The influence of altitude and rivers on strontium isotope data – insights from Slovenian plants

The diverse landscape of Slovenia provides us with an excellent opportunity to understand and unravel more secrets
from our bioavailable Sr dataset. While only a small country, the alpine mountains in the north, the karst plateaus in
the southwest, and the vast glacier-fed river systems can make it challenging to create maps of bioavailable strontium
in Slovenia. In our large-scale study, we use plant samples to examine how factors such as altitude and proximity to
rivers influence Sr isotope data. Triple sampling of tree, shrub, and grass from 101 locations across Slovenia serve
as the initial dataset. All samples were analyzed for stable (δ88Sr) and radiogenic (87Sr/86Sr) strontium isotopes.
Strontium isotope data vary with weathering, which in most cases can be correlated to altitude and the proximity to
water sources. In water-rich regions the correlation between Sr isotopic values and the bedrock becomes unclear,
because of a large amount of Sr transport across geological boundaries. While mapping of bioavailable Sr in geographically diverse regions is challenging, our results in Slovenia provide a promising start framework towards creating
complex isoscapes.