Modern, industrial agriculture is dependent upon fertilizers – chemicals often sprayed on fields with abandon. As important as fertilizers are to our way of life, you may not suspect that phosphorus, the main ingredient, is running out; yet it is.
Phosphorus for fertilizer is mined from rocks. It is applied as part of fertilizers to fields then washes out, eventually being buried deep in the ocean. Once fertilizer is washed away, it is not recovered and the finite resource is being used up.
In a new study published in the journal Science of the Total Environment, wildlife is raised as a possible solution to dwindling levels of phosphorus. The study authors include Dr. Andrew Abraham, a postdoctoral researcher at Northern Arizona University, and Chris Doughty, associate professor of Ecoinformatics.
“In the past, animals such as whales, sea birds, fish and bears played a key role in returning phosphorus from ocean depths back onto land,” said Dr. Abraham.
“In doing so, they collectively retained this nutrient in the biosphere, supporting a more fertile planet. Today, however, species extinctions, diminished population abundances and the erection of fences and dams have reduced this nutrient transport service by more than 90 percent.”
With wildlife populations shredded and animal mobility diminished by human structures, the main movement of phosphorus is by humans. We tend to be incredibly inefficient with our use of this nutrient, losing much of it to the ocean.
“Through our research, we were able to show that historically, wild animals transported a large amount of phosphorus that is on par with other important flows such as dust deposition and wildfires,” said Dr. Abraham.
“Importantly though, wildlife can return phosphorus back to the land. By restoring interconnected animal communities, ancient pathways of natural fertilization can be revitalized, helping to conserve an irreplaceable element.”
Animals naturally move phosphorus through their urine, dung and even their own bodies. This is important not only for agriculture but crucially for the health of natural ecosystems as well.
To maintain this ecological service, the scientists suggest a trading scheme similar to the carbon market. This way local communities could benefit either from mined phosphorus or natural sources like phosphorus from bird dung. Scientists hope that this approach could help restore wildlife populations and maintain the healthy function of the Earth.