Dive into the lake with us to discover the mysteries of the water

Lakes are bodies of water that do not directly connect to the ocean.

There is a mixture of shallow, deep, temporary or permanent lakes.

Lakes hold 98% of the liquid surface freshwater which makes them a crucial part of chemical, physical and biological processes.

The Lake District is home to 16 lakes, including the largest natural lake in England, Windermere.

In the Lake District ribbon lakes were left at the end of the last glacier, over 200,000 years ago.

Lakes are important ecosystems. Many organisms rely on freshwater lakes for survival. Humans also depend on lakes for services such as tourism, drinking water, waste removal, industrial activity, and recreation.

Lakes are important habitats for many species within the Lake District National Park. Three endangered fish can be found in the lakes: the Vendace (Coregonus vandesius), the Schelly (Coregonus lavaretus) and the Arctic Charr (Salvelinus alpinus), below.

Arctic Charr are an endangered species that depend on fresh water lakes in the Lake District.

Fish play a key role in the food web of lakes. Recently, there has been a shift towards dominant fish species that can survive in a wide range of temperatures. Some of these species feed directly on zooplankton, such as water flea which under normal circumstances help control phytoplankton growth. In the future, this could increase algal blooms.

Fig 1: The process of eutrophication

When a lake becomes more enriched with nutrients harmful algal blooms grow. This process is called eutrophication. The infographic on the right shows the process of lake eutrophication.

Eutrophication is accelerated by nutrient pollution from humans. This is one of the greatest problems facing lakes all over the world. Lake Windermere is struggling with eutrophication. Blue and green algae is a regular occurrence at some locations of the lake but it is feared that it is becoming more frequent.

Climate warming is exacerbating lake eutrophication. In warmer temperatures, a lake’s growing season is longer. Nutrients are more available in warmer temperatures and predation of phytoplankton is lower. This produces more algal growth in higher temperatures. Resultingly climate change induced warmer water temperatures are making the ability to meet water quality goals much harder.

Though nutrients occur naturally, they are also added by human activities such as farming. Fertilizers which contain phosphorous and nitrates, runoff from fields into the watershed and eventually accumulate in rivers and lakes. This adds more organic matter to lakes, increasing the growth of algal blooms.

Why is eutrophication bad?

Some algal blooms are toxic and harmful to humans and animals. If ingested blue green algae can kill pets, livestock and other animals in the area. Algal blooms also reduce the amount of oxygen in the water which can kill aquatic fish, animals, and plants. Over time this could reduce population numbers of endangered species.

If you spot blue green algae call the Environmental Protection Agency to report a sighting.

Waste from town residents and businesses add pollutants to lakes. Cleaning products containing phosphates can enter the lake and accelerate algal blooms. When buying laundry and washing up liquids try to purchase ones with natural ingredients that will biodegrade. Some shops sell Ecover or if you are in the Lake District you can head to stores like the Rattle Ghyll which stocks cleaning products in a zero waste section.

Motors churn up the lake bottom in shallower areas. This stirs up the lake sediment making phosphorous more available. When phosphorous reaches the surface of the water, they feed algae and cause and algal bloom. This stirring effect also reduces water quality due to suspended packages.

Invasive species are threatening the Lake District’s wildlife. The Floating pennywort, Australian swamp stonecrop, American signal crayfish and the killer shrimp are species that have devastating effects in lakes.

Invasive species are problem because:

  • They can out-compete native species, reducing population sizes.
  • They grow and spread rapidly in a new environment and can dominate a lake overtime.
  • When they become established in a lake they are costly and difficult to control.

Invasive species can hitchhike on footwear, boats and equipment. To help prevent the spread of invasive species when ever you leave a river, tarn or lake South Cumbria Rivers Trust have three crucial steps for you to take.

Check – Clean – Dry

Stop the spread of invasive aquatic species logo
  • Check your equipment and clothing for living organisms. Pay particular attention to damp or hard to inspect areas.
  • Clean and wash all equipment, footwear and clothes thoroughly. If you do come across any organisms, leave them at the water body where you found them or on a hard surface to die out.
  • Dry all equipment and clothing. Some species can live for many days in damp conditions.

Help Clean Up The Lake Shore

Reduce boat speeds on the lake,, wash your walking boots and remember to pick up your litter. These small actions can have a positive effect and reduce harm to wildlife and the environment.

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