To understand a marine ecosystem requires a knowledge of the interactions and processes that take place to make up the system. A better understanding of these systems will support better management and conservation of them. One of the most challenging aspects of studying the natural world is to find out how organisms interact with each other in a natural environment. These interactions can take place directly between 2 or more species i.e. predation (one animal eats the other), symbioses (2 animals existing together in a relationship) or competition (2 or more animals compete for the same resources). They can also occur in far more subtle ways. For example, heavy predation on one type of species can affect the ecological interactions that might exist between the prey and a 3rd species. This is known as a ‘trophic cascade’.
Ecosystems are built up by these direct and indirect interactions. However scientists are often unaware of many of the simple processes that occur. In order to study ecological interactions, scientists observe the system and its inhabitants to document how they interact and build a view of how whole systems function. This aspect of science is made especially tricky in the marine environment due to the limitations of our observation window (we are unable to observe organisms for days on end as with terrestrial animals). Much of what we know about ecological interactions has been discovered from work in the rocky shores where animals are slow moving and easily observed.
Experimental investigations of species interactions on rocky shores have had a powerful influence on advances in ecology. Until recently, however, most of this research was limited in scale with respect to space and time. As a consequence, generalities in how species interactions shape ecosystems have been slow to emerge. A long-held assumption in coastal ecological research has been that the dynamics of rocky intertidal and subtidal communities were largely independent of oceanic factors such as nutrients, phytoplankton, zooplankton, temperature, and currents. Our recent studies along the coasts of California and Oregon have demonstrated that benthic and nearshore pelagic environments are often strongly linked via recruitment, larval transport, nutrients and the flux of food for particle-feeding invertebrates. Hence, in order to fully understand the dynamics of these communities, and thereby derive the knowledge needed to conserve and protect them, spatial and temporal scales need to be expanded to match the scales upon which both benthic and pelagic components of the system vary. Such increases in scale also demand expansions of research scope to include a much more integrative and interdisciplinary approach to understanding of nearshore community and ecosystem dynamics.