The results indicate that: Breton Sound estuary
acted conservatively with respect to TE The highly
charged phosphate anion, PO4-, is readily sorbed
by clay and detrital organic particles at high concentrations,
while at lower concentrations PO4- is
released into the water, thus maintaining moderate
ambient concentrations (Jitts 1959). This buffering
process occurs in two distinct steps, with sorption/
desorption of PO4- directly onto particle surfaces
occurring very rapidly (minutes-days), and
then slow (days-months) diffusion of PO4- toward
the interior of the particles (Froelich 1988). Cyclic
aerobic and anaerobic conditions in the top several
centimeters of the wetland soil also affect the
sorption and release of phosphate (Patrick and
Khalid 1974). Sharp et al. (1982) found these sorption-
desorption processes provide a buffering
mechanism for phosphorus in the Delaware estuary.
Madden et al. (1988) showed that TP behaved
similarly in Fourleague Bay, Louisiana, with little
change in concentration throughout the year. The
same processes most likely account for the conservative
behavior of the Breron Sound estuary with
TP. Burial is the only mechanism by which phosphorus
is permanently lost from the system (Richardson
1985). Flocculafion, and subsequent deposition,
of dissolved organic and inorganic matter
during the mixing of river and sea water is an important
removal mechanism for phosphorus (Sholkovitz
1976). The TP loading rate for the region
north of the first two water quality monitoring stations
ranged from 0.9 to 2.0 g m -2 yr -1, higher
than the interior marsh burial rate found by
DeLaune et al. (1981) of 0.8 g m -~ yr -1, which may
explain the low removal efficiency of 0% to 46%
found in the Breton Sound estuary.