Organic Geochemical Investigations of Urban Sediments by Pyrolysis-Gas Chromatography / Mass Spectroscopy

Pyrolysis-Gas Chromatography / Mass Spectrometry (Py-GC/MS) can be used to study the organic matter in sedimentary environments. An urban sediment is not simply defined by proximity to a city. Because cities have anthropogenic contamination, one important urban sediment characteristic is ongoing recontamination. Another is legacy contamination from industrial activity and a third is the alteration of natural bio-geochemical systems. Two case studies are presented. The surface sediments of the Gateway National Recreation Area were sampled during the summer of 2007. The ratio of two pyrolysis products, Vinylguiacol, from terrestrial plant lignins, and Indole, from proteins, (VGI Index) is moderately well correlated with the sediment C/N ratios. A low VGII (0.33) suggests that the primary input of organic matter along the shores of the National Park’s Jamaica Bay is terrestrial while the inputs are primarily marine in areas where there has been a dramatic loss of salt marshes. In contrast, healthy marshes on the park’s nearby Sandy Hook unit had a VGII of 0.82. The VGII could also be correlated with the Carbon Preference Index (CPI) (r = 0.54) and the Syringol / Vanillyl (S/V) ratio (r = 0.87). Increased values of the CPI often indicate an organic input from terrestrial plants while increasing S/V values are often associated with grasses. A Principle Component Analysis (PCA) grouped the sample points associated with either water pollution control plants or combined sewer overflows into one component. This serves to reinforce the observation that most of the current freshwater inputs to Jamaica Bay have been from sewer discharges. The suitability of Py-GC/MS to study conditions in a sediment core is the focus of the second case study. A 2-meter sediment core was obtained from the Passaic River’s Dundee Lake. The core was taken from a highly disturbed part of the river and clear temporal trends were not discernible. Compounds of the same chemical class showed clear patterns of co-occurrence and correlations were frequently 0.9 or higher among petrogenic compounds. These results suggest related co-deposited compounds tend to remain together despite disturbance. Because the majority of human populations now live near the coastlines a more sustainable sediment management policy needs to replace the current system of “dredge and dump.” One challenge in the future will be to have an adequate supply of sediment to protect the coasts against rising sea levels. Characterizing the organic matter in those sediments is another potentially useful application of py-GC/MS

Phonetic Constraints and L1 Transfer of an English Phonological Rule in Spanish L2 Pronunciation

One particular area of concern for L2 Spanish students whose L1 is English is the pronunciation of Spanish rhotics. This study investigates L2 Spanish rhotic production in beginning learners, specifically addressing the possible effects that the different ways to produce rhotics in English (retroflex and bunched) have on the acquisition of Spanish tap and trill. It also addresses the influence that a phonological rule involving taps in English has on the acquisition of the same phone in Spanish. Results from multiple linear regressions involving forty-eight students enrolled in beginning Spanish foreign language classes show that English rhotic articulation alone is a significant predictor of trill accuracy and is a predictor of tap accuracy when controlling for amount of Spanish exposure. Concerning the effect of an L1 phonological rule on the production of Spanish rhotics, results from a paired samples t-test show that a significantly high percentage of accurately produced taps were found in words that follow the same phonological rule that produces taps in English. These results suggest that a theory of the second language acquisition of phonology should consider both phonological and physiological factors

The Acquisition of Case in Spanish Pronominal Object Clitics in English-Speaking College-Level L2 Learners

The Second language acquisition (SLA) of Spanish pronominal object clitics (POCs) has been a topic of research with regards to clitic placement (Houston, 1997; Lee, 1987; LoCoco, 1987; VanPatten, 1984; and VanPatten & Houston 1998), acquiring specific dialectal norms (Geeslin, García-Amaya, Hasler-Barker, Henriksen, & Killam, 2010), and functional usage with datives (Zyzik, 2006). A thorough investigation of how second language (L2) learners acquire Spanish POCs in university-level Spanish classes in the United States including accusative POCs has not yet been carried out. This dissertation extends our knowledge of how these learners acquire Spanish POCs and how instruction impacts the acquisition process. Zyzik (2006) suggested that L2 learners create a dative POC prototype based on Animacy instead of Case as native speakers do. The first study of this dissertation extends Zyzik’s work by investigating L2 learners’ processing and use of Spanish pronominal object clitics, including the accusative POCs. A total of 121 L2 learners completed sentence-completion and cloze tasks to investigate how Animacy and Case influenced the way they distinguished Spanish POCs. Results from mixed ANOVAs show that lower proficiency L2 learners base POC distinctions on Animacy. However, more advanced learners show indications of shifting toward a Case-based system. A second study was conducted in order to test whether instruction was effective in preempting (Rutherford, 1989) an Animacy-based system. A second group of 115 L2 learners from different proficiency levels were divided into two groups (instructed and control). These participants completed similar tasks to the first study at three different times (pre-test, post-test, delayed post-test). Between the pre-test and post-test, learners in the instructed group received instruction on Spanish POCs. Results from mixed ANOVAs indicate that instruction was not more effective than exposure to Spanish POCs through the tasks performed. The finding that both participant groups showed evidence of the preemption of an Animacy-based system is taken as evidence that the tasks themselves effectively led learners to change their POC systems. An explanation of this phenomenon is that the tasks provided a type of computer-mediated processing instruction, forcing learners to process the POCs and notice additional possible contexts, effectuating the change

The Effects of Thermal Stress and Algal Competition on the Early Life-History Stages of Porites astreoides and the Development of Stress-Detecting Biomarkers for Use in Scleractinan Corals

Scleractinian coral populations are declining worldwide in response to numerous stressors operating on both global and regional scales. Rising sea surface temperatures associated with global climate change and the increasing frequency of coral-macroalgae competitive interactions are two of the gravest ecological drivers facing coral reef ecosystems. However, little is known about how these stressors interact to impact corals, their health, and potential modes of population recovery. These threats also highlight the need to develop reliable techniques that detect stress in multiple life-history stages of hermatypic corals prior to the degradation of coral reef habitats. To address these concerns we evaluated the effects of elevated sea surface temperatures (+3.5°C), Dictyota menstrualis competition, and their combined impacts on three life-history stages of the reef-building coral Porites astreoides. Elevated temperature induced sub-lethal stress yet had varied responses that were contingent on the life-history stage being examined. Hyperthermal stress did not consistently effect the transcriptional expression of heat shock proteins (Hsp) 16 or 60, but was readily detected utilizing biomarkers of the oxidative stress pathway. The presence of D. menstrualis significantly reduced coral survival and recruitment beyond simple space occupation in every coral life-history stage examined.While macroalgal exposure and elevated temperature had distinct effects on coral survival and physiological condition, the combination of both stressors induced a synergistic impact on biomarkers of oxidative stress in coral larvae. The results highlight the potential of biomarkers of oxidative stress for detecting hyperthermal stress in scleractinian corals. They also support the accepted notion that benthic macroalgae compete with reef-building corals via direct contact for space on coral reefs and that elevated temperatures can reduce the health of the coral holobiont. In addition, the results indicate that larvae from P. astreoides are more susceptible to the impacts of hyperthermal stress compared to established corals and that multiple perturbations can interact to exacerbate coral health

Effects of Mutations on the Molecular Dynamics of Oxygen Escape from the Dimeric Hemoglobin of Scapharca inaequivalvis

Like many hemoglobins, the structure of the dimeric hemoglobin from the clam Scapharca inaequivalvis is a “closed bottle” since there is no direct tunnel from the oxygen binding site on the heme to the solvent. The proximal histidine faces the dimer interface, which consists of the E and F helicies. This is significantly different from tetrameric vertebrate hemoglobins and brings the heme groups near the subunit interface. The subunit interface is also characterized by an immobile, hydrogen-bonded network of water molecules. Although there is data which is consistent with the histidine gate pathway for ligand escape, these aspects of the structure would seem to make that pathway less likely. Locally enhanced sampling molecular dynamics are used here to suggest alternative pathways in the wild-type and six mutant proteins. In most cases the point mutations change the selection of exit routes observed in the simulations. Exit via the histidine gate is rarely seem although oxygen molecules do occasionally cross over the interface from one subunit to the other. The results suggest that changes in flexibility and, in some cases, creation of new cavities can explain the effects of the mutations on ligand exit paths

The Healthy Futures Project

This article discusses the formation of the Healthy Futures Network which is an informal network of schools in the North West who began meeting over a period of several months seeking to address issues relating to the Health and Wellbeing of young people. The health focus was mainly on Obesity and Physical activity. There was however a recognition of the need to address underlying contribution factors relating to health and wellbeing. In 2014, this informal “Network” became the ‘Healthy Futures Network’, a cross-sector partnership between the University of Chester and 8 schools from the North West of England funded by Health Education England (North). The Project was designed to assess how a collaborative network of schools at a regional/sub-regional level could work together to promote health and wellbeing, and to improve emotional health and wellbeing of their pupils. This project was also part of an engagement strategy for raising aspiration and awareness of potential career education opportunities within the NHS

Organic Geochemical Investigation of a Highly Contaminated Urban Waterway: The Gowanus Canal, Brooklyn, New York, USA

The Gowanus Canal is an industrial waterway constructed in the mid-19th century by widening and deepening a natural tidal channel. It is ca. 3 km in length and empties into Gowanus Bay, an arm of New York Harbor. Its banks, reinforced by bulkheads and piers, became the site of intensive industrial activity, including oil refining, coal gasification, soap making and tanning. Even though much of the industrial activity along the canal has ceased, its sediments remain highly enriched in organic and inorganic contaminants, with combined sewer outfalls continuing to transport pollutants into the canal. The canal area remains densely populated and community pressure is providing impetus for remediation and redevelopment (U.S. Army Corps of Engineers, 2004). As part of a program of continuing sediment quality monitoring, a series of 10 grab samples were collected along the length of the canal. Standard environmental chemical analyses were performed (volatile and semi-volatile organics, PCBs, metals). Dried sediment samples were also analyzed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermodesorption-gas chromatography/mass spectrometry (TD-GC/MS). Py-GC/MS results from two samples are presented. Sample 15A was collected near the mid-point of the canal and is the most highly enriched in parent PAHs, up to several hundred mg/kg. Sample 29A was collected near the head of the canal, i.e., the point farthest inland, with parent PAH concentrations of 5-70 mg/kg. The pyrolyzates contain phenols, pyrroles, indoles and guaiacols as both terrestrial and aquatic biomass signatures, but these are overshadowed by the 3 to 5 ring PAHs, parent and methylated, for sample 15A and by sterenes and fatty acids for sample 29A. For sample 15A, the phenanthrene series (up to the C3-alkylphenanthrenes), the pyrene series (up to C2-alkylpyrenes and isomers), and the chrysene series (including methylchrysenes and isomers) are strongly predominant, along with benzofluoranthenes and benzopyrenes. The dibenzothiophene and benzonaphthothiophene series attest to a significant organosulfur component within the mixture. The pyrolyzate of sample 29A contains the same aromatic compounds, but at much lower concentrations. Rather, there is the striking predominance of C27 and C29 sterenes, along with C16 and C18 fatty acids. Steradienes, C28 sterenes, alkylnitriles and alkylamides are also detected, but at lower concentrations. The sterenes and fatty acids are minor components in sample 15A as well. The PAH distributions are characteristic of creosote, a coal-tar derivative and by-product of coal gasification. If these had been due to petroleum or petroleum product contamination, more abundant petroleum biomarker compounds would be expected. These were detected by TD-GC/MS using selected ion monitoring, but in trace quantities only. The sterenes and fatty acids likely derive from raw and/or partially treated sewage. In spite of the recent reopening of the flushing tunnel at the head of the canal after decades of disuse, it is evident that acute sediment pollution persists in the Gowanus sediments