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The role of the 13C isotope of the Tree Ring in Recording of Carbon Cycle Change in Atmosphere Pujiindiyati, E. Ristin
Jurnal ILMU DASAR Vol 15 No 1 (2014)
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (653.112 KB) | DOI: 10.19184/jid.v15i1.310

Abstract

Some natural materials such as tree rings, rocks, sediments, ice cores, coral reefs, shell fish and micro fossil record the chemical, physical and biological changes in atmosphere that had taken place in the past. One of these changes which are recorded in tree rings is C-13 isotope. Through the measurement of ratio of 13C compared to 12C (defined as 13C value), it can be known atmospheric CO2 conditions in the past to reflect the present conditions. Present value of 13C in atmospheric CO2 is -7.5 ‰ that had decreased gradually from -6.69 in 1956. Pre-industrial 13C value in atmospheric CO2 is not available. However, the historical records of those are stored in tree rings. Starting from pre-industrial era about 1850 up to 2000, the records of 13C value in some tree rings which are spread in northern hemisphere showed decreasing value ranging from 0.60/00 to 2.30/00. Major factors contributing to variability of these 13C values are pollution effects and climatic effects. Besides those, some effects such as choice of the wood components, inner ring variability and juvenile stage of trees are also correlated to variability of 13C value. Records of 13C value from tree rings defined that atmospheric CO2 from pre-industrial era were between 240 ppm and 310 ppm then this concentration continuously increase to 340 ppm at present. Integrated biospheric carbon flux calculated for 13C records in tree rings using four models from the year of 1850 to 1975 showed an increasing value between 135 Gt and 345 Gt. Keywords : Tree rings, C-13 isotope, atmospheric CO2
INVESTIGATION OF DISSOLVED SULPHATE IN VARIOUS GEOTHERMAL FIELDS OF SUMATRA USING OXYGEN AND SULPHUR ISOTOPES Pujiindiyati, E. Ristin; Abidin, Zainal
Indonesian Journal of Chemistry Vol 6, No 2 (2006)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (270.027 KB) | DOI: 10.22146/ijc.21756

Abstract

There are at least 30 high temperature systems; eleven active volcanoes, five degassing volcanoes and one caldera volcano controlled by Sumatra Fault Zone over a length of 1700 km. To understand this geothermal field system, some information about geochemistry including isotope composition in its fluid is needed. Sulphur-34 and oxygen-18 isotopes in dissolved sulphate pair have been used to determine the origin of acidic fluid of sulphate and to evaluate the process involved. The fluids from eight hot springs, two fumaroles, four deep wells and crater have been collected in along Sumatra geothermal fields. Sulphur-34 (d 34S (SO4), 0/00 CDT) and oxygen-18 (d 18O (SO4), 0/00 SMOW) in sulphate is analyzed according to Robinson-Kusakabe and Rafter method, respectively. The d 34S (SO4) values from Sibayak wells are more enriched of 16.8 0/00 to 18.2 0/0 that may indicate the dissolution of anhydrite minerals or isotope partitioning in hydration of SO2. The d 34S (SO4) values from two fumaroles (Pusuk Bukit - North Sumatra and Rantau Dadap - South Sumatra) are at depleted value of -0.150/00 and 1.80/00, those are close to d 34S from magmatic sulphur.  In general, the d 34S (SO4) of springs spread in a wide range of 5.250/00 to14.20/00 and show a mixing process between atmospheric sulphate and sulphate from deep wells. The d 18O (SO4) from wells exhibits depleted value around -3.60/00 suggesting that 87.5% of sulphate oxygen is derived from groundwater oxygen and 12.5% is derived from atmospheric molecular oxygen in sulphide oxidation reaction. In the other hand, hot springs (except Semurup), crater and fumaroles have enriched value of d 18O (SO4). These enriched values suggest that a higher percentage of atmospherically derived oxygen compared to those from the depth.
INTERPRETATION OF OXYGEN –18 ISOTOPE IN SULPHATE FROM DEEP GROUNDWATER IN JAKARTA AREA Pujiindiyati, E. Ristin; Wandowo, Wandowo; Abidin, Zainal
Indonesian Journal of Chemistry Vol 7, No 1 (2007)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (151.057 KB) | DOI: 10.22146/ijc.21709

Abstract

It has been done a determination of d 18O (SO42-) and d 18O (H2O) value from Jakarta deep groundwater with depth 40-140 m. The aim of this research is to know some procesess influencing the composition of oxygen isotope in groundwater sulphate. A method commonly used to determine d 18O (H2O) value is according to Epstein-Mayeda. CO2 gas resulted from   equilibration process between water sample and CO2 gas standard in which oxygen isotopic reaction has occurred, is injected to mass spectrometer. For determination of d 18O (SO42-) value, Rafter method is used. CO2 gas released from reducing sulphate of water sample with graphite is injected to mass spectrometer. The results of d 18O (H2O) values obtained in this experiment have a narrow range from  -5,04 0/00 to  -6,65 0/00 SMOW whereas their d18O (SO42-) values have a wider range from +8,3 0/00 to +17,4 0/00 SMOW.  The more constant values of d 18O (H2O) performed that evaporation effects might not occur.  Based on the similarity between d18O (SO42-) values of deep groundwater and that of marine evaporite sulphate rocks, it is supposed that sulphate of Jakarta deep groundwater was derived from dissolution of this rocks. There was an indication of seawater intrusion around Pejagalan and Kamal Muara Penjaringan area based on the similarity between their d18O (SO42-) values and d18O (SO42-) of modern seawater.  The contribution of oxygen from water in sulphide oxidation reaction ranged 0% to 12% suggesting that oxygen in deep groundwater sulphate was mainly derived from atmospheric molecular oxygen.
INVESTIGATION OF STABLE ISOTOPE OF 18O AND 2H IN SHALLOW GROUNDWATER FROM KARAWANG AREA Pujiindiyati, E. Ristin
Indonesian Journal of Chemistry Vol 8, No 2 (2008)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (285.228 KB) | DOI: 10.22146/ijc.21614

Abstract

Karawang area is well known as an agriculture area and 2% area is utilized for industries. Clean water demands increase due to developing industry development and population increasement. The origin of groundwater is necessary to keep the sustainability of water resources in this area. Stable isotopes such as 18O and 2H can be used as a parameter to trace the ground water origin. The methods used were Epstein-Mayeda and Zinc reduction for analysis 18O and 2H, respectively. Sampling period was conducted in major dry season in year 2002. The result showed that evaporation effect had influenced to the content of both isotopes in its shallow groundwater that caused a slope shift from its local meteoric line. The origin of its shallow groundwater was from rainwater infiltrating directly in less than 10 m altitude. Citarum River showed more depleted values in both isotopes compared to shallow groundwater and it indicated that its water might originate from spring at the altitude of 600 m.