We can't abandon the lake to death by eutrophication
But that's the fate awaiting Lake Atitlán if urgent action is not taken to combat the main causes of nutrient overloading in the lake - poor wastewater management, chemical agriculture, and commercial tilapia farming.
Eutrophication, or depletion of oxygen, occurs when the water is overloaded with the nitrogen and phosphorus, the nutrients on which algae feed, including the toxic cyanobacteria. Although nitrogen and phosphorus occur naturally and are essential plant nutrients, nutrient overloading imbalances the ecosystem.
Algae can multiply quickly when there is an overabundance of nitrogen and phosphorus, and they deplete the dissolved oxygen level in the lake by breathing it. After the algae dies, sinks, and decays it is broken down by bacteria, a process which can use up all the available oxygen deeper down in the lake. As the low oxygen layer rises, the species that used to inhabit that water die off.
This graphic shows how eutrophication is killing Lake Atitlán from the bottom up.