Is 90% percent of plankton gone ?

A recent article in the sunday post caused a stir by claiming that 90% of all plankton in the oceans is gone. According to another article at Arstechnica its not as bad as stated by the sunday post, but still - offcourse - alarming. Even the original author is cited and engaged in the comments section at ars, if you are interested you'll find the article at arstechnica.com