Isoprene hotspots at the Western Coast of Antarctic Peninsula during MASEC′16

Isoprene (C5H8) plays an important role in the formation of surface ozone (O3) and the secondary organic aerosol (SOA) which contributed to the climate change. This study aims to determine hourly distribution of tropospheric isoprene over the Western Coast of Antarctic Peninsula (WCAP) during the Malaysian Antarctic Scientific Expedition Cruise 2016 (MASEC′16). In-situ measurements of isoprene were taken using a custom-built gas chromatography with photoionization detector, known as iDirac. Biological parameters such as chlorophyll a (chl-a) and particulate organic carbon (POC) were compared to the in-situ isoprene measurements. Significant positive correlation was observed between isoprene and POC concentrations (r2 = 0.67, p < 0.001), but not between isoprene and chl-a. The hotspots of isoprene over maritime Antarctic were then were investigated using NAME dispersion model reanalysis. Measurements showed that isoprene mixing ratio were the highest over region of King George Island, Deception Island and Booth Island with values of ∼5.0, ∼0.9 and ∼5.2 ppb, respectively. Backward trajectory analysis showed that air masses may have lifted the isoprene emitted by marine algae. We believe our findings provide valuable data set of isoprene estimation over the under sampled WCAP

A Review of Southeast Asian Oil Palm and Its CO2 Fluxes

Palm oil production is a key industry in tropical regions, driven by the demand for affordable vegetable oil. Palm oil production has been increasing by 9% every year, mostly due to expanding biofuel markets. However, the oil palm industry has been associated with key environmental issues, such as deforestation, peatland exploitation and biomass burning that release carbon dioxide (CO2) into the atmosphere, leading to climate change. This review therefore aims to discuss the characteristics of oil palm plantations and their impacts, especially CO2 emissions in the Southeast Asian region. The tropical climate and soil in Southeast Asian countries, such as Malaysia and Indonesia, are very suitable for growing oil palm trees. However, due to the scarcity of available plantation areas deforestation occurs, especially in peat swamp areas. Total carbon losses from both biomass and peat due to the conversion of tropical virgin peat swamp forest into oil palm plantations are estimated to be around 427.2 &plusmn; 90.7 t C ha&minus;1 and 17.1 &plusmn; 3.6 t C ha&minus;1 year&minus;1, respectively. Even though measured CO2 fluxes have shown that overall, oil palm plantation CO2 emissions are about one to two times higher than other major crops, the ability of oil palms to absorb CO2 (a net of 64 tons of CO2 per hectare each year) and produce around 18 tons of oxygen per hectare per year is one of the main advantages of this crop. Since the oil palm industry plays a crucial role in the socio-economic development of Southeast Asian countries, sustainable and environmentally friendly practices would provide economic benefits while minimizing environmental impacts. A comprehensive review of all existing oil plantation procedures is needed to ensure that this high yielding crop has highly competitive environmental benefits

The structural and luminescence properties of strontium borotellurite glass doped with europium and dysprosium

A series of strontium borotellurite glasses with the general formula xSrO·(100-x)[0.5B2O3·0.5TeO2], (15 = x = 35 mol%) have been prepared. In addition, glass samples with the composition 20SrO·40B2O3·40TeO2 and 30SrO·35B2O3·35TeO2 doped with Europium, Eu3+ and Dysprosium, Dy3+, (1 mol% each) were also prepared. All the glass samples were prepared using melt quenching method, followed by annealing process at 400 oC for 6 hours. The structural property of the glass samples was characterized using X-ray diffractometer (XRD) and Fourier transform infrared spectrometer and the luminescence property using fluorescence spectrometer. The XRD diffraction patterns showed the amorphous phase of the glass sample. Infrared spectra reveals that increased of strontium in borotellurite glass significantly promote conversion of [BO3] to [BO4] and [TeO4] to [TeO3] in the structural units. This conversion indicated some disintegration of boroxol rings into network structures while strontium acted as network modifier. The emission spectra line of undoped and doped glasses is in the visible range. The emission spectra line of undoped glass at 513 nm originated from the glass host. The emission spectra lines from Eu3+ doped glass are due to transition of Eu3+ ion at 5D0?7F0 (580 nm), 5D0?7F1 (593 nm), 5D0?7F2 (613 nm) and 5D0?7F3 (652 nm). Meanwhile the emission spectra lines from Dy3+ doped glass are due to transition from 4F9/2?6H15/2 (483 nm), 4F9/2?6H13/2 (578 nm) and 4F9/2?6H11/2 (660 nm). The emission spectra lines from Eu3+ and Dy3+ doped glass are shown at 483 nm, 513 nm, 578 nm, 613 nm and 660 nm. The results revealed that the emission intensity of Eu3+ and Dy3+ doped glass are dependent on host composition. Furthermore, the luminescence decay curve for Eu3+ doped glass showed multi-exponential decay with lifetimes for 20SBT:1Eu3+ glass are 1 ns and 22 ns, while for 30SBT:1Eu3+ glass, the lifetimes are 1 ns and 18 ns

Assessment on the distributions and exchange of anionic surfactants in the coastal environment of Peninsular Malaysia: a review

Terrestrial anionic surfactants (AS) enter the marine environment through coastal region. Despite that, in general limited knowledge is available on the coastal AS transfer pathway. This paper aims to assess the distributions and exchange of AS in the Peninsular Malaysia coastal environments, adjacent to the southern waters of South China Sea and Strait of Malacca. An assessment case study was conducted by a review on the available data from the workgroup that span between the year 2008 and 2019. The findings showed that AS dominated in the sea surface microlayer (SML, 57%) compared to subsurface water (SSW, 43 %). AS were also found to have dominated in fine mode (FM, 71 %) compared to coarse mode (CM, 29 %) atmospheric aerosols. SML AS correspond to the SSW AS (p < 0.01); however, highest enrichment factor (EF) of the SML AS was not consistent with highest SSW AS. Direct AS exchange between SML and FM and CM was not observed. Furthermore, the paper concludes AS mainly located in the SML and FM and could potentially be the main transfer pathway in the coastal environment

Structural and luminescence properties of Eu3+ and Dy3+-doped magnesium boro-tellurite ceramics

Boro-tellurite ceramics with the composition of 60B2O3-10TeO2-30MgO-1Eu2O3-1Dy2O3 in mol % were prepared by solid-state reaction method. The samples were characterized by x-ray diffraction (XRD), photoluminescence (PL) and FTIR spectroscopy. The XRD studies have revealed the presence of MgTe2O5 and MgB6O10.7H2O crystalline as the major and minor phases in these samples. The FTIR spectra reveal the presence of B-O vibrations of B-O-B, BO3 and BO4 bridging oxygen and Te-O stretching modes of Te2O, TeO3 and TeO4 units in the prepared ceramics. The PL peaks were assigned to the Eu3+ transitions 5D07F0 at 580 nm, 5D07F1 at 591 nm and 596 nm, 5D07F2 at 612, 618 and 621 nm, 5D07F3 at 651 nm, and 5D07F4 at 692 nm and 702 nm when excited at 394 nm

Carbon Emissions from Oil Palm Induced Forest and Peatland Conversion in Sabah and Sarawak, Malaysia

The palm oil industry is one of the major producers of vegetable oil in the tropics. Palm oil is used extensively for the manufacture of a wide variety of products and its production is increasing by around 9% every year, prompted largely by the expanding biofuel markets. The rise in annual demand for biofuels and vegetable oil from importer countries has caused a dramatic increase in the conversion of forests and peatlands into oil palm plantations in Malaysia. This study assessed the area of forests and peatlands converted into oil palm plantations from 1990 to 2018 in the states of Sarawak and Sabah, Malaysia, and estimated the resulting carbon dioxide (CO2) emissions. To do so, we analyzed multitemporal 30-m resolution Landsat-5 and Landsat-8 images using a hybrid method that combined automatic image processing and manual analyses. We found that over the 28-year period, forest cover declined by 12.6% and 16.3%, and the peatland area declined by 20.5% and 19.1% in Sarawak and Sabah, respectively. In 2018, we found that these changes resulted in CO2 emissions of 0.01577 and 0.00086 Gt CO2-C yr&minus;1, as compared to an annual forest CO2 uptake of 0.26464 and 0.15007 Gt CO2-C yr&minus;1, in Sarawak and Sabah, respectively. Our assessment highlights that carbon impacts extend beyond lost standing stocks, and result in substantial direct emissions from the oil palm plantations themselves, with 2018 oil palm plantations in our study area emitting up to 4% of CO2 uptake by remaining forests. Limiting future climate change impacts requires enhanced economic incentives for land uses that neither convert standing forests nor result in substantial CO2 emissions

Spatial-temporal variations in surface ozone over Ushuaia and the Antarctic region: observations from in situ measurements, satellite data, and global models

The Antarctic continent is known to be an unpopulated region due to its extreme weather and climate conditions. However, the air quality over this continent can be affected by long-lived anthropogenic pollutants from the mainland. The Argentinian region of Ushuaia is often the main source area of accumulated hazardous gases over the Antarctic Peninsula. The main objective of this study is to report the first in situ observations yet known of surface ozone (O3) over Ushuaia, the Drake Passage, and Coastal Antarctic Peninsula (CAP) on board the RV Australis during the Malaysian Antarctic Scientific Expedition Cruise 2016 (MASEC’16). Hourly O3 data was measured continuously for 23 days using an EcoTech O3 analyzer. To understand more about the distribution of surface O3 over the Antarctic, we present the spatial and temporal of surface O3 of long-term data (2009–2015) obtained online from the World Meteorology Organization of World Data Centre for greenhouse gases (WMO WDCGG). Furthermore, surface O3 satellite data from the free online NOAA-Atmospheric Infrared Sounder (AIRS) database and online data assimilation from the European Centre for Medium-Range Weather Forecasts (ECMWF)-Monitoring Atmospheric Composition and Climate (MACC) were used. The data from both online products are compared to document the data sets and to give an indication of its quality towards in situ data. Finally, we used past carbon monoxide (CO) data as a proxy of surface O3 formation over Ushuaia and the Antarctic region. Our key findings were that the surface O3 mixing ratio during MASEC’16 increased from a minimum of 5 ppb to ~ 10–13 ppb approaching the Drake Passage and the Coastal Antarctic Peninsula (CAP) region. The anthropogenic and biogenic O3 precursors from Ushuaia and the marine region influenced the mixing ratio of surface O3 over the Drake Passage and CAP region. The past data from WDCGG showed that the annual O3 cycle has a maximum during the winter of 30 to 35 ppb between June and August and a minimum during the summer (January to February) of 10 to 20 ppb. The surface O3 mixing ratio during the summer was controlled by photochemical processes in the presence of sunlight, leading to the depletion process. During the winter, the photochemical production of surface O3 was more dominant. The NOAA-AIRS and ECMWF-MACC analysis agreed well with the MASEC’16 data but twice were higher during the expedition period. Finally, the CO past data showed the surface O3 mixing ratio was influenced by the CO mixing ratio over both the Ushuaia and Antarctic regions. Peak surface O3 and CO hourly mixing ratios reached up to ~ 38 ppb (O3) and ~ 500 ppb (CO) over Ushuaia. High CO over Ushuaia led to the depletion process of surface O3 over the region. Monthly CO mixing ratio over Antarctic (South Pole) were low, leading to the production of surface O3 over the Antarctic region