Seeing is believing.
It is well known that the contamination of lakes and rivers in Guatemala is increasing by the day.
This is no news and it is pure mathematics. The contamination increases proportionally to the population explosion, industrialization and uncontrolled urbanization around the lakes and rivers.
The sewage, solid, liquid and industrial waste is dumped indiscriminately into the different water bodies' additionally massive deforestation and intensive agriculture around the water bodies is also a big problem. All is directly related to overpopulation of humans.
The recent "algae bloom" in Lake Atitlan has triggered an enormous alarm in the population and the media. Many people are panicking and basically believe that something drastic has happened to Lake Atitlan in just a few days, but this assumption is wrong.
The problem has been steadily increasing for many years. But now, because it is has become finally visible to everybody's eyes, the problem has finally become tangible, we have: "algae bloom". Now people start to react.
Guatemala has the same phenomenon in Lake Amatitlan although this is due to specie of blue green algae. Well, algae is the wrong word, what we see is actually something called: cyanobacteria. Cyanobaceria grow because of excessive levels of nutrients including phosphor and nitrogen in the water.
The cyanobacteria in Atitlan have been identified as Lyngbya hironymusii (Lyngbya hieronymusii), actually a rarity among the cyanobacterias.
In lake Amatitlan the predominant species are Microcystis aeruginosa, one of the most common species in the world.
Both these cyanobacteria need sunlight and nutrients to be able to grow. But the growth behavior is totally different. The Lyngbya in Atitlan grows on the bottom and on substrates like rock and aquatic plants versus the Microcystis in Amatitlan that are suspended in the water.
So why is Atitlan blooming?
This could be caused by several factors but the principal are the same. Not enough light reaches the Lyngbya or underlying plants and they start to rot creating gases that are trapped under the mat of Lyngbya that then loses its grip to the substrate and floats to the surface as flakes or mats. These mats then reduce the light underneath the water surface and more Lyngbya and even plants starts to die due to lack of light and more mass floats to the surface. The phenomenon can easily been seen around the lake as green mats are formed and gas bubbles are trapped underneath them.
Lyngbya types of cyanobacteria only exist in clear water like in Atitlan. What also could create this bloom is the presence of free floating cyanobacteria, Microcystis that limit the light penetration into the water. This is really an alarming situation as we are getting close to the point of no return. Or at least a much bigger problem that will take a lot more time, effort and money to fix.
The blooming of Microcystis is also related to light but in a different way. As these microorganisms are free floating and have the capacity to regulate their buoyancy, they start to float to the surface because they are shading themselves and start to compete for the light at the surface, thereby creating a sometimes thick scum at the surface.
In both cases the blooming can be compared with collective suicide and a big amount of cyanobacteria will die-off. That will then create another effect; it releases toxins into the water.
This phenomenon is well documented in the case of Microcystis and the toxin is called microcystin. In the case of Lyngbya it is less known but it probably hase similar symptoms as the one caused by microcystin such as skin rashes and stomach related illnesses. It is known that cattle exposed to large quantities of microcystin have died from it.
So how do we get rid of these disturbing and potentially dangerous creatures?
The answer is easy. Remove or reduce one or both of the growth factors. Light and nutrients!
This is actually easier said than done but the most sensible way is to remove or limit the nutrients flowing into the lake.
So, how could this be done?
- Stop pumping raw sewage into the lakes and its tributaries by implementing effective water treatment plants from all households and industries around the lake and tributaries.
- Stop the deforestation and implement a comprehensive reforestation plan to stop the soil erosion that contributes with a large amount of nutrient flow into the lake.
- Reduce the use of fertilizers to a minimum around the lake.
The fact is, that the cyanobacteria and algae are some of nature's best ways of absorbing nutrients like phosphor and nitrogen in the water and it will do so with all its force until we stop feeding it to them.
That we might get poisoned by drinking the water or swimming in it could be seen as Mother Nature getting back at us in a small way.
This is a serious crisis, but a crisis is also the best time to join forces, accept that we all are to blame for not doing enough and it is a tremendous opportunity to solve the environmental problem of lake Atitlan for the future.
Photos Jack Cooper and Dennis Lynch
Related links
Help save Lake Atitlan, Guatemala, Tuesday, 27 October 2009
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