Physical processes, biotic processes and human activities all act to shape marine ecosystems. Future management of these valuable ecosystems requires an integrative approach that takes into account complicated organismal interactions, oceanographic processes that span large scales of time and space, and how anthropogenic effects interact with the natural environment. The temperate west coasts of North and South America represent a unique opportunity for comparison, as many of the same oceanographic processes, particularly upwelling, occur off both coasts. Additionally, a number of marine ecosystems in both areas have surprising parallels. Here we present an overview of the oceanographic processes that dominate the coastlines, and give examples of ecosystems and the effects that oceanography, human activities and their interaction have on the communities