Characterization of kerogens and study of their evolution by infrared spectroscopy: carbonyl and carboxyl groups

Measurements of the absorption coefficient of the band around 1710cm^?1, combined with adequate chemical treatments, allow an evaluation of the importance of carbonyl, carboxylic acid and ester groups in various series of kerogens. The concentration of carbonyl and acid groups, the concentration of oxygenated functions other than carbonyl or carboxyl, and the total oxygen content are higher in shallow kerogens originating from higher plants than in those containing an important algal contribution; however the concentration of ester groups varies in the opposite direction.The carboxylic acid groups are the most sensitive to catagenetic evolution or pyrolysis. The carbonyl groups are removed progressively as evolution proceeds but a fraction of them is retained up to advanced degrees of evolution.Study of the band at 1630cm^?1 has shown that, besides the bending vibration of molecular water, there is some contribution of bridged quinones and unsaturated hydrocarbons. However at least 50% of the absorption coefficient is due to polyaromatic structures. This band is generally much more intense for kerogens originating from higher plants.     

A Systematic Review of the Socioeconomic Factors that Influence How Marine Protected Areas Impact on Ecosystems and Livelihoods

Marine protected areas (MPAs) are among the most widely accepted methods of marine management. MPAs are not, however, always placed such that they can maximize impact on conservation and livelihoods. Current MPA guidelines fall short in focusing primarily on biophysical criteria, overlooking interrelated socioeconomic factors. We identified 32 socioeconomic factors that influence whether MPA placement has an impact on biodiversity and/or livelihoods and weighted the quality of evidence using a novel “Evidence for Impact” Score. Results suggest that stakeholder engagement, poverty, population density, and strong leadership have most potential to positively impact biodiversity and/or livelihoods, but the direction of impact (i.e., positive or negative) can be context-dependent. We found a generally poor evidence base for impact evaluation of socioeconomic factors: though some factors were highly cited, few studies actually evaluate impact. Results indicate the need for a more interdisciplinary approach to MPA placement and more empirical studies that assess impact.     

Assessment of mercury contamination and human exposure associated with coastal disposal of waste from a cinnabar mining operation, Palawan, Philippines

 An integrated geochemical and toxicological assessment of environmental mercury contamination and attendant human exposure in Honda Bay, Palawan was undertaken in 1995 following a nationally reported pollution scare centered on a coastal jetty, Sitio Honda Bay, constructed using approximately 1 million tons of tailings and beneficiation waste from a cinnabar mine. Mercury (Hg) data for marine and fluvial sediments, fish tissues and human hair indicate that the toxicological hazard is considerably lower than initially reported by state environment and health officials. Typical Hg concentrations in surficial Honda Bay sediments were found to lie within the global background range (<60 μg/kg). Downcore profiles provide no evidence of enhanced Hg fluxes coincident with the onset of mining and/or coastal tailings disposal. The mean and median Hg concentrations recorded in tissues of six species of Honda Bay fish are compliant with thresholds established by the US Environmental Protection Agency (US-EPA) for marketable stocks. Earlier reports of 'Minamata range' Hg concentrations in fish and shellfish from Honda Bay remain unsubstantiated. Geochemical analyses of samples of the Sitio Honda Bay substrate have confirmed the prevalence of solid-phase Hg concentrations to ca. 340 mg/kg. The speciation of Hg is, however, dominated by secondary oxides of low bioavailability. The mean Hg concentration in hair from Sitio Honda Bay residents (4.41 mg/kg) was found to be statistically analogous to that for a neighbouring coastal community unimpacted by the coastal disposal of mine waste. A negligible residential exposure factor is thus inferred for the former. Relatively high hair Hg burdens prevail throughout the coastal Honda Bay population, consistent with significant methyl Hg ingestion through daily fish consumption. The data presented provide no environmental or toxicological justification for immediate remedial action. Received: 14 May 1998/Accepted: 1 September 1998     

Sediment budget controls on foredune height: Comparing simulation model results with field data

The form, height and volume of coastal foredunes reflects the long‐term interaction of a suite of nearshore and aeolian processes that control the amount of sand delivered to the foredune from the beach versus the amount removed or carried inland. In this paper, the morphological evolution of more than six decades is used to inform the development of a simple computer model that simulates foredune growth. The suggestion by others that increased steepness of the seaward slope will retard sediment supply from the beach to the foredune due to development of a flow stagnation zone in front of the foredune, hence limiting foredune growth, was examined. Our long‐term data demonstrate that sediment can be transferred from the beach to the foredune, even with a steep foredune stoss slope, primarily because much of the sediment transfer takes place under oblique rather than onshore winds. During such conditions, the apparent aspect ratio of the dune to the oncoming flow is less steep and conditions are not as favourable for the formation of a stagnation zone. The model shows that the rate of growth in foredune height varies as a function of sediment input from the beach and erosion due to storm events, as expected, but it also demonstrates that the rate of growth in foredune height per unit volume increase will decrease over time, which gives the perception of an equilibrium height having been reached asymptotically. As the foredune grows in size, an increasing volume of sediment is needed to yield a unit increase in height, therefore the apparent growth rate appears to slow. Copyright © 2018 John Wiley & Sons, Ltd.     

ANALYSIS OF COUNT DATA USING POISSON REGRESSION*

In geographical research the data of interest are often in the form of counts. Standard regression analysis is inappropriate for such data, but if certain assumptions are met, a form of regression based on the Poisson distribution can be used. This paper illustrates the use of Poisson regression in the computer package GLIM with an example from historical geography. Apprentice migration to Edinburgh is regressed on a combination of categorical, count, and continuous explanatory variables.     

Impacts of environmental degradation on rivers,with some examples from the Hawkesbury‐Nepean system

Environmental degradation is a widespread contemporary problem. It will be exacerbated by Greenhouse. The alteration of the land surface by humans is examined in terms of on-site impacts as well as off-site effects in other storages, notably rivers. Examples of bank erosion in the Hawkesbury-Nepean system are related to regime shifts, dams and dredging. Examples of environmental pollution by different forms of sewage disposal are given for Wollondilly Shire. It is suggested that much more relevant information is required to effect total catchment management.