Emerging Issue Summary
Overview and Management Relevance:
Coastal salinization of terrestrial or freshwater environments may be an issue to land managers for at least two reasons. First, it will cause changes in habitat structure, such as plant species composition, which in turn may cause changes in how or which animals use the land or waters. This in turn could impact subsistence use of those resources. Second, large quantities of freshwater are often necessary for ice road/pad construction during oil and gas exploration drilling, development, and maintenance. Coastal salinization could reduce the availability of or access to such waters.
There are at least six pathways, the first five of which are sensitive to climate change, for introduction of marine salts into the terrestrial environment:
The extent of coastal saline habitats and salt-killed tundra along the Arctic coast is poorly known. On the Colville and Fish Creek deltas, coastal habitats (salt marsh, coastal dwarf shrub) cover approximately 24 km2 (Jorgenson, pers. comm.). However, no data are yet available to assess trends in the extent of these habitats across the North Slope.
In addition, there currently exists about 26 km2 of recently (i.e., within the past few decades) salt-killed vegetation on the Colville and Fish Creek deltas due to storm surges in tapped lake basins, and there may be as much as 100 km2 of salt-killed vegetation along the entire coast (Jorgenson, pers. comm.). This phenomenon is sensitive to climate change (e.g., through sea level rise or changing weather patterns) and increasing rates of shoreline erosion. Coastal salinization, where it occurs, changes plant species composition and may subsequently impact some birds and mammals.
The studies needed to assess the trade-offs that would be involved in allowing saline water for ice road construction have not been done. Such studies would include the effects on vegetation of differing levels of salinity, the potential for melt water from ice roads to be trapped and concentrated through evapotranspiration, and the potential for diluting salinity during the spring thaw by trapping additional snow in the immediate vicinity throughout winter.
Coastal salinization would not affect groundwater in the sense the latter term is normally used. Due to the extent and depth of permafrost on Alaska’s arctic coastal plain, there is no hydraulic connection from the surface through permafrost to any groundwater below. Salinization would affect only the “groundwater” in the active layer, normally only tens of centimeters deep. This is important, however, because this is where most biological activity occurs.
In addition to these broad concerns, the NSSI Senior Staff Committee provided the STAP with specific questions relevant to coastal salinization. STAP responses to these questions are presented below: