Examines estuarine circulation and stratification, sediment dynamics, biogeochemical processing, and the biological communities these support.
Trapping is the organizing theme. Material that would disperse in open water settles and remains in an estuary, and the locations where it accumulates are determined by circulation rather than by proximity to a source. The Aldwych microplastic survey is used as the extended case: three sheltered inlets held concentrations an order of magnitude above the remainder of the system, and none of the three is near an obvious input.
That result changed where the regional monitoring program samples, on the reasoning that measuring the well-flushed portion of an estuary characterizes flushing. The course treats the episode as an example of monitoring design rather than as a finding.