What is a water source?
A water source is a place where water comes from, for example rivers and streams, lakes, wells, and seas. This water can be treated and then used for drinking, cooking, bathing and other activities like swimming or kayaking.
Microorganisms within water systems
Microorganisms are found naturally in all water sources, these can include nitrogen-fixing bacteria which return nutrients to the soil or pathogens like Norovirus and Influenza virus.
E. Coli is another example. This is often used as an indicator species for water quality. This is where concentrations of certain microorganisms are tested to judge the safety of the water. E. Coli is used as it’s naturally found in the body of humans and other warm-blooded animals and Its presence in water typically indicates there is faecal material in it but, here we are concerned about how much E. coli is present rather than whether it is or not.
Algae within water systems
Algae are another form on microorganism, they are a single-celled plant which are related to kelp and nori which is used in sushi. They are very useful for adding oxygen to the water and recycling nutrients helping to maintain the ecosystem.
Most often we see green algae which is harmless to humans and beneficial to water systems. However, there is also blue-green algae which can produce toxins called cyanotoxins which are harmful to humans and animals.
Animals and water systems
Animals can use the water as a resource for drinking or cooling down on a hot day, it’s also a habitat for many fish, invertebrates, and amphibians which also use the water for breeding. These animals rely on the water for survival and engineer the habitats to create complex food webs and nutrient systems which enable their survival.
They also leave excreta in and around the water, this can be deemed as a pollutant but it’s also built into the food webs and nutrient systems making it exceptionally important for microorganisms.
Over 10% of freshwater and wetland animal species are at threat of extinction in the UK with over 90% of wetland habitats being lost in the UK over the last 100 years.
If you would like to know more about microbiology, microorganisms, and pathogens, the following resources may be useful:
Wildlife Trust – Water
Outdoor Swimming Society – Algae and algal blooms
Water Microbiology – Bacterial Pathogens, water quality indicators
Aquatic Microorganisms – A wider resource on aquatic microorganisms
Swimming with Sewage 