Because transition and post-transition metals in natural waters can serve as productivity-limiting micronutrients or as toxins, the processes that govern concentration, distribution, and/or speciation of these elements are of critical importance in a wide range of geochemical contexts. These processes include, but are not limited to, biological consumption, reactions at mineral surfaces, organic complexation, redox reactions, and sediment diagenesis. This session will present recent studies in natural, experimental, and computational systems aiming to elucidate past and present relationships between metal chemistry of natural waters, biological use of transition metals, abiotic reactions affecting trace metals, and geochemistry of marine and terrestrial sediments that record evolution of these relationships over geological time.
This session is organized by Laura Wasylenki (firstname.lastname@example.org) and Lev Spivak-Birndorf (email@example.com) of Indiana University.
Microorganisms exert a significant control on a number of element cycles in environments past and present largely through metabolism. A detailed look at metabolic processes requires linking the geochemistry of an environmental system with investigation of specific biochemical reactions being utilized by microorganisms. In essence, the chemistry inside the cell is tied to the chemistry outside the cell. Characterizing the geochemical setting outside a cell requires understanding chemical details (aqueous speciation, mineralogy, cell-mineral-water interactions, symbiosis between microbial communities) at the appropriate scale (single cell to community niches to larger spatial relationships). Understand cellular chemistry requires detection of the detailed biochemistry each cell may be employing (genomic, proteomic, enzyme based analyses) in both controlled lab and field settings. This session seeks to bring together researchers investigating detailed chemistry both inside and outside microbial cells towards understanding how microbial metabolisms interact with different environments using a variety of approaches.
Conveners: Greg Druschel, Kevin Mandernack, EJ Crane, Lisa Pratt
Owing to the rising global demand for, and consumption of hydrocarbon‑based products, the interest in unconventional resources such as shale gas has been increasing. In the United States, gas production from shales has increased from 0.39 TCF in 2000 to 4.80 TCF in 2010 and currently accounts for more than 20 percent of the total U.S. natural gas production. Interest in hydrocarbons from unconventional tight shale reservoirs has grown in other countries as well. The current focus on worldwide shale gas exploration and extraction necessitates a better understanding of the source rock/reservoir characteristics of shale gas formations as well as the environmental consequences of shale gas development.
This symposium will focus on the geochemistry of gas shales. We invite the submission of papers on various aspects of the geochemistry of shales and shale gas, as well as the geochemical issues related to gas extraction, such as fracture stimulation and its environmental implications.
Organizers: Maria Mastalerz (firstname.lastname@example.org) and Nancy R. Hasenmueller (email@example.com), Indiana Geological Survey, Indiana University, 611 North Walnut Grove Avenue, Bloomington, IN 47405‑2208
The kinetics of geochemical and microbial reactions in aqueous systems has to be considered to better describe biogeochemical processes in fresh and marine waters in low or high temperature conditions. Redox reactions, gas diffusion and reactions, isotopic fractionations, water-rock interactions, and microbial processes often cannot be assessed using an equilibrium approach. In addition, rates of specific processes measured in the natural environment often are not comparable to existing kinetic rate laws derived from laboratory experiments. This session seeks to illustrate several approaches to describing geochemical and microbial kinetics in field and/or laboratory environments. We encourage submissions based on any combination of field, lab, and/or theoretical treatment of kinetic parameters, and their eventual application to describe important processes in fresh and marine waters.
Understanding the growth and dissolution of minerals is of critical importance in order to quantitatively predict rates and reactions at a variety of scales, such as including rates derived from laboratory experiments in reactive transport models. Growth and dissolution of minerals are controlled by a variety of factors, that can change across the orders of magnitude differences in these spatiotemporal scales. For instance, at the nanoscale, growth and dissolution is controlled by ion (or other molecular species) attachment to and detachment from the surface, however accurately including these reactions into large-scale models is a major challenge. Other distinct processes affect growth and dissolution at the pore scale and larger, such as pore-size volume, fluid flow, and surface roughness will need to be included in reactive reactive transport simulations. This session aims to highlight recent experimental and computational work on the kinetics of reactions occurring on mineral surfaces, including studies at the nanoscale, the pore scale, and the macroscale. We are also particularly interested in research that bridges these spatiotemporal scales.
This session is organized by Man Xu, Jacquelyn Bracco, Andrew Stack, and Steven Higgins.