Simulations of changing salinity and water level
We conducted two scenarios of increasing salinity (+5 ppt, +10 ppt) and
one scenario of decreasing salinity (-5 ppt) to understand how sensitive
the model is to changes in average annual salinity. A 5 ppt decrease in
salinity (equivalent to 18% decrease relative to average salinity) over
the growing season increased GPP by 39%, whereas a 5 ppt increase in
salinity lowered GPP by 46% (Fig. 6). A 10 ppt salinity increase
(equivalent to a 36% increase relative to average salinity) led to a
80% decrease in GPP relative to the observed salinity. The non-linear
shape of the salinity response function dictates that increasing
salinity would lead to a lower proportion of change in GPP (Fig. 1).
However, increasing salinity also decreased plant height, which makes
vegetation more susceptible to flooding effects.
We conducted one scenario in which the mean tide level decreased by 10
cm, and three scenarios in which mean tide level increased by 10 cm, 20
cm, and 50 cm (XX%, XX%, and XX% of mean high tide levels,
respectively) (Fig. 7). Lowering the water level by 10 cm resulted in a
2% increase in cumulative GPP. Increasing water level by 10 cm, 20cm,
and 50 cm resulted in predicted GPP declining by 2.8%, 6.3%, and
12.4%, respectively. Changing the water level did not substantially
change plant height except the scenario of +50 cm water level, which
decreased the maximum plant height by 12%.