Phytoremediation

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Phytoremediation solutions are immediate and inexpensive

It is absolutely critical that we buy time for Lake Atitlán's damaged ecosystem and help it to survive the onslaught of constant pollution, until the nutrient and pathogen problems are eliminated at source. Phytoremediation, the process of decontaminating water by using plants to absorb or break down pollutants, is the simplest and least expensive way to achieve this.

It uses plants and solar energy to decrease contamination in water and soils, sludges, sediments, surface water, and groundwater by filtering pathogens and removing excess nutrients. Tul reforestation, floating gardens, and floating rings are three phytoremediation solutions that we can implement right now.

Tul reforestation

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The native tul plant is a natural biofilter that is critical to Lake Atitlán's natural defense against contamination, nutrient overloading, algal blooms, and oxygen depletion.

Tul grows rapidly, in very dense clusters. The plants absorb excess nitrogen and phosphorus, and the biofilm of bacteria that adheres to the surface of the plants also consumes nutrients and pathogens, enabling the lake to maintain a healthy equilibrium. Tul forests prevent shoreline erosion and they are important for the lake's biodiversity as they provide habitat and breeding grounds for many species of fish and animals.

In 2010 abnormally high rainfall caused the lake to rise more than three meters. Most of the tul forests were drowned, enabling the subsequent accumulation of nutrients.

The local Tuleros' associations have managed and harvested the tul forests for generations. They saved and replanted tul and established new, sustainable forests, but these areas are not large enough to offset the effects of constant pollution.

Floating gardens & floating rings

Floating gardens are an ancient science from the Aztec and Inca times. Floating 'wetlands' - rafts covered with soil and plants - clean the water and provide food. Modern floating gardens are built of wood and non-biodegradable mesh tubes, which are filled with plastic to create buoyancy. This structure is covered with mesh and sand, allowing plant roots to hang down into the water.

The plant roots absorb excess nitrogen and phosphorous. A biofilm of beneficial bacteria forms on the raft and roots, which consumes even more nutrients and filters metals, pathogens and other pollutants. All this makes the lake water clearer, allowing light penetrate deeper and enabling aquatic plants to grow deeper down, thereby restoring oxygen and reversing eutrophication. Organic matter that attaches to the underside of floating islands provides food for fish, and the islands themselves provide habitat for birds.

Floating rings are like giant hula hoops filled with water hyacinths. This fast-growing plant can be an invasive nuisance if it grows out of control in non-native environments. When controlled by a floating ring, however, the water hyacinth becomes a highly effective resource for phytoremediation. The plants' roots hang down up to a foot below the water surface, creating a huge floating filtration area that absorbs excess nutrients from the water quickly and filters pathogens. The plants can also be harvested every 2-3 weeks and used for organic composting.

Recommended viewing

Highlights from our tul reforestation campaign.

"Chajil Ch'upup" (Guardians of the Tule)- Actuality Media

This great short film explores the world of Juan, an Tz'utujil Mayan whose family has fished Lake Atitlan for generations.

Actuality Media helps  students and young professionals to create media on change-makers in developing communities around the world.