Why we need to fix the world's freshwater algae problem

While we experience terrible drought and flooding events more frequently due to climate change, another significant hazard is hidden beneath the surface. To be more precise, the surface of our freshwater supplies. Accessible freshwater on earth is limited. Even though 70% of the planet is covered in water, humans can only access 0.01%, more than half of which is in lakes. Within these lakes, fragile ecosystems maintain the water quality. Once the balance in these ecosystems is disturbed, the water quality will deteriorate, making the water unusable for consumption or agriculture.

Compared to land-based pollution, what happens beneath a lake's surface only becomes apparent after the ecosystem's balance has changed, and the process is almost irreversible. Eutrophication, a process where nitrogen and phosphorus build up in a water body, is one of the main pollution issues endangering freshwater lakes. The growth of potentially harmful algae blooms (HAB), which can be extremely toxic, results from eutrophication. Globally, over 100,000 lakes experience HABs. The impact on public health directly from toxic algal blooms is severe, and the presence of HABs in lakes alone leaves millions of people without access to water each year.

In 2009, researchers defined the planetary boundaries. They are nine outer limits of change to the Earth's systems that could trigger environmental changes in which civilization's continuity is threatened. One boundary already crossed is the flow of nitrogen and phosphorous.

Nitrogen and phosphorous are nutrients for all living organisms on earth. They are crucial for agriculture, the growth of livestock and healthy ecosystems. But we have changed the cycles of nitrogen and phosphorous more than any other element: Over 50% of the phosphate used in agriculture and industries finally ends up in our waterways. Once in our waterways, they may affect rivers and wetlands, and eventually accumulate in the sediment of our lakes.

Nitrogen and phosphorous have flowed into our lakes since industrialization, building up in the sediment layers where they went unnoticed for a long time. During these years, ecosystems started changing in these lakes.

An entire ecosystem can change under the influence of algae. First, algae reduce light penetration into the water column. Algal blooms also cause an increased pH and a decrease in oxygen in the water column. Next, aquatic plants, fish and important bacteria within the lake will die. After that, the sediment of a lake starts releasing its nutrient residues and other potentially harmful elements, like heavy metals. The additional nutrients released will fuel more algal blooms, and as time goes on, there is less chance that the ecosystem's balance will return.

HABs have serious health, environmental and economic effects on people worldwide. For example, the Toledo water crisis in 2014, where half a million residents were ordered not to drink or even touch their water. In the city of Wuxi on Lake Taihu's northern shore in China, over 2 million people went a week without access to clean water. Additionally, the principal source of drinking water for Kisumu, Kenya, was poisoned by a bloom in 2004, cutting off the water supply to over 500,000 people.

Avoiding drinking contaminated water cannot completely protect the public's health, as contaminated lakes still threaten people, animals and the environment. After being in contact with affected water, the short-term effects on humans may include skin irritation, nausea and even paralysis. The long-term effects are still being researched, but are already known to include liver cancer, the neurological disease ALS and Alzheimer's disease. Toddlers can have permanent liver damage by swallowing five gulps of infected water. Recent studies have also indicated that preventing contact with the water may not be enough either as algal toxins are becoming aerosol, affecting the respiratory systems of people living around these lakes.

Though it is important to prevent nitrogen and phosphorous from flowing into our waterways, it will not provide a solution to already affected lakes. To reverse the changes in the ecosystem set in motion many years ago, we need to actively prevent algae from blooming, so the original organisms may grow back. Currently, only 4% of the costs incurred due to harmful algal blooms go into monitoring and managing lakes to prevent such episodes. Additionally, most of these funds go to the most problematic lakes. However, if lakes are to be remediated earlier, catastrophic changes to the ecosystem can be prevented.

FutureProofLakes is a non-profit whose mission is to conserve the ecosystems of the world's lakes. First, by providing near-real-time data on the water quality of small, medium and large lakes worldwide. This can be accomplished by using weekly-processed satellite pictures. Using algorithms, this information is converted into visuals depicting specific water quality indicators, such as turbidity and algal concentration. These photos can go back as far as 35 years and are so comprehensive that they can spot the risk of harmful algae blooming in a lake.

FutureProofLakes aims, through this effort, to identify shifting ecosystems before communities suffer the negative impacts of harmful algal blooms. Based on the data collected, the group also produces prediction models to enable communities to remediate their water sources and reverse the eutrophication process early. This is important in developing countries, as resources are not always available for monitoring or remediation. Due to global warming, these areas are often badly affected.

Through monitoring, the group addresses problems early on and raises awareness for the impact harmful algal blooms have on public health. The information gathered forms the basis of more detailed research on these lakes and access to finance for implementing sustainable long-term solutions.