by Federal scientists published their annual forecast for the harmful algae flowers of Lake Erie on June 26, 2025 and expect a slight to moderate season. Anyone who comes into contact with toxic algae can be exposed to health risks. And in 2014, when toxins from algal flowers contaminated the water supply in Toledo, Ohio, was also a moderate year.
We asked Gregory J. Dick, who headed the cooperative institute for Great Lakes Research, a center at the University of Michigan financed by the Federal States, which, among other things, examines harmful algae flowers why they are such a problem.
1. What causes harmful algae flowers?
Harmful algae flowers are dense spots of excessive algae growth that can occur in any kind of water body, including ponds, reservoirs, rivers, lakes and oceans. When you see them in fresh water, they usually see cyanobacteria, also referred to as blue -green algae.
These photosynthetic bacteria have been living on our planet for billions of years. In fact, they were responsible for the oxygen-containing earth atmosphere, which enabled plant and animal life as we know it.
Algae are natural components of ecosystems, but cause problems if they multiply in high density and so we call flowers.
Harmful algae flowers form on the water surface scum and produce toxins that can damage ecosystems, water quality and human health. They were reported in all 50 US states, all five large lakes and almost every country around the world. Blue algae flowers are becoming increasingly common in internal waters.
The main sources for harmful algae flowers are excess nutrients in the water, typically phosphorus and nitrogen.
In the past, these excess nutrients came mainly from sewage and phosphorus cleaning agents, which were used in laundry machines and dishwasher pairs that land on waterways. The US environmental laws in the early 1970s addressed this by demanding wastewater treatment and the ban on phosphorus cleaning agents with spectacular success.
Today, agriculture is the main source of excess nutrients made of chemical fertilizers or manure that are applied to agricultural fields to grow plants. Rainstorms wash these nutrients into streams and rivers, which they deliver in lakes and coastal areas, where they fertilize algae flowers. In the United States, most of these nutrients come from corn production on an industrial scale, which is largely used as animal feed or for the production of ethanol for petrol.
Climate change exacerbates the problem in two ways. First, cyanobacteria grow faster at higher temperatures. Secondly, climate -related failures, especially large storms, cause more nutrients to bloom, which led to Blooms of record agreements.
2. What does the DNA test of your team tell us about the harmful algae flowers of the eries?
Harmful algae flowers contain a mixture of cyanobacteria species that can produce a number of different toxins, many of which are still discovered.
When my colleagues and I recently sequenced DNA from the Eriesee water, we found new types of microcystines, the notorious toxins that were responsible for the contamination of Toledos drinking water supply in 2014.
These new molecules cannot be proven with traditional methods and show some signs of toxicity, although further studies are necessary to confirm their effects on human health.
We also found organisms that are responsible for the production of saxitoxin, a strong neurotoxin that is known for paralytic shellfing poisoning on the Pacific coast of North America and elsewhere.
Saxitoxins have been detected for some time at low concentrations in the large lakes, but the recent discovery of hotspots of genes that make the toxin makes them an emerging problem.
Our research results indicate that warmer water temperatures could increase their production, which raises concerns that saxitoxin will occur more frequently with climate change. However, the controls of toxin production are complex, and more research is required to test this hypothesis. Federal Monitoring programs are of essential importance for the persecution and understanding of the emerging threats.
3. Should people worry about these flowers?
Harmful algae flowers are unsightly and stinking and make them a concern of relaxation, real estate values and companies. You can disrupt food networks and damage life in the water, although a recently carried out study indicated that its effects on the Lake Erie food network have not yet been significant.
However, the greatest influence is the toxins that produce these algae, which are harmful to people and fatal to pets.
The toxins can cause acute health problems such as gastrointestinal symptoms, headaches, fever and skin irritation. Dogs can die of sea water with harmful algae flowers. The aspiring science suggests that long -term exposure to harmful algae flowers, for example for months or years, can cause or worsen chronic, cardiovascular and gastrointestinal problems and can be associated with liver cancer, kidney disease and neurological problems.
In addition to exposure through direct intake or skin contact, the latest examinations also show that inhaling toxins that get into the air, affect health and cause concerns for the residents and boat drivers on coasts. However, further research is required to understand the risks.
The 2014 Toledo drinking water crisis illustrated the enormous potential for algae flowers that harm damage in the large lakes. Toxine infiltrated the drinking water system and were detected in processed municipal water, which led to a three -day advice. The episode affected the residents, hospitals and companies and ultimately cost the city an estimated 65 million US dollar.
4. Flowers seem to start at the beginning of the year and take longer – why does that happen?
Warmer waters extend the duration of the flowers.
In 2025, Noaa discovered these toxins earlier than ever. The 2022 blossom in the Eriesee remained until November, which is rare, if not unprecedented.
Scientific studies on the Erie des Western Lake show that the potential cyanobacteria growth rate has increased by up to 30% and the length of the flowering period from 1995 to 2022 has grown by up to one month, especially in warmer, flat waters. These results match our understanding of cyanobacterial physiology: flowers like hot – cyanobacteria grow faster at higher temperatures.
5. What can be done to reduce the likelihood of algae flowers in the future?
The best and perhaps only hope to reduce the size and the appearance of harmful algae flowers is to reduce the amount of nutrients that reach the large lakes.
In the Eriesee, where nutrients mainly come from agriculture, this means improving agricultural practices and restoring wetlands to reduce the number of nutrients that flow from agricultural fields into the lake. Early indications suggest that Ohio’s H2OHIO program, which works with farmers to reduce the drainage, make some profits in this regard, but future funds for H2OHio are uncertain.
In places such as the upper Lake, where harmful algae flowers are driven by climate change, the solution is likely to be that the rapid increase in greenhouse gases in the atmosphere is increasing and reversing the fast person.
This article will be released from the conversation, a non -profit, independent news organization that brings you facts and trustworthy analyzes to help you understand our complex world. It was written by: Gregory J. Dick, Michigan University
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Gregory J. Dick receives the funds for harmful algae flower research from the National Oceanic and Atmospheric Administration, the National Science Foundation, the United States Geological Survey and the National Institutes for Health. He is a member of the Science Advisory Council for the environmental and political center.
