With depths of several kilometers, the world's oceans are a complex environment that is probably the most poorly studied ecosystem on earth. Today, we will examine the same biogeochemical processes that we studied in terrestrial ecosystems, wetlands, lakes, and rivers. We will look at NPP, decomposition, and C storage. We will also see that ocean productivity is affected by trace minerals, such as Fe, which are required by phytoplankton. We will continue our comparative analysis of ecosystems by comparing ocean processes with those from other major ecosystem types.
Oceans are much more than big pools of salt water.
I. Ocean circulation is of the most important biogeophysical processes on Earth. As we saw in the beginning part of the course, ocean gyres created by the Coriolis effect are important for circulating warm tropical water to the poles and establishing global patterns of climate. However, ocean circulation is much more complicated than this simple 2-dimensional description suggests. Oceans stratify just like lakes so that warm, light water sits on top of colder dense water. However, unlike lakes where surface and bottom waters may mix during fall and spring turnover, oceans exhibit a specific pattern of mixing throughout the year that resembles a conveyer belt .