Salt Marshes: An Interesting Ecosystem to Study Phytoremediation pp. 723-736
Authors: (I. Cašador, B. Duarte, Institute of Oceanography, Faculty of Sciences, University of Lisbon, Campo Grande, Lisbon, Portugal)
Abstract: Salt marshes located in estuaries frequently receive large inputs of nutrients (Cašador, et al., 1993; Tobias et al., 2001), and also of particulate and dissolved organic matter. Salt marsh plants retain suspended particles and associated anthropogenic metals transported by the tides. This high nutrient input makes salt marsh one of the most productive ecosystems of the planet. In highly industrialized estuaries, along with this nutrient input there is also a large input of heavy metals (Figure 1) which will be accumulated in salt marsh sediments (Cašador at al., 1996; Doyle and Otte, 1997). These high inputs make salt marshes key zones for the biogeochemistry of the estuary, but also for metal cycling (Cašador et al., 2000). When accumulated in salt marsh sediments, metals can become adsorbed to the sediment constituents, uptaken by plant roots and translocated to their aboveground organs. With this a new cycle is initiated: plants uptake metals, translocate them, eventually decay and die, remobilizing the metals in the sediments in a new speciation process with microbial intervention.