Recent studies showed the potential of stable isotopes of the macronutrient calcium (δ^44/40Ca) and non-essential strontium (δ^88/86Sr) as new trophic level indicators in terrestrial vertebrates and marine teleost fishes. In this study, we tested whether similar Ca and Sr isotopic fractionation trends existed in macroinvertebrate dominated stream food webs compared to vertebrates despite their physiological differences. We have determined the δ^44/40Ca and δ^88/86Sr values as well as the ⁸⁷Sr/⁸⁶Sr ratios of stream macroinvertebrates and of small gobies and of their potential metal sources (stream water, periphyton, terrestrial plant litter) collected in May and November 2018 in upper and lower reaches of two streams in the Lake Biwa catchment, central Japan.

The data are organized in different spreadsheets for each sample type (Rock cobbles, Stream water, Periphyton, Plant litter, Aquatic macroinvertebrates, fishes). Each spreadsheet contains information of the sample type including stream name (Ado, Yasu), stream location (Upper, Lower), sampling month (May, November), where relevant the order and scientifc name of specimens, the δ^44/40Ca and δ^88/86Sr values with two standard deviations, the ⁸⁷Sr/⁸⁶Sr ratios with two standard errors, the Ca and Sr concentrations and the calculated log(Sr/Ca) ratios of the samples.

In May and November 2018, stream macroinvertebratres and small gobies, and their potential Ca and Sr sources (periphyton, plant litter, stream water) and rock cobbles as initial sources were collected in upper and lower reaches of two streams in the Lake Biwa catchment, central Japan. Following specimens identification, sample drying, grinding and digestion, samples were analyzed for Ca and Sr concentrations on the ICP-MS. Calcium and strontium have been purified using column separations, and Ca and Sr stable isotope ratios (δ^44/40Ca and δ^88/86Sr) and ⁸⁷Sr/⁸⁶Sr ratios have been analyzed using Thermal Ionization Mass Spectrometry (TIMS).

δ^44/40Ca of rock cobbles were not determined.

δ^44/40Ca data are reported relative to NIST915b.

δ^88/86Sr values and ⁸⁷Sr/⁸⁶Sr ratios could not be determined for all specimens because the sample amount was not always sufficient (ND = not determined).