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Joaquin Ruiz

Publications and source records attributed to Joaquin Ruiz.

4 recordsLinked to original sources
USGS2017

CO2 diffusion into pore spaces limits weathering rate of an experimental basalt landscape

Basalt weathering is a key control over the global carbon cycle, though in situ measurements of carbon cycling are lacking. In an experimental, vegetation-free hillslope containing 330 m 3 of ground basalt scoria, we measured real-time inorganic carbon dynamics within the porous media and seepage flow. The hillslope carbon flux (0.6–5.1 mg C m –2 h –1 ) matched weathering rates of natural basalt landscapes (0.4–8.8 mg C m –2 h –1 ) despite lacking the expected field-based impediments to weathering. After rainfall, a decrease in CO 2 concentration ([CO 2 ]) in pore spaces into solution suggested rapid carbon sequestration but slow reactant supply. Persistent low soil [CO 2 ] implied that diffusion limited CO 2 supply, while when sufficiently dry, reaction product concentrations limited further weathering. Strong influence of diffusion could cause spatial heterogeneity of weathering even in natural settings, implying that modeling studies need to include variable soil [CO 2 ] to improve carbon cycling estimates associated with potential carbon sequestration methods.

Geology↗
USGS2015

The Landscape Evolution Observatory: a large-scale controllable infrastructure to study coupled Earth-surface processes

Zero-order drainage basins, and their constituent hillslopes, are the fundamental geomorphic unit comprising much of Earth's uplands. The convergent topography of these landscapes generates spatially variable substrate and moisture content, facilitating biological diversity and influencing how the landscape filters precipitation and sequesters atmospheric carbon dioxide. In light of these significant ecosystem services, refining our understanding of how these functions are affected by landscape evolution, weather variability, and long-term climate change is imperative. In this paper we introduce the Landscape Evolution Observatory (LEO): a large-scale controllable infrastructure consisting of three replicated artificial landscapes (each 330 m 2 surface area) within the climate-controlled Biosphere 2 facility in Arizona, USA. At LEO, experimental manipulation of rainfall, air temperature, relative humidity, and wind speed are possible at unprecedented scale. The Landscape Evolution Observatory was designed as a community resource to advance understanding of how topography, physical and chemical properties of soil, and biological communities coevolve, and how this coevolution affects water, carbon, and energy cycles at multiple spatial scales. With well-defined boundary conditions and an extensive network of sensors and samplers, LEO enables an iterative scientific approach that includes numerical model development and virtual experimentation, physical experimentation, data analysis, and model refinement. We plan to engage the broader scientific community through public dissemination of data from LEO, collaborative experimental design, and community-based model development.

Arizona↗
USGS1985

Use of strontium isotopes to constrain the timing and mode of dolomitization of upper Cenozoic sediments in a core from San Salvador, Bahamas

The 87 Sr/ 86 Sr ratios and the activity ratios of 234 U/ 238 U and 230 Th/ 238 U have been measured in dolomites from a 168-m-deep core taken on the island of San Salvador, Bahamas. These data suggest two periods of dolomitization. The first episode dolomitized Miocene age sediments during the latest Miocene, and the second dolomitized the Pliocene portion of the core and was still active as recently as 150 ka. The late timing of the second episode argues against penecontemporaneous models of dolomitization for the Pliocene sediments. Instead, dolomitization is favored either as a result of mixing-zone development during the large Pleistocene sea-level changes or by movement of seawater through the platform.

San Salvador Island↗