Résumé
The diatom Thalassiosira minima was first recorded in the Baha Blanca Estuary in 1992. In 19921993 it exhibited a broad seasonal occurrence. A recent survey (20062007) showed a seasonal appearance restricted mainly to summer together with a greater relative abundance within the phytoplankton. A close connection was found with warmer, more saline and highly turbid conditions experienced in recent summers in the estuary. Whether these changes will impact the estuary trophic dynamics remains an open question.