizers) is causing this, not just warming.

Jonathan Strauss
Jonathan Strauss

"need warm temperatures and the nutrients phosphorus and nitrogen to grow"    =  it's an increase of artificial fertilizers and agricultural run-off!    not JUST climate change.

fang dai
fang dai

I never thought it would be so serious~

Tyla Haak
Tyla Haak

Can it please be noted that algal blooms in general are incredibly important and essential for all life, Including us! They are responsible for the large majority of photosynthesis (and oxygen production) on Earth-more so than trees. They also fuel all aquatic ecosystems as they are the primary producers of the ocean and all marine life require them for food (if not them directly, organisms later up the trophic levels that feed on these phytoplankton) There are also only about 40 species of algae blooming species that are toxic.. compared to the thousands that aren't so the overwhelming majority of algal blooms we experience are completely harmless and in fact beneficial. 


Marilyn Tolliver
Marilyn Tolliver

Oh, yes, and who's bright idea was it to dumb our trash in the ocean???  We humans are idiots and I don't see any alarm in the country governments around the world to fix the problem NOW!  Oh, no, we'll just leave that to the next generation, if there is one !!!!!  I am so angry about this that I am going to write to my state senators everyday until I see something happen or until we can elect government officials who will actually work together for the good of the citizens and not throw temper tantrums like 2 yr olds.  It seem like one official takes to crying when things are going wrong.  We need to replace each and every one of them, lower their salaries, and make it very easy to impeach them if they are not doing their jobs.  Any comments??????

Marilyn Tolliver
Marilyn Tolliver

This is not only sad, but it is incredibly frightening.  We need water to live.  I used to have dreams that in the future, when I turned on my faucet, only mud came out.  Those were real nightmares because I was raising children on my own.  Happy they were dreams then, but............this algae bloom is really frightening, especially because it is so toxic !!!!!


Majid Naghdi
Majid Naghdi

A similar problem occurs in humans and other animals sometimes. 

I think we (humans) are the main cause of disturbances in ecosystems. 

Natural sources of air pollution - population growth and limited resources, clean energy, and the like.

Fornik Tsai
Fornik Tsai

Algae affect the balance of the whole world.

Mojtaba Najafy
Mojtaba Najafy

I read somewhere that wisdom meant being able to see the bigger picture and the long term effects of our actions. By this standard, humanity especially in late 20th and early 21st centuries has failed in its environment test. The estimates and forebodings of the effects of our actions had been going on for quite a while. But every now and then the companies and governments who didn't want any bump in their road to monetary goals would find ways to make the delusion that everything was ok. And now we see that it's not. 

If there is one thing to learn. It's that you could not leave the job to them. People need to get involved with this. In addition to doing our share of the task, we should force them to establish the right of the environment. A universal set of boundaries and musts to preserve the world we live in.

John Reyesvilla Méndez
John Reyesvilla Méndez

El dióxido de carbono es materia prima importante para todos los seres vivos capaces de hacer fotosíntes y, cuanto mayor sea la proporción de dióxido de carbono, su efecto trófico se apreciará más.

Claudia Burns-Walters
Claudia Burns-Walters

Unchecked, and if not changed soon, the insatiable thirst of a few for power and money will cause an unsatisfied thirst for water for many.  However, I think that we are all guilty to  some degree because we want some or more than what we need of what the industries that contribute to this problem offer.  And industry would rather make profits than a clean and safe environment.


And don't forget the rest of nature / animals that suffer also.  The actions of humans, who, arguably, should suffer the consequences of their actions, always affects nature, who is generally full of innocent victims.


End of rant...

Julie Foser
Julie Foser

The Sewer Plants need to be investigated too.  When one inch of rain falls our sewers overflow 70,000 gallons of raw sewage into the lake.  I am sure that changes the bacteria levels and PH level of the lake. Maybe start by requiring them to be fixed first.  That would be a start.

Laik Rajesh
Laik Rajesh

Is there any research going on to modify the toxic algae at genetic level, into human friendly, microbes, can bacteria be helpful to remove the pollution?R& D needs to be started .

Laik Rajesh
Laik Rajesh

What is the root cause behind  this water pollution, The cause should be monitored to prevent from in other parts of the worlds, this find the solution globally, then we can identify the precautionary measures would have to be taken to stop.

Paul Petiprin
Paul Petiprin

OK!  Crisis!  Now what?  Will the polluters be fined?  Will the causes be addressed or will we again stand back and emit a collective, "Oh No!"

Julie Foser
Julie Foser

I posted a photo that I took June 29, 2013 I submitted hoping to win the National Geographic competition for clean up efforts.  There is also another issue facing Lake Erie. Toxic algae and also the sewer plants in Buffalo, NY.  I would think that thousands of gallons of sewage water would change the balance of the Lake.  Here is my photo of Mr. Nasty Turtle.  I took many shots from the Lake.  These are some disturbing photos of the destruction I found in 2013.

http://yourshot.nationalgeographic.com/photos/3530310/

Pololota Polo
Pololota Polo

@Hrabina Krystyna remember that when you clean your pond you are "planting" this algae in to the sewer and the to the lake, river or sea where your sewer flows... just saying...

Jonathan Strauss
Jonathan Strauss

I Think there needs to be buffer zones around these lakes where native plants can be replanted en mass.  Ban Golf courses or lawns which require huge amounts of fertilizers unless we wish to continue this trend.  That means all business owners, homeowners and farms owners that are established near the lake and waterways feeding into it need to be monitored if not held accountable for using such chemicals. Education is the key.

Pololota Polo
Pololota Polo

@Marilyn Tolliver Do that! Write letters and email them everyday. Don't vote in such a..holes and impeach them if possible. It is the only way to solve part of the problem.

Jane Lee
Jane Lee expert

@Laik Rajesh The problem is too much nitrogen and phosphorus running into the lakes. And those materials come from fertilizers used on farms and private lawns, as well as from leaky septic tanks.

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