Extreme survivors

Collage of ocean plankton; source: wikipedia; CC BY-SA 3.0
3 May 2016

Published in PNAS: Plankton have evolved to survive a wide range of conditions, thanks to their unexpectedly vast ocean travels, a new study co-authored by UTS researchers suggests.

Plankton are microscopic organisms that support the marine food web, providing food for whales, fish and crustaceans.

The researchers modelled how plankton drift with ocean currents, and revealed for the first time the range of temperatures that plankton travel through. In most locations, they endure temperature extremes that go beyond what is predicted by models of global warming.

The results were from three million virtual plankton. Their journey through the oceans is influenced by ocean surface currents that can transport drifting particles up to 3,500 kilometers in 500 days - about the equivalent of a person rowing from California to Hawaii. During this journey the plankton are subjected to temperature changes of up to 10°C more than if they stayed in one location.

According to lead author Associate Professor Martina Doblin, studies on how climate change may potentially effect plankton need now to take into account these exposures to fluctuating temperatures.

For example, waters in the Southern Indian Ocean have a seasonal temperature range of 13 °C to 18 °C, and ocean temperatures are projected to only warm up to a few degrees in the next century. But as the study shows, plankton travelling through these waters experience temperatures as low as 5°C and as high as 20°C.

Plankton is important, he said in a university statement, as they are responsible for half the Earth’s oxygen and for global fisheries yields.

Story based on information provided by the University of Technology Sydney.