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Here's the climate's role in toxic blue-green algae and algae blooms

Some weather and environmental factors that tend to promote algal blooms include light winds, slow moving or relatively still water and nutrient pollution

WASHINGTON — They are hard to get rid of, they can be toxic, and sometimes, quite frankly they stink. We're talking about harmful algal blooms or HABs

Some weather and environmental factors that tend to promote algal blooms include light winds, slow moving or relatively still water and nutrient pollution.  

Nutrient pollution occurs when storm water moves across farms or your lawn, and that water then flows into nearby lakes and streams carrying with nutrients such as nitrates or phosphorus. It essentially gives the algae vitamins to grow big and strong. Nutrient pollution is likely to occur after periods of heavy rain and flooding. 

HABs can pose a threat to humans, be deadly for pets, contaminate drinking water, contaminate or even kill seafood and marine life.

Credit: WUSA
A warning sign for the toxic blue-green algae known as cyanobacteria at Lake Needwood on Aug. 13, 2019.

RELATED: New EPA app helps warn you about toxic blue-green algae

Research indicates that with climate change the environment may be primed to support more frequent and intense algal blooms.  

Climate change may impact algal blooms in several ways, here are two that stick out:

1) Warmer Water - yep that will do it. Blue-green algae, the kind we've seen in Maryland and Virginia recently, just happen to like warm water. The Environmental Protection Agency noted that warmer water doesn't allow water to mix as well. This allows the algae to grow thicker.  

  • Also, algae can float to the surface faster in warmer water, because small organisms can move through warm water easier.
  • Just like you and I like to lay out in the sun and catch some rays ... so does algae. Algal blooms soak up sunlight which makes the water warmer and this promotes more blooms. 

2) Carbon Dioxide - Algae not only likes carbon dioxide, it needs it to survive. Higher levels of carbon dioxide can really get algae growing quickly, especially blue-green algae.  

RELATED: Here are toxic algae hot spots at popular DMV recreational areas

By the way, carbon dioxide levels are the highest that they have been in the last 400,000 years according to NASA's Global Climate Change website.  

Other impacts may come from changes in salinity, sea level rise, rainfall patterns and coastal up-welling. 

Mitigating the Risk 

Here are a few things you can do around your home to help slow down nutrient pollution which leads to HABs. The Environmental Protection Agency suggests to be water and energy efficient along with some other tips. 


  • Choose phosphate-free detergents, soaps, and household cleaners.
  • Select the proper load size for your washing machine.
  • Use the appropriate amount of detergent; more is not better. 


  • Pick up pet waste.
  • Try not to walk pets near rivers and streams or bodies water. Instead try grassy areas or parks.
  • Pick up after your pet.


  • Use a commercial car wash; commercial car washes are required to properly dispose of wastewater and many filter and recycle their water.
  • If washing your car at home consider the following actions:
    • Wash your car on a surface like grass or gravel (not concrete or asphalt) so water is filtered before reaching a water body.
    • Use nontoxic, phosphate-free soaps.    

The EPA has a complete list of ways to reduce nutrient pollution.

RELATED: Blue-green algae: What it is and how to spot it

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