New research led by NASA researchers has found populations of the microscopic marine plants, phytoplankton, have decreased in the Northern Hemisphere. An analysis using a NASA model in combination with ocean satellite data between 1998 and 2012, showed a 1% decrease of phytoplankton per year.
Research: Decadal Trends in Global Pelagic Ocean Chlorophyll: A New Assessment Combining Multiple Satellites, In Situ Data and Models, Journal of Geophysical Research: Oceans.