Brentford Dock algae bloom. There are two major causes of algae/algal blooms (a boom in the algae population) in a water system, high temperatures and the introduction of high quantities of nutrients.
Algae blooms are a warning sign that there is an excessive abundance of the nutrients phosphorus and nitrogen in the water. During the maturing of the bloom the water in Brentford Dock marina became turbid, looking greenish-brown and becoming greener as the algae proliferated to the water’s surface.
Algae growth can cause the foul smelling water and a layer of scum on the water surface as witnessed at Brentford Dock, and this may pose a health risk if cyanobacteria (formerly known as blue-green algae) are present.
Once it has gone through its life cycle and dies the algae starts to decompose and is fed upon by bacteria, the bacteria multiplies in the water leading to a decline in the dissolved oxygen levels in the water. This could lead to the stressing of or death of aquatic life through a lack of dissolved oxygen and an increase level of toxins which are the product of the decay and bacterial consumption. Not all algal blooms are toxic, however those that are can be harmful to humans and pets.
Algae nutrient sources include:
Greywater (which is domestic waste water excluding sewage) and black water (water that has come in to contact with excrement/faecal matter) are considered contributors to the formation of algal blooms. Greywater is water often contaminated with, fats, soap and detergents. Soap and detergents can be a source of phosphates into the water, a nutrient that promotes algae growth.
Black water is waste water containing bodily wastes (faeces and urine), such as from toilets. Faeces and urine are both rich in nitrogen and if they are released in excess in to a water system can, therefore, contribute to excessive algae growth.
There is no evidence that the eutrophication (excessive nutrient enrichment) of the Brentford Dock marina was a consequence of excessive use of fertilizers on Brentford Dock running off in to the marina leading to the Brentford Dock algae bloom. Residents are unaware that fertilizers are used by the gardening company. Furthermore, residents have NO knowledge that there are or have been farm animals grazing at Brentford Dock whose faecal matter may have entered into the marina.
Residents have witnessed the release of both grey and black water over an extensive period of time into the marina. Pumps on boats starting up followed by the smell of faeces and urine are a giveaway sign. These occurrences and smells were experienced long before the arrival of the Brentford Dock algae bloom. The Brentford Dock management (Brentford Dock Ltd, chaired by Veronica Wray/deputy chair Mike Edwards, and John Antrobus of Michael Richards (Michael Richards & Co) who are Brentford Dock’s managing agents) however deny this fact although residents have often witnessed it actually occurring.