Biogeochemical Modeling of the Response of Forest Watersheds in the Northeastern U.S. to Future Climate Change

In this dissertation I assessed the potential hydrochemical responses of future climate change conditions on forested watersheds in the northeastern U.S. using climate projections from several atmosphere ocean general circulation models (AOGCMs) under different carbon dioxide (CO2) emissions scenarios. The impacts of changing climate on terrestrial ecosystems have been assessed by observational, gradient, laboratory and field studies; however, state-of-the-art biogeochemical models provide an excellent tool to investigate climatic perturbations to these complex ecosystems. The overarching goal of this dissertation was to apply a fully integrated coupled hydrological and biogeochemical model (PnET-BGC) to evaluate the effects of climate change and increasing concentrations of atmospheric CO2 at seven diverse, intensively studied, high-elevation watersheds and to evaluate aspects of these applications. I downscaled coarse scale results to local watersheds and applied these values as input to a biogeochemical model, PnET-BGC. I conducted my research in this dissertation in three phases. In phase one, I used PnET-BGC to evaluate the direct and indirect effects of global change drivers (i.e., temperature, precipitation, solar radiation, CO2) on biogeochemical processes in a northern hardwood forest ecosystem at the Hubbard Brook Experimental Forest (HBEF) New Hampshire, USA. A sensitivity analysis was conducted to better understand how the model responds to variation in climatic drivers, showing that model results are sensitive to temperature, precipitation and photosynthetically active radiation inputs. Model calculations suggested that future changes in climate that induce water stress (decreases in summer soil moisture due to shifts in hydrology and increases in evapotranspiration), uncouple plant-soil linkages allowing for increases in net mineralization/nitrification, elevated leaching losses of NO3- and soil and water acidification. Anticipated forest fertilization associated with increases in CO2 appears to mitigate this perturbation somewhat. In phase two, I compared the use of two different statistical downscaling approaches- Bias Correction-Spatial Disaggregation (BCSD) (Grid-based) and Asynchronous Regional Regression Model (ARRM) (station-based) - on potential hydrochemical projections of future climate at the HBEF. The choice of downscaling approach has important implications for streamflow simulations, which is directly related to the ability of the downscaling approach to mimic observed precipitation patterns. The climate and streamflow change signals indicate that the current flow regime with snowmelt-driven spring-flows in April will likely shift to conditions dominated by larger flows throughout winter. Model results from BCSD downscaling show that warmer future temperatures cause midsummer drought stress which uncouples plant-soil linkages, leading to an increase in net soil nitrogen mineralization and nitrification, and acidification of soil and streamwater. In contrast, the precipitation inputs depicted by ARRM downscaling overcame the risk of drought stress due to greater estimates of precipitation inputs. In phase three of this research, I conducted a cross-site analysis of seven intensive study sites in the northeastern U.S. with diverse characteristics of climate, soil and vegetation type, and historical land disturbances to assess the range of forest-watershed responses to changing climate. Model results show that evapotranspiration increases across all sites under potential future conditions of warmer temperature and longer growing season. Modeling results indicate that spruce-fir forests will likely experience temperature stress and decline in productivity, while some of the northern hardwood forests are likely to experience water stress due to early loss of snowpack, longer growing season and associated water deficit. This latter response is somewhat counter-intuitive as most sites are expected to have increases in precipitation. Following increases in temperature, ET and water stress associated with future climate change scenarios, a shifting pattern in carbon allocation in plants was evident causing significant changes in NPP. The soil humus C pool decreased significantly across all sites and showed strong negative relationship with increases in temperature. Cross-site analysis among different watersheds in the Northeast indicated that dominant type of vegetation, and historical land disturbances coupled with climate variability will influence future responses of watersheds to climate change. The variability in hydrochemical response across sites is due to vegetation type, soil and geological characteristics, and historical land disturbances

The Tao of open science for ecology

The field of ecology is poised to take advantage of emerging technologies that facilitate the gathering, analyzing, and sharing of data, methods, and results. The concept of transparency at all stages of the research process, coupled with free and open access to data, code, and papers, constitutes “open science.” Despite the many benefits of an open approach to science, a number of barriers to entry exist that may prevent researchers from embracing openness in their own work. Here we describe several key shifts in mindset that underpin the transition to more open science. These shifts in mindset include thinking about data stewardship rather than data ownership, embracing transparency throughout the data life‐cycle and project duration, and accepting critique in public. Though foreign and perhaps frightening at first, these changes in thinking stand to benefit the field of ecology by fostering collegiality and broadening access to data and findings. We present an overview of tools and best practices that can enable these shifts in mindset at each stage of the research process, including tools to support data management planning and reproducible analyses, strategies for soliciting constructive feedback throughout the research process, and methods of broadening access to final research products

Construction and Climate Change; Challenges and Opportunities: A Case Study of the Northeast U.S

Abstract The Northeast megalopolis of the United States, which covers a high-density corridor from Washington, D.C., north to Boston, is one of the most developed environments in the world. It contains a gigantic, complicated, and intertwined network of supporting infrastructure with average score of D+, hence requiring substantial rehabilitation and renewal. The 2020 North American Construction report forecasted a CAGR of 8.4% by 2024 despite the pandemic. The pace of growth will recover from 2021 onwards as the ongoing infrastructure investments and smart city projects will add momentum for the region’s construction industry. On the other hand, climate change impacts are underway across the globe and the Northeast of the U.S. is not an exception. Populations and aging infrastructures that they depend on, are highly vulnerable to climate hazards including heat waves, as well as flooding due to a combination of sea level rise, storm surge, and extreme precipitation events. In this study, future projections of climate change in the Northeast of the U.S. were used to explore their potential impacts on construction industry including but not limited to safety of workforce, selection of building materials and their lifecycle, logistics, scheduling, costs, and insurance. The challenges and opportunities that construction industry faces under climate change were also covered. Later, the feedback loop between the construction and climate change were discussed as well as how sustainable construction practices could mitigate climate change impacts while providing safety for construction workforce. Finally, this paper focuses on resilience, buildings carbon footprint, green infrastructure, sustainability, and a prototype decision-support tool for construction projects to better manage weather risk from contract to project completion, known as Climate-i Construction, and how construction industry can benefit from them under 21st century changing climate.</jats:p

Exploring 3D Printing Potentials for Sustainable, Resilient, and Affordable Housing

The construction industry showed remarkable resiliency during the global pandemic, and it is a worldwide engine for economic growth. However, many construction companies are predominantly building with traditional techniques and have not adapted to utilize available technological advancements. Therefore, industry is behind the curve to address global issues such as combating climate change and providing more affordable housing. Thus, it is necessary to continue the exploration of options to utilize available technologies that offer innovative solutions to today’s global challenges and pivot toward a more sustainable and inclusive future. Nowadays, 3D printing is one of the fastest-growing technologies in construction. This building method could provide answers to the above-mentioned issues and open new and exciting opportunities for the construction industry. This paper will examine how 3D printing can contribute to solving the needs for more sustainable, resilient, and affordable housing. The technology of 3D printing is explained, focusing on the use of 3D printing of structures for housing construction. Once the technology behind 3D printed houses is conveyed, the sustainability and cost benefit analysis of this construction method are explored and compared with traditional construction techniques. The sustainability aspect is explored through analyzing and comparing other similar sized traditionally built homes. Similarly, the affordability of this construction method is compared with current techniques to determine the benefits of this type of construction. Upon the conclusion of the work, a clear pathway is provided on how to utilize 3D printing in constructing more sustainable, resilient, and affordable housing for the future.

Enhancing Student Learning Experience by Incorporating Virtual Reality into Construction Safety and Risk Management Class

For years, the construction industry was notorious for being slow in adopting new technologies. However, in the past decade, this trend started to change. Technologies such as building information modeling (BIM), drone, autonomous equipment, 3D printing, artificial intelligence (AI), virtual reality (VR), and augmented reality (AR) were developed and used by the industry at a breakneck speed. While VR/AR technologies have been around for quite a long time, they have been gaining more attention by the AEC (Architecture, Engineering, and Construction) industry recently. These technologies have proven to benefit construction projects in many ways. From preconstruction to construction, they can add value and save time and money. One of the great advantages of these technologies is training for jobsite safety and hazard recognition. To create more interactive learning experience and prepare students for a rapidly changing industry, VR technology was utilized in Construction Safety and Risk Management class in the Construction Management program at Wentworth Institute of Technology. This paper describes how VR technology was incorporated as a pilot study into the class curriculum and provided students with a different and more engaging learning experience, as well as how it helped them learn the subject matter better.</jats:p