Browsing by Subject "Climate"

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    A 4600-year record of lake level and hydroclimate variability from an eastern Andean lake in Colombia
    (2016-05) Rudloff, Owen M.; Bird, Broxton Williams; Gilhooly, William, III; Filippelli, Gabriel M.
    Hydroclimatic variability in the eastern Colombian Andes is examined using a decadally-resolved, multiproxy lake sediment record from Laguna de Ubaque, Colombia. Hydroclimate trends are examined and compared to existing local, regional, and trans-Andean records to enhance existing knowledge of Late Holocene Colombian precipitation and assess potential hydroclimatic forcing mechanisms in tropical South America. Sedimentological analyses, including percent lithics, grain size, C:N and magnetic susceptibility are sensitive to hydroclimate and lake level while charcoal size and concentrations reflect fire variability. Results show that deep lacustrine conditions characterized by laminated deposits were not established until approximately 3500 cal yr B.P., prior to which, terrestrial C:N values and unstructured sediments indicate that drier, marsh-like conditions prevailed. Between 3500 and 2000 cal yr B.P., interrupted only by a 300-year arid interval from 2800 to 2500 cal yr B.P., greatly increased overall clastic deposition indicates a broad precipitation maximum while decreased sand deposition and the preservation of finely laminated sediment indicate deep lake conditions. After 2000 cal yr B.P., decreased clastic deposition suggests reduced precipitation, but the continued accumulation of laminated sediments indicates that conditions were wet enough to fill the basin continuously until the present day. These observations address two of the driving questions of Andean paleoclimate: were the northern and southern Andes in vi phase during the Holocene, or out of phase, and what are the main drivers of Holocene Andean climate? We find that the early part of Ubaque’s record more closely resembles southern Andean precipitation records until 2000 cal yr B.P., at which point it abruptly switches to resemble northern precipitation records. We attribute this to a combination of the southward migration of the intertropical convergence zone (ITCZ), and an increase in eastern Pacific sea surface temperatures (SST). In addition, we find that Colombian hydroclimate records exhibit a bimodal precipitation pattern, which we attribute to their location either on the Andean slopes or in the high interior Andes.
  • Thumbnail Image
    Item
    Climatic and geographic predictors of life history variation in Eastern Massasauga (Sistrurus catenatus): A range-wide synthesis
    (Plos, 2017-02-14) Hileman, Eric T.; King, Richard B.; Adamski, John M.; Anton, Thomas G.; Bailey, Robyn L.; Baker, Sarah J.; Bieser, Nickolas D.; Bell Jr., Thomas A.; Bissell, Kristin M.; Bradke, Danielle R.; Campa III, Henry; Casper, Gary S.; Cedar, Karen; Cross, Matthew D.; DeGregorio, Brett A.; Dreslik, Michael J.; Faust, Lisa J.; Harvey, Daniel S.; Hay, Robert W.; Jellen, Benjamin C.; Johnson, Brent D.; Johnson, Glenn; Kiel, Brooke D.; Kingsbury, Bruce A.; Kowalski, Matthew J.; Lee, Yu Man; Lentini, Andrew M.; Marshall, John C.; Mauger, David; Moore, Jennifer A.; Paloski, Rori A.; Phillips, Christopher A.; Pratt, Paul D.; Preney, Thomas; Prior, Kent A.; Promaine, Andrew; Redmer, Michael; Reinert, Howard K.; Rouse, Jeremy D.; Shoemaker, Kevin T.; Sutton, Scott; VanDeWalle, Terry J.; Weatherhead, Patrick J.; Wynn, Doug; Yagi, Anne; Department of Biology, School of Science
    Elucidating how life history traits vary geographically is important to understanding variation in population dynamics. Because many aspects of ectotherm life history are climate-dependent, geographic variation in climate is expected to have a large impact on population dynamics through effects on annual survival, body size, growth rate, age at first reproduction, size-fecundity relationship, and reproductive frequency. The Eastern Massasauga (Sistrurus catenatus) is a small, imperiled North American rattlesnake with a distribution centered on the Great Lakes region, where lake effects strongly influence local conditions. To address Eastern Massasauga life history data gaps, we compiled data from 47 study sites representing 38 counties across the range. We used multimodel inference and general linear models with geographic coordinates and annual climate normals as explanatory variables to clarify patterns of variation in life history traits. We found strong evidence for geographic variation in six of nine life history variables. Adult female snout-vent length and neonate mass increased with increasing mean annual precipitation. Litter size decreased with increasing mean temperature, and the size-fecundity relationship and growth prior to first hibernation both increased with increasing latitude. The proportion of gravid females also increased with increasing latitude, but this relationship may be the result of geographically varying detection bias. Our results provide insights into ectotherm life history variation and fill critical data gaps, which will inform Eastern Massasauga conservation efforts by improving biological realism for models of population viability and climate change.
  • Thumbnail Image
    Item
    Global Synthesis of Drought Effects on Food Legume Production
    (PLOS, 2015-06-10) Daryanto, Stefani; Wang, Lixin; Jacinthe, Pierre-André; Department of Earth Sciences, School of Science
    Food legume crops play important roles in conservation farming systems and contribute to food security in the developing world. However, in many regions of the world, their production has been adversely affected by drought. Although water scarcity is a severe abiotic constraint of legume crops productivity, it remains unclear how the effects of drought co-vary with legume species, soil texture, agroclimatic region, and drought timing. To address these uncertainties, we collected literature data between 1980 and 2014 that reported monoculture legume yield responses to drought under field conditions, and analyzed this data set using meta-analysis techniques. Our results showed that the amount of water reduction was positively related with yield reduction, but the extent of the impact varied with legume species and the phenological state during which drought occurred. Overall, lentil ( Lens culinaris ), groundnut ( Arachis hypogaea ), and pigeon pea ( Cajanus cajan ) were found to experience lower drought-induced yield reduction compared to legumes such as cowpea ( Vigna unguiculata ) and green gram ( Vigna radiate ). Yield reduction was generally greater when legumes experienced drought during their reproductive stage compared to during their vegetative stage. Legumes grown in soil with medium texture also exhibited greater yield reduction compared to those planted on soil of either coarse or fine texture. In contrast, regions and their associated climatic factors did not significantly affect legume yield reduction. In the face of changing climate, our study provides useful information for agricultural planning and research directions for development of drought-resistant legume species to improve adaptation and resilience of agricultural systems in the drought-prone regions of the world.
  • Thumbnail Image
    Item
    Investigating the Effects of Synoptic-Scale Climatic Processes on Local-Scale Hydrology by Combining Multi-Proxy Analyses of Lacustrine Sediments and Instrumental Records
    (2022-09) Gibson, Derek Keith; Bird, Broxton; Gilhooly, William, III; Jacinthe, Pierre-André; Licht, Kathy; Wang, Xianzhong
    Paleoclimate records from North and South America were used to develop a holistic understanding of global paleo-hydroclimatic drivers across a range of boundary conditions. Here, geophysical analysis of lacustrine sediment stratigraphy at Lago de Tota, Boyaca, Colombia provided evidence for significant lake-level fluctuations through the late Quaternary and produced a record that potentially spans the last 60 ka. Seismic data revealed a series of off-lap and on-lap sequences in the upper ~20 m of sediments that indicated large amplitude changes in lake-level, driven by variability in the mean latitude of the Intertropical Convergence Zone as controlled by insolation- and ocean circulation-driven hemispheric temperature gradients during glacial/stadial and interglacial/interstadial events. In North America, late Holocene flood recurrence in the Midwest and Holocene changes in the mean latitude of the polar front jet stream were investigated through multi-proxy examinations of sediment cores collected from swale lakes in northern Kentucky and southern Indiana, and a glacially formed kettle lake in northern Indiana. These results showed that the midlatitude jet stream was displaced to the south during the late Holocene, which increased the amount of Midwestern precipitation sourced from the northern Pacific and Arctic, especially during prolonged cool conditions. During these cool periods, when atmospheric flow was meridional and a greater amount of precipitation was delivered from the northerly sources, Ohio River flooding increased. During warm conditions, when clockwise mean-state atmospheric circulation advected southerly moisture from the Gulf of Mexico into the Midwest, flooding on the Ohio River decreased. At present, streamflow in the Midwest is demonstrated here to be generally increasing, despite atmospheric conditions typically associated with reduced streamflow in the paleo-record, due in part to increasing precipitation and modern land-use dynamics. Together, these studies demonstrate the sensitivity and vulnerability of local-scale hydrological processes to synoptic climate change.
  • Thumbnail Image
    Item
    Safety at Work: Individual and Organizational Factors in Workplace Accidents and Mistreatment
    (Emerald Publishing, 2015-01-01) Andel, Stephanie A.; Hutchinson, Derek M.; Spector, Paul E.
    The modern workplace contains many physical and interpersonal hazards to employee physical and psychological health/well-being. This chapter integrates the literatures on occupational safety (i.e., accidents and injuries) and mistreatment (physical violence and psychological abuse). A model is provided linking environmental (climate and leadership), individual differences (demographics and personality), motivation, behavior, and outcomes. It notes that some of the same variables have been linked to both safety and mistreatment, such as safety climate, mistreatment climate, conscientiousness, and emotional stability.
  • Thumbnail Image
    Item
    Spatial transmission and meteorological determinants of tuberculosis incidence in Qinghai Province, China: a spatial clustering panel analysis
    (Springer (Biomed Central Ltd.), 2016-06-02) Rao, Hua-Xiang; Zhang, Xi; Zhao, Lei; Yu, Juan; Ren, Wen; Zhang, Xue-Lei; Ma, Yong-Cheng; Shi, Yan; Ma, Bin-Zhong; Wang, Xiang; Wei, Zhen; Wang, Hua-Fang; Qiu, Li-Xia; Department of Epidemiology, Richard M. Fairbanks School of Public Health
    BACKGROUND: Tuberculosis (TB) is the notifiable infectious disease with the second highest incidence in the Qinghai province, a province with poor primary health care infrastructure. Understanding the spatial distribution of TB and related environmental factors is necessary for developing effective strategies to control and further eliminate TB. METHODS: Our TB incidence data and meteorological data were extracted from the China Information System of Disease Control and Prevention and statistical yearbooks, respectively. We calculated the global and local Moran's I by using spatial autocorrelation analysis to detect the spatial clustering of TB incidence each year. A spatial panel data model was applied to examine the associations of meteorological factors with TB incidence after adjustment of spatial individual effects and spatial autocorrelation. RESULTS: The Local Moran's I method detected 11 counties with a significantly high-high spatial clustering (average annual incidence: 294/100 000) and 17 counties with a significantly low-low spatial clustering (average annual incidence: 68/100 000) of TB annual incidence within the examined five-year period; the global Moran's I values ranged from 0.40 to 0.58 (all P-values < 0.05). The TB incidence was positively associated with the temperature, precipitation, and wind speed (all P-values < 0.05), which were confirmed by the spatial panel data model. Each 10 °C, 2 cm, and 1 m/s increase in temperature, precipitation, and wind speed associated with 9 % and 3 % decrements and a 7 % increment in the TB incidence, respectively. CONCLUSIONS: High TB incidence areas were mainly concentrated in south-western Qinghai, while low TB incidence areas clustered in eastern and north-western Qinghai. Areas with low temperature and precipitation and with strong wind speeds tended to have higher TB incidences.
  • Thumbnail Image
    Item
    Targeting Undergraduates in Library Diversity Initiatives
    (2008-10-03) Hollingsworth, Jaena; Palmer, Kristi L.
    While many libraries actively recruit graduate and post-graduate library science students, IUPUI University Library’s diversity recruitment program focuses on an undergraduate audience who might not have otherwise considered librarianship as a profession. The fellowship’s rewards are threefold: It allows the library to immediately increase diversity among its student staff; the fellows’ projects purposefully create a more welcoming atmosphere within the library; and it introduces a variety