Temperature‐influenced species competition in mass cultures of marine phytoplankton

Five marine phytoplankton species ( Phaeodactylum tricornutum, Thalassiosira pseudonana, Skeletonema costatum, Monochrysis lutheri , and Dunaliella tertiolecta ) were grown in enriched laboratory continuous cultures and natural populations were mass cultured outdoors for 16 months. Competition among the species was shown to be highly dependent on temperature, although the actual production of plant organic matter at the low growth rates used was relatively independent of this variable. Control of marine species in mass cultures does not appear economically feasible, but this drawback may be overcome by selecting herbivorous shellfish that are capable of assimilating those temperature‐dependent phytoplankton species dominating in a particular locale.