The oceans are warming and nutrient and light environments are changing. Since primary producers play a key role in the capacity of the world’s oceans to absorb anthropogenic carbon emissions (about 30% of anthropogenically derived CO2 have been entered the world’s oceans during the past two centuries), it is essential to predict how global change affects phytoplankton assemblages. Great efforts have been made to evaluate the effect of global change on the growth and performance of photosynthetic organisms, due to their key importance as primary producers in the aquatic food webs, however, there are geographical regions that have been poorly explored. The Patagonian waters constitute one of the most important fishery areas of the Atlantic Ocean Basin, however, our knowledge about ecosystems, supporting aquatic food web in this area remains limited. To fill the knowledge gap, we try to evaluate the effect of global change on plankton assemblages in Patagonia, Argentina, in collaboration with Prof. Helbling W., Dr. Villafañe V. E. and Dr. Valiñas M.S at Estación de Fotobiología Playa Unión.