Ocean and coastal acidification off New England and Nova Scotia

Author Posting. © The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 2 (2015): 182-197, doi:10.5670/oceanog.2015.41.New England coastal and adjacent Nova Scotia shelf waters have a reduced buffering capacity because of significant freshwater input, making the region’s waters potentially more vulnerable to coastal acidification. Nutrient loading and heavy precipitation events further acidify the region’s poorly buffered coastal waters. Despite the apparent vulnerability of these waters, and fisheries’ and mariculture’s significant dependence on calcifying species, the community lacks the ability to confidently predict how the region’s ecosystems will respond to continued ocean and coastal acidification. Here, we discuss ocean and coastal acidification processes specific to New England coastal and Nova Scotia shelf waters and review current understanding of the biological consequences most relevant to the region. We also identify key research and monitoring needs to be addressed and highlight existing capacities that should be leveraged to advance a regional understanding of ocean and coastal acidification.This project was supported in part by an appointment to the Internship/Research Participation Program at the Office of Water, US Environmental Protection Agency (EPA), administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the US Department of Energy and the EPA. JS acknowledges support from NASA grant from NNX14AL84G NASA-CCS

Extraction and Analysis of Xylitol in Sugar-Free Gum Samples by GC-MS with Direct Aqueous Injection

Xylitol, a sugar substitute frequently used in sugar-free gum, is generally considered harmless to humans but it can be extremely toxic to dogs. Dog-owning customers are becoming increasingly aware of the risks associated with xylitol-containing chewing gums. However, there remains some uncertainty if these chewing gums are still dangerous to dogs after they have been partially consumed. In this work, a reliable low-cost analytical method has been developed to quantify the xylitol in sugar-free gum samples. Xylitol was extracted from gum samples using water as a solvent. Extractions were analyzed by GC-MS with direct aqueous injection (DAI). This method was successfully applied to over 120 samples including fresh gum and 5 min, 15 min, and 30 min chewed gum samples

Sorption of Phosphate on Douglas Fir Biochar Treated with Magnesium Chloride and Potassium Hydroxide for Soil Amendments

With increasing climate variability, a sustainable crop production approach remains an indispensable concern across the globe. In this study, P retention/availability of MgCl2.6H2O/KOH modified Douglas fir biochar was assessed. The MgCl2·6H2O/KOH treated Douglas fir biochar was prepared by sequentially treating Douglas fir biochar with magnesium chloride and potassium hydroxide solutions. The biochar’s surface area, pore volume, morphology, and elemental compositions were determined using BET, SEM, SEM/EDS, and powder X-ray analyzes. Both surface area and pore volume were reduced by more than 97% following modification. Similarly, the morphology and elemental compositions changed after modification. The maximum P adsorbed corresponding to Langmuir–Freundlich model was 41.18 mg g−1. P sorption on biochar soil mixture was pH dependent. More studies are required to establish the field applicability of P-laden MgCl2 ·6H2O/KOH-modified Douglas fir biochar as a soil additive

A Regioselective Synthesis of 6‑Alkyl- and 6‑Aryluracils by Cs₂CO₃- or K₃PO₄‑Promoted Dimerization of 3‑Alkyl- and 3‑Aryl-2-Propynamides

A regioselective synthesis of 6-alkyl- and 6-aryluracils was developed by the dimerization of 3-alkyl- and 3-aryl-2-propynamides promoted by either Cs₂CO₃ or K₃PO₄. A range of 3-aryl-2-propynamides, with both electron-deficient and electron-rich 3-aryl substituents, were successfully reacted in high yields. Cs⁺ acts as a soft Lewis acid to polarize the carbon–carbon triple bond, and solid K₃PO₄ interacts with carbonyl oxygen, promoting intermolecular nucleophilic attack by the only weakly nucleophilic amide nitrogen. Experiments were conducted to support the proposed mechanism

Effects of Growth Parameters on the Analysis of Aspergillus flavus Volatile Metabolites

Aspergillus flavus produces dangerous secondary metabolites known as aflatoxins, which are toxic and carcinogenic, and their contamination of agricultural products results in health issues and economic hardships in the U.S. and around the world. Early identification of aflatoxigenic isolates of A. flavus is the key in the management of these fungi. An emerging detection method for specific fungi identification involves the analysis of microbial volatile organic compounds (MVOCs) released by the fungi. Complicating this approach is the understanding that many factors influence metabolic production, including growth parameters, such as growth media, temperature, spore counts and oxidation stress. In addition, analytical and data analysis methods can also influence the results. Several growth and analysis methods were evaluated and optimized in order to better understand the effect of the methods on fungi MVOC signatures. The results indicate that carboxen/polydimethylsiloxane (CAR/PDMS) has the best extraction efficiency for the MVOCs emitted by A. flavus. Both chemical defined agar (CDA) and chemical defined liquid (CDL) are suitable growth media for MVOC emission studies. The highest MVOC production was found at 30 °C. Log transformation was considered one of the best data pretreatment methods when analyzing MVOC data and resulted in the best principal component analysis (PCA) clustering in the experiments with different growth media. This study aims to elucidate fungal volatile organic compounds (VOCs) differences due to variations in growth parameters as a first step in the development of an analytical method for the monitoring of aflatoxigenic A. flavus contamination in crop storage facilities

Phosphorus-enriched biochar for the remediation of heavy metal contaminated soil

Phosphorus-rich materials (PRMs) are widely used soil remediation agents because they are biocompatible, abundant, non-toxic, and have a high affinity for heavy metals in soil. However, PRMs tend to aggregate at the nanoscale and are susceptible to phosphorus leaching, which limit their application in soil remediation. Dispersing PRMs on porous biochar (BC) is a promising solution to the aggregation and phosphorus leaching issues. The resulting phosphorus-enriched BC (PBC) has excellent adsorption capabilities for heavy metals. This review focuses on recent advances in PBC synthesis and their application in soil remediation. A thorough evaluation of the biomass and phosphorus precursors used for PBC synthesis and a summarization of the common approaches in the synthesis of PBC are carried out in this review. Advantages of PBC for soil remediation are surveyed and reviewed in brief. Thereafter, heavy metal immobilization mechanisms (e.g., precipitation, ion exchange, sorption, etc.) of PBC in soil is highlighted. Finally, the preparation of engineered PBC (ePBC) composites by incorporating auxiliary components (e.g., iron, microorganisms, layered double hydroxides, etc.) with PBC is discussed along with the advantages of ePBC over PBC in soil. This review aims to convene disseminated knowledge and provide a detailed array of information required to gain a thorough understanding of PBC

Sustainable phosphate removal using Mg/Ca-biochar hybrids: Current trends and future outlooks

The Ca/Mg-biochar hybrids have outstanding phosphate adsorption abilities over most modified adsorbents when applied in stoichiometric amounts; recent MgO-functionalized lignin-based bio-charcoal reported the highest phosphate uptake (906.8 mg/g). Apart from large phosphate uptake, Ca/Mg-rich biochars offer a variety of advantages like non-renewable phosphate recovery, soil amendment, resource utilization, waste management and conversion, etc. However, complex preparation methods, expensive metallic reagents, and/or the need for energy-intensive equipment limit the economic interest for these composites. Therefore, in this review, the latest Mg/Ca-biochar synthesis methods are evaluated, emphasizing the value of utilizing green/ waste materials and reagent-free fabrication methods leading to sustainable development. Among the loaded elements, Ca and Mg are employed to provide a prospect of high phosphate uptake as well as increased phosphate recovery. The spent Ca/Mg-biochar hybrids with large phosphate loadings can be implemented as safe slow-release phosphate fertilizers or can be recycled using practical methods; a recent study found that basification followed by tap water addition recovered over 82% phosphate, after reusing the absorbent for 4 cycles, without affecting its stability. At the end of the review, the real-time applications, and limitations of these biochars, important knowledge gaps in the literature, and future directions are summarized, aiming to promote the sustainable utilization of Ca/Mg-modified biochar in various environmental applications

Remediation of Aqueous Phosphate Agricultural Runoff Using Slag and Al/Mg Modified Biochar

Slag and Al/Mg oxide modified Douglas fir biochar (AMOB) were compared for their phosphate adsorbing abilities for use individually or in combination for simulated agriculture run-off remediation in wetlands. Aqueous batch and column sorption experiments were performed for both low-cost materials. AMOB was prepared in bulk using a novel green method. Material analyses included XRD, elemental analysis, SEM, EDX, and BET. Biochar and slag have different phosphate removal mechanisms. In short residence times (≤2 h), adsorption phenomena dominate for both adsorbents. Surface area likely plays a role in adsorption performance; slag was measured to be 4.1 m2/g while biochar’s surface area was 364.1 m2/g. In longer residence times (>2 h), the slow leaching of metals (Ca, Al, and Mg) from slag continue to remove phosphate through the precipitation of metal phosphates. In 24 h, slag removed more free phosphate from the solution than AMOB. Preliminary fixed bed column adsorption of slag or AMOB alone and in tandem was performed adopting a scaled-up model that can be used to remediate agricultural runoff with high phosphate content. Additionally, a desorption study was performed to analyze the efficiency of material regeneration. While AMOB does not release any adsorbed phosphates, slag slowly releases 5.7% adsorbed phosphate over seven days

Electronic Spectorscoply of CF3OCF_{3}O in a Supersonic Jet

Author Institution: Laser Spectroscoy Facility, Department of Chemistry, The Ohio State University; Department of Chemistry, University of Michigan, ; Department of Chemistry, H. L. Hunter Chemistry Laboratory , Clemson UniversityThe jet-cooled LIF spectrum of the $CF_{3}O \widetilde{A} \leftarrow \bar{X}$ electronic transition has been observed. Rotational analysis of the high resolution spectrum of the origin band suggests that $CF_{3}O$ has nominal $C_{3v}$ symmetry in both its ground and first excited state. Vibrational analysis of the dispersed fluorescence spectrum indicates that the Jahn-Teller effect is considerably stronger in $CF_{3}O$ compared to $CH_{3}O$. The details of analysis will be presented