ovcre.upvisayas

Zygote culture and zoospore release experiment of a green seaweed Monostroma nitidum Wittrock (Chlorophyta) for possiblemass cultivation in Taiwan

UPV

Philippine Journal of Natural Sciences

Zygote culture and zoospore release experiment of a green seaweed Monostroma nitidum Wittrock (Chlorophyta) for possible mass cultivation in Taiwan

Anonymous
by: Hsih-Hsin Chen, Ai-Meng Cheng, Chuan-Wen Chen, Ching-Yi Cheng, Masayoshi Matsuoka, Li-Chin Chou, Hisao Ogawa, and I Chiu Liao

Abstract

Artificial seed production and field culture experiments of Monostroma nitidum Wittrock, a green seaweed grown in Taiwan, was conducted. Mature fronds were collected on February 20, 2017. Gametes were released in the following morning from them and their fusion was observed. Zygotes developed into cyst-like forms called Codiolum-cyst and were cultured under room conditions with temperature range of 23–290C until they grew to 36.3±3.2 μm in August. Dark treatment to induce the maturity was applied to them from September 12 to October 30. On November 1, zygotes kept under dark conditions were taken out to the outdoor tank to release zoospores and to collect them on culture nets, which were then kept for five weeks in the tank. The nets were opened in the sea at Jiang-Mei on December 8, 2017. Young fronds about 5–8 cm in length were observed on January 10, 2018 which grew to over 10 cm in length by February 6, 2018. Through the experiments, the dark treatment proved to be effective in inducing gamete release and to synchronizing zygote maturity of M. nitidum.

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Keywords: tropical seaweed, Monostroma nitidum, artificial seed production, culture condition
ovcre.upvisayas

Influence of fish feeds with plant proteins on sediment quality conditions: A microcosm experiment

UPV

Philippine Journal of Natural Sciences

Influence of fish feeds with plant proteins on sediment quality conditions: A microcosm experiment

Anonymous

by: Jirah P. Mamigo, Sheila Mae S. Santander-de Leon

Abstract

Plant proteins have been widely utilized for aquaculture however its environmental effects remained understudied. A microcosm experiment was conducted to determine the effects of feed types (feeds with plant protein vs feeds with fishmeal only) and feed levels on sediment quality conditions. Sediments were treated with three feed types composed of different protein sources: a) fishmeal only (FM) b) soybean, copra, and fishmeal (SC); and c) soybean, wheat, and fish meal (SW) at low feed (LF, 0.07 g) and high feed (HF, 0.40 g) levels; and incubated for 20 days. Results revealed that all feed treatments created anoxic (redox potential, -103 to -135 mV) and toxic sulfidic sediment conditions (FM, > 2.5 mg. g-1, and SC and SW > 1.7 mg. g-1). Effects of differences in feed types were apparent on higher pore water Ammonium – N concentrations in plant-added fish feeds SC (414.08 ± 29.32 ppm) and SW (310.45 ± 113.18 ppm) than in FM (249.43 ± 86.95 ppm) at HF level. Protein concentration in sediments was highest in SW feed type. Effects of LF and HF did not show significant differences but both clearly showed poor sediment quality conditions when compared to sediments without feeds. The results suggest that the current use of plant-proteins as an alternative to fishmeal in aquaculture feeds may pose similar deleterious effects to sediment quality.

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Keywords: fish feeds, plant protein, fishmeal, sediment quality, total sulfides

ovcre.upvisayas

EDTA-Modified magnetic graphite oxide for preconcentrating Hg2+ from water for XRF analysis

UPV

Philippine Journal of Natural Sciences

EDTA-Modified magnetic graphite oxide for preconcentrating Hg2+ from water for XRF analysis

Anonymous

by: Sherwin L. Escayo, Erwin P. Enriquez

Abstract

The performance of EDTA-modified magnetic graphite oxide (EDTA-mGO) as a potential preconcentration agent for XRF analysis of Hg2+ from water was investigated in this study. First, EDTA-mGO was prepared following a stepwise reaction: 1) graphite was oxidized using modified Hummer’s method to produce graphite oxide (GO), 2) co-precipitating Fe3O4 nanoparticles onto synthesized GO and 3) Fe3O4–GO was reacted with EDTA in acetic acid solution. The synthesized EDTA-mGO was characterized using FTIR, XRD, DLS and SEM. Next, 25 mg of EDTA-mGO was used to preconcentrate 250.0 mL Hg2+ aqueous solution (0.0, 0.1, 0.3, 0.5, 0.7, 1.0 and 1.5 ppm) at pH 7.5 for 10 min. Results of XRF analysis of water samples containing Hg2+ showed that the characteristic Hg X-ray lines (Lα1=9.989 keV; Lβ1=11.824keV) were enhanced using the EDTA-mGO as preconcentration agent. In addition, the sensitivity of the XRF analysis of Hg2+ from water was amplified ~1500 times. LOD and LOQ of the XRF analysis with preconcentration were much lower than the XRF analysis without preconcentration and were calculated to be 0.246 ppm and 0.747 ppm, respectively. The improved detection and quantification of Hg2+ from water is attributed to the strong association between Hg2+ and EDTA-mGO. Overall, EDTA-mGO was shown to be a potential preconcentration agent for the XRF analysis of Hg2+ from water.

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Keywords: modified graphite oxide, EDTA, Fe3O4, preconcentration agent, XRF, mercury (II) ion
ovcre.upvisayas

Profile of PAHs in soot collected from exhaust of diesel driven vehicles in Iloilo

UPV

Philippine Journal of Natural Sciences

Profile of PAHs in soot collected from exhaust of diesel driven vehicles in Iloilo

Anonymous

by: Pilar Mercedes A.Retiracion, Rica P. Cainglet, Feby E. Carmen

Abstract

Air pollution is a global issue. Motor vehicle emissions is one of the primary contributors to this phenomenon. There have been significant national and international efforts to reduce the worldwide distribution of pollutants, including the implementation of the Clean Air Act and the Motor Vehicle Air Pollution Control Act. In Iloilo City, urban development gave way to the increase in the number of business establishments and the number of operating vehicles as well. In this study, analysis of polycyclic aromatic hydrocarbons (PAHs), a component of particulate matter, which is one of the major categories of pollutants, was done in soot collected from the exhaust of vehicles. Two types of diesel fuelled vehicles were considered: bus and jeepney. Samples were prepared for analysis using modified EPA-8270-C determination of semi volatile compounds. Extracts were subjected to gas chromatography-mass spectrometry analysis. Total ion chromatograms (TIC) of the 16 US Environmental Protection Agency PAHs were initially produced and these were further examined by generating the extracted ion chromatograms (EIC). Confirmed PAH peaks were integrated and plotted to the calibration curves of the prepared external standards to calculate the concentrations of the PAHs. Results showed that five PAHs were detected, in various concentrations. Jeepneys have higher levels of PAH compared to buses. The highest total PAH concentration is recorded for jeepney (1-7 years) at 21. 67 ppm, while the lowest is for bus (8-14 years) at 1.32 ppm. Although confirmed to be present, the toxicity level to humans of these PAHs in soot is low due to limited direct exposure.

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Keywords: Polycyclic aromatic hydrocarbons, motor vehicle, diesel