Lakes worldwide are experiencing more severe algal blooms

Climate change is likely hampering recovery efforts

Carnegie Institution for Science

Ho, Michalak, and Pahlevan's study of algal blooms in lakes over a 30-year period found that Florida's Lake Okeechobee deteriorated. Toxic algal blooms resulted in states of emergency being declared in Florida in 2016 and 2018. Credit NASA Earth Observatory image made by Joshua Stevens, using Landsat data from the U.S. Geological Survey.
Ho, Michalak, and Pahlevan’s study of algal blooms in lakes over a 30-year period found that Florida’s Lake Okeechobee deteriorated. Toxic algal blooms resulted in states of emergency being declared in Florida in 2016 and 2018. Credit NASA Earth Observatory image made by Joshua Stevens, using Landsat data from the U.S. Geological Survey.

Washington, DC– The intensity of summer algal blooms has increased over the past three decades, according to a first-ever global survey of dozens of large, freshwater lakes, which was conducted by Carnegie’s Jeff Ho and Anna Michalak and NASA’s Nima Pahlevan and published by Nature.

Reports of harmful algal blooms–like the ones that shut down Toledo’s water supply in 2014 or led to states of emergency being declared in Florida in 2016 and 2018–are growing. These aquatic phenomena are harmful either because of the intensity of their growth, or because they include populations of toxin-producing phytoplankton. But before this research effort, it was unclear whether the problem was truly getting worse on a global scale. Likewise, the degree to which human activity –including agriculture, urban development, and climate change–was contributing to this problem was uncertain.

“Toxic algal blooms affect drinking water supplies, agriculture, fishing, recreation, and tourism,” explained lead author Ho. “Studies indicate that just in the United States, freshwater blooms result in the loss of $4 billion each year.”

Despite this, studies on freshwater algal blooms have either focused on individual lakes or specific regions, or the period examined was comparatively short. No long-term global studies of freshwater blooms had been undertaken until now.

Ho, Michalak, and Pahlevan used 30 years of data from NASA and the U.S. Geological Survey’s Landsat 5 near-Earth satellite, which monitored the planet’s surface between 1984 and 2013 at 30 meter resolution, to reveal long-term trends in summer algal blooms in 71 large lakes in 33 countries on six continents. To do so, they created a partnership with Google Earth Engine to process and analyze more than 72 billion data points.

“We found that the peak intensity of summertime algal blooms increased in more than two-thirds of lakes but decreased in a statistically significant way in only six of the lakes,” Michalak explained. “This means that algal blooms really are getting more widespread and more intense, and it’s not just that we are paying more attention to them now than we were decades ago.”

Although the trend towards more-intense blooms was clear, the reasons for this increase seemed to vary from lake to lake, with no consistent patterns among the lakes where blooms have gotten worse when considering factors such as fertilizer use, rainfall, or temperature. One clear finding, however, is that among the lakes that improved at any point over the 30-year period, only those that experienced the least warming were able to sustain improvements in bloom conditions. This suggests that climate change is likely already hampering lake recovery in some areas.

“This finding illustrates how important it is to identify the factors that make some lakes more susceptible to climate change,” Michalak said. “We need to develop water management strategies that better reflect the ways that local hydrological conditions are affected by a changing climate.”

###

This research was supported by the U.S. National Science Foundation, the Natural Sciences and Engineering Research Council of Canada, a Google Earth Engine Research Award, a NASA ROSES grant, and by a USGS Landsat Science Team Award.

The Carnegie Institution for Science is a private, nonprofit organization headquartered in Washington, D.C., with six research departments throughout the U.S. Since its founding in 1902, the Carnegie Institution has been a pioneering force in basic scientific research. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.

From EurekAlert!

Get notified when a new post is published.
Subscribe today!
0 0 votes
Article Rating
78 Comments
Inline Feedbacks
View all comments
MarkW
October 16, 2019 7:15 am

They admit that they have no evidence that global warming is playing a part in any of these blooms, however they assume that it must be, therefore we have to do something about it.

October 16, 2019 7:51 am

Now they need to total up all the CO2 that is being consumed by algae, phytoplankton, seaweed, trees, grass, and crops each year and compare that total to annual emissions of anthropogenic carbon. How many trees next to expressways are needed to consume all the traffic emissions?

October 16, 2019 8:09 am

And yet just six weeks ago, ocean ‘acidification’ was an existential threat to algae.

https://wattsupwiththat.com/2019/08/28/global-warming-study-co2-damages-algae/

So everything will just balance out. Carry on.

Brian Valentine
October 16, 2019 8:24 am

“No consistent pattern when fertilizer, temperature, rainfall etc are considered.”

If the latter two are not correlated to the algae growth then how is this “climate” related?

My exasperation, and my feeling of hopelessness, are DEFINITELY correlated with “climate alarmism.” it gets worse by the DAY

Michael Jankowski
October 16, 2019 8:30 am

Major pet peeve…many of these “algal” blooms are of the “blue-green alage” variety…which is a misnomer. Cyanobacteria is not algae. It happens to be one of the more infamous bloomers (in part because it can fix atmospherix nitrogen and out-compete algae), including the Lake O mess a few years ago in FL.

Scientists misreporting cyanobacteria as algae is irreponsible and misleading to the public.

tty
October 16, 2019 8:35 am

Actually to permanently remove carbon from the biosphere increased algal blooms are just the thing. One of the most important mechanisms for removing carbon dioxide from the atmosphere is when phytoplankton dies and sinks to the bottom of the lake/sea. If the the bottom is anoxic the organic material collects there and ultimately gets incorporated into the sediments. Large and frequent blooms are most likely to create anoxic bottoms.

This is the main mechanism which creates organics-rich shales and therefore ultimately (in rare cases) oil and natural gas.

Edwin
October 16, 2019 8:38 am

Since the article mentions Florida’s problems I must wade in to the fray. None of the algae problems in Florida are related to climate change. We identified the problems in some detail at least as early as the late 1970s. I helped organize conferences to review the problems and to propose solutions during the mid-1980s. There were two basic problems, the divergence of freshwater and nutrient pollution. In spite of identifying these problems in some detail little was done until there were crises. Then everyone went running around like this was some sudden emergency. Then to confuse the issue the news media and some so called scientists blamed red tide, K. brevis, on nutrient pollution in spite of the fact that red tides have been documented in the Gulf of Mexico since the time of the Spanish explorers.

Our states problem is directly related to the extreme populations growth. In 1960 there were a bit over 3 million people in Florida the majority of those living in Jacksonville, Miami, Tampa-St. Pete, and Pensacola. Orlando was sleepy backwater where the industries were citrus and aerospace. The population would double in the winter. Interestingly no one in their right mind moving to Florida then moved to the coast because of hurricanes. Today there are over 25 million residents with an additional forty million tourists at any give time. Imagine the amount of domestic waste and stormwater due to harden services we face today.

So what are the scientists doing, holding their hand out or demand they be given research dollars to “solve” the problem. Of course fixing the problem requires tax dollars, primarily at the local level.

Michael Jankowski
Reply to  Edwin
October 16, 2019 4:45 pm

“…red tides have been documented in the Gulf of Mexico since the time of the Spanish explorers…”

And now people are trying to erase that from history, a la the MWP.

Andrew Kerber
October 16, 2019 10:41 am

So according to the article, the link to climate change is ‘warmer lakes dont recover as fast as cooler lakes’ . Physics is evidently not a strong point of the authors, clearly cooler lakes are going to be the larger lakes, and thus have a more diverse biome, and more water to deal with the bloom.

Elle Webber
October 16, 2019 11:55 am

This is “the first-ever global survey”, yet they claim to have seen an increase in algae bloom? Don’t you need a baseline before you can say there has been a change? An increase from what?

I grew up in agricultural areas. Algae in lakes have always been associated with fertilizer runoff and sewage leakage (agricultural as well as human). If this study had wanted to look at the effects of purported warmer weather on algae in freshwater, it should have controlled for the known effects of runoff and studied only uncontaminated lakes. That is so elementary that not doing so must be deliberate. This study therefore is an insulting sham.

Michael Jankowski
Reply to  Elle Webber
October 16, 2019 4:59 pm

“…Ho, Michalak, and Pahlevan used 30 years of data from NASA and the U.S. Geological Survey’s Landsat 5 near-Earth satellite, which monitored the planet’s surface between 1984 and 2013 at 30 meter resolution, to reveal long-term trends in summer algal blooms in 71 large lakes in 33 countries on six continents…”

So they used 30 yrs of data and claim to have found a trend.

“…If this study had wanted to look at the effects of purported warmer weather on algae in freshwater, it should have controlled for the known effects of runoff and studied only uncontaminated lakes…”

Yes, some sort of normalization would be in order for fertilizer and such. But using uncontaminated lakes makes nutrients the limiting factor, so that’s not a useful study. They seem to have been studying lakes where temperature and precipitation (i.e., runoff) may have been the limiting factors. So it was “deliberate” but appropriate in this case IMHO. An analogy would be wanting to identify the impacts of a plant-based diet on cancer patients. They aren’t saying climate change is the sole cause of blooms…they are arguing it makes them more frequent and/or worse.

michael
Reply to  Michael Jankowski
October 17, 2019 10:02 pm

Yes they argue that but the data does not actually support the conclusion due to the faulty methodology of the study. You do need a baseline. Lake Tahoe in California / Nevada has had zero increase in algae blooms since strict controls were put into place on runoff into the lake of sewage. The basin has seen a huge increase in population in the period in this study and zero increase in algae bloom. That would suggest the study is simply voodoo dressed up as science.

October 16, 2019 3:19 pm

Campanile Oct.16 has it correct. Its that nasty CO2 molecule yet again.

Seriously does the water purification process remove the nasties, if not perhaps spraying the Algae is necessary.

MJE VK5ELL

Michael Jankowski
October 16, 2019 5:35 pm

As far as Lake Okeechobee goes…they found a 0.02 deg C/decade trend in temperature. So the highlight of the press release has basically been unchanged in temperature.

Among the lakes they studied, Lake O had among the highest fertilizer trends…and rainfall trends. So they can try to blame the latter contribution partly on climate change. However, they claim this trend is 114 mm/decade, or 4.5 inches per decade(!) in Supplementary Table 1. I call bullspit. Off by a factor of 10 . I’ll have to track-down their source. The Florida Climate Center trend for Orlando, for example, is -0.28 inches per decade.

Their source? “…Precipitation data were obtained from the combination of Climate Research Unit (CRU) Time Series 3.295 and the National Centers for Environmental Prediction (NCEP) / National Center for
Atmospheric Research (NCAR) Reanalysis 196 products available through the North American
Carbon Program (NACP) Multi-Scale Synthesis and Terrestrial Model Intercomparison Project
(MsTMIP) driver data. Sub-daily values at 0.5° × 0.5° spatial resolution globally were
Supplementary Methods 6 summed by calendar year to obtain annual total precipitation values for 1984-2010 based on data availability…”

Actual rainfall in Lake O and upstream watersheds is readily available. Their reanalysis precipitation data is a load of crap. I understand that it may be necessary to use that for a lake in Africa, for example…but come on!

Alex
October 16, 2019 10:00 pm

It is vice versa. Not warmer climate induces the algal blooms. Algal blooms make the climate warmer.
However, not blooms on lakes. The seas are blooming either. This is the cause of global warming.

Kristi Silber
October 16, 2019 10:14 pm

Funny how so many people here reject the conclusions of the research. Why? Why do people think they know these systems, and what has been done in the way of studying them, so much better than the researchers themselves? It’s simply not rational. If the study had found that there was no influence of climate change, the same people, I suspect, would hail the study as well-executed, knowing no more about it than they do about it now.

Gator
Reply to  Kristi Silber
October 17, 2019 5:35 am

More projection from the left.

Michael Jankowski
Reply to  Kristi Silber
October 17, 2019 11:05 am

For starters, they didn’t isolate any impacts of climate change. They found no consistent pattern of cause for increases in frequency and intensity. They just linked better recovery to ponds with the least amount of warming. Sure, the point of the article and blame is climate change obviously, but I wouldn’t say their paper found an influence of climate change.

For me in particular:
(1) The issues raised in FL in 2016 and 2018 were because of Lake Okeechobee, which is contained in their study. The 2016 and 2018 issues there were cyanobacterial blooms, not algae as the article suggests and authors discuss. I did see mention of cyanobacteria in the paper, but the fact that the quotes from the authors still lump those in with algae shows this is about alarmism instead of science.
(2) I saw their data concerning precipitation increases for Lake Okeechobee…at a rate of 4.5 inches per decade. It is based on reanalysis models and not actual measurements. It is off by a factor of 10 or more. There are a host of rainfall data resources that immediately indicate this as bogus.

I’ll be digging into #2 and some other issues more this weekend. From what I saw of their methods, I’m not sure they captured the entirety of the contributory area into Lake Okeechobee. If they did, the claim of a rainfall trend of +4.5 inches/decade is even more ridiculous. I’ve got 12 yrs of engineering practice here in FL and deal with rainfall data regularly.

If I can poke those holes into their finding of a location right down the road from me, it raises issues about their data elsewhere, particularly the rainfall data generated by reanalysis models. It also begs the question as to what happened during peer review. That rainfall trend should have jumped right out at a reviewer.

Kristi Silber
Reply to  Michael Jankowski
October 20, 2019 12:10 am

Michael,

“Sure, the point of the article and blame is climate change obviously” Why is this obvious? When they started, they didn’t know what their results would be; perhaps they might have pointed to fertilizer run-off as the only significant contributor. Even if they were interested in the potential effects of climate change, what’s wrong with that?

If there was better recovery in cooler water bodies, climate change has the potential to play a role. That doesn’t mean that in every lake algal blooms will get worse. For instance, if a lake is fed by melting mountain snow and climate change leads to greater snowfall in the watershed, it could ameliorate algal blooms. Or increased rainfall could make the lake deeper and cooler, with higher stream flow leading to greater heat exchange between surface and deep layers.

You don’t have to conclusively demonstrate a past influence of climate change in order to discuss potential effects, which could vary based on all kinds of other factors.

I don’t have access to the paper, so cannot evaluate your comments – except for the point about cyanobacteria, which are also known as blue-green algae because they photosynthesize. The abstract refers to phytoplankton, of which some are bacteria, some are protists, and most are plants.

A rainfall trend of +4.5″/decade does sound implausible, especially since the time coverage is less than 3 decades; I would have to read the paper myself to see what it says. No offense. The data were not just from reanalyses (what exactly is wrong with using them?), but also from station data. “Precipitation data were obtained from the combination of Climate Research Unit (CRU) Time Series 3.2 and the National Centers for Environmental Prediction (NCEP) / National Center for Atmospheric Research (NCAR) Reanalysis 1 products available through the North American Carbon Program (NACP) Multi-Scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) driver data” – though I don’t know how they were combined.

I don’t see where you are getting your supplemental info. The tables I found don’t include the data you cite.

Regardless, my point stands: people are very ready to condemn research that doesn’t accord with their beliefs, without even reading the original papers. I’ve seen this time and again. They are also ready to assume researchers are intentionally fudging data, misconstruing results, etc. in order to support AGW theory. This is symptomatic of a pervasive distrust of the scientific community – not just climate researchers, but anyone who does any research that has a potential climate change component – which seems to be more often based on their own biases than on competent assessment of the research.

Michael Jankowski
Reply to  Kristi Silber
October 17, 2019 11:24 am

I’ll add another…their Supplemental Information 1 includes another US lake, “Clear Lake.” There are lots of lakes with that name in the US, but the one that comes up in google searches associated with algal blooms (well, actually cyanobacteria again) is in CA, and it matches the lat and long in the SI1. SI1 says the trend in precipitation there is nearly 4.5 inches/decade as well (in an area that averages 38 inches per year). Not in my backyard and not a location I am familiar with, but I can look up enough surrounding rainfall history to see that it’s garbage. The alleged “permanent drought” in CA coinciding with this absurd increase in local rainfall should have raised a red flag with any reviewer.

Only three locations had a decade trend in mm of 100 or more, and Clear Lake and Lake Okeechobee were two of them. Stood-out like a sore thumb. They happen to fall within 1 mm/decade of each other as well, which is an interesting coincidence. But nobody bothered to check actual instrumental data compared to the reanalysis data that was used?

michael
Reply to  Kristi Silber
October 17, 2019 9:56 pm

The study is simply full of giant gaping holes, If you read the commenters on the lake in Florida and look u the actual rainfall numbers, the holes are obvious. Other commenters point out other problems in different areas with the study. Lakes are very sensitive to fertilizer inputs. The algae are mostly starving until somebody or something dumps a bunch of fertilizer in the water and the algae go on a growing spree. As others have pointed out Florida , as only one example, has had a huge population increase with a resulting increase in sewage all of which at some point flows into some body of water and boom the algae have a field day.

Olavi Vulkko
October 17, 2019 8:23 am

Climate chance has nothing to do with that. Erosion, fertilizers from the fields and wastewaters causing that.

michael
October 17, 2019 9:40 pm

The USA population has increased 60 percent from 1970, Chad increased 15 times from 1960. I suspect the increase in bloom has a whole lot to due with untreated sewage and agriculture runoff into most of those lakes. The problem from a science standpoint is the period measured is tiny compared to say the last 15000 years so whether there is an actual increase or just some cyclic increase is unknown. If you look at hurricane activity there is a different cyclic activity going on over time which may be the similar with greening and this studies findings. All these people did was take a tiny cross section of time and pretend that it has some meaning as they have zero data on actual water mineral and temperatures in any of those lakes even in the tiny time period they looked at. At best the study is interesting and at worse Voodoo used by the doom and gloomers for propaganda.

Tony Garcia
October 22, 2019 1:13 pm

If all that was required for the runaway reproduction of algae was fertiliser input, the industrial production of algae for consumption by us in various forms would not be a problem. What has been found to be a problem there was availability of sunlight, which amongst other things limited the algae’s ability to produce Carbon from Carbon Dioxide in order to reproduce. I see in this a direct parallel to experiments carried out in the sea with iron fertilisation, where I believe the mechanism at work is the oxidation of a metal removing the Oxygen from Carbon Dioxide and providing the organism with Carbon that it can acquire without expending energy in photosynthesis. Should this be correct, it may prove important in the course of major volcanic eruptions; One of the consequences is a decrease in insolation, with concommitant crop failures. If algae can be persuaded to grow in such a sunlight-limited environment, it could stave off mass famine….

Johann Wundersamer
October 27, 2019 9:31 pm

“Geo Rubik October 16, 2019 at 10:39 am

When I go fishing I see algae blooms in most lakes that are river/stream fed. These lakes are fed by runoff from ag and urban areas. Most of this water is stained dark and can have silt. No algae blooms in landlocked spring fed lakes.”

Why do eutrophic lakes have low oxygen?

In eutrophic (more productive) lakes, hypolimnetic DO declines during the summer because it is cut-off from all sources of oxygen, while organisms continue to respire and consume oxygen. … In oligotrophic lakes, low algal biomass allows deeper light penetration and less decomposition.

https://www.google.com/search?q=no+oxigen+in+landlocked+lakes&oq=no+oxigen+in+landlocked+lakes&aqs=chrome.

https://www.google.com/search?q=alpes+toplitz+Lake&oq=alpes+toplitz+Lake+&aqs=chrome.