Blue-green algae blooms are being reported more frequently every year. The intensity of a bloom can vary from a nuisance for a week or two through to extremely toxic and persistent for months on end.
These algae are actually not algae, they are technically classed as a cyanobacteria, but whatever you call them they are annoying and potentially a large health hazard so management of them is important. In most places these blooms are seasonal and tend not to proliferate all year round. This is not true in tropical areas where the temperatures can be high enough for blooms to occur at any time. Most regions suffer from blooms when the recipe of warm temperatures and nutrient levels are suited for the blooms to develop. There is nothing that can be done about managing temperature throughout the year, but nutrient levels can be managed and it is the nutrients that are feeding the bloom. For blue-green algae, and also water weeds like Salvinia and Hyacinth, their growth occurs because there is nitrogen and phosphorus available in the water, feeding their growth. To reduce the growth, reduce the polluting nutrients; ammonia, nitrate and phosphate.
Not all blue-green algae are toxic and for those that are, they are not toxic all the time. But when the conditions are ‘just so’, then off they go. The problem with them becoming toxic is that when this happens then the water has to be avoided. Boiling the water does nothing to the toxins, so we can’t drink it, and for farm dams and recreational areas, animals may drink the water and it can make them very sick and it may be fatal to them. In a country where water resources are limited, it is very important that water, and the nutrients in it are managed, to keep it fit for consumption by all users; animals and humans.
A secondary problem, as well as the toxins, is that as the cells of the blue-green algae die off they can gather up into stinking, horrid masses on the water’s surface and the bacteria that break them down use all the oxygen in the water, and this is when fish kills occur.
Low oxygen events and fish kills can also happen during intense blooms of algae and blue-green algae when there is so much algae, all respiring at night and using up the oxygen. With low oxygen causing fish deaths, from tens to tens of thousands of fish. You don’t have to search far in the news to find a story about thousands of fish being washed up dead due to an algal bloom somewhere in the world.
The problems with blue-green algae blooms in water storages, wastewater treatment, effluent storage, irrigation dams and farm dams all relate back to the levels of nitrogen and phosphorus in the water. Managing the water to lower these nutrient levels is the key to keeping water healthy and free of algal blooms and free of the larger water weeds that choke waterways. To find out how to lower nitrogen and phosphorus levels in the waterbodies you manage check out our information on How Diatomix Works.
Hope your water is healthy, and don’t forget you can contact us if you have questions about the water in your life.