This research project will focus on the effects of PAHs on marine phytoplankton by studying their short term toxic responses and long term adaptation to the continuous presence of PAHs in their environment. By maintaining an experimental environment with persistent levels of PAHs, we will be studying processes involved in adaptation over longer periods of time. This leads to questions on how the fitness of the population is affected by continuous exposure. Another interesting aspect of this study will involve the revival of dormant phytoplankton cysts from sediment cores to study the responses to PAHs between different time periods in immediate history.