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GCE III - Key Finding in 2015

    What causes wetland salinization?

    Wetland salinization alters the soil-water environment, increasing ionic concentrations and altering chemical equilibria and mineral solubility. The effects of these changes typically include decreased inorganic nitrogen removal, decreased carbon storage, and increased generation of toxic sulfides. In a review of wetland salinization, Herbert et al. (2015) reviewed documented cases of salinization in the literature, most of which are concentrated in Australia, Europe, and the Atlantic coast of the US (Fig. 1). They identified five mechanisms that contribute to the secondary salinization of inland freshwater wetlands: 1) vegetation clearance; 2) intensive irrigation; 3) river regulation; 4) mining and extraction and 5) de-icing salts, and five mechanisms that apply in coastal wetlands: 1) seawater intrusion linked to sea level rise; 2) reductions in freshwater flow; 3) alterations of subsurface flow; 4) anthropogenic alteration of coastal geomorphology and 5) storm surges. We are studying all of the latter mechanisms in the GCE-LTER program. The paper points out that salinization represents a growing widespread threat to inland and coastal wetlands especially given the fact that almost all of these mechanisms may be intensified by global climate change. The factors identified here can be used to identify wetlands currently undergoing salinization and those at potential risk in the future.


    Fig. 1 Distribution of documented cases of freshwater wetland salinization. The absence of data from large geographic areas of the world does not imply the absence of wetland salinization. From Herbert et al. (2015).


This material is based upon work supported by the National Science Foundation under grants OCE-9982133, OCE-0620959, OCE-1237140 and OCE-1832178. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.