Last week marked an important step in the most comprehensive study of water quality in the Bellbird Biological Corridor. Dr. Thomas Shahady returned to gather another round of samples, continuing to solidify some hypotheses in his water research.
Shahady is the current director of the Center for Water Quality at Lynchburg College in Virginia. He practices a three-pronged research model with students and interns he teaches in both the U.S. and Costa Rica.
He has been gathering data from 18 field sites in the Bellbird Biological Corridor since 2013. By taking multiple trips to UGACR every year, his information is adding up to give us a general idea of what concerns the community will face.
Researchers Martha Garro Cruz and José Montero tagged along with Darixa Hernandez and Shahady for three days to continue the collection of data and samples. The methods comprise three key steps:
1.) Physical parameters: A cross section is chosen to measure the depth across every meter of the river’s width. This gives us information on water volume.
The velocity is also measured at each of these points using a flow meter. The combined information is used to measure the river discharge.
2.) Chemical parameters: Water samples are collected in order to measure phosphorus and nitrogen levels. This can tell us if there’s any external input of these chemicals by fertilizers, for example. A YSI multimeter is used to measure pH, ammonium levels, dissolved oxygen, and water temperature.
3.) Biological parameters: Samples of the aquatic macroinvertebrates are taken by placing a square net facing upstream, then turning over rocks and leaf litter in front of the net. Macroinvertebrates are released from their habitat and drifted into the net by the water current. Based off their continuing research, they have developed a percentage model of what the standard content should be for each family of macroinvertebrates. Only certain families of macroinvertebrates are resistant to large amounts of pollution. This makes it possible to decipher water quality based on what aquatic life is present.
Escherichia coli and number of fecal coliform colonies present are also assessed. Water samples are collected and then taken to the lab where the water is filtered through a membrane, a growth medium for bacteria is added and then these are placed in petri dishes. After three days of incubation, blue (E. coli) and red (other coliform colonies) are counted.
Keeping track of the macroinvertebrate populations in the stream can be conducted as citizen science – all you need is a net, containers, and an insect key. This is why Shahady wants to show a correlation between chemical pollution and invertebrates present. The goal is to empower the communities to be more cognizant about the pollution levels in their water shed.
Through this research, Shahady has discovered several alarming issues. He is faced by the ambiguity of what happens with Costa Rica’s waste water (black and gray water).
They are now aware of field sites where water is simply disappearing. Farmers (and a pineapple plantation) have been extracting an unregulated amount of water for irrigation when the weather is dry. In a single river the difference is drastic based on the amount of anthropogenic influence in adjacent locations.
After compiling all of the results, Shahady will have plentiful evidence to show community representatives. The results will be published in written form along with an index for citizens to monitor their river and streams, driving more policies to be implemented to water quality in the Bellbird Biological Corridor. Check out the links below for Thomas Shahady’s visual presentations.
Assessment of Stream Water Quality in BellBird Biological Corridor: www.periscope.tv/w/1BRKjAvPgNwxw
Creation of Water Quality Index: www.periscope.tv/w/1ypKdAvqbQdGW
Blog by Photojournalism Intern Charles Austin Boll, with special contributions by Darixa Hernandez.