Guatemala's Lake Atitlán, surrounded by volcanoes and Maya settlements, has been taken over by a massive bloom of cyanobacteria (blue-green algae). I'll be traveling to a K'iche' Maya village not far from this place in a couple of weeks. The image comes from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite.
It's no shock to realize that decades of environmental damage have led to this, but it is still very weird to see an image that shows this huge, seemingly pristine body of water transformed into a big pool of slime, with growing "dead zones" where fish and other critters can no longer survive. Guatemala is facing a widespread hunger crisis already -- so, for the at-risk human populations around the lake who live off a subsistence farmer/fisher lifestyle, this means more hunger, more death.
Cyanobacteria are a serious problem both because they are toxic to humans and other animals and because they create dead zones. As the bacteria multiply, they form a thick mat that blocks sunlight. Dense blooms can also consume all of the oxygen in the water, leaving a dead zone where other plants and animals cannot survive. The density of the bloom also affects the cyanobacteria. Since only the top layer of the bloom receives life-sustaining light, the bacteria in the rest of the bloom die and decay, releasing toxins into the water. These highly toxic harmful algal blooms cause illness in people and other animals.
Update: Kara Andrade of Hablaguate points us to an article related to this item, in TIME. There has also been some reporting in PrensaLibre, El Periodico (Spanish language publications in Guatemala) and The Revue . Snip from TIME piece:
With the future of one of its major tourist attractions in question, the Guatemalan government has announced an ambitious multi-part plan to cut sources of phosphorous. It calls for the construction of 15 sewage-treatment plants, a government-led conversion to organic farming for 80% of farmers in the lake's watershed during the next three years, and for educating residents and tourists about the environment. The cost: about $350 million, a huge expenditure for an impoverished country. "The problem has been accumulating for years but Guatemala has other expensive problems and, apparently, this was not a priority," says Margaret Dix, a Universidad Del Valle scientist who has studied the lake since 1976. "It needs money, input and a commitment. ... I think it can be restored to a large extent in four or five years. But it will never be like it was 100 years ago."