DENDROCHEMISTRY AS AN INDICATOR OF SOIL SALT CONCENTRATIONS

As trees grow they produce clear annual growth rings. The widths of these rings are commonly used as climate proxies; however, the chemical composition of the rings are possibly also providing information of environmental conditions under which the tree grew. We collected sediment and pine tree stem disks along a transect from a salt-marsh inland, away from any potential salt effect. Soil and individual tree rings will be analyzed by ICP-MS to determine elemental ratios. We hypothesize that Sr/Ca ratios in the wood will provide an excellent proxy of soil salinity. Strontium mimics calcium biologically, so Sr/Ca ratios are often taken up in the same ratio as is found in the environment. At salinities less than 5, Sr/Ca ratios in water typically show a strong positive correlation with salinity. If this ratio is recorded in the trees, then the wood may hold a record of past soil salinity changes caused by, for example, hurricanes, tsunami run up or road salt applications.