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An eco-friendly phenol biosensor from Bacillus biofilm was prepared and investigated. The biofilm, which produced tyrosinase enzyme, was successfully immobilized on a screen-printed carbon electrode surface. A total of 72 Bacillus isolates were utilized because of their capability to produce tyrosinase enzyme in tyrosine media. Among them, Bacillus isolate code 100 was selected because it produced an adequate amount of tyrosinase enzyme and a high potentiostat current. The response surface methodology was also used to optimize the phenol sensing condition through an electrochemical method. Results showed that the optimum condition was achieved after 6 days on a phosphate buffer solution (pH of 8), with an optical density of 0.33. Furthermore, the limits of detection and quantification were 3.0 and 13 ng/L, respectively. The measurements of precision yielded a relative standard deviation of < 5%, which is remarkable. Although the biosensor material was used for 35 days, the current throughout was still maintained at 90%, indicating that the evaluated biosensor material has the potential to be used for phenol monitoring on environmental samples in the near future. [ABSTRACT FROM AUTHOR]

The aim of this research was to use tilapia farming waste as a nutrient for plant growth in recirculation systems in order to make use of water efficiently and to reduce pollution materials entering the aquatic environment. Aquaculture wastes such as residual feed and faeces, after experiencing decomposition, can be utilized as a nutrient supply for plants. During the 35 days of study, butterhead lettuce could grow well relying on the supply of nutrients from fish farming waste. Relative growth (RGR) of P2 treatment (10 pot plants) was 0.07 ± 0.02. It was almost the same as in the treatment of P3 (20 pot plants) amounted to 0.07 ± 0.01. Similarly, the specific growth of butterhead was of 7.49 ± 1.21 in P2 and 6.86 ± 1.02 in P3. The use of tilapia fish farming waste as a nutrient on water recirculation system was able to support butterhead lettuce growth. [ABSTRACT FROM AUTHOR]

Due to the change of land use, Ciliwung watershed suffered from physical degradation. Considering the increasing land use change along the Ciliwung watershed, it was necessary to perform a research on land use change and its impact on the river water quality (BOD, COD, DO). The land-use forms were divided into six categories: waterbody, bareland, forest, built-up area, agriculture and paddy field. The level of correlation was measured by Pearson correlation. The change of land use of waterbody, bareland, forest, built-up area and dry land agriculture influenced the river water quality. Waterbody had positive effect on water quality, while bareland and built-up area had a negative effect on water quality. [ABSTRACT FROM AUTHOR]

In the recirculation aquaponic system (RAS), fish farming waste was utilized as a nutrient for plant, minimizing the water need, reducing the waste disposal into the environment, and producing the fish and plant as well. The study aimed to examine the growth of romaine lettuce ( Lactuca sativa L. var. Longifolia) in aquaponic system without the addition of artificial nutrient. The nutrient relies solely on wastewater of nile tilapia ( Oreochromis niloticus) cultivation circulated continuously on the aquaponic system. The results showed that tilapia weight reached 48.49 ± 3.92 g of T3 (tilapia, romaine lettuce, and inoculated bacteria), followed by T2 (tilapia and romaine lettuce) and T1 (tilapia) of 47.80 ± 1.97 and 45.89 ± 1.10 g after 35 days of experiment. Tilapia best performance in terms of growth and production occurred at T3 of 3.96 ± 0.44 g/day, 12.10 ± 0.63 %/day, 96.11 ± 1.44 % and 1.60 ± 0.07 for GR, SGR, SR, and FCR, respectively. It is also indicated by better water quality characteristic in this treatment. Romaine lettuce harvests of T2 and T3 showed no significant difference, with the final weight of 61.87 ± 5.59 and 57.74 ± 4.35 g. Overall, the integration of tilapia fish farming and romaine lettuce is potentially a promising aquaponic system for sustainable fish and horticulture plant production. [ABSTRACT FROM AUTHOR]

Dumai coastal water is one of coastal area that very active in Indonesia, since it has national and international shipping lanes. Furthermore along coastal waters of Dumai are locate various industries likely influencing coastal environmental water quality. The study aimed to examine oil content in water and bottom sediment. The highest oil content in water was found at Lubuk Gaung station 11 (0.719 ppm), western part of the research location. This might be related to the monsoon season change in which sea water current changes toward west direction during April–May 2015. Sediment oil content at Purnama station 4 (3591 ppm) was the highest. It might be attributed to the existence of industries along the coast. The high oil concentration in sediment might affect coastal ecosystems. [ABSTRACT FROM AUTHOR]

Spreading heavy metals in the water column may subsequently be accumulated in sediment because of low solubility then become sensitivity indicator for aquatic organism. Ecological risk is assessed through the heavy metals concentration in the surface sediment. Sediment samples were grabbed from 20 stations in Mahakam Delta. Hakanson method was used to identify ecological potential risk of heavy metals pollution. The results showed that Zn (70.63 mg/kg), Cr (4.93 mg/kg), Cd (0.11 mg/kg) and Ni (33.48 mg/kg) exceeded Threshold Effect Level. Furthermore Ni exceeded Probable Effect Level. Ecological potential risk of heavy metals sequence was Pb>As>Cd>Ni>Zn>Cr>Cu. The criteria of ecological risk on Pb and as were considerable risk ( E r i Pb: 52.18 and E r i As: 50.00 and the others were low risk. Moreover, the potential ecological risk sequence of study were ST18> ST3> ST8> ST1> ST7> ST6> ST11> ST20> ST19> ST4> ST16> ST5> ST9> ST15> ST2> ST13> ST14> ST17> ST10> ST12. The criteria of ST 18, ST 3, ST 8, ST 1 and ST 7 belonged to considerable risk, ST 12 was low risk and others location were medium risk. Heavy metals input in Mahakam Delta are possibly caused by human activities such as industrial, mining, household activities, and from natural process by erosion and natural water flow. [ABSTRACT FROM AUTHOR]

The Mahakam Delta typically consisting of several ecosystems has been identified as one of biodiversity hotspot in Kalimantan Island. In order to provide phytoplankton distribution, diversity and abundance data, a research on 4 stations representing delta plain (ST1) and delta front (ST2, ST3, ST4) was performed. The studies describe phytoplankton community existing in this region and multivariate analysis using correspondent analysis (CA). There were 48 taxa phytoplankton belonging to Bacillariophyceae (35), Dinophyceae (6), Chlorophyceae (4), and Cyanophyceae (3). The highest taxa occurred in ST3 with diversity index of 2.09, followed by ST2 (1.95), ST1 (1.15), and ST4 (0.9). Diversity index of ST3, ST2, and ST1 delta was categorized as moderate stable community, while ST4 was categorized as unstable community. Bacillariophyceae was not only as the highest diversity class but also as the highest abundance, recorded in ST3. The abundance class ranged 1.4x105 cell/m 3 to 2.2x106 cell/m 3 . Generally, phytoplankton diversity and abundance in delta front was higher than that in delta plain. Human activities and physical process likely influenced diversity and abundance of phytoplankton in Delta Mahakam. [ABSTRACT FROM AUTHOR]

The study was to investigate whether offshore oil and gas exploration would be responded by fish community. Trawling was made at 2 locations inside and 1 location outside the block. There were 49 taxa, consisting of 45 fishes and 4 non-fishes. 30 taxa (67%) belong to pelagic group indicating an off-shore fish community (depth >200 m). The shallower the depth will result in the higher the species number.Unstable condition inside the block was unrelated with oil and gas exploration.High species number outside the block was influenced by depth. Satellite images depicting fishing ground will be very helpful for the fishermen for fishing activities. [ABSTRACT FROM AUTHOR]

Accurate information of paddy fields over wide areas is essential to support sustainable agricultural and a food security program. Monitoring of these lands continuously, using remote sensing technology, will provide information related to the cropping intensity in the field, as well as its dynamics change. We characterized seasonal vegetation dynamics from long-term multi-temporal MODIS satellite datasets in order to determine cropping intensity and to analyze the dynamics change in paddy field of Java. The results indicate that the methodology employed in this research distinguished many specific uses in paddy fields as means of their cropping intensity. Moreover, the seasons were the most important factor affected the dynamics change in the agricultural system. Extreme climate variability caused many paddy fields, especially in non-irrigated land, to remain barren as well the planting time was postponed. Indeed, characterizing the long-term vegetation dynamics of paddy field provides information about the characteristics and trends in these land use types, either caused by natural factors or human activities. [ABSTRACT FROM AUTHOR]