The focus of my work is on changes in the distribution and abundance of the benthic green macroalgae Enteromorpha spp. over different time scales. This project is taking place in Elkhorn Slough, Monterey Bay, CA. Elkhorn Slough is a naturally occurring estuary that opens into Monterey Bay through Moss Landing Harbor. The slough has been the subject of many questions about changes occurring that are a result of anthropogenic influences and the long term effects. Eutrophication is a common result of anthropogenic inputs and is a concern within the slough. It has been suggested that Enteromorpha spp. is a good indicator of eutrophication because of its opportunistic nature and high nutrient uptake rates. I am using aerial photographs from the last quarter century to investigate long term changes in the amount of area covered by Enteromorpha spp. to make inferences about anthropogenic inputs from both the harbor and the adjacent farmlands. I am using seasonally sampling to investigate within year differences and to establish a seasonal pattern, if it exists, and if the pattern is comparable to other estuaries worldwide. Finally I am investigating within month variation in the distribution and abundance of Enteromorpha spp. in relation to tidal influences. Many authors have suggested the tidal as a mechanism for dispersal and removal of mats of Enteromorpha spp., yet this hypothesis remains untested. By sampling intensely within different months I hope to understand the effect of tide (amplitude, current, duration) on the distribution and abundance of algal mats within Elkhorn Slough. I will also be able to comment on the best sampling strategy to be able to detect changes in Enteromorpha spp. distribution and abundance.