Algal blooms disrupt holidaymakers across Europe
Something rotten: Visitors to Copenhagen's harbour were greeted by an algal bloom and a horrendous stench in August 2006.
Instead of pristine and inviting bathing waters, tourists are being met by toxic algal blooms. The recent hot and calm weather in Europe has provided perfect conditions for algae. While surface waters have remained still and undisturbed, algae blooms have flourished uninterrupted. However, the blooms are also helped by nutrient inputs caused by human activities.
Nitrogen and phosphorus are critical nutrients for algae growth. Some algae, especially the blue/green algae found in Scandinavia, can absorb atmospheric nitrogen. Consequently, they can bloom in waters where only phosphorus is present. Nitrogen and Phospherus enter coastal waters as a result of human activities, such as run-off from agricultural land, fish farming and inadequately treated waste water. Phosphorus is found in everyday household products such as detergents, soap and shampoos.
It is not unnatural for the population of algae to increase in summertime. And algae are an important part of the food chain, as they provide food for animal (zoo) planktons which are in turn eaten by fish and other aquatic wildlife. However, today's levels of algal blooms appear excessive. Most importantly is that human activities and favourable summer conditions combine to increase the levels of algal blooms. With the likelihood of climatic change bringing warmer summers in the future, today's excessive algae blooms may become more of a common sight in European waters.
Health effects of algae:
Some algae contain toxins, and therefore represent a health threat to humans and animals. These toxins vary depending on the species of algae. Some types of algae can cause skin and eye irritations, but the main risk comes from swallowing contaminated water. The symptoms of poisoning from toxic algae include nausea, bowel or intestine problems and fever.
Nevertheless, adults would have to swallow a considerable amount of water before any adverse health effects would occur. These incidents are highly unlikely and very rare. However, care should be taken with small children. Health authorities recommended that children should refrain from bathing in these waters. Similarly, pets and farm animals could also be put at risk by drinking contaminated water.
Relevant EEA reports and information:
The changing faces of Europe's coastal areas
Phytoplankton algae in transitional and coastal waters
Fact-sheet on harmful phytoplankton
The European Environment - State and Outlook
Impacts of Europe's changing climate (chapter 3.4.)
Nutrients in European ecosystems
Announcement from 2003 on algal blooms:
Nutrients in transitional, coastal and marine waters
Chlorophyll in transitional, coastal and marine waters
Source apportionment of nitrogen and phosphorus inputs into the aquatic environment
Additional information sources:
http://www.smhi.se/ see "algblomning"