The Everglades National Park lies at the southern tip of Florida, facing the stepping-stone string of islands that extends far into the Gulf of Mexico towards Key West. A vast area of swamp, thick vegetation, shallow lakes and water channels, the Everglades looked intimidating and impenetrable to the first European explorers who visited the area.
The large local population of alligators and crocodiles probably didn’t help.
It remains largely uninhabited to this day, despite being surrounded by heavily populated urban areas including Miami.
While the southwestern corner of the Everglades is now legally protected as a national park, the 20th century was unkind to the region.
Drainage channels and dikes, built in the early and mid 20th century to reduce flooding and reclaim land for agriculture, disturbed the natural flow of water across the the whole of southern Florida.
Lake Okeechobee, Florida’s largest, was surrounded by flood defences.
Two thousand square kilometres of former marshland next to the lake – a quarter of the historical Everglades region – disappeared under sugarcane fields.
The degraded Everglades of today reflect this past century of damage, with large areas lost entirely, and the remaining protected landscapes continuing to be harmed by pollution and disrupted water flow.
We have been working for the past few months with the Everglades Foundation and US challenge prize organisers Verb Inc on a prize to reverse the damage to the Everglades from one of its most serious pollutants: phosphorus.
The problem with phosphorus is not that it’s toxic, but that it is so good for plants. Phosphorus-based compounds are one of the main components of agricultural fertilisers, included because it encourages vigorous growth of plants’ roots and shoots. For sugarcane, a type of grass, this is great. For the Everglades, this is a disaster.
The ecosystem of the Everglades developed over millennia, with rain and river water washing through the marshland, creating a region very low in dissolved nutrients. Nutrient-hungry, fast-growing plants couldn’t grow there, and so a unique ecosystem emerged, based on plants that could thrive with very few nutrients.
With the influx of fertilised water in the mid 20th century, this suddenly changed, and invasive species have been able to establish themselves in the Everglades – outcompeting and smothering the Everglades’ native plants and destroying the habitats its animals relied on.
Restoring the balance to the Everglades’ ecosystem will have to involve solving the problem of phosphorus pollution.
There are ways of getting dissolved phosphorus out of water, such as constructed wetlands that use plants to extract the phosphorus.
But they are expensive, take up a lot of space, and often aren’t much good at bringing concentrations down to the very low levels the Everglades had in the past.
The Everglades Foundation’s $10m George Barley Prize – which will launch in 2016 – will incentivise companies to develop new technologies that can extract phosphorus from the water at radically lower costs than before.
The technologies developed in this process will be useful around the world.
Although the Everglades is a uniquely tough environment to restore, as the required phosphorus level is so low, the problem of fertiliser pollution in waterways is widespread around the world. Even outside of fragile ecosystems like national parks, fertiliser runoff causes serious problems like algal blooms, eutrophication and fish death.
Developing a low-cost technology for phosphorus removal will help restore degraded ecosystems around the world – and ensure that the surviving parts of the Everglades remain as intimidating and impenetrable as ever.
Illustration: Science Practice/Nesta