Examining Interdisciplinary Sustainability Institutes at Major Research Universities: Innovations in Cross-Campus + Cross-Disciplinary Models

This is a study of the distinctive characteristics, activities, challenges and opportunities of a specific type of sustainability institute, one that spans the many disciplines of the university and, to do so, reports to upper administration (provost or vice president of research). Among research universities within the Association of American Universities (AAU), 19 were identified, and 18 agreed to participate in this study. Directors are sent a 71-question survey in January 2017 that covered issues of Governance, Research, Education, Engagement, Campus Operations and Best Practices

Aerosol Mixing State: Measurements, Modeling, and Impacts

Atmospheric aerosols are complex mixtures of different chemical species, and individual particles exist in many different shapes and morphologies. Together, these characteristics contribute to the aerosol mixing state. This review provides an overview of measurement techniques to probe aerosol mixing state, discusses how aerosol mixing state is represented in atmospheric models at different scales, and synthesizes our knowledge of aerosol mixing state’s impact on climate‐relevant properties, such as cloud condensation and ice nucleating particle concentrations, and aerosol optical properties. We present these findings within a framework that defines aerosol mixing state along with appropriate mixing state metrics to quantify it. Future research directions are identified, with a focus on the need for integrating mixing state measurements and modeling.Key PointsWe define aerosol mixing state and connect it to the physicochemical properties of aerosol particlesWe discuss existing measurements and models to understand chemical and physicochemical mixing stateWe explain the connection between aerosol mixing state and climate‐relevant aerosol propertiesPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150540/1/rog20184_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150540/2/rog20184.pd

Lake spray aerosol generation: a method for producing representative particles from freshwater wave breaking

Wave-breaking action in bodies of freshwater produces atmospheric aerosols via a similar mechanism to sea spray aerosol (SSA) from seawater. The term lake spray aerosol (LSA) is proposed to describe particles formed by this mechanism, which have been observed over the Laurentian Great Lakes. Though LSA has been identified from size distribution measurements during a single measurement campaign, no measurements of LSA composition or relationship to bubble-bursting dynamics have been conducted. An LSA generator utilizing a plunging jet, similar to many SSA generators, was constructed for the generation of aerosol from freshwater samples and model salt solutions. To evaluate this new generator, bubble and aerosol number size distributions were measured for salt solutions representative of freshwater (CaCO3) and seawater (NaCl) at concentrations ranging from that of freshwater to seawater (0.05–35 g kg−1), synthetic seawater (inorganic), synthetic freshwater (inorganic), and a freshwater sample from Lake Michigan. Following validation of the bubble and aerosol size distributions using synthetic seawater, a range of salt concentrations were investigated. The systematic studies of the model salts, synthetic freshwater, and Lake Michigan sample indicate that LSA is characterized by a larger number size distribution mode diameter of 300 nm (lognormal), compared to seawater at 110 nm. Decreasing salt concentrations from seawater to freshwater led to greater bubble coalescence and formation of larger bubbles, which generated larger particles and lower aerosol number concentrations. This resulted in a bimodal number size distribution with a primary mode (180 ± 20 nm) larger than that of SSA, as well as a secondary mode (46 ± 6 nm) smaller than that of SSA. This new method for studying LSA under isolated conditions is needed as models, at present, utilize SSA parameterizations for freshwater systems, which do not accurately predict the different size distributions observed for LSA or resulting climate properties. Given the abundance of freshwater globally, this potentially important source of aerosol needs to be thoroughly characterized, as the sizes produced are relevant to light scattering, cloud condensation nuclei (CCN), and ice nuclei (IN) concentrations over bodies of freshwater

Factors controlling the transfer of biogenic organic species from seawater to sea spray aerosol.

Ocean waves transfer sea spray aerosol (SSA) to the atmosphere, and these SSA particles can be enriched in organic matter relative to salts compared to seawater ratios. A fundamental understanding of the factors controlling the transfer of biogenic organic matter from the ocean to the atmosphere remains elusive. Field studies that focus on understanding the connection between organic species in seawater and SSA are complicated by the numerous processes and sources affecting the composition of aerosols in the marine environment. Here, an isolated ocean-atmosphere system enables direct measurements of the sea-air transfer of different classes of biogenic organic matter over the course of two phytoplankton blooms. By measuring excitation-emission matrices of bulk seawater, the sea surface microlayer, and SSA, we investigate time series of the transfer of fluorescent species including chlorophyll-a, protein-like substances, and humic-like substances. Herein, we show the emergence of different molecular classes in SSA at specific times over the course of a phytoplankton bloom, suggesting that SSA chemical composition changes over time in response to changing ocean biological conditions. We compare the temporal behaviors for the transfer of each component, and discuss the factors contributing to differences in transfer between phases

Detection of Active Microbial Enzymes in Nascent Sea Spray Aerosol: Implications for Atmospheric Chemistry and Climate

The oceans cover nearly three-quarters of the Earth's surface and produce vast quantities of sea spray aerosols (SSA). Studies have shown that due to ocean biology SSA particles are comprised of much more than just sea salt and often include proteins, lipids, sugars, viruses, and bacteria. In this study, we show for the first time that a diverse array of microbial enzymes (protease, lipases, and alkaline phosphatase) are transferred from the ocean into the atmosphere and often become even more active with measured activities in SSA particles that are 1-2 orders of magnitude higher than those in bulk seawater. We hypothesize that these enzymatic reactions are enhanced in the interfacial environment of droplets and aerosols that can dynamically modify surface chemical species and properties. Simulations reveal that enzyme-containing SSA particles can rapidly coagulate with other preexisting aerosols, thus transferring the impact of enzyme reactions to a broad range of marine aerosols. These biotic reaction pathways are expected to profoundly change the composition of marine aerosols, particularly at the interface, and thus will impact cloud properties in marine environments. Future studies are needed to determine how photochemistry, changing ocean conditions in a warming climate, and other external factors will influence the activities of these enzymes and their impact on the composition of the marine atmosphere