PhytoplanktonDiatom and dinoflagellate species have declined since 1958 in both shelf and oceanic waters. Though there were no significant trends in phytoplankton abundance in the Irish Sea between 1996 and 2010, longer-term trends indicate a decline in both diatom and dinoflagellate abundance. Abundance of both species groups on the Malin shelf have increased since 2004; abundance also increased in the coastal waters of south and southwest Ireland between the years 1990 and 2010.
