Tree-ring δ18O from an Alpine catchment reveals changes in glacier stream water inputs between 1980 and 2010

Giovanni Leonelli, Giovanna Battipaglia, Paolo Cherubini, Matthias Saurer, Rolf T.W. Siegwolf, Maurizio Maugeri, Barbara Stenni, Maria Letizia Fumagalli, Manuela Pelfini, Valter Maggi
2019 Arctic, Antarctic, and Alpine Research  
2019) Tree-ring δ 18 O from an Alpine catchment reveals changes in glacier stream water inputs between 1980 and 2010, ABSTRACT The tree-ring stable carbon and oxygen isotope chronologies from two forest sites located in the Forni Glacier forefield (Italy)-one along the glacier stream (GL) and the other toward the valley slope (SL)-were analyzed with the aim of disentangling the precipitation and glacier meltwater inputs in source water δ 18 O, as reflected by the tree-ring cellulose δ 18 O. The
more » ... llulose δ 18 O. The cellulose δ 18 O from the GL trees has a negative correlation with winter and summer temperatures, whereas the cellulose δ 18 O from the SL trees has a positive correlation with precipitation δ 18 O. The isotopic signature of the source water at the GL site is also influenced by waters of glacial origin, as confirmed by the 18 O-depleted glacier meltwater inputs (GMWI_δ 18 O) estimated by means of an isotope model. The GMWI_δ 18 O values are consistent with the mean difference measured between the δ 18 O in the glacier stream and in the precipitation and the winter and summer temperature explains up to 37 percent of the GMWI_δ 18 O variance. Our results show an increasing influence of glacier meltwater throughout the past decade for the GL site. Our analysis opens new opportunities to reconstruct changes in water regimes of the glacier streams by means of the tree-ring cellulose δ 18 O. ARTICLE HISTORY
doi:10.1080/15230430.2019.1623607 fatcat:mkcgwjp3erbyzfubwsgvrmzoum