There have been dramatic changes and losses in fundamental species such as phytoplankton and krill, changes in the growing season, and population distributions of commercial species are already changing in some ocean regions, driving dependent extractive industries to adapt. Ocean chemistry is also changing, and at a rate faster than at any other time over the past 55 million years. As the seas absorb more carbon dioxide from the atmosphere, lower pH levels - ocean acidification - are expected to retard rates of shell formation and growth.