Hyporheic Exchange With and Without Traveling Surface Waves

Vaughan R. Voller, University of Minnesota

Hyporheic exchange, the flow of surface water into and out of sediment substrates, play an important role in controlling temperature, pollutant, and dissolved oxygen levels in aquatic. A key driver for hyporheic flow is pressure variations over the water/sediment interface. Here, we compare and contrast, for a range flume conditions, hyporheic exchange in a flowing current with and without travelling surface waves. This is achieved experimentally by using a vertical array of electrical conductivity probes to track the movement of a conservative solute tracer in a gravel bed of a recirculating flume . In analyzing the experiment we fit a basic advection-dispersion model to the measured values of the solute uptake at our probe locations. This fitting shows, in the presence of waves, a significant (an order of magnitude or more) enhancement of the dispersion coefficient. Our hypothesis is that moving waves on the water surface drives a vertical pumping within the solute bed that, in turn, enhances the dispersion. This is confirmed by constructing a numerical simulation that directly accounts for the wave induced pressure fluctuations at the water/sediment interface and a vertically oscillating (pumping) velocity within the bed itself. We show that, on appropriate setting of the fluctuation amplitude (within the expected experimental range), predictions from the simulation exactly recover the fits to the experimental measurement.

4:00 PM - 5:00 PM

How Good is Bicycling for the Environment?

Mark Chopping, Montclair State University

Bicycling has been promoted as a means to reduce our dependence on climate-warming fossil fuel burning, clean the air in our streets, promote personal health, and fight widespread obesity. It is often postulated that there are obvious environmental benefits associated with increasing participation in cycling as a transportation alternative, since the bicycles’ fuel is the banana and/or the muffin. This presentation will discuss why mass bicycling might not be quite as good for the environment as you may imagine – though it is still very, very good indeed.

4:00 PM - 5:00 PM

Growing a Sustainable City: The Question of Urban Agriculture

Hamil Pearsall, Temple University

This presentation examines urban agriculture in Philadelphia and highlights the challenges of institutionalizing this historically informal urban activity into formal city policy over the last two decades. Urban agriculture has become a symbol of Philadelphia’s economic revitalization, sustainability, and increasingly, its gentrification. Often characterized by advocates as an urban panacea, gardening and farming seem to promise solutions to many different urban problems, such as blighted vacant lots, food insecurity, stormwater runoff, and neighborhood decline. However, questions of land tenure, the use of economic resources, and the long-term viability of urban agriculture shape the political discourse about the future of growing in the city and its role in promoting urban sustainability. Through archival research, a media content analysis, and interviews with urban farmers, gardeners, and city officials, this research examines urban agriculture’s role in Philadelphia’s transition to economic and environmental sustainability.

4:00 PM - 5:00 PM

Extreme Weather and the Arctic Meltdown: How Are They Connected?

Jennifer A. Francis, Rutgers University

Does it seem as though the weather gods have gone crazy lately? It is not your imagination. The question on everyone's minds is why? And is it related to climate change? In this presentation, Dr. Francis will explain new research that links increasing extreme weather events with the rapidly warming and melting Arctic during recent decades. Evidence suggests that Arctic warming is causing weather patterns to become more persistent, which can lead to extremes such as droughts, cold spells, heat waves, snowy winters, and some flooding events.

4:00 PM - 5:00 PM

Reactive Iron Mineral Coatings in Redox Transition Zones and Their Impact on Natural Attenuation

Lisa Axe, New Jersey Institute of Technology

Reactive Fe mineral coatings play an important role in contaminant attenuation in redox transition zones at sites with subsurface contamination. An anaerobic 60 foot core was collected from the Chambers Works Site in Deepwater, NJ. Working in a glovebox, two-inch subsamples were used to evaluate redox transition zones using bulk composition, redox potential, pH, VOCs in the headspace, as well as abundant bacteria. A number of redox transition zones were identified and further studied with a suite of complementary analyses to characterize the surface chemistry. Analyses have included sequential extraction (phases and speciation), x-ray diffraction (mineralogy), x-ray fluorescence (composition), fieldemission scanning electron microscopy (surface morphology down to the nm scale) with energy dispersive analysis (surface composition), and bench-scale experiments. Results reveal a clear trend in reactive iron (II)/(III) mineral coatings throughout transition zones. Reactive iron mineral coatings reveal iron (II) minerals pyrite, mackinawite, pyrrhotite, and siderite in a transition zone running through an aquitard. Ferrihydrite, goethite, and lepidocrocite were dominant iron (III) minerals in a transition zone that was observed in an aquifer, while pyrite, greigite and gypsum were the most abundant mineral coating in an upper aquitard transition zone. Overall, the most significant reactive mineral coatings were observed in redox transition zones located in aquitards where there is Fe2+/Fe3+ cycling. Ongoing studies are focused on abiotic degradation pathways for halogenated solvents present in the system.

4:00 PM - 5:00 PM

Sustainable Waste Reutilization in Achieving Closed-Loop Economy and Mitigating Climate Change in New Jersey

Serpil Guran, Rutgers University

As urbanization increases, global solid-waste generation is accelerating and it is estimated that a city resident generates twice as much waste as their rural counterpart of the same affluence. If we account for the fact that urban citizens are usually richer, they generate four times as much. Sustainable waste reutilization is very important especially when it comes to organic waste. Especially, organic waste reutilization and generating energy (power & heat) and recovering nutrients to be used for agriculture is considered as one of the important pathways for mitigating climate change and creating closed-loop economy.

4:00 PM - 5:00 PM

The Role of Ground-Source Heat Pumps in Achieving New Jersey’s 80% by 2050 Goal: Addressing Emissions from the Buildings Sector

Sheryl Tembe, NJDEP

Emissions reduction and renewable energy sources are vital to health of New Jersey. Governor Murphy’s executive orders and recent legislation target actions to improve our environment and create a sustainable future. The buildings sector is recognized as the second largest source of greenhouse gas emissions in New Jersey behind transportation, with the majority of emissions due to fossil fuel-based heating and cooling. To reach state’s goal of 80% emissions reduction by 2050, reduction strategies for the built environment must implement technologies that displace fossil fuels and maximize clean and low-carbon electricity. Heat pumps are a key technology because of their high efficiency and capability to integrate with the increasing electrification of systems and end uses. Ground-source heat pumps notably deliver the highest efficiencies and therefore the deepest emissions reductions, even in extreme weather conditions. This presentation will discuss the current market conditions, challenges to adoption, and the NJDEP efforts to support the deployment of ground-source heat pumps.

4:00 PM - 5:00 PM

Emerging Models of Nitrogen and Carbon Cycling in Engineered Wastewater Treatment Processes

Kartik Chandran, Columbia University

The engineered nitrogen cycle provides a rich framework to study the structure, function and interactions within mixed microbial communities. The knowledge objtained from such studies also allows us to harness the potential of such communities towards achieving multiple goals including the production of clean water, treatment of drinking water and the synthesis of commodity chemicals and fuels, among others. Within the spectrum of engineered nitrogen cycling processes, autotrophic biological nitrogen removal (BNR) offers an energy and resource efficient alternate to conventionally followed approaches. The successful implementation of autotrophic BNR processes is contingent upon the selective retention of aerobic and anaerobic ammonia oxidizing organisms over nitrite oxidizing organisms. While significant work has been conducted examining the microbial ecology, metabolism and modeling aspects relating to autotrophic BNR processes, the focus has mainly been on the nitrogen cycle. Discussions on organic and inorganic carbon (the preferred substrate for several communities in these processes) are somewhat uncommon. In this work, we first consider the impact of organic and inorganic carbon supply as a driver for interactions amongst different communities present in autotrophic nitrogen removal processes. The metabolic basis for some of these interactions is then evaluated based on a more fundamental look at select members of such communities. Further, the interplay between conventionaly understood protagonists of the microbial N-cycle and some newly discovered bacteria, including those catalyzing complete ammonia oxidation (comammox) is also discussed.

4:00 PM - 5:00 PM

Tracking Soil Signatures of the 16 Mile Fire, Delaware State Forest, PA

Jennifer Callanan, William Paterson University

The high intensity 16 Mile Fire that burned in the Delaware State Forest, PA was not typical in forests of this region. This study tracks the chemical signature in the soil as a result of the combustion of biomass and associated ash inputs. Chemical signatures related directly to the fire impacted soils were observed, with some remaining after one year’s time. These lasting signatures may influence the future structure of the forest. The results of this study begin to address implications of high intensity fire in forests of the northeast as changing climatic conditions may begin to influence their fire regimes.

4:00 PM - 5:00 PM

The Fate of Sulfur During Melting and Crystallization: Implications for Sulfur Transfer from Mantle to the Crust-Atmosphere System

Shuo Ding, CUNY Queens College

Sulfur (S) is one of the most abundant volatiles; one that has a fundamental impact on various magmatic processes, from the mantle to the Earth’s surface. Ocean island basalts (OIB) are one of the critical probes for understanding the chemical, lithological and thermal variations in the Earth’s mantle. Therefore, S abundances of primary OIB that sample peridotite partial melts, as well as deeply recycled components, can provide a better understanding of the long-term S cycle on Earth. In this study, we developed a model to describe the behavior of sulfide and copper (Cu) during decompression melting of the mantle by combining experimental constraints on mantle melting and empirical models of sulfur content at sulfide saturation (SCSS). Our calculation shows that the total S inventory of the heterogeneous mantle source of OIBs is higher than that of mid ocean ridge basalts (MORB) due to the presence of subducted eclogites and sediments, which might play an important role in retaining sulfide in the Earth’s shallow mantle. The release of sulfur to the atmosphere during volcanic eruptions can perturb climate on a local-global scale and cause significant environmental impact by forming acid rains. In a case study, we look at the behavior of sulfur during the 2006 eruption of Augustine volcano, Alaska by combining the geochemistry of melt inclusions and modeling of S behavior during crystallization of the pre-eruption stage. Our analysis shows that pre-eruptive vapor and the precipitation of S-bearing minerals have played critical roles in controlling S release during intermediate-silicic volcanic eruptions.

4:00 PM - 5:00 PM

How Do Polar Ice Sheets and Sea Level Behave Under a Changing Climate?

Sandra Passchier, Montclair State University

Nearly 3 billion people live within 100 km of the coastline, many in large urban centers. In predictions of sea level rise, the future role of polar ice sheets is one of the most critical uncertainties under the present extreme rise in greenhouse forcing of the climate system. This talk will show how geoscientists address the Earth system processes involved in melting ice sheets under warmer climates, and introduce the objectives of an upcoming deepsea drilling expedition to the area with greatest ice loss in West Antarctica.

4:00 PM - 5:00 PM

Incentives for Coastal Persistence

Porter Hoagland, Woods Hole Oceanographic Institution

Inundation, erosion, and property damages and losses are being observed at increasing rates in coastal areas. It is now well-recognized that rising sea levels, increases in storm intensities, and inadequate structural protections are contributing to the significant physical destruction of and economic losses to coastal properties. Scientists, coastal zone managers, and the general public have begun to call for implementing policies of resilience and adaptation to these losses, including retreating from the coast, yet humans continue to live—and even increase their presence—along the nation’s shorelines. What causes such persistence? It has become commonplace to identify lower-than-actuarially-fair premiums for participation in the National Flood Insurance Program as the main culprit in incentivizing coastal persistence. Flood insurance premiums may be only part of a much more complex array of incentives, however. We have taken some initial steps at identifying and scaling other programs and community interactions that appear to enable coastal persistence. We review these incentives, relying upon some illustrations from experiences in Massachusetts. Gaining a better understanding of the full array of incentives for coastal persistence—and their complex interactions—could help to enable the design of policies for lessening coastal destruction and loss.

4:00 PM - 5:00 PM

Disrupting Desalination: Novel Energy Efficient Technologies for Hypersaline Brines

Ngai Yin Yip, Columbia University

Management and treatment of hypersaline brines, e.g., produced water from oil and gas extraction, zero liquid discharge effluent, and flue gas desulfurization wastewater, are of growing environmental importance. Prevailing practice of distilling brines is highly energy-intensive and costly because the evaporation of water is enthalpically unfavorable. Here, we present two novel technologies for hypersaline desalination: cascading osmotically mediated reverse osmosis (COMRO) and temperature swing solvent extraction (TSSE). The first technology, COMRO, utilizes the novel design of bilateral countercurrent reverse osmosis stages to lessening the osmotic pressure difference across the membrane, thereby simultaneously depressing the hydraulic pressure needed and reducing energy demand. The second technology, TSSE, is membrane-less, not based on evaporative phase-change, and utilizes low-grade waste heat to drive the separation. Working principles of the technologies are presented, the desalination performance are examined, and implications for the treatment of hypersaline brines are discussed.

4:00 PM - 5:00 PM