Modeling the effect of temperature, solar radiation and salinity on Bolboschoenus maritimus sequestration of mercury

Abstract

Some tidal wetland halophytes are extremely important for pollution control but due to global climate change, wetlands and their ecosystem services may suffer considerable modifications. In this context we modeled the growth and mercury (Hg) sequestration by Bolboschoenus maritimus on the most contaminated area of a temperate shallow coastal lagoon historically subjected to heavy Hg load, under gradients of climate driven variables. For calibration purposes we used field data on temperature, salinity, solar radiation, plant biomass, plant decomposition and mercury concentration in the plants. Ten different methods evaluated model performance. We then simulated B. maritimus mercury sequestration under different environmental scenarios involving increases and decreases in temperature, salinity and cloud cover. The largest effects were related to high salinity scenarios but all variables presented an inverse relation with Hg-sequestration. Our results point to a progressive decrease on Hg-sequestration until the end of the century.