Less and less phytoplankton

2010/07/29 Aulestiarte Lete, Izaro - Elhuyar Zientziaren Komunikazioa

• Biologia
• Ozeanografia

A group of researchers at Dalhousie University in Canada has announced that the amount of phytoplankton at sea drops by about 1% annually. Phytoplankton is the basis of the marine food chain and plays an important role in the carbon cycle.

It was already known that the amount of phytoplankton has decreased considerably in the last 30 years. In fact, researchers have satellite verified that the concentration of chlorophyll in the oceans has decreased. However, this information offered by satellites extends from the late 1970s to the present day.

However, research conducted over the past three years by members of the Dalhousie University of Canada has wanted to collect all the information collected throughout the century about phytoplankton. This has included water transparency data from 1900 to today, chlorophyll measurements since 1950 (measured directly in water samples) and data obtained via satellite. They have seen that phytoplankton biomass has been decreasing throughout the century. In the last 50 years, for example, the decline has been 40%. The average annual decrease is 1%.

According to researchers, the number of phytoplankton has decreased more in areas where the ocean is warming. And, therefore, they consider that climate change is influenced by this reduction.

Photo: Karl Bruun, Nostoca Algae Laboratory. Image courtesy of Nikon Small World.