PALEOPRODUCTIVITY VARIATIONS IN THE EASTERN CENTRAL EQUATORIAL PACIFIC OCEAN ON GLACIAL TIMESCALES

Indiana University-Purdue University Indianapolis (IUPUI)Paleoproductivity records during the late Pleistocene are sparse. The equatorial Pacific and the Southern Ocean are collectively responsible for the majority of the new production in the oceans. The nutrient and carbon mass balances of these regions must be constrained in order to fully understand net global biological productivity on glacial timescales. The geochemistry of two east-central equatorial Pacific Ocean cores (02° 33.48 N; 117° 55.06 W) and (00° 15.42 S; 113° 00.57 W) are used to examine changes in biological productivity due to nutrient upwelling on glacial timescales during the Pleistocene. The cores were recovered in March 2006 on the AMAT03 cruise, a site survey cruise for IODP Proposal 626. The total concentrations of Ca, Ti, Fe, Al, P, Ba, S, Mg, Sr, Zn and Mn were determined by a total sediment digestion followed by analysis by inductively coupled plasma-atomic emission spectrometry (ICP). Original solid forms of P for 34 evenly spaced samples throughout one core were determined using the P Sequential Extraction technique. This study is attempting to compare upwelling and productivity records by determining temporal records of nutrient proxies, using Latimer and Filippelli (2006) which focused on the Southern Ocean. Equatorial upwelling and Southern Ocean upwelling both appear to exhibit strong glacial timescale variability. The P geochemistry results indicate that the P signal is largely biological. The equatorial Pacific evidence, in accordance with Southern Ocean patterns, supports a nutrient budget-driven productivity signal over time. Gabriel M. Filippelli, Ph. D, Committee Chai

Water Privatization in the Philippines: The Need to Implement the Human Right to Water

Water is widely recognized as an essential element to sustain life, yet attaining universal access to clean drinking water remains a perplexing issue throughout the lesser-developed world. In 1997, with backing from private investment and the World Bank, the Philippine government privatized the municipal water utility of Manila in an effort to improve service and promote efficiency. Nearly ten years later, privatization has failed to produce results and instead has engendered a contentious and polemical debate about the merits of privatization. Indeed, for policy makers, the case study of Manila has become a focal point in the debate about whether private companies or governments should operate municipal water utilities. This Comment argues that current models for water services, whether private or public, will continually fail to address the economic, social, and political needs of lesser-developed nations unless they recognize the human right to water. Although it has not attained the status of binding international law, the human right to water offers an alternative model for understanding the terms of the privatization debate. In the context of privatization, states must protect the human right to water through strong regulatory measures that guarantee access to water and prevent private companies from infringing on this right. Privatization in the Philippines currently does not protect the human right to water, and in future plans, the Philippine government should take steps to acknowledge and protect this right through strong regulatory controls and a universal access plan. This issue is timely for the Asian Pacific region, with its large number of failing privatized water systems. Water as a human right will be a useful model for the entire region

Fire ant response to management of native grass field buffers

Imported fire ants are invasive and cause injury to people, crops, livestock and wildlife. Disturbance may increase abundance and activity of fire ants. However, native grass field buffers established for grassland birds require periodic disturbance. I experimentally tested if fire ant mound density and foraging activity changed after burning and disking in native grass buffers and examined relationships among fire ants, vegetation, and grassland bird and butterfly metrics in undisturbed buffers. In 2008, disking increased mound density and foraging activity, but burning did not. In 2009, disking had no effect, but effects of disking the previous season persisted. Fire ant metrics were not related generally to bird or butterfly metrics. Mound density and foraging activity were related negatively to grass cover and related positively to forbs. Burning had less influence on abundance and activity of fire ants, and may better conserve grassland habitats in areas with fire ants

Assessing the Persistence and Mobility of Organic Substances to Protect Freshwater Resources

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The effects of soil organic matter on leaching of hexavalent chromium from concrete waste: Batch and column experiments

Concrete is one of the most common building materials in the world and in accordance with the world’s shift to a circular economy, there is a need of an increase in concrete reuse and recycling. One of the environmental concerns linked to concrete recycling is the leaching and spread of hexavalent chromium (Cr(VI)). In the present study the Cr(VI) leaching from crushed concrete waste and the effects of soil organic matter (SOM) on chromium (Cr) speciation has been investigated in realistic reuse scenarios by the means of batch shale tests and layered column tests. The effects of concrete properties (pH, grain size and age) on Cr(VI) leaching was also studied. Cr leaching from concrete alone is mainly in the form of Cr(VI), with the pH of the leachate being >10. The smaller the grainsize of the concrete, the higher the Cr(VI) concentration is in the leachate. There was no correlation between the age of the concrete and concrete leaching. When exposed to SOM the Total-Cr concentration in the leachate was reduced. The reduction increased with higher TOC level, with a 99% reduction at very high TOC (25%). The results indicate that Cr(VI) leaching from recycled concrete waste can be mitigated by exposing it to SOM in the desired recycling scenario.publishedVersio

Effects of Erythropoietin and Glycogen Synthase Kinase 3 on Hypoxia Inducable Factor-1α

Cancerous tumors adjust their signaling pathways to facilitate survival in a hypoxic environment. The pro-angiogenic transcription factor hypoxia inducible factor -1α (HIF-1α) is stabilized in hypoxia and promotes tumor cell survival, proliferation, and metastasis by inducing transcription of many targets including vascular endothelial growth factor (VEGF). High expression levels of HIF-1α have been correlated with aggressive tumor types. As such, HIF-1α is an attractive candidate for targeted therapies in ovarian cancer. Though there have been attempts at developing chemotherapies that inhibit HIF-1α, to this date there remains no approved anti-angiogenic drug that directly targets HIF-1α. Because the cytokine EPO (erythropoietin) is transcriptionally regulated by HIF-1α, we hypothesized that negative feedback inhibition from EPO to HIF-1α would decrease HIF-1α protein levels. In fact, exogenous EPO significantly inhibited hypoxia-induced HIF-1α expression in cultured human ovarian cancer cells in a dose-dependent fashion and significantly reduced hypoxia-induced VEGF transcription to near basal levels. Furthermore, although EPO is a growth factor, there was no difference in cell growth with EPO treatment in either the normoxic or hypoxic condition at any time point tested. The negative feedback of EPO on HIF-1α was not limited to ovarian cancer cells as EPO efficiently inhibited hypoxia-induced HIF-1α stabilization in MCF-7 breast cancer cells. Initially, we hypothesized that EPO inhibition of HIF-1α was through activation of GSK3 (glycogen synthase kinase). Though EPO likely does not signal through activation of GSK3, initial experiments investigating this pathway generated promising results and prompted the continued exploration into the regulation of HIF-1α by GSK3. Therefore, the second goal of this dissertation was to investigate the role of GSK3 phosphorylation on HIF-1α protein levels and proteosomal degradation. Recently, GSK3 has been implicated in the degradation of HIF-1α, the role of GSK3 in the regulation of HIF-1α in hypoxia has yet to be studied. We hypothesized that phosphorylation by GSK3 would target HIF-1α for proteosomal degradation in an oxygen-independent manner. In support of this hypothesis, we show that GSK3 inhibition in hypoxia lead to an increase in stabilization of HIF-1α that was echoed by an increase in VEGF transcription, suggesting an augmentation of HIF-1α transcriptional activity. Overexpression of GSK3 significantly decreased both HIF protein and VEGF transcription. Further, these studies identified five putative GSK3 sites within the HIF-1α protein that were necessary for phosphorylation by GSK3. Mutation of these sites also induced HIF-1α stabilization in normoxia and hypoxia beyond that of wild-type HIF-1α. From these results, we propose a model whereby GSK3 phosphorylates and subsequently destabilizes HIF-1α thus halting HIF-1α−dependent VEGF transcription. The work presented in this dissertation illustrates two ways in which the HIF-1α pathway can be modulated. Further exploration and exploitation of these pathways could prove to be therapeutically advantageous in the treatment of cancer

Instream vegetation survey of Marsh Creek

Agriculture can have a vast impact on stream ecosystems through increasing erosion and nutrient inputs. Vegetation influences an array of ecosystem characteristics in streams, including concentrations of dissolved oxygen and nutrients. Physical characteristics can be influenced as well, including flow velocity, turbidity, light penetration, and turbulence. Using the Braun-Blanquet cover scale we measured instream vegetation cover at six sites along Marsh Creek, a stream in southeastern Idaho that has seen strong anthropomorphic influences through the development of agriculture, both croplands and pastures. We found that in stream vegetation cover was high overall, but varied across sites. Mean vegetation cover across all sites was 25-50%. The highest cover observed was 75-100% and the lowest was 5-25%. From this data we can see variations from site to site as you move downstream but no discernible patterns are evident. Surveys will be continued through the summer to assess temporal trends across sites, and vegetation cover will be compared with dissolved oxygen and turbidity data to assess relationships between vegetation and water quality. This study will yield important information about stream ecosystem responses to agriculture and the role of instream vegetation

Monitoring alkylphenols in water using the polar organic chemical integrative sampler (POCIS): determining sampling rates via the extraction of PES membranes and Oasis beads

Polar organic chemical integrative samplers (POCIS) have previously been used to monitor alkylphenol (AP) contamination in water and produced water. However, only the sorbent receiving phase of the POCIS (Oasis beads) is traditionally analyzed, thus limiting the use of POCIS for monitoring a range of APs with varying hydrophobicity. Here a “pharmaceutical” POCIS was calibrated in the laboratory using a static renewal setup for APs (from 2-ethylphenol to 4-n-nonylphenol) with varying hydrophobicity (log Kow between 2.47 and 5.76). The POCIS sampler was calibrated over its 28 day integrative regime and sampling rates (Rs) were determined. Uptake was shown to be a function of AP hydrophobicity where compounds with log Kow < 4 were preferentially accumulated in Oasis beads, and compounds with log Kow > 5 were preferentially accumulated in the PES membranes. A lag phase (over a 24 h period) before uptake in to the PES membranes occurred was evident. This work demonstrates that the analysis of both POCIS phases is vital in order to correctly determine environmentally relevant concentrations owing to the fact that for APs with log Kow ≤ 4 uptake, to the PES membranes and the Oasis beads, involves different processes compared to APs with log Kow ≥ 4. The extraction of both the POCIS matrices is thus recommended in order to assess the concentration of hydrophobic APs (log Kow ≥ 4), as well as hydrophilic APs, most effectively. © 2017 Elsevier Lt