Many know London for its stormy skies and constant rain. Yet, believe it or not, there was a time when London locals were looking to add water to their community. During the 1600s London’s canal network began. Thanks to the canals, the sleepy farm towns outside the city center were transformed into the bustling boroughs of Little Venice, Camden, Hackney, Shoreditch, and Mile End.
Today, the city of London has grown to completely surround the canal channels making them entirely urbanized water networks. I became curious about the environmental health of these channels in response to the urban environment. Since I pass the canals daily and enjoy the beauty they bring on a surface level, I wanted to find out more about what was happening below the surface. Thus I headed out to Paddington Basin, Regents Canal, and Camden Lock to perform simple water quality assessment tests in the hopes of revealing some of the unseen characteristics of London’s beloved canals.
First stop: THE PADDINGTON BASIN
The Paddington Basin was chosen because it is the new “it” spot for London’s business women and men. Before the 1980s this areas was an unused swampland. However, in 1980 a series of development projects transformed the space into an open interactive business basin, complete with food trucks, the waterside, and clean-lined glass skyscrapers to reflect all its glory. Socially, it is clear to see why so many businesses have flocked to the area. It’s new, close to the Paddington tube station, and the canal serves as a much-needed break from the city’s usual swaths of pavement.
However, environmentally, this sleek basin space is a textbook example of the effects of urban development on water quality. Below the glare of smiling businessmen and shimmering buildings lies an environment literally gasping for breath. The increased population in the area has led to a subsequent increase in pollution. Meanwhile, the slabs of cement used to build the basin have led to increased run-off into the canal. Coupled, these changes likely caused the excessive concentrations of reactive phosphate (levels > 1.0mg/l) I found in the canal. Phosphate is a macronutrient utilized by plants to support cell development and growth. In a normal marine environment, it is a limiting factor. This means that the amount of phosphate in the water directly influences the number of plants, algae, and phytoplankton that are able to grow. However, excessive phosphate levels usually lead to three things.
1st. Straight away the canal’s Microalgae gobble the phosphate up. With the extra phosphate fuel, they begin to asexually reproduce. Every microalga can make two copies of itself. Those copies make two more copies, and this chain continues until we see a classic example of exponential reproduction. In environmental science, this is called a bloom. Normally this process would be checked by the limited amount of phosphate in the water, however, in this water, due to human activity, the phosphates levels are extremely high and thus there is no check in place.
2nd. After all the microalgae live their short, albeit phosphate-rich, little lives, they die. Problem solved right? I wish! When the microalgae die, decomposing bacteria in the water immediately begin consuming them. As they feed, they take in large quantities of oxygen. In worst cases, they use up all the dissolved oxygen in the water. Whoops. In science, this is called hypoxia because the water is experiencing anoxic conditions.
3rd. The lack of oxygen leads to a fish kill. This basically means that the marine environment has become a dead zone. If phosphate levels are lowered to the proper amounts, then the marine environment can recover. However, if they spike again, the whole dramatic process, formally known as eutrophication, restarts.
The beautiful Paddington Basin is a perfect example of how humans can praise the natural environment by incorporating it into the urban fabric of a city. Yet in doing so, unknowingly harm much of the unseen ecosystems. With a bit of mitigation and reconstruction of the Paddington Basin drainage network, eutrophication in this area could be solved. But until this happens, the Paddington fish are holding their breath!
Thanks for the Read!
Stay Tuned for the Regents Canal, and Camden Locke!
“Nature holds the key to our aesthetic, intellectual, cognitive, and even spiritual satisfaction”. — E.O. Wilson