Researchers from Oregon State University, NASA and other organizations said today that they have succeeded for the first time in measuring the physiology of marine phytoplankton through satellite measurements of its fluorescence – an accomplishment that had been elusive for years.The bottom map shows the global distribution of phytoplankton fluorescence.
With this new tool and the continued use of the MODIS Aqua satellite, scientists will now be able to gain a reasonably accurate picture of the ocean's health and productivity about every week, all over the planet...
"Until now we've really struggled to make this technology work and give us the information we need," said Michael Behrenfeld, an OSU professor of botany. "The fluorescence measurements allow us to see from outer space the faint red glow of tiny marine plants, all over the world, and tell whether or not they are healthy. That's pretty cool"...
They've already made some discoveries about the correlation between iron levels in the oceans and phytoplankton growth.
Some surprises are already in.
It was known, for instance, that parts of the equatorial Pacific Ocean, some regions around Antarctica and parts of the sub-Artic Pacific Ocean below Alaska were limited in production by the poor availability of iron. The newest data, however, show that parts of the northern Indian Ocean during the summer are also iron limited – a phenomenon that had been suggested by some ocean and climate models, but never before confirmed.
"Iron is often brought to the oceans by dust coming off terrestrial regions, and is a necessary nutrient that often limits the potential for marine phytoplankton growth," said Allen Milligan, an OSU assistant professor of botany and co-author of this study, which is being published in the journal Biogeosciences.
"If forces such as global warming, circulation changes or the growth of deserts change the amount of dust entering the oceans, it will have an impact on marine productivity," Milligan said. "Now we'll be able to track those changes, some of which are seasonal and some of which may happen over much longer periods of time. And we'll also be able to better assess and improve the climate models that have to consider these phenomena."