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Item Open Access A Limnological Examination of the Southwestern Amazon, Madre de Dios, Peru(2012) Belcon, Alana UrneshaThis dissertation investigates the limnology of the southwestern Peruvian Amazon centered on the Madre de Dios department by examining first the geomorphology and then the ecology and biogeochemistry of the region's fluvial systems.
Madre de Dios, Peru is world renowned for its prolific biodiversity and its location within the Andes biodiversity hotspot. It is also a site of study regarding the development of the Fitzcarrald Arch and that feature's geomorphological importance as the drainage center for the headwaters of the Madeira River - the Amazon's largest tributary and as well as its role as a physical divider of genetic evolution in the Amazon. Though each of these has been studied by a variety of prominent researchers, the ability to investigate all the aspects of this unique region is hampered by the lack of a regional geomorphological map. This study aims to fill that gap by using remote sensing techniques on digital elevation models, satellite imagery and soil, geology and geoecological maps already in publication to create a geomorphological map. The resulting map contains ten distinct landform types that exemplify the dominance of fluvial processes in shaping this landscape. The river terraces of the Madre de Dios River are delineated in their entirety as well as the various dissected relief units and previously undefined units. The demarcation of the boundaries of these geomorphic units will provide invaluable assistance to the selection of field sites by future researchers as well as insights into the origin of the high biodiversity indices of this region and aid in planning for biodiversity conservation.
Secondly this study examines 25 tropical floodplain lakes along 300 km of the Manu River within the Manu National Park in the Madre de Dios department. Alternative stable state and regime shifts in shallow lakes typically have been examined in lakes in temperate and boreal regions and within anthropogenically disturbed basins but have rarely been studied in tropical or in undisturbed regions. In contrast this study focuses on a tropical region of virtually no human disturbance and evaluates the effects of hydrological variability on ecosystem structure and dynamics. Using satellite imagery a 23 yr timeline of ecological regime shifts in Amazon oxbow lakes or "cochas" is reconstructed. The study shows that almost 25% of the river's floodplain lakes experience periodic abrupt vegetative changes with an average 3.4% existing in an alternative stable state in any given year. State changes typically occur from a stable phytoplankton-dominated state to a short lived, <3 yr, floating macrophytic state and often occur independent of regional flooding. We theorize that multiple dynamics, both internal and external, drive vegetative regime shifts in the Manu but insufficient data yet exists in this remote region to identify the key processes.
To complete the investigation of tropical limnology the third study compares and contrasts the nutrient-productivity ration of floodplain and non-floodplain lakes globally and regionally. For over 70 years a strong positive relationship between sestonic chlorophyll-a (Chl-a) and total phosphorus (TP) has been established with phosphorus generally viewed as the most limiting factor to productivity. Most of these studies, however, have focused on northern, temperate regions where the lakes are typically postglacial, isolated and fed by small streams. Relatively little work has been done on floodplain lakes which are semi or permanently connected to the river. This study examines the relationship between nutrients and productivity in floodplain lakes globally through an extensive literature synthesis. Values for total phosphorus, total nitrogen and chlorophyll-a were collected for 523 floodplain lakes, represented by 288 data points while 551 data points were collected for 5444 non-floodplain lakes. Analysis revealed that globally, floodplain lakes do not show any significant difference in the total phosphorus/chlorophyll-a relationship from that found in non-floodplain lakes but significant differences are seen between tropical and temperate lakes. We propose that the term `floodplain' lake should serve as purely a geographical descriptor and that it is lacking as an ecological indicator. Instead factors such as precipitation seasonality, hydrological connectivity and regional flooding regimes are better indicators of high or low productivity in floodplain lakes.
Item Open Access Beef Production in Brazil: A Value Chain Approach to Reducing Deforestation(2013-04-24) Gonnella, Carrie; Holt, Jana; Hill, Louise; Braunz, AmyDeforestation in the Brazilian Amazon is a persistent environmental problem due to its contributions to global climate change and biodiversity loss. The beef industry is a major contributor to this problem with an estimated 60-75% of deforestation caused by conversion of rainforest to pasture land. The World Wildlife Fund (WWF) and the Global Roundtable on Sustainable Beef (GRSB) are seeking advice on initiatives to pursue that will make significant contributions to the reduction of deforestation. This masters project analyzes the drivers of deforestation related to the production of Brazilian beef and identifies initiatives that could help reduce deforestation. For each initiative considered, benefits, risks, and barriers are explored. In addition, an analysis of the Brazilian beef value chain is undertaken to determine which segments of the chain hold the most appealing leverage points for implementing initiatives to combat deforestation. Based on the results of this analysis, this paper recommends that WWF and the GRSB pursue efforts to improve land use planning, diversification of farm income, and implement financial mechanisms, such as REDD+. This paper also lays out a timeline for undertaking these initiatives, specific roles that the GRSB can play in each of these initiatives, and key stakeholders that the GRSB must engage with to be successful at positively impacting the problem of deforestation in the Amazon.Item Open Access Compositional Trends in the Primary Floodplain Forest of the Manu National Park, Peru(2009-04-24T19:14:21Z) Yavit, NoahOver the past ~20 years, various stand-level assessments of undisturbed Amazonian forests have revealed an increase in stem turnover (resulting from increases in recruitment and mortality), an increase in stem density and an increase in basal area growth rates. However, a more detailed analysis of the genus or species level changes within these forests is required to adequately assess the carbon-level dynamics of the region. The only assessment to examine undisturbed community composition at this level was undertaken in 2004 by Laurance et al. in Manaus, Brazil. This study revealed a directional shift towards fast growing, canopy emergents at the expense of slower growing genera, ultimately indicating a reduction in the carbon sequestration ability of these forests. Laurance goes on to cite rising atmospheric CO2 levels as the only capable factor of driving his observed trends. Importantly, if such a uniformly distributed gas as CO2 is responsible for the observed changes, we would expect to see similar shifts across the entire Amazon Basin, if not pan-tropically. The analysis here examines 15 years of data across 7-undisturbed treeplots in Manu National Park, Peru for alterations in community composition at the genus level. Analyses of population density and basal area across the entire lifetime of the plots have revealed that the numbers of genera found to be changing at the p <0.05 significance level are more than two times greater than would be expected from chance alone. However, an examination of corresponding wood density values reveals that these genera are not exhibiting a directional shift similar to that observed by Laurance in 2004. Numerous potential reasons behind the trends observed in Laurance’s forests, such as recent disturbance or local depletion of seed dispersers by past hunting, are explored.Item Open Access Entrepreneurial Attractiveness: Amazon, Google, and the Search for Innovative Hot Spots(2018-04-18) Kropf, AnnaRecent economic literature suggests that entrepreneurship in technological fields can spur economic growth, making it a popular topic for city development officials. Yet, this increasingly popular phenomenon is met by many economic questions. One of those questions is which characteristics of metropolitan areas are attractive to entrepreneurs. To answer the question of attractiveness on both the small business and corporate levels, I compare across two case studies: Amazon’s search for a second headquarters and Google’s tech hub network. Using principal component analysis, I statistically deduce seven components of attractiveness from an original 34 variables. These components are then weighted using three methods—a case study, a survey, and an empirical method—to produce comparable indices of attractiveness. Generally, I find that sizeable population and healthy economy are the strongest components. However, the statistically insignificant components that can change an urban area’s ranking considerably are talent and geographic network effects. Ultimately, creating policy to maximize these aspects can change a city’s innovative trajectory.Item Embargo Ethics of Artificial Intelligence, Robotics and Supra-Intelligence(2020) Kasbe, Timothy DAll things were created by Him and for Him:
Ethics of Artificial Intelligence, Robotics and Supra-Intelligence
Fascination with automation has captured the human imagination for thousands of years. As far back as 800 CE, when Baghdad was at its height as one of the world’s most cultured cities, its House of Wisdom produced a remarkable text, “The Book of Ingenious Devices.” In it were beautiful schematic drawings of machines years ahead of anything in Europe—clocks, hydraulic instruments, even a water-powered organ with swappable pin-cylinders that was effectively a programmable device.
The fascination with automation has come a long way since then. Technological advancements in the last seventy years have provided unprecedented opportunities for humans to explore not only automation, but now also the creation of intelligent and superintelligent machines. These machines promise to mimic human qualities and even supersede humanity in every manner of task and intelligence. The explosion of, and ready access to, information through the internet has proved to be challenging in some regards but has also eased other aspects of life. An example of this would be the way long-lost friends can be reunited through the click of a mouse. Similarly, news accompanied by pictures and videos is now readily available in real-time. These conveniences have also brought unintended consequences. Despite this newfound connectivity, social challenges such as loneliness and suicide are on the rise. Technology has also opened the door to problems such as cyberbullying, election manipulation, and fake news. Information, whether it be accurate or not, spreads across the world at unprecedented speeds, carrying with it change, sometimes for the better, but not always. This is all happening before the anticipated age of superintelligence.
This thesis examines the distinct nature of humanity and God in view of the emergence of superintelligence. Can we see this “new creation” as an addition to God’s creation of humans, angels, and Satan? If that be the case, then questions of ethics and theology need to be addressed. For instance, who gets to program these new superintelligent “beings?” As things stand today, the individuals and corporations with the deepest pockets are racing to be the first to produce superintelligent beings. The so-called “technology horse” has already bolted, with government policy struggling to keep up. Unseen in this race is the prophetic and ethical voice of the church, regarding the meaning of life, and what living in this new reality will look like.
More questions are raised than can be answered in this paper. How does the Church stay true to its message of hope in a world where robots will likely take over everyday jobs? Where will humanity find meaning and contentment? What are we to think about the idea of a basic universal wage? How will such a shift impact migrant and the poor? In this paper I establish a framework for the church to consider different aspects of these challenges, even as people are welcomed weekly into the community of faith.
This thesis represents extensive research into the philosophy and practice of safety engineering, paired with personal experiences as a professional in the technology industry who is also deeply committed to being a disciple of Christ. Primary works I have drawn from extensively include Hauerwas and Wells’ Blackwell Companion to Christian Ethics, and Jungian archetypes in comparing and contrasting biological beings to technological creations. The paper starts with creation accounts from Genesis and the Enuma Elish as a way of exploring the “being” category as it appears on this planet. Personal insights gained working in both enterprise and startup businesses, as well as in my own professional development, have contributed to this work and may be found throughout. This thesis represents a labor of love through which I have learned a great deal about my own profession and faith. However, it is my sincere hope that it will be much more. Through this dissertation I hope to see companies both big and small taking note of the ethical issues discussed here, even as they find themselves unleashing artificial intelligence in the marketplace. At the same time, I expect churches and religious organizations will benefit from this discussion and will, I hope, move to engage more deeply with culture and the marketplace as new opportunities and risks emerge from the implementation of artificial intelligence. If the observations that I have made and the recommendations that I have set forth can inspire even one person to carefully examine his or her identity in Christ, then this work will be successful beyond its original purpose as an academic work.
Item Open Access Examining Trends in Birth Location and Birth Attendance Among Women in the Amarakaeri Communal Reserve(2018) Jones, ClayDespite global improvements in maternal mortality rates, preventable maternal deaths are still an issue for many populations. Indigenous populations, especially those in Latin America, often do not utilize delivery services for a number of reasons, not the least of which are cultural beliefs, geographic challenges, and ability to pay for services. The primary objective of this study is to examine the birth location and birth attendance trends across time of Amazonian Indigenous women compared to women of Andean Highland decent. Additionally, the study aims to compare the education levels, urban status, and income levels of these populations. This analysis uses survey data from families in Amarakaeri Communal Reserve in Amazonian Peru. Bivariate analysis and multivariate logistic regression were used to examine birth location and birth attendance across time. Since 1990, Amazonian Indigenous women in the study sample are increasingly giving birth at health posts in the attendance of nurses, but most still elect to give birth at home with a relative as an attendant. From this, it is concluded that women of Amazonian Indigenous decent are increasingly seeking out skilled birth attendants, but barriers to utilization may remain. Further descriptive research is necessary to ascertain the reasons why Amazonian Indigenous women still prefer giving birth at home, and additional modeling is necessary to determine the effects of potential influencing variables, such as urban status, education levels, and income levels.
Item Open Access Implications of CMIP6 Projected Drying Trends for 21st Century Amazonian Drought Risk(Earth's Future, 2020-10-01) Parsons, LARecent exceptionally hot droughts in Amazonia have highlighted the potential role of global warming in driving changes in rainfall and temperatures in the region. The previous generation of global climate models projected that eastern Amazonia would receive less future precipitation while western Amazonia would receive more precipitation, but many of these models disagreed on future precipitation trends in the region. Here Coupled Modeling Intercomparison Project, Phase 6 (CMIP6) models are used to examine the shifting risk of eastern Amazonian droughts under high and low future greenhouse gas emissions scenarios. This new generation of models shows better agreement that most of the Amazonian basin will receive less future rainfall, with particularly strong agreement that eastern and southern Amazonia will dry in the 21st century. These models suggest that global warming may be increasing the likelihood of exceptionally hot drought in the region. With unabated global warming, recent particularly warm and severe droughts will become more common by midcentury, but reducing the rate of greenhouse gas emissions can make extremely hot and dry years less common in the future. Simulated future rainfall changes in Amazonia under high greenhouse gas emissions are associated with changes in the tropical Pacific, but many climate models struggle to reproduce observed trends in the tropical Pacific. These shortcomings highlight the need to improve confidence in global climate models' ability to simulate observed trends in the tropics, even if more CMIP6 models agree on the sign of future rainfall trends.Item Open Access Improving the Modeling of Government Surveillance Data: a Case Study on Malaria in the Brazilian Amazon(2013) Valle, DenisThe study of the effect of the environment (e.g., climate and land use) on disease typically relies on aggregate disease data collected by the government surveillance network. The usual approach to analyze these data, however, often ignores a) changes in sampling effort (i.e., total number of individuals examined), b) the fact that these data are biased towards symptomatic individuals, and; c) the fact that the observations (e.g., individuals diagnosed and treated for the disease) often directly influence disease dynamics by decreasing infection prevalence. Here we highlight the consequences of ignoring the problems listed above and develop a novel modeling framework to circumvent them. We illustrate this modeling framework using simulated and real malaria data from the Western Brazilian Amazon.
Our simulations reveal that trends in the number of disease cases do not necessarily imply similar trends in infection prevalence or incidence, due to the strong influence of concurrent changes in sampling effort. Furthermore, we show that ignoring decreases in the pool of infected individuals due to the treatment of part of these individuals can significantly hinder inference on underlying patterns of infection incidence. We propose an innovative model that avoids the problems listed above. This model can be seen as a compromise between more phenomenological statistical models and more mechanistic disease dynamics models; in particular, a validation exercise reveals that the proposed model has higher out-of-sample predictive performance than either one of these alternative models. Our case study on malaria in the Brazilian Amazon reveals surprising patterns in infection prevalence and incidence, which might be partially attributed to seasonal rainfall variation.
We have proposed and applied a novel modeling approach that avoids problems that have plagued several earlier analyses of government surveillance disease data. We illustrate how ignoring these problems can significantly hinder inference on the effect of environmental factors on disease dynamics. This modeling approach is likely to be useful for the modeling of various diseases using government surveillance data.
Item Open Access Investigating the Geological and Biogeographical Cenozoic History of the Amazon-Andes Region(2019) Wheatley, Alexander AlanThe Amazon-Andes region of tropical South America plays host to the world’s largest river, its highest biodiversity and one of its highest mountain chains, as well as a long and complex history. As such, it represents an ideal location to study the interplay between geology, climate and biodiversity. In this thesis I first present a statistical analysis of the usefulness of paleocurrent data in reconstructing that complex history, using high-resolution topographic data from the Shuttle Radar Topography Mission to develop and test a river network model of the modern Amazon River watershed, followed by new zircon geochronology provenance data from the Alter do Chão Formation in Brazil, with implications for hypothesized Miocene drainage reversal in Amazonia. I then present potentially the first attempt to utilize phylogenetic data to inform our understanding of the uplift history of the Andes, using a simple biogeographic model of vicariant speciation along with phylogenetically-established dates for isolation events to compare varying simulations of Andean uplift over the past 10 million years.
I will conclude (1) that paleocurrent analysis is likely of very limited use in watershed-scale investigations, while highlighting the complexity of river flow patterns within a large basin such as the Amazon, and (2) that the topography found at the modern day Huancabamba Depression likely did not reach its current elevation earlier than ca. 3 million years.
Item Open Access Is the Interoceanic highway exporting deforestation? A comparison of the intensity of regional Amazonian deforestation drivers within Brazil, Bolivia and Peru(2008-04-25T14:22:36Z) Delgado, CesarThe Inter-Oceanic highway is a 1.9 billion dollar project that bisects southern Amazonia between the triple border region of Peru, Brazil and Bolivia. Many believe that a project of this magnitude will not only spur the trade of goods and services between these countries, but fear that Brazil’s appalling deforestation rates will exacerbate the existing deforestation trends within Peru and Bolivia. By applying remote sensing techniques and a statistical logistic regression model I was able to depict deforestation prior to 1989, the increase between 1989 and 2000 and the cumulative effect by the year 2000, in the area of the Inter-Oceanic highway and other related human infrastructure. I found that the Peruvian deforestation rates will be exacerbated and, despite common belief, the Inter-Oceanic highway is not going to be the main culprit, but the secondary road network and population centers, that the highway will encourage. Furthermore, I project that the urban explosion of certain population centers will put under severe pressure the protected areas of Tambopata in Peru and the extractive reserve of Chico Mendes in Brazil. Finally we acknowledge that countries unique socioeconomic dynamics can clearly contradict the results of classic Pan-Amazonian deforestation models.Item Open Access Malaria Transmission in Border Regions of the Western Amazon: Incorporating watersheds into timeseries analysis to address disease reintroduction and spillover along the Ecuador-Peru border(2021-04-30) Kumar, RaniSince 2010, Amazon-basin countries have experienced a 600% increase in malaria cases, the most rapid increase compared to any other region of the world. Border regions have been implicated as important hot spots of malaria transmission, particularly in Latin America. This study focuses on the Amazon border between Ecuador and Peru, a region that exhibits a steep gradient of transmission intensity, with Peru having a much higher incidence of malaria than Ecuador. The study provides a framework for incorporating watersheds into timeseries analysis to better predict malaria spatial temporal trends along borders. Results demonstrate that malaria control based on ecologically defined spatial areas could potentially provide more effective disease management than malaria control based on administrative boundaries.Item Open Access Promoting Investments in Ecosystem Services: the Case of the Peruvian Amazon(2010-04-23T15:03:18Z) Romero-Wolf, Robert MartinNatural capital and the Ecosystem Services (ES) that flow from it are essential to civilization as they provide both the conditions and the processes that sustain human life. Peru possesses the third largest tropical forest cover in the world and is undoubtedly one of the planet’s mega-diverse countries. This document focuses on exploring the viability of markets for ES as a tool for funding conservation in the Peruvian Amazon given the current highly charged climate surrounding natural resource management policies that the government must deal with. Qualitative research methods were used to analyze interviews conducted with high level government officials, NGO directors and bilateral agency program managers in Peru to gain insights into the gaps in existing natural resource management policies that create risks for developing markets for ES. Issues such as institutional capacity, multi-stakeholder decision making, land-use planning, definition and enforcement of property rights, consultation and free, prior and informed consent from local communities for major investment projects as well as the strictness and enforcement of regulations around Environmental Impact Assessments stand out as key shortcomings in Peru’s natural resources management policies that create risks for the development of ES markets. Most of the key issues identified in this investigation are not specific to ES markets; rather they are general issues that must be considered for good practices in natural resource management. As such, creating ecosystem service markets will do little if anything to improve the long-term sustainability of Peru’s natural capital and the ecosystem services that flow from it if these issues are not addressed as part of an integrated natural resource management strategy.Item Open Access Remote Sensing of Fire, Flooding, and White Sand Ecosystems in the Amazon(2009) Adeney, Jennifer MarionHuman and natural disturbance affect the Amazon basin at several spatial and temporal scales. In this thesis, I used satellite-detected hot pixels to examine patterns of human-caused disturbance and protected areas in the Brazilian Amazon from 1996-2006. Deforestation fires, as measured by hot pixels, declined exponentially with increasing distance from roads. Fewer deforestation fires occurred within protected areas than outside and this difference was greatest near roads. However, even within reserves, more deforestation fires occurred in regions with high human impact than in those with lower impact. El Niño-related droughts affected deforestation fires most outside of reserves and near roads. There was no significant difference in fire occurrence among inhabited and uninhabited reserve types.
Within this context of disturbance in the Brazilian Amazon basin, I examined relatively undisturbed savanna-like `campina' ecosystems. I reviewed the literature on campinas and discussed their variation and their significance for beta diversity. As one of two case studies, I assessed spatio-temporal patterns of disturbance (fire and blowdowns), and vegetation change from 1987 to 2007 in campinas in the central Brazilian Amazon using Landsat imagery. In 2001 images, an increase in open areas corresponded with significantly more visible signs of disturbance, likely precipitated by the 1997-98 El Niño. Bird community data indicated a trend of more generalist/savanna species in more frequently disturbed campinas.
As the second case study, I used daily 500 m resolution MODIS reflectance data to assess seasonal and inter-annual flooding in ~33,000 km2 of campinas in the Negro river basin. Flooding cycles of these wetland campinas critically influence regional ecosystem processes. Flooded areas ranged from 15,000 km2 at the end of the rainy season (August-Oct) to little, if any, open water in the driest times (Jan-Mar). Predictable seasonal flood pulses occurred, but also displayed high inter-annual variability. This variability was weakly correlated with the Multivariate El Niño Southern Oscillation Index (MEI).
Campina ecosystems are an important, but largely overlooked, component of the biodiversity of the Amazon basin. My research shows that climate, particularly ENSO-associated droughts, strongly affects campinas even in remote areas, just as it increases fire frequencies in more populated regions of the Amazon.
Item Open Access Role of Surface Evapotranspiration on Moist Convection along the Eastern Flanks of the Andes(2014) Sun, XiaomingThe contribution of surface evapotranspiration (ET) to moist convection, cloudiness and precipitation along the eastern flanks of the Andes (EADS) was investigated using the Weather Research and Forecasting (ARW-WRF3.4.1) model with nested simulations of selected weather conditions down to 1.2 km grid spacing. To isolate the role of surface ET, numerical experiments were conducted using a quasi-idealized approach whereby at every time step the surface sensible heat effects are exactly the same as in the reference simulations, whereas the surface latent heat fluxes are prevented from entering the atmosphere.
Energy balance analysis indicates that local surface ET along the EADS influences moist convection primarily through its impact on conditional instability, because it acts as an important source of moist entropy in this region. The energy available for convection decreases by up to ~60% when the ET contribution is withdrawn. In contrast, when convective motion is not thermally driven, or under conditionally stable conditions, latent heating from the land surface becomes secondary. At the scale of the Andes proper, removal of surface ET weakens upslope flows by increasing static stability of the lower troposphere, as the vertical gradient of water vapor mixing ratio tends to be less negative. Consequently, moisture convergence is reduced over the EADS. In the absence of local surface ET, this process operates in concert with damped convective energy, suppressing cloudiness, and decreasing daily precipitation by up to ~50% in the simulations presented here.
When the surface ET is eliminated over the Amazon lowlands (AMZL), the results show that, without surface ET, daily precipitation within the AMZL drops by up to ~75%, but nearly doubles over the surrounded mountainous regions. This dramatic influence is attributed to a dipole structure of convergence-divergence anomalies over the AMZL, primarily due to the considerable cooling of the troposphere associated with suppressed convection. Further examination of moist static energy evolution indicates that the net decrease in CAPE (Convective Available Potential Energy) over the AMZL is due to the removal of surface ET that is only partially compensated by related regional circulation changes. Because of the concave shape of the Andean mountain range, the enhanced low-level divergence promotes air mass accumulation to the east of the central EADS. This perturbation becomes sufficiently strong around nightfall and produces significant eastward low-level pressure gradient force, rendering wind currents more away from the Andes. Moisture convergence and convection over the EADS vary accordingly, strengthened in the day but attenuated at night. Nocturnal convective motion, however, is more widespread. Analytical solutions of simplified diagnostic equations of convective fraction suggest that reduction of lower troposphere evaporation is the driving mechanism. Additional exploratory experiments mimicking various levels of thinning and densification of AMZL forests via changes in surface ET magnitude demonstrate that the connection between the AMZL ET and EADS precipitation is robust.
Item Open Access Seasonal and Interannual Variations of Carbonaceous Aerosols over the Amazon(2020) Hu, AllenThis study examines the seasonal and interannual variabilities of carbonaceous aerosols, including black carbon (BC) and organic carbon (OC), over the years of 2005-2016 by using outputs from the NASA GISS ModelE simulations and observations from the OMI instrument aboard Aura, AERONET stations in Amazon region, and the GoAmazon aircraft campaigns.
Simulated seasonal variations and spatial distributions of surface concentrations of BC and OC in Amazon agree well with those of biomass burning emissions. The concentrations are the highest in the dry season (July-September) and lowest in the wet season (February-May), and the locations of high concentrations follow those of high emissions. ModelE is found to underestimate concentrations of OC and BC. Comparisons of the vertical profiles of OC from ModelE with GoAmazon observations in 2014 show that ModelE underestimates OC at all altitudes. In the dry season, when biomass burning dominates, ModelE captures 42%-86% of OMI AAOD in Amazon over 2005-2016, suggesting a low bias in simulated BC concentrations. Simulated seasonal variations in AOD and AAOD in ModelE differ from OMI observations; simulated AOD (AAOD) values are the highest in the dry season, while OMI observed AOD (AAOD) values are the highest in October-January.
Interannual variations in BC and OC are quantified by relative deviation from the mean (RDEVM). Interannual variations of BC and OC in dry season are much higher than those in wet season. RDEVM values are in the range of -63.2% to 127.2% (-70.8% to 143.8%) for BC (OC) in dry season and in the range of -17.8% to 32.7% (-26.3% to 53.4%) for BC (OC) in wet season. Simulated OC concentrations have larger interannual variability than simulated BC for both the dry and wet seasons. We also found that, compared with OMI observations, ModelE overestimates the interannual variability of AOD and AAOD in the Amazon region for both the dry and wet seasons.
Results from this study contribute to the understanding of aerosol distributions in the Amazon and have implications for the impact of carbonaceous aerosols on climate on an interannual timescale.
Item Open Access Temporal Trends in Secondary Forest Carbon Sequestration(2012-04-27) Derwin, Jill M.With heightened concerns about climate change and greenhouse gas emissions, understanding the mechanics of carbon sequestration is becoming more important than ever. The world’s tropical forests are being sought for their increased ability to capture carbon in hopes that they might provide a solution to offset the emissions of industrialized nations. Techniques for the promotion of carbon sequestration are being explored in all disciplines with plans spanning international markets. The Brazilian Amazon is of particular interest in these discussions, however comprehensive data on carbon sequestration in the region has yet to be seen, reducing the accuracy of estimates of potential carbon sequestered. This study compared the carbon content of different-aged secondary forest stands to reach a deeper understanding of temporal trends in forest carbon sequestration using geospatial analysis and remote sensing techniques. I used Landsat 5 Thematic Mapper satellite images to create a multi-temporal classification of forested and non-forested areas for 1984 to 2006. I then merged the classifications to estimate age the secondary forests present to the east of the Brazilian Amazon over this 22-year period. The resulting tree ages were compared to standing aboveground carbon based upon existing estimates from the Woods Hole Research Center’s Pan-Tropical Forest Carbon dataset. An increase in accumulated carbon for increasingly older secondary forests was observed over an area of 58,038 km2. Deforestation rates in the study area have been generally decreasing since 1984, however in more recent years rising deforestation rates have been noted. Additionally, correlations were noted between carbon and latitude, precipitation, and temperature across the study area.Item Open Access The Cenozoic History of the Andean Foreland in Southeastern Peru(2018) Salenbien, WoutResults from two geographical study areas are presented in this dissertation, contributing important new information about the Cenozoic geological, environmental and biological regime. At the first locality along the Manu River (11.90°S, 71.34°W) I present a revised age and reinterpret the depositional environment. Age determination consisted of radiometrically dating detrital zircons, pushing the technical boundaries of this technique, paired with radiocarbon analyses of depositional organic material. Constraining the depositional environment relied on geochemical and sedimentological analyses. The revised age, 0.13±0.04 Ma instead of ~9 Ma, and depositional environment, as a fluvial overbank deposit instead of estuarine or marginal-marine deltaic deposits, have major implications for research previously published on the outcrop.
A second section is realized along the Alto Madre de Dios river and is situated in a piggyback basin belonging to the frontmost active deformation zone of the Sub Andean Zone, located approximately 12.8°S and 71.3°W. The section spans from the Paleocene to the Quaternary in time and allows a constraint on the influence of the Andean orogeny on the Madre de Dios foreland basin and the fauna and flora it contained through the Cenozoic. Field work has yielded a series of fossil localities that have been constrained in age through use of U/Pb dating of detrital zircons. Notable fossil finds include Early Miocene marsupials, xenarthrans, rodents, notoungulates, and bats. A new primate recovered from the section is the first record of a primate from the Early Miocene of the Amazon Basin. Reconstruction of the depositional environment for each formation was performed by a combined use of sedimentology, geochemistry, and paleontology. Stable isotopic analyses on depositional organic material indicates continental depositional settings for all formations, whereas stable isotopic analyses on abiogenic carbonates provide constraints on the degree of diagenetic alteration of sediments varying with age and structural setting. Sedimentary facies are consistent with deposits being formed in fluvial and overbank environments, consisting of fine-grained floodplain deposits, point bar deposits, conglomerate channels and fossil-bearing channel lag deposits. Average grain size for the section shows a coarsening trend towards younger deposits, consistent with the approach of, and incorporation into an active orogen, as supported by provenance data from detrital zircon analyses.
Item Open Access The Effects of Canopy Light on Sapling Growth in a Lowland, Primary Amazonian Forest(2009-04-24T20:13:11Z) Arora, SamirLight is an important factor governing seedling establishment and tree growth in tropical forests. A series of hemispherical lens canopy pictures were taken in a long-term, permanent tree plot at Cocha Cashu Biological Station, Manu National Park, Madre de Dios, Peru in 2003 and 2008. From these photographs, canopy light models were constructed to investigate changes in understory light conditions over the five year period. The resulting light data was then correlated with tree sapling data from the same plot, to determine the relationship between canopy light and sapling growth at the site. Extensive analysis of the canopy pictures and calculated light values revealed two important findings. The first is that grouped series of hemispherical photographs yield data that is internally consistent, and whose values correctly characterizing light conditions within a given study location. The second finding is that hemispherical pictures are weakly autocorrelated, making any attempt to spatially or temporally correlate individual sets of light values difficult. As a result, the study is inconclusive, yielding no distinct trends in canopy light over the five year period nor any significant relationships between canopy light changes and sapling growth.Item Open Access The Impact of Flooding on Malarial Transmission within Roadway Communities in the Peruvian Amazon(2014) Hansen, RossSevere flooding inundated the lowlands of Peru between 2011 and 2012. The rainfall and ensuing elevation in river levels coincided with a marked increase in human malaria. This study analyzes sampled Anopheles mosquitoes in twenty communities located on a new roadway system within the lowland Peruvian Amazon over a period of twelve months. 3,913 mosquitoes were captured and tested for Plasmodium sporozoite proteins via laboratory ELISA. Over eighty five percent (85%) of the samples were Anopheles darlingi. Half of the sampled communities reported at least one positive mosquito during the four rounds of collection. Transmission intensity was highly variable between communities, including the observation of spatial clustering of mosquito infectivity between communities near block sixteen (16). A negative binomial regression demonstrated smaller communities, closer to a river, were subject to higher mosquito densities. These same geographic sites did not exhibit statistically significant predicted rates of mosquito infectivity. Therefore, no additional conclusions can be made with regards to river distance on malaria burden. However, the observed heterogeneous patterns of malaria in collection sites could be driven by farm-to-market travel, previously explored in other investigations.