Researchers warn that marine life could be dramatically affected as climate change threatens to cause severe reduction of plankton–the key source of nutrient−in some ocean regions by the end of the century.
There are plenty more fish in the sea − but not for too much longer in some parts of the world, researchers say. And the reason is very simple: the food on which they all depend faces a marked decline.
Phytoplankton are the single-celled plants that are the basic building blocks of most marine life. In particular, they sustain zooplankton − tiny animals that are eaten in turn by fish. The study found evidence that, by 2100, zooplankton biomass will be 11% less than it is today, with obvious implications for the fish that feed on them.
The report says that sea surface temperature is predicted to increase by 2ºC on average globally by 2080-2100. The consequences of this increase will include changes in ocean circulation and higher water column stratification, where water of different densities forms distinct layers instead of mixing, affecting the availability of nutrients.
The depletion expected in the amount of plankton in the marine food web could reduce fish biomass in 47% of the total global ocean area, especially in tropical oceans.