Gas clathrates are composed

The Southern Ocean is a critical component of global climate and carbon cycling. Although an overall regional carbon sink, observations indicate uptake behavior fluctuates on seasonal to decadal scales, and there is much uncertainty surrounding the drivers of that variability. Our focus is in the Drake Passage, the narrowest and southernmost constriction of the Antarctic Circumpolar Current and a well sampled sector of the Southern Ocean.

Beneath the geologically complex ice shell of Europa, Jupiter’s innermost icy satellite, likely lies a vast, saline subsurface ocean that may hold conditions favorable for life. Key to that question is how processes in the ice shell, represented as a myriad of geologic features on the surface, facilitate material transport between the surface and subsurface ocean. The formation of the young, elliptically shaped surface disruptions, lenticulae and chaotic (chaos) terrain that range from < 10 km to > 1000 km diameter, may represent one such process.

Recovery of rare earth elements (REEs) from coal fly ash (CFA) is a promising resource recovery and waste recycling option that might bring about significant economic and environmental benefits. However, many challenges need to be addressed in order to develop cost effective and environmentally friendly techniques for REE recovery from CFA. The overall goal of this dissertation is to develop a synergistic approach to simultaneously achieve REE recovery from CFA and waste reduction.

The tropical Pacific is a dominant influence on global climate, from interannual to glacial-interglacial timescales. How this system will respond to anthropogenic greenhouse gas forcing, however, remains an area of large uncertainty. In order to better our understanding of how the tropical Pacific ocean-atmosphere system has responded to greenhouse gas forcing in the past, I have generated new reconstructions of sea surface temperature (SST) in the central equatorial Pacific over the last ~150,000 years.

Biomass burning is a significant source of gas- and particle-phase carbon in the atmosphere. It emits thousands of volatile organic compounds (VOCs) that can contribute to the formation of secondary organic aerosol (SOA). Recent studies have shown that furans are an important class of VOCs and constitute a significant portion of biomass burning plumes.

Organic aerosols (OA) have long been thought to only scatter incoming solar radiation and have a cooling effect on climate. However, a fraction of OA, referred to as brown carbon (BrC), absorbs light in the lower visible to ultraviolet range. BrC can be emitted from incomplete combustions and can also be generated through secondary processes. The radiative impact of BrC on climate is difficult to assess owing to the lack of knowledge about emissions and the evolution of BrC aerosol.

Mud volcanism, a specific type of subsurface sediment mobilization process known to occur on Earth, has been suggested to explain the formation

On Earth, evolved felsic crust is commonly associated with plate tectonics, specifically subduction zones, and preexisting silicic crust. As Mars
lacks both, felsic rock is unexpected there. However, new studies via remote sensing and in situ observation indicate a wider range of primary rock
compositions on Mars, suggesting an incomplete understanding of how these materials form. Nili Patera, a caldera on the Syrtis Major shield

Nitrogen oxides (NO x NO NO 2 originating from combustion, lightning and soil, are the main drivers of the tropospheric ozone formation and important precursors of secondary organic aerosols, with consequences for human health, climate and ecosystem Isoprene, the most important biogenic volatile organic compounds (globally, accounts for about half of the BVOC emissions 500 Tg yr 1 Its rapid oxidation in the presence of NO x is a main driver of atmospheric chemistry Detailed and accurate estimations of NO x emissions and a better understanding of isoprene chemis