ABSTRACT:

We present oxygen (d18O) and hydrogen (d2H) isotope ratios (relative to VSMOW and in permil notation) of precipitation, stream, lysimeter and plant xylem waters collected over several years in a tropical montane cloud forested watershed in southern Peru (-13.192550, -71.587950). The stable isotope data can be used to trace the flow of water through ecosystems and addresses the sources of water that sustain streams and trees. Reported oxygen and hydrogen isotopes in precipitation have been corrected for orographic isotope effects. The plant xylem waters were corrected back to their source water isotope composition (sensu Benettin et al., 2018) – we report both the corrected isotope ratios and the uncorrected isotope ratios. From the oxygen isotope ratios, we calculate seasonal origin indices (sensu Allen et al., 2019) of stream, lysimeter and plant xylem waters, reported here. We also provide a Matlab script to load the data from Burt et al., 2023 and calculate the young water fraction of these pools and fluxes of water (sensu Kirchner, 2016), as well as generate uncertainty intervals for the young water fractions using a bootstrap resampling regime.

ABSTRACT:

This dataset includes oxygen (d18O) and hydrogen (d2H) isotope ratios in streams and precipitation across the Andes mountains and Amazon foreland floodplain in southern Perú. Samples were collected approximately twice monthly from 2015–2020. Data presented here can be used to calculate the fraction of streamflow comprised of recent precipitation (e.g., the young water fraction sensu Kirchner, 2016). These data are used in Burt et al., 2023 to understand how precipitation moves through watersheds across the geomorphic gradient of the Andes mountains and Amazon floodplain. We also provide a Matlab script that will calculate flow-weighted young water fractions and carry out a bootstrap resampling routine to generate uncertainty intervals (e.g., Figure 8 from Burt et al., 2023)