With this data, we expand the data set characterizing the Critical Zone geochemistry along the Chilean Coastal Cordillera provided by Oeser et al. (2018). This data set completes the results of bulk geochemical analysis of bedrock and regolith with those of bulk analysis of major plants and those of the bio-available fraction in saprolite and soil (determined using a modified sequential extraction method on bulk regolith samples after Arunachalam et al., 1996;He et al., 1995;Tessier et al., 1979). For all those compartments of the Earth’s Critical Zone, we further present radiogenic (87Sr/86Sr) and stable (δ88/86Sr) strontium isotope ratios. A detailed graphical presentation and discussion of this data as well as method description is given in Oeser and von Blanckenburg, (2020a): Do degree and rate of silicate weathering depend on plant productivity? and Oeser and von Blanckenburg, (2020b): Strontium isotopes trace biological activity in the Critical Zone along a climate and vegetation gradient.
Using this data, we were thus, able to determine weathering rates and nutrient uptake along the “EarthShape” climate and vegetation gradient in the Chilean Coastal Cordillera and to identify the sources of mineral nutrients to plants. Ultimately, we were able to budget inventories, gains and losses of nutritive elements in and out of these ecosystems and to quantify nutrient recycling. We found that the weathering rate does not increase from north to south along the climate gradient. Instead, the increase in biomass growth rate is accommodated by faster nutrient recycling. Instead, the increase in biomass nutrient demand is accommodated by faster nutrient recycling. In the absence of an increase in weathering rate despite a five-fold increase in precipitation and NPP, we hypothesize that plant growth might in fact dampen weathering rates. Radiogenic and stable Sr isotopes in combination with mass balance calculations were used to detect the Sr sources and quantify its fluxes in four ecosystems along the “EarthShape” climate and vegetation gradient. Estimated whole-plant Sr isotope compositions reveal a preferential uptake of light Sr from soil solution and subsequent export of fractionated organic material from the ecosystems. This export correlates well with erosion rate E and potentially impairs the ability for direct Sr acquisition from solid plant debris and thus reduces the recycling factor of Sr and possibly Ca and that of other mineral nutrients, too.
All samples are assigned with International Geo Sample Numbers (IGSN), a globally unique and persistent Identifier for physical samples. The IGSNs are provided in the data tables and link to a comprehensive sample description in the internet.
Tables included in this data publication:
Table S1: Chemical composition, radiogenic strontium (87Sr/86Sr), stable strontium (δ88/86Sr), and molar Ca/Sr ratios of representative bedrock samples from Pan de Azúcar, Santa Gracia, La Campana, and Nahuelbuta
Table S2: Weathering indices CDF and τ, radiogenic strontium (87Sr/86Sr), stable strontium (δ88/86Sr), and molar Ca/Sr ratios of the 2 × 4 regolith profiles.
Table S3: Concentration of the bio-available fraction, comprised of the water-soluble and the exchangeable fraction.
Table S4: Concentration of the water-soluble and the exchangeable fraction, and the relative amount of the bio-available fraction (pooled water-soluble and exchangeable fraction) on bulk regolith.
Table S5: Chemical composition of the study sites’ single plant organs along with their respective radiogenic strontium (87Sr/86Sr), stable strontium (δ88/86Sr), and molar Ca/Sr ratios