The reason why bird poop is a concern is because the fecal matter is rich in phosphorus and nitrogen, and these provide the nutrients and growth factors needed for algae to bloom. An algal bloom is when a rapid increase in the population of algae in a water system occurs. The effects are very evident: the discoloration in the water as a result of the pigments. Sometime ‘algal blooms’ are the result of actual algae, at other times they are causes by cyanobacteria. The phrase “harmful algal bloom” is reserved for an algal bloom that causes negative impacts to other organisms through the production of natural toxins.
Assessing the causative factors for algal blooms has been undertaken at the Maji Agricultural Reservoir in Wonju, Gangwond-do, South Korea, led by Dr. Tae Kwon Lee. Dr. Lee noticed that where an area of water receives a relatively high concentration of bird feces the possibility of an algal bloom occurring increases significantly.
Around the Maji lake area, which is of economic importance since farmers draw upon the water to support agriculture, there has been an increase in the numbers of cormorants. These are large and conspicuous waterbirds, black in color.
Dr. Lee’s study has shown additional nutrients added to the ecosystem from bird feces have a cascading effect. To test this out, he recreated a pond-like ecosystem in his laboratory. Here he ran studies varying the quantities of bird feces. Each study ran for 21 days with the algal levels measured. With these studies he showed how increases in bird feces led to a rise in algal level, in terms of growth rates and total biomass.
The effect was long-lasting, as Dr. Lee states in a research note: “feces in the water acted as a nutrient source for days.” He adds: “Our results confirmed the changes in nutrient condition and microbial community in water caused by a small amount of feces.”
Dr. Lee is calling on greater bird control for where waterways are at risk from toxic algal blooms. The findings about the adverse impact of bird feces are published in the Journal of Environment Quality. The research paper is titled “Short-term Effects of Great Cormorant Droppings on Water Quality and Microbial Community of an Artificial Agricultural Reservoir.”
