Cockroaches are rarely a welcome presence. But if you find them along a riverbed in Costa Rica, feel free to dive in. Roaches, snails and many other macro-invertebrates (animals without a backbone that are visible without a microscope) can serve as bio-indicators: living measurements of water health in river and riverbank communities. Their presence or absence can reveal a lot about the impact of human activities on an aquatic ecosystem.
While indicator species vary by geographical region, here in the Caribbean lowlands of Costa Rica, cockroaches signal water wellness. An abundance of snails, on the other hand, indicates pollution, as they thrive when higher concentrations of organic pollution (such as manure, sewage and agricultural or industrial chemicals) are present.
Training the future stewards of our planet
Easy to learn, monitoring water quality using bio-indicators is simple enough for elementary-school students to implement – as one graduation project proved in 2007.
For the project, José Itzep (‘07, Guatemala) and Rosario Solís (’07,¬ Guatemala) worked with students at the nearby Las Mercedes School and at Guácimo High School to measure water quality for the neighboring communities of Pocora and Guácimo. They did so using the Biological Monitoring Working Party–developed in England in the 1970s as a “cheap, quick and reliable water quality evaluation method,” according to Professor Kohlmann—adapted for Costa Rica (known as BMWP-CR). Wading into Dos Novillos and Guácimo Rivers and climbing down the Las Mercedes and Guácimo High School ravines to collect data, José, Rosario and the students focused on the presence of the Perlidae (stonefly) family. Its presence in high numbers indicated excellent water health; conversely, the fewer stoneflies present, the poorer the water’s health.
While they were not able to link water quality problems to specific events or sources of pollution, José and Rosario saw students “develop environmental conscience, organization abilities, and the assimilation of the technique in the community water evaluation processes.” In their report, one young person at the Las Mercedes School shared: “During the bio-monitoring process, we realized that the rivers are polluted, and that we as human beings contribute to this pollution. That’s why we shouldn’t throw trash in the rivers, and we need to tell everyone about the water’s importance.”
“Like watching a movie rather than taking a photo”
According to EARTH Professor Bert Kohlmann, bio-indicator monitoring systems offer a far bigger and more useful picture than the expensive chemical tests conventionally used. He explains, “They’re much more sensitive indicators… It’s like watching a movie rather taking a photo.”
Professor Kohlmann began researching bio-indicators in 1999, when he learned about them on a sabbatical to the University of Saarland, Germany. Through his research and advocacy since then, he has helped to establish their importance internationally. Serving as a scientific consultant for the Mexican government, he has helped the country to embrace bio-indicators as standard best practice in measuring water health. Now, the International Atomic Energy Agency (IAEA), part of the United Nations’ Food and Agriculture Organization has followed Mexico in doing so.
Professor Kohlmann’s work has also benefitted the University of Costa Rica’s Environmental Pollution Research Center (known as CICA, in Spanish). Karla Ruíz, research coordinator at CICA’s Ecotoxicology Laboratory comments: “Dr. Kohlmann has been the IAEA’s technical expert and has transferred this technique to environmental professionals in Latin America, including colleagues from El Salvador, Chile, Costa Rica and Argentina, among others. In addition, Dr. Kohlmann has promoted using the system in communities…transferring knowledge to farmers and others who live near the water basins under study through the BMWP index.”
Through the publication of his upcoming book on field evaluations of bio-pesticides’ impact on water quality (to be published by the International Atomic Energy Agency), Professor Kohlmann aims to continue educating others on bio-indicators’ potential.
He visited EARTH’s Gúacimo campus for two weeks in May with Professor Betsabe Lares, a researcher at Argentina’s National University of Comahue, to learn more about microbiology and photography’s applications to bio-indicators. He has appreciated the bio-indicators’ precision in his evaluation of the agricultural water basin of his country’s Auracanía region; in fact, he used Professor Kohlmann’s protocol and expresses gratitude for the guidance it offered him.
One bio-indicator Professor Palma has monitored is the bivalve filter mollusc known as the pea clam or fingernail clam (Sphaeriidae family, Musculium genus), found in Chile’s Tijeral River. Its presence can indicate the amount of iron in the river, since this small invertebrate bioaccumulates the element in its freshwater environment. In this way, measuring the number of bivalve filter molluscs along the river, before and after pesticide use, can show pesticides’ effects on river and riverbank communities in ways that chemical tests will not. For such a vital resource as water, the difference matters. For this reason, Professor Palma especially likes bio-indicators’ applicability in rural areas. With a basic understanding of bio-indicators, rural communities can do the tests themselves and better understand their local environmental issues.
In particular, farmers may want to measure how their activities affect the water – and plan accordingly. Now, with the bio-indicator guidelines as a reference, producers and their communities can act together on their own science-based judgments to shape their decisions.
Help EARTH develop innovative and applicable solutions to the environmental challenges facing tropical communities with a gift to our research programs today.
You must be logged in to post a comment.