Biogeochemical processes in the ACE Basin study area can be considered on a
variety of scales. A biogeochemical
study on a relatively small scale, such as
a mud flat, may focus on the effect of burrowing activity by polychaete
worms
on nitrogen fluxes
(e.g., Kristensen et al. 1985). On the other hand, a study on
a much larger scale, like that of the entire Edisto River watershed, may track
the transformation of nitrogen through the aquatic food web. For instance,
stable isotopes
could be used to infer the contribution of nitrogen from
wastewater treatment facilities upstream to the nitrogen found in estuarine
organisms residing at the mouth of the Edisto River in St. Helena Sound, as has
been done by McClelland et al. (1997) in the Waquoit Bay estuarine ecosystem.
Both the mud flat and the watershed in these examples represent ecological
systems (ecosystems).
