Digital Commons Network^™

Examining Dissolved Gases In A Changing Climate, Allison Staniec

Doctoral Dissertations

Changing climate scenarios predict a variety of effects across land, ocean, and atmosphere. In this dissertation the effect of several climate change related phenomena on dissolved gases in the coastal ocean and across the ocean-atmosphere interface is examined. Warming temperature, as predicted by the IPCC (2014), has direct impacts on the capacity of water to act as a reservoir for dissolved gases through its effect on their solubility (Chang, 2010). The first portion of this dissertation addresses dissolved gases in a coastal estuary, where warming is expected to be accelerated relative to the open ocean. A representative gas, oxygen, is …

A Regional Vulnerability Assessment For The Dungeness Crab (Metacarcinus Magister) To Changing Ocean Conditions: Insights From Model Projections And Empirical Experiments, Halle Berger

Master's Theses

Among global coastal regions, the Northern California Current System (N-CCS) is already experiencing effects from ocean acidification and hypoxia during the summer, primarily due to the region’s seasonal upwelling, current systems, and high productivity. Oxygen, pH, and temperature conditions are expected to become more stressful with continued fossil fuel emissions under global climate change, posing a serious threat to the region’s fisheries. N-CCS fishing communities rely heavily on the economically and culturally important Dungeness crab (Metacarcinus magister). The fishery is currently sustainably managed, but potential negative impacts from changing ocean conditions on Dungeness crab life stages and populations …

Fine-Scale Climates And Evolution Alter Species Responses To Climate Change, Christopher Nadeau

Doctoral Dissertations

Predictions suggest that climate change could cause the extinction of up to a million species. However, scientists debate the accuracy of these predictions. In this dissertation, I explore whether often-ignored aspects of climate and biology alter predictions of climate change impacts. In Chapter 1, I show that studies predicting extinction risk under climate change ignore important aspects of climate by using climate data with coarse spatial and temporal resolutions. In Chapter 2, I propose that the degree to which climates vary over space and time in a region can predict the vulnerability of species to climate change. I suggest that …

Evaluating Climate Change Impacts On Drinking Water Reservoirs And Wastewater System Resilience In Connecticut, U.S.A., Cristina Mullin

Doctoral Dissertations

Societies depend on the proper functioning and resilience of critical infrastructure systems including those for drinking water and wastewater, but these systems are vulnerable to natural and anthropogenic stressors. For example, wastewater systems are especially susceptible to extreme weather events while drinking water systems are vulnerable to diminished source water quality — both of which can disrupt proper functioning. Climate change and human development, economic problems, and pollution further challenge water system resilience. Despite the criticality of these systems and known vulnerabilities, little scholarship exists that aims to interrogate their resilience. This dissertation attempts to narrow this gap in the …

Floral Preformation In The Warming Boreal Forest: The Effects Of Temperature On The Development Of Vaccinium Vitis-Idaea, Eileen Schaub

Master's Theses

The boreal forest is experiencing climate change at twice the rate of other regions. Although changes in flowering phenology are a known consequence of warming temperatures, much is unknown about the effects of temperature anomalies on floral development. Boreal angiosperms preform flowers a year or more in advance and are consequently subject to varied environmental conditions across that time. My thesis examines the effects of temperature on floral development in order to understand how boreal taxa will respond to climate change.

Collection of Vaccinium vitis-idaeafrom natural populations in Fairbanks, Alaska was carried out over the growing seasons of 2017 …

Predicting Pelargonium Responses To Climate Change In A Biodiversity Hotspot Throughout South Africa, Tanisha Marie Williams

Doctoral Dissertations

Climate change is causing major shifts in species distributions, which fundamentally alters the species composition and functioning of biological communities across the globe. Projections suggest that by 2100 up to one of every six species will become extinct. Such drastic changes will have significant impacts on biodiversity patterns and ecosystem functioning. Ecologists are faced with the pressing work of trying to understand how plants will respond to changing and increasingly stressful environments. To predict the long-term effects and magnitude of species responses, it is imperative that species adaptive responses are understood across the entirety of their geographic ranges. My dissertation …

Vulnerability Of Small Island Developing States Across Multiple Scales, Neil Oculi

Doctoral Dissertations

Abstract: Small Island Developing States (SIDS) are among the countries most vulnerable to climate change because of their isolation, geopolitical stature, and limited resources. Climate change will continue to exacerbate SIDS’ vulnerabilities. With this in mind, in this dissertation, I will investigate implications of vulnerabilities of SIDS at global, regional, and local scales.

The first chapter examines the discourse on vulnerability to climate change and its many complexities. Among these is the constant tension between policy makers and academics about vulnerability. This chapter unpacks these complexities in order to analyze how SIDS deal with the notion of vulnerability at the …

Birds And Berries: Projecting The Responses Of Seed Dispersal Networks To Climate Change, Manette E. Sandor

Doctoral Dissertations

Climate change has caused species range shifts, with more predicted in coming decades. Range shifts could result in secondary threats such as spatial mismatch with mutualist partners and movement out of protected areas. We found that due to range shifts, shrub species richness will be lost at higher elevations, and species turnover will peak at middle elevations. Areas of bird species turnover will only partially overlap with areas of shrub species turnover, which could result in broken interactions between partners. Our projections suggest that climate change will result in clear winners and losers with some species gaining and others losing …

Land-Atmosphere Interactions And Regional Climate In West Africa And South America, Amir Erfanian Javadian Entezar Yazd

Doctoral Dissertations

Land, atmosphere, and oceans interact with each other through energy, mass, and momentum exchanges. These interactions regulate climate variability and influence climate changes at the regional scale. One notable example of highly influential land-atmosphere-ocean interactions on regional climates is monsoonal systems that influence a substantial portion of the world’s population. In this dissertation, the present and future climates of West Africa (WA) and South America (SA), two important monsoon regions, were studied utilizing Regional and Global Climate Models (RCMs and GCMs), mathematical techniques and data mining tools, and observational data (in-situ, remote-sensing, and reanalysis). The objective is to advance our …

Analysis Of A Newly Digitized Long-Term Dataset Of Environmental Observations From Long Island Sound, Jacob Snyder

Master's Theses

Project Oceanology, a non-profit oceanographic educational organization has been collecting data including pH, oxygen, and temperature conditions as well as abundances of benthic invertebrates and near-shore fish catches since 1972 from Eastern Long Island Sound. These data had been stored solely on single-copy paper sheets and were therefore inaccessible to analysis. I digitized more than 100,000 abiotic measurements and 50,000 species abundance and size data collected over the past 45 years, and developed a web-based SQL database housed on the Long Island Sound Integrated Coastal Observing System (LISICOS) server. The database will ultimately become a searchable, downloadable, user-friendly web-based tool …

Coastal Protection, Environmental Change, And The Heterogeneity Of Preferences: A Case Study Of The Eastern Shore Of Virginia, Ian T. Yue

Master's Theses

There is growing interest amongst the environmental management community to understand the feedback links between human and environmental systems, particularly the way humans value the natural environment and how such valuation affects behavior, choice, and actions. One prominent method for examining these linkages has been to consider the framework of ecosystem services: the naturally-occurring processes, functions, or outputs that are utilized (actively or passively) to produce human well-being. Especially in the context of climate change, ecosystem services can be used to gauge the value humans place on their surrounding environment, given that the supply of ecosystem services is expected to …

The Extinction Of The Carolina Parakeet And Multiple Dimensions Of Global Parrot Biodiversity, Kevin R. Burgio

Doctoral Dissertations

The study of the ecology of a species has traditionally ceased when that species goes extinct, despite the benefit to current and future generations of potential findings. We used the Carolina parakeet to develop a framework investigating the distributional limits, migratory habits, and extinction process as a means to recover important information. We developed a comprehensive database of every known occurrence of this iconic species. Using a combination of environmental niche modeling and extinction estimating analyses, our results demonstrate that the Carolina parakeet’s range was smaller than previously believed, the eastern and western subspecies occupied different niches with broad geographic …

Climate-Induced Habitat Fragmentation Affects Metapopulation Structure Of Arctic Grayling In Tundra Streams, Heidi E. Golden

Doctoral Dissertations

Climate change is altering ecosystems across the globe, with ecological and evolutionary consequences affecting species persistence and biodiversity. I investigated the effects of changing hydrology on Arctic grayling (Thymallus arcticus) metapopulation structure, microgeographic differentiation, movement patterns and vital rates using neutral genetic microsatellite markers, remote sensing of PIT-tagged individuals, body condition and ovarian histology. Arctic grayling within the study area on Alaska’s North Slope comprised five distinct genetic clusters. River distance and dry zones were significant factors explaining genetic differentiation among locations. Migration was low and asymmetrical among genetic clusters, but higher from headwater populations to the large …

A Threatened Ecosystem In A Human-Dominated Landscape: Tidal Marsh Conservation In The Face Of Sea-Level Rise, Christopher R. Field

Doctoral Dissertations

Biological conservation is a crisis-driven discipline that is inextricably linked to its broader social, political, and economic context. Historically, conservation research has often been conducted within ecology disciplines and with limited links to this broader context, which has contributed to a gap between research and its real-world implementation. One impediment to creating stronger interdisciplinary links is that it requires the integration of many types of data from across a range of disciplines. Owing to the difficulty of such integration, questions related to the relative importance of different types of knowledge in conservation decision-making have remained largely unexplored. I collected data …

Understanding The Hydrological Impacts Of Climate Variability And Climate Change Based On Numerical Modeling And Observations, Dana Thomas Parr

Doctoral Dissertations

The objective of this dissertation research is to better understand the hydrological impacts of climate variability and climate change. This objective is first addressed in a two-part study focusing on the Northeast US using the Connecticut River Basin as a case study. Changes to the hydrological cycle are investigated for the past several decades using precipitation and river discharge data from observations and soil moisture and evapotranspiration (ET) from the VIC hydrological model. From 1950-2011 a clear increase of precipitation intensity is identified, together with increasing precipitation amount, discharge, runoff ratios, and soil moisture. The ET trend is negligible. This …

Manipulation Of Larval And Winter Habitat Reveals Potential Effects Of Urbanization And Climate Change On Wood Frogs In Connecticut, Jason H. O'Connor

Master's Theses

Human activity can result in both local and global changes in the environment which in turn can affect other organisms and may result in population declines and loss of biodiversity. At the local scale, human activity often causes changes in habitat quality. For example, development and agriculture increase water turbidity which can influence wetland communities. At a global scale, carbon emissions are altering Earth’s climate, leading to increasing air temperatures. Using Wood Frogs, Lithobates sylvaticus, a wide-ranging, pond breeding amphibian, I sought to determine how sediment input affects larval amphibians and to assess how predicted loss of snow cover …

Observed And Simulated Processes Linked To The Recent Climate Variability And Changes Over The Greater Horn Of Africa, Vincent O. Otieno

Doctoral Dissertations

The main objective of this dissertation is to document characteristics of the processes and mechanisms associated with 20^th and 21^st century spatio-temporal modes of climate variability and changes over the Greater Horn of Africa (GHA) region.

This thesis research comprises three major parts. The first part used output from ten Earth System Models (ESMs) from the fifth phase of coupled model intercomparison project to characterize seasonal and annual mean precipitation cycle over the Greater Horn of Africa (GHA) region. Each ESM had at least 2 ensemble members. In spite of distributional anomalies of observations, ESM ensemble means were …

Effects Of Increasing Temperature And Ocean Acidification On The Microstages Of Two Populations Of Saccharina Latissima In The Northwest Atlantic, Sarah Redmond

Master's Theses

Saccharina latissima (Linnaeus) C.E.Lane, C.Mayes, L.D. Druehl and G.W.Saunders, is the most widely distributed species of kelp in the western North Atlantic, occurring from the Arctic to Long Island Sound. The effects of global climate change on these ecologically and economically important cold temperate species at the southern range of their distribution are unknown. This study investigated the impact of the combined stressors of increased temperature (16, 19, 22, 25 & 28°C) and reduced pH (7.9, 7.8, 7.7, & 7.6) on the gametophyte and juvenile sporophyte stages of sugar kelp populations from Maine and Long Island Sound. Spore germination and …

Can Acartia Spp. Adapt To Climatic Warming? Heritable Within-Population Genetic Variation In Life History Traits, Benjamin L. Cournoyer

Master's Theses

To predict the response of the biota to environmental change requires information on intrapopulation variation in life history traits and the proportion of phenotypic variation attributable to genes, heritability. Yet, knowledge of these parameters in marine populations is very limited. In the present study, I consider phenotypic plasticity and heritability of temperature-dependent, fitness-related life history traits in two coastal copepod species, Acartia tonsa and Acartia hudsonica, from Long Island Sound, a temperate estuary on the east coast of the USA. Acartia hudsonica is a purportedly cold-adapted species and A. tonsa a warm-adapted one. I used a full-sibling, split family design …