Modern coral from Arno Atoll (Marshall Islands) Sr/Ca, Mg/Ca, δ18O, δ13C, and skeletal density bimonthly interpolated data

This dataset includes geochemical and densitometric data from a modern (1954–2017 CE) Porites microatoll slab collected in November 2017 from Arno Atoll, Marshall Islands. Powder samples were extracted along the growth axes of the coral at 1 mm resolution (9.0 samples per annual band). Trace elements were measured using an Agilent 720 (axial) inductively coupled plasma optical emission spectrometer at MARUM, University of Bremen, Germany. Mean Sr/Ca of JCp-1 standards measured along with this coral was 8.899±0.032 mmol mol-1 (n = 15; 1 sd). Stable isotopes were measured using a Finnigan MAT 252 mass spectrometer equipped with an automated Kiel III carbonate preparation device at the Stable Isotope Laboratory of MARUM, Bremen, Germany. Skeletal density was measured using a γ-densitometer at the Goethe University, Frankfurt am Main, Germany. The age model is based on coral Sr/Ca and the HadISST data set, using one tie point per annual cycle corresponding to the summer SST peak (minimum in Sr/Ca). The geochemical and skeletal density records were then linearly interpolated to an evenly spaced bimonthly resolution (6 samples year⁻¹).