The summary is made by artificial intelligence and checked by a human.
The state of Littoistenjärvi has deteriorated.
The lake was chemically cleaned to make it clear in 2017.
The cleaning chemical binds phosphorus, which provides a growth medium for blue-green algae.
The bonds are not durable and phosphorus starts to be released again after about 5–10 years have passed since the treatment.
Climate change is weakening the quality of water bodies worldwide.
In actual Finland There is a lake on the border between Lieto and Kaarina, the river used to be amazingly clear, but now at the beginning of July it is unfit for swimming.
The badly eutrophic Littoistenjärvi was chemically cleaned in 2017. Almost 200 tons of cleaning chemicals were injected into the lake, and the lake changed from a murky lake filled with blue-green algae to crystal clear in one day.
This summer, the condition of the water body has deteriorated again.
About that told formerly MTV news.
from the University of Turku retired aquatic ecologist Jouko Sarvala probably knows Littoistenjärvi better than anyone else. He has studied the lake for more than 40 years.
Littoistenjärvi was treated with polyaluminum chloride in May 2017 according to Sarvala’s proposal. He explains that chemical cleaning was the only solution left to improve the condition of the lake.
“A strong push was needed to balance the ecosystem,” says Sarvala.
Reprocessing according to him, would be appropriate, but it is difficult to get financing. The procedure is expensive, the previous renovation cost more than 200,000 euros.
Jouko Sarvala considers the restoration of Littoistenjärvi his most important water project.
After processing the lake became clear in one day, says Sarvala. He remembers how the parking lots and sidewalks were filled with cars. People gathered at the lake to marvel at the water, which was even described as unnaturally clear.
Sarvala says that the water in the lake was not meant to remain extremely clear. The bright sparkle lasted for a few weeks, after which the depth of vision stabilized at about 2 meters. Littoistenjärvi is a shallow lake, it is a little more than 3 meters deep at its deepest point and the average depth of the lake is 2.2 meters, so the lake remained relatively clear despite the cloudiness.
A week ago, a blue-green algae raft waved at Littoinen’s beach.
the lake is a joy for many. According to the Littoistenjärvi management board’s estimate, up to hundreds of thousands of people swim there every year.
The pressure of local recreational use is strong, and the special expert of the ELY center in Varsinais-Suomen Harri Helminen I think that’s why it’s worth starting the planning of a new chemical cleaning now that the condition of the lake has deteriorated.
“The condition remained good four years after the procedure, then the state of the lake changed, but now it looks bad,” says Helminen.
Used for cleaning polyaluminum chloride binds phosphorus released from the bottom of the lake, which provides growth space for blue-green algae. However, the chemical does not create lasting bonds, but phosphorus begins to be released little by little. The state of the lake changes to its former state when about 5–10 years have passed since the treatment, says Helminen.
Phosphorus dissolves in water more abundantly as the water temperature rises, so the long hot periods in early summer created good growth conditions for cyanobacteria.
Helminen says that similar chemical cleanings have only been done for a few lakes in Finland. According to him, the procedure is like the last straw.
The clarity of the water varies from place to place in the lake, for which Jouko Sarvala cannot tell the reason.
Littostenjärvi’s problems are also common in other shallow lakes in Finland and in the world. According to Sarvala, the deterioration of the quality of water bodies is significantly affected by climate change.
“Everywhere we are struggling with these problems”, Sarvala laments euphoria.
According to the EU water directive, all water bodies in Finland should be put in good condition. Helminen states that this is practically impossible.
“However, direction and goal are important,” he says.
Read more: The bottom of Littoistenjärvi, which was cleared a year ago, now looks “like the Amazon” – four new lakes will be cleaned this summer
Read more: The chemicals brightened Littoistenjärvi’s turquoise Mediterranean, this is what the lake looks like now – “The good effects lasted longer than expected”
Read more: 200 tons of chemicals turned a lush Finnish lake as turquoise as the Mediterranean Sea – “The change is absolutely incredible”
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