Protist communities

Long-Term Shifts in Plankton Communities Signal Warming’s Impact on Oslofjord

The Oslofjord's plankton community is rewriting the expected script of climate change. Comparing 2009-2011 to 2023-2024, we found a 5.6-fold drop in the dinoflagellate-to-diatom ratio, driven largely by a decline in the heterotrophic genus *Gyrodinium*. This challenges the assumption that warming consistently favors heterotrophic taxa in temperate waters. The data is empirical, measured, and clear. For broader context on shifting marine baselines, our coverage of Mediterranean Phytoplankton Diversity Shifts Observed Over 25 Years offers a valuable comparison.