Global warming is making it harder to clean up the iconic River Thames in the UK, according to a new study involving scientists from Durham University.
Rising temperatures are increasing algal growth, which can be dangerous to fish and other aquatic life, despite a dramatic drop in phosphorus loads in the last 40 years. Phosphorus is normally needed for algal blooms to form.
Rising temperatures
Scientists looked at 150 years of water quality data from the River Thames - the longest record of its kind in the world. The data is helping us understand how human activity has changed the river over time.
The team's analysis showed that phosphorus levels have gone down by about 80% because of better sewage treatment and farming practices. But rising water temperatures are still causing more algae to grow.
Harmful algae
The rising river temperatures driven by climate change are increasing the risk of so-called spring diatom blooms and summer cyanobacterial blooms.
These blooms can be dangerous because they block sunlight, reduce oxygen in the water when they decompose, and can sometimes release toxins. This harms fish and other aquatic life. It also makes drinking water more expensive to clean and limits activities like swimming, fishing, and sailing.
Scientists say that reducing phosphorus in the river is still important, but climate change is making it even harder to control algae. Even with all the progress in cleaning up the Thames, warmer water is keeping the algae problem alive.
