Phytoplankton In The Southern Ocean
September 19, 2013

Algorithm Provides A More Accurate Estimate Of Southern Ocean Phytoplankton

[ Watch the Video: Phytoplankton Observed By NASA Satellites ]

April Flowers for - Your Universe Online

Until now, NASA satellites might have missed as much as 50 percent of the phytoplankton in the Southern Ocean. This would make it far more difficult to estimate the potential carbon capture of this vast area of the sea.

A new study from the University of Tasmania's Institute for Marine and Antarctic Studies (IMAS), published in the Journal of Geophysical Research, has led to the development of an algorithm that produces substantially more accurate estimates of Southern Ocean phytoplankton populations.

“This new algorithm allows us to detect changes in plankton numbers that have previously gone unnoticed," said Rob Johnson, a PhD student who led the research with Associate Professor Peter Strutton.

“This better understanding of the phytoplankton population will, in turn, allow us to gain a much more accurate idea of how much carbon this ocean can take up.”

We should not underestimate the importance of phytoplankton and their role in our planetary ecosystem. The base of the marine food chain is made of phytoplankton, which produce half the oxygen on Earth and are partly responsible for the ocean uptake of at least a third of total human induced CO2 emissions.

That makes understanding why existing ocean color satellites systematically underestimated the chlorophyll concentration (a proxy for phytoplankton biomass) of the Southern Ocean and Antarctica vital to conservation efforts.

The research team compared more than 1,000 Southern Ocean phytoplankton samples, collected over ten years, to satellite measurements to get the observations needed to make valid comparisons and develop the new algorithm.

The French Antarctic vessel MV L'Astrolabe collected the majority of these samples through a collaborative and long-term monitoring program between the CSIRO, the Australian Antarctic program, and the French Antarctic Program.

The new algorithm was used to process satellite data and make comparisons, which quickly made it clear that the algorithm produced a much closer estimate of phytoplankton numbers than past satellite measurements.

“Our improved satellite chlorophyll algorithms will be used to produce higher-accuracy observations on the vitally important phytoplankton of the Southern Ocean and Antarctica,” said Strutton.

“This will go a long way towards improving our understanding of how the Southern Ocean works and how the movement of carbon is changing in these remote waters.”

The researchers plan to make their improved data freely available to the global research community through the Integrated Marine Observing System (IMOS).