Natural improvements of geochemical conditions of acid sulfate soils caused by free tidal inundation and its effects on the mangrove seedlings

Acid sulfate soils (ASS) are one of the stressor factors that cause many mangrove restoration projects to fail. Achieving successful rehabilitation in an ASS affected area requires an understanding of the geochemical conditions that influence the establishment and growth of mangrove seedlings. This study evaluated the effect of tidal inundation on geochemical conditions on sub layer to better understand their impacts on the density, establishment, and growth of mangrove seedlings. This study also examined the geochemical conditions under which mangrove seedlings can establish naturally, and/or be replanted in abandoned aquaculture ponds. The study area was in an area of abandoned aquaculture ponds situated in the Mare District, adjacent to Bone Bay, South Sulawesi, Indonesia.The pH, pHfox, redox potential, organic content, water soluble sulfate, SKCl, SPOS, and grain size of the soil from the sediment core at + 10 - 15 cm depth near roots were measured using. Pyrite analysis were conducted for the top and sub sediments. The density, establishment, and the relative root growth of Rhizophoraceae were also determined. Free tidal inundation at abandoned pond sites improved the sediment quality. The high density, establishment, and growth of mangrove seedlings were characterized by freely drained areas with a higher pH (field and oxidisable), lower organic content, and high proportion of silt/clay. Higher density and growth also correlated to reduced environments. Sulfur species did not influence the density, establishment, and growth of the seedlings directly. The supply of propagules from the mangrove stands, or access from good waterways were also important for seedlings to establish naturally.

Neutralization of acid sulfate solutions using bauxite refinery residues and its derivatives

This investigation has shown that by transforming free caustic in red mud (RM) to Bayer hydrotalcite (during the seawater neutralization (SWN) process) enables a more controlled release mechanism for the neutralization of acid sulfate soils. The formation of hydrotalcite has been confirmed by X-ray diffraction (XRD) and differential thermalgravimetric analysis (DTG), while the dissolution of hydrotalcite and sodalite has been observed through XRD, DTG, pH plots, and ICP-OES. Coupling of all techniques enabled three neutralization mechanisms to be determined: (1) free alkali, (2) hydrotalcite dissolution, and (3) sodalite dissolution. The mechanisms are determined on the basis of ICP-OES and kinetic information. When the mass of RM or SWN-RM is greater than 0.08 g/50 mL, the pH of solution increases to a suitable value for plant life with aluminum leaching kept at a minimum. To obtain a neutralization pH greater than 6 in 10 min, the following ratio of bauxite residue (g) in 50 mL with a known iron sulfate (Fe2(SO4)3) concentration can be determined as follows: 0.04 g:50 mL:0.1 g/L of Fe2(SO4)3.

The effects of geochemical conditions on the establishment and growth of mangrove seedlings in acid sulfate soil environments

Acid sulfate soils (ASS) is a stress factor that is responsible for the failure of some mangrove restoration projects, including abandoned aquaculture ponds converted from mangrove ecosystems. Through experimental and field studies, this research provides a better understanding of the biogeochemistry of ASS disturbance and the response of mangrove seedlings (Rhizophoraceae) under high metal levels and acidic conditions. This study found that mangrove restorations under ASS disturbance can work but with lower numbers of survived seedlings. To prevent toxicity under high levels of metal, seedlings retained metals in their roots and sparingly distributed them into aerial parts with low mobility. The presence of high levels of potential acidity parameters would allow pyrite to oxidise, thus increasing metal levels and acidity, which in turn affected the survival and growth of the seedlings.

Recovery of fish and crustacean communities during remediation of tidal wetlands affected by leachate from acid sulfate soils in north-eastern Australia.

In the 1970s, acid sulfate soils (ASS) distributed within about 720 ha of predominantly mangrove and salt pan wetlands at East Trinity in north Queensland were developed after the area was isolated from tidal flooding by a surrounding seawall and the installation of tidal gates on major drainage creeks. Following drainage and oxidation of these estuarine acidic sediments, resultant acid leachate caused considerable, ongoing environmental problems including regular fish kills. A rehabilitation program covering much of these former tidal wetlands commenced in 2000 using a lime-assisted tidal exchange management regime. Changes in the established populations of estuarine fish and crustaceans were monitored in the two creeks (Firewood and Hills Creeks) where tidal flows were reinstated. In Firewood Creek between 2001 and 2005, there was a progressive increase in fish species richness, diversity and abundance. The penaeid prawn Fenneropenaeus merguiensis was a major component of the cast net catches in the lower sections of both Firewood and Hills Creeks but its relative abundance decreased upstream of the tidal gates on the seawall. Well established stocks of predominantly juvenile, male Scylla serrata resident upstream of the tidal gates indicated suitable habitats with acceptable water and sediment quality and adequate availability of food. The regular fish kills that occurred prior to the management regime abated and, overall, the implementation of the rehabilitation program is yielding positive benefits for the local fisheries.

On acid sulfate soils of the coastal aquaculture ponds of Bangladesh

With the stimulus of the very high international market value of penaeid shrimp, new pond areas for shrimp farming are rapidly being added in Bangladesh. Unfortunately, this expansion is occurring with the loss of some natural mangrove forests and with soils and sediments that are far from ideal for aquaculture. In this study, two representative shrimp farming areas were surveyed and pH, in profile depth, was recorded. It was found that the shrimp farming areas of the Chakaria Sundarban are more acidic than those of the Khulna-Satkhira region due to the acid sulfate soils.

CHARACTERISTICS OF FATTY ACID METHYL ESTERS (FAMEs) AND ENZYMATIC ACTIVITIES IN SEDIMENTS OF TWO EUTROPHIC LAKES

Enzymatic activities and fatty acid methyl esters (FAMEs) in the sediments of two eutrophic lakes in Wuhan city were investigated. The results showed phosphatase and dehydrogenase activities in the lotus zone and plant floating bed zone were significantly lower than those in other sites, and urease activity was the highest where microorganism agents were put in. Fatty acid group compositions indicated the predominance of aerobic bacteria in the surface sediments in shallow lakes. The ratios of FAMEs specific for bacteria and Gram-positive bacteria exibited significant differences between the two lakes. The results of trans to cis indicated that the microorganisms in Lake Yuehu could adapt themselves to environmental stress better. The enzymatic activities and FAMEs showed differences in different sites, indicating that ecological restoration measures and environmental conditions could affect lake sediment to some extent. But the monitoring, work would be done in series to exactly evaluate the effect of the remediation measures.

Selected Gamma Aminobutyric Acid (GABA) Esters may Provide Analgesia for Some Central Pain Conditions.

Central pain is an enigmatic, intractable condition, related to destruction of thalamic areas, resulting in likely loss of inhibitory synaptic transmission mediated by GABA. It is proposed that treatment of central pain, a localized process, may be treated by GABA supplementation, like Parkinson's disease and depression. At physiologic pH, GABA exists as a zwitterion that is poorly permeable to the blood brain barrier (BBB). Because the pH of the cerebral spinal fluid (CSF) is acidic relative to the plasma, ion trapping may allow a GABA ester prodrug to accumulate and be hydrolyzed within the CSF. Previous investigations with ester local anesthetics may be applicable to some GABA esters since they are weak bases, hydrolyzed by esterases and cross the BBB. Potential non-toxic GABA esters are discussed. Many GABA esters were investigated in the 1980s and it is hoped that this paper may spark renewed interest in their development.

A critical evaluation of Raman spectroscopy for the analysis of lipids: fatty acid methyl esters.

The work presented here is aimed at determining the potential and limitations of Raman spectroscopy for fat analysis by carrying out a systematic investigation of C-4-C-24 FAME. These provide a simple, well-characterized set of compounds in which the effect of making incremental changes can be studied over a wide range of chain lengths and degrees of unsaturation. The effect of temperature on the spectra was investigated over much larger ranges than would normally be encountered in real analytical measurements. It was found that for liquid FAME the best internal standard band was the carbonyl stretching vibration nu(C = O), whose position is affected by changes in sample chain length and physical state; in the samples studied here, it was found to lie between 1729 and 1748 cm(-1). Further, molar unsaturation could be correlated with the ratio of the nu(C = O) to either nu(C = C) or delta(H-C = ) with R-2 > 0.995. Chain length was correlated with the delta(CH2)(tw)/nu(C = O) ratio, (where "tw" indicates twisting) but separate plots for odd- and even-numbered carbon chains were necessary to obtain R-2 > 0.99 for liquid samples. Combining the odd- ani even-numbered carbon chain data in a single plot reduced the correlation to R-2 = 0.94-0.96, depending on the band ratios used. For molal unsaturation the band ratio that correlated linearly with unsaturation (R-2 > 0.99) was nu(C = C)/delta(CH2)(SC) (where "sc" indicates scissoring). Other band ratios show much more complex behavior with changes in chemical and physical structure. This complex behavior results from the fact that the bands do not arise from simple vibrations of small, discrete regions of the molecules but are due to complex motions of large sections of the FAME so that making incremental changes in structure does not necessarily lead to simple incremental changes in spectra.

Conformations, vibrational frequencies and Raman intensities of short-chain fatty acid methyl esters using DFT with 6-31G(d) and Sadlej pVTZ basis sets

Density functional calculations, using B3LPY/6-31G(d) methods, have been used to investigate the conformations and vibrational (Raman) spectra of three short-chain fatty acid methyl esters (FAMEs) with the formula CnH2nO2 (n = 3-5). In all three FAMEs, the lowest energy conformer has a simple 'all-trans' structure but there are other conformers, with different torsions about the backbone, which lie reasonably close in energy to the global minimum. One result of this is that the solid samples we studied do not appear to consist entirely of the lowest energy conformer. Indeed, to account for the 'extra' bands that were observed in the Raman data but were not predicted for the all-trans conformer, it was necessary to add-in contributions from other conformers before a complete set of vibrational assignments could be made. Provided this was done, the agreement between experimental Raman frequencies and 6-31G(d) values (after scaling) was excellent, RSD = 12.6 cm(-1). However, the agreement between predicted and observed intensities was much less satisfactory. To confirm the validity of the approach followed by the 6-3 1 G(d) basis set, we used a larger basis set, Sadlej pVTZ, and found that these calculations gave accurate Raman intensities and simulated spectra (summed from two different conformers) that were in quantitative agreement with experiment. In addition, the unscaled Sadlej pVTZ, and the scaled 6-3 1 G(d) calculations gave the same vibrational mode assignments for all bands in the experimental data. This work provides the foundation for calculations on longer-chain FAMEs (which are closer to those found as triglycerides in edible fats and oils) because it shows that scaled 6-3 1 G(d) calculations give equally accurate frequency predictions, and the same vibrational mode assignments, as the much more CPU-expensive Sadlej pVTZ basis set calculations.

Protocatechuic Acid Alkyl Esters: Hydrophobicity As a Determinant Factor for Inhibition of NADPH Oxidase

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of fatty acid ethyl esters in dried blood spots by LC-MS/MS as markers for ethanol intake: application in a drinking study.

The forensic utility of fatty acid ethyl esters (FAEEs) in dried blood spots (DBS) as short-term confirmatory markers for ethanol intake was examined. An LC-MS/MS method for the determination of FAEEs in DBS was developed and validated to investigate FAEE formation and elimination in a drinking study, whereby eight subjects ingested 0.66-0.84 g/kg alcohol to reach blood alcohol concentrations (BAC) of 0.8 g/kg. Blood was taken every 1.5-2 h, BAC was determined, and dried blood spots were prepared, with 50 μL of blood, for the determination of FAEEs. Lower limits of quantitation (LLOQ) were between 15 and 37 ng/mL for the four major FAEEs. Validation data are presented in detail. In the drinking study, ethyl palmitate and ethyl oleate proved to be the two most suitable markers for FAEE determination. Maximum FAEE concentrations were reached in samples taken 2 or 4 h after the start of drinking. The following mean peak concentrations (c̅ max) were reached: ethyl myristate 14 ± 4 ng/mL, ethyl palmitate 144 ± 35 ng/mL, ethyl oleate 125 ± 55 ng/mL, ethyl stearate 71 ± 21 ng/mL, total FAEEs 344 ± 91 ng/mL. Detectability of FAEEs was found to be on the same time scale as BAC. In liquid blood samples containing ethanol, FAEE concentrations increase post-sampling. This study shows that the use of DBS fixation prevents additional FAEE formation in blood samples containing ethanol. Positive FAEE results obtained by DBS analysis can be used as evidence for the presence of ethanol in the original blood sample. Graphical Abstract Time courses for fatty acid ethyl ester (FAEE) concentrations in DBS and ethanol concentrations for subject 1 over a period of 7 h. Ethanol ingestion occured during the first hour of the time course.

Characterization and Degradation of Fatty Acid Methyl Esters and Biodiesel in Artificial Seawater Under UV Exposure Using Raman Spectroscopy

Thesis (Master's)--University of Washington, 2016-06