The Summer Heat Triggers Algal Blooms

Posted by NYPIRG on August 1, 2022 at 7:52 am

Another hot summer and fresh reminders all around us of how global warming is destroying our environment.  Unprecedented heat waves, huge wildfires, once-in-a-millennium droughts, all are examples of the impacts that a rapidly heating planet is having on the world around us. 

The decades-old predictions of how climate changes would destabilize the world’s climate have turned out to be accurate – and in some ways underestimated the negative impacts.

The heat, the droughts, the fires, the famines are all obvious examples.  But there are other threats that are less obvious.

After a blistering heat wave last week, lakes across New York State are warming up.  Warmer waters make it more likely that we all will use these freshwaters for our own recreation.  But that use, as well as the use of freshwaters for drinking sources, are under threat of an insidious poison – algal blooms.

The blooms are a blue-green slimy substance that floats in water.  Harmful algal blooms aren’t your typical green surface ooze that you may see on the top of lake waters.  While ugly to look at when at the surface, a bloom can also be dangerous, so much so that the state has a blanket policy warning to stay out of the water should there be evidence of one.

The heating planet drives the production of algal blooms.  Warmer temperatures prevent water from mixing, allowing algae to grow thicker and faster.  Algal blooms absorb sunlight, making water even warmer and promoting more blooms. 

While every algal bloom isn’t toxic – some algal species can produce both toxic and nontoxic blooms – toxic blooms can cause problems for swimmers and other recreational users in the form of rashes or allergic reactions.  People who swim in a bloom may experience health effects, including nausea, vomiting, headaches, respiratory problems, skin rash and other reactions.  There have also been reports nationwide of dogs and livestock dying shortly after swimming or wading in a bloom.

Heat alone doesn’t stimulate algal blooms.  As we know, climate changes have also caused stronger, more powerful storms, storms that release much more rainwater than in storms of the past.  Those incredible downpours swiftly flush whatever is sitting on the land directly into lakes, so instead of letting a natural filtration process take place, nutrients that would benefit the soil are washed into surface waters and wreak havoc in the water in the form of algal blooms.

The nutrients these blooms primarily rely on are phosphorus and nitrogen.  The algal blooms have increased due to a rise in nutrient runoff from sources such as soil erosion from fertilized agricultural areas and lawns, erosion from river banks, river beds, land clearing (deforestation), and sewage effluent.  All of these are the major sources of phosphorus and nitrogen entering waterways.  These nutrients coupled with warm, calm water is the recipe for an algal bloom.

Usually, algal blooms crop up in late summer and early fall.  This year, they have begun showing up in lakes across New York.  The DEC has identified 77 algal blooms as of the middle of July. 

To check out the New York lakes where algal blooms are a concern, you can go to the DEC website, which has a harmful algal bloom notifications webpage that it updates regularly.  You can Google “DEC algal blooms map” to see the listings and how to file a possible bloom siting.

While much of western North America has experienced droughts and wildfires, the northeast has largely avoided those catastrophes.  But we are enduing our own crisis in the form of algal blooms.  New York State has experienced a tenfold increase in the number of waterbodies experiencing a bloom over the past 10 years and $6 billion in mitigation expenses and lost economic value.

While we all must do everything possible to reduce the world’s reliance on fossil fuels and aggressively embrace energy efficiency programs and alternative energy sources, due to the amount of CO2 in the atmosphere, the planet will continue to heat up.  There is not much that New York can do to reduce the damage that has already been done and that is fueling the current rising heat of the planet.  But when it comes to protecting surface waters and drinking water supplies, the state has to do a lot more to reduce the runoff from agriculture, landscaping and wastewater sources.  New York must be proactive about protecting drinking water supplies and recreational waters.  The costs for prevention are cheaper than the cost of remediation and illness.