Search

Grasslands (natural, semi-natural and improved) occupy approximately one-third of the terrestrial biosphere and are key for global ecosystem service provision, storing up to 30% of soil organic carbon (SOC). To date, most research on soil carbon (C) sequestration has focused on croplands where the levels of native soil organic matter (SOM) are typically low and significant potential exists to replenish SOM stocks. However, with the renewed push to achieve "net zero" C emissions by 2050, grasslands may offer an additional C store, utilising tools such as biochar. Here, we critically evaluate the potential for biochar as a technology for increasing grassland C stocks, identifying a number of practical, economic, social and legislative challenges that need to be addressed before the widescale adoption of biochar may be achieved. We critically assess the current knowledge within the field of grassland biochar research in the context of ecosystem service provision and provide opinions on the applicability of biochar as an amendment to different types of grassland (improved, semi-improved and unimproved) and the potential effect on ecosystem provision using a range of application techniques in the topsoil and subsoil. We concluded that the key question remains, is it possible for managed grasslands to store more C, without causing a loss in additional ecosystem services? To address this question future research must take a more multidisciplinary and holistic approach when evaluating the potential role of biochar at sequestering C in grasslands to mitigate climate change. Highlights: Carbon (C) rich grassland soils may offer an additional C store, utilising tools such as biochar Identification of practical, economic, social and legislative challenges for scaled adoption of biochar in grasslands Key question: will enhanced C storage in grasslands soils cause a loss in additional ecosystem services? [ABSTRACT FROM AUTHOR]

Fly-ash derived zeolites have recently -received great attention as cheaper adsorbents to remove heavy metals from water since they can be synthesized from a waste product. In this study, we evaluated the single- and multi-cation adsorption efficiencies of fly-ash derived NaP1 for the removal of zinc (Zn), copper (Cu) and lead (Pb). We also determined precipitation and leaching from NaP1 during the adsorption. Results showed that the uptake capacities for Zn (34 mg/g) and Pb (192 mg/g) were higher than other fly-ash derived NaP1 and adsorbents such as clinoptilolite and activated carbon. The Cu uptake was estimated ~ 14.6 mg/g. Pb2+ > Cu2+ > Zn2+ is the order for the metal cation selectivity of NaP1. Langmuir adsorption isotherm and pseudo-second order kinetic model fitted best for all elements. The metal uptake occurred in 15 min. Diffusion of hydrated metals through microporous channels is the rate-determining step.Article Highlights: Fly-ash derived NaP1 adsorbed 34.2 mg g−1 Zn2+, 14.6 mg g−1Cu2+ and 192 mg g−1 Pb2+. Ion selectivity of NaP1 is in the order of Pb2+ > Cu2+ > Zn2+. Langmuir and pseudo-second order kinetic models fitted best for all elements. The metal uptake occurred in 15 min for both single and multi-element adsorption. Leaching and precipitation were evaluated. [ABSTRACT FROM AUTHOR]

The Neoproterozoic era (1,000–542 Myr ago) was an era of climatic extremes and biological evolutionary developments culminating in the emergence of animals (Metazoa) and new ecosystems. Here we show that abundant sedimentary 24-isopropylcholestanes, the hydrocarbon remains of C30 sterols produced by marine demosponges, record the presence of Metazoa in the geological record before the end of the Marinoan glaciation (∼635 Myr ago). These sterane biomarkers are abundant in all formations of the Huqf Supergroup, South Oman Salt Basin, and, based on a new high-precision geochronology, constitute a continuous 100-Myr-long chemical fossil record of demosponges through the terminal Neoproterozoic and into the Early Cambrian epoch. The demosponge steranes occur in strata that underlie the Marinoan cap carbonate (>635 Myr ago). They currently represent the oldest evidence for animals in the fossil record, and are evidence for animals pre-dating the termination of the Marinoan glaciation. This suggests that shallow shelf waters in some late Cryogenian ocean basins (>635 Myr ago) contained dissolved oxygen in concentrations sufficient to support basal metazoan life at least 100 Myr before the rapid diversification of bilaterians during the Cambrian explosion. Biomarker analysis has yet to reveal any convincing evidence for ancient sponges pre-dating the first globally extensive Neoproterozoic glacial episode (the Sturtian, ∼713 Myr ago in Oman). [ABSTRACT FROM AUTHOR]

An introduction to conjugated steroids and the justification for their analysis is provided covering both environmental and biological samples. Determining conjugated steroids or indeed any organic chemical which is conjugated upon excretion from the body has relevance in diagnostic monitoring, forensic screening and environmental analysis (from the endocrine disrupter perspective). The various analytical approaches and the accompanying issues are application-dependent. There are numerous options at each stage of analysis, from extraction, hydrolysis, derivatisation, and detection, and advances can be confined to the specific application for which it was developed. Emphasis is placed on the choice of separation and how gas or liquid chromatography necessitates different preparative stages to enable conjugated steroid determination. Possible future directions and research for conjugated steroid analysis are discussed. [ABSTRACT FROM AUTHOR]

The article focuses on the application of coals as sorbents for the removal of chromium (Cr) from aqueous waste streams. Coals and biomass can remove ions from aqueous solutions and due to their relatively low cost in relation to traditional sorbents they can be considered for environmental protection purposes. Peats, lignites and high volatility bituminous coals have high removal and reduction capacities for Cr(IV) and therefore they have the potential to be used as barrier materials for removing Cr(VI) from aquatic streams. Redox mechanisms play an important role with the sorption of the resultant Cr(III) being aided by the functionalities arising from oxidation of the coal.