Biology
Permanent URI for this communityhttp://hdl.handle.net/1903/11810
Browse
3 results
Search Results
Item EXPLORING THE TEMPERATURE AND HYDROLOGIC RESPONSE OF TROPICAL OCEANS TO VOLCANIC ERUPTIONS OVER THE LAST 400 YEARS USING CORAL GEOCHEMISTRY(2020) Perez Delgado, Zoraida Paola; Kilbourne, Kelly H.; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Volcanic eruptions perturb the Earth’s climate system. Open questions remain about the response of the hydrologic cycle and internal variability. Coral skeletal strontium to calcium ratios (Sr/Ca) and oxygen isotopic ratios (δ18O) record temperature and seawater oxygen isotopic signatures in the oceans, thus climatic perturbations from eruptions maybe recorded in the coral skeletal chemistry. I quantify the temperature and hydrologic response of the tropical climate system to eruptions since 1640 CE based on coral geochemical records. Data from all basins except the central and eastern Pacific show cooling and increases in seawater δ18O within the first three years of an eruption. Statistical significance of identified signals was tested by comparing against non-eruption sections from the records. Analyses with paired Sr/Ca and δ18O illustrate that the number of observations still limits detection of small signals provided by the eruptions.Item The Impact of Cool Roofs in Different Climatic Regions: A Quantitative Empirical Analysis(2014) Petry, Kimberly Johanna; McIntosh, Marla S; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This research investigated regional climate differences and weather impacts on the effectiveness of cool roofs. In most US climate zones, cool roofs can reduce energy consumption because they reflect more sunlight and heat than standard roofs. Since temperatures are expected to increase in many regions, cool roofs may offer greater energy and cost savings than currently estimated. Energy consumption by Department of Energy (DOE) Research Laboratory buildings across the US with cool and standard roofs were assessed using metered energy datasets collected from 2003-2013. Statistical tests were conducted to compare differences in energy consumption of buildings between cool and standard roofs at sites in different climatic regions. In order to better understand the effectiveness of cool roof technologies in a future that is expected to become increasingly warmer, data collected from weather stations near each DOE site were used to interpret the potential influences of weather patterns on cool roof energy savings. This research confirmed that cool roofs do reduce energy consumption, especially at sites with warmer summers and milder winters. Regression analyses of energy consumption and temperature data were conducted to identify associations between air temperatures and heating and cooling degree-days with seasonal energy consumption. While the energy consumption of buildings with cool roofs was generally less than buildings with standard roofs, the differences in energy consumption varied depending on building use and building size.Item Climate forcing of phytoplankton dynamics in Chesapeake Bay(2006-05-23) Miller, William David; Harding, Jr., Lawrence W; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Climate has long been recognized as an important driver of phytoplankton dynamics. In Chesapeake Bay, climate variability is manifest as differences in timing and magnitude of freshwater flow. Interannual differences of freshwater flow influence phytoplankton through effects on light and nutrient distributions. Understanding how climate forces temporal and spatial patterns of phytoplankton biomass (Chla) and primary productivity (PP) is an important area of research as we attempt to predict effects of climate change and nutrient enrichment on estuarine ecosystems. This Dissertation describes climate forcing of Chla and PP using a synoptic climatology to quantify climate variability and ocean color remote sensing to assess phytoplankton variability. I developed a synoptic climatology using surface sea-level pressure data for the eastern United States to characterize regional climate because large-scale climate indices are not strongly expressed in this region. The long time series (1989-2004) of remotely sensed ocean color measurements provided high spatial and temporal resolution that allowed me to resolve interannual differences of Chla and PP. I show that the frequency-of-occurrence of synoptic-scale weather patterns during winter explained 54% of the variance in spring freshwater flow to Chesapeake Bay through interannual differences in precipitation and water storage in the basin as snow and ice. Winter weather patterns were also linked to interannual variability of several characteristics of the spring phytoplankton bloom (timing, position, magnitude) through their effects on precipitation and freshwater flow. Multiple linear regression models of winter weather pattern frequencies on regional Chla explained between 23-89% of the variance of the time series. Climate variability in winter-spring also influenced summer and annual integral production through nutrient loading associated with the spring freshet, explaining between 43-62% of the variance of integral production. Finally, I quantified the effects of Hurricane Isabel on Chesapeake Bay phytoplankton dynamics and showed that event-scale climate perturbations can have significant impacts on ecosystem dynamics as well as seasonal and regional carbon cycling. Together these analyses highlight the importance of climate forcing of Chla and PP in Chesapeake Bay and support predictive models that explain significant amounts of the variance of these important ecosystem properties.