Judul: Growth, Concentration Chlorophyll-a, and Structure of Macroalgae Gracilaria edulis in the Culture Media Containing Copper
Abstrak: The physiological responses (specific growth rate, concentration of chlorophyll-a, morphological and anatomical structure of the vegetative cells) of the marine macroalga Gracilaria edulis at the different concentrations of copper (0.01 as control, 0.04, 0.06 and 0,5 ppm) delivered continuously for 28 days under controlled laboratory conditions were investigated. Result showed that the degree of copper toxicity depends on both factor the concentration and exposure time. Copper concentration and day of exposure decreased significantly the specific growth rate (SGR) of the Gracilaria edulis but only 0,5 ppm Cu decreased the chlorophyll-a content when compared to control. Of the various physiological end points measured, growth proved to be the most sensitive response than chlorophyll-a with reductions in specific growth rate (SGR). The reason for this could be related to a greater sensitivity of the enzymes involved in growth than those related to chlorophyll-a or a greater energy needs to maintain cellular integrity and metabolic processes under sublethal Cu stress. In all cases, the main effect on vegetative cells were structure changes in cortex and subcortex cells, compared to control, macroalgae exposed to copper showed depigmentation and blending in the lateral branches, heavy staining of the cell wall and severe damage of cell membrane, while the mucilage and the cell walls was densely fibrillar, thick and heavily stained, the cortex cell was clearly vacuolated, the presence of endophytic on the cell wall and endophytic spores in the mucilage. The presence vacuoles should be related to a metal immobilization mechanism, minimizing the Cu toxicity for cells. The epiphytic bacteria can act as a biofilter diminishing the availability of Cu for macroalgae accumulation.
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Judul: Pemanfaatan ganggang mikro sebagai bioindikator perairan yang tercemar
Abstrak: This study aimed to determine the sensitivity of some freshwater microalgae from Indonesia to the heavy metal contaminants (Hg, Cd, As and Pb) and pesticides. Result of the selection of ten isolates of microalgae grown in BG 11 medium obtained three strains which have the fastest growth rate: ICBB 9111, ICBB ICBB 9113 and 9114. Third is selected microalgae strains were identified as: Synechoccus sp. ICBB 9111 (originally there in Mt Salak, Bogor), Chlamydomonas sp. ICBB 9113 (paddy field of Ciomas - Bogor) and Chlorella vulgaris ICBB 9114 (origin Telaga Warna, Puncak, Bogor). To test the sensitivity of microalgae to heavy metals, three selected bacteria are grown in a medium containing heavy metals Cd, Hg, As and Pb at a concentration of 1.25 ppm, 2.50 ppm, 5.00 ppm and 10.00 ppm. Observation of the optical density (OD) performed on the first 30 minutes up to 96 hours. Based on visual observations obtained during this period that two strains of micro-algae growth stalled. Both strains of microalgae are Synechococcus sp. ICBB 9111 and Chlamydomonas sp. ICBB 9113. In contrast to Chlorella vulgaris ICBB 9114 still survive, especially in the medium containing metal ions Cd and Pb, whereas in medium containing Hg and As these strains are not able to survive. The next stage of research is the analysis of metal content, which is not absorbed by the micro algae biomass. From the analysis found that Hg and As are almost entirely absorbed by algae and micro-media content in each of the remaining <0.001 ppm and <0,002 ppm. Whereas for Cd and Pb only a small portion is absorbed by microalgae. Based on the results of the durability of each micro algae in media containing different heavy metals. ICBB Chlorella vulgaris strain 9114 has the durability and adaptability to heavy metals higher than the strain Chlamydomonas sp. ICBB 9113. While Synechococcus sp. ICBB 9111 had the highest sensitivity of all four metals tested. In addition to heavy metals tested, three strains were also tested sensitivity to the herbicide; isoprophylamine glyphosate and paraquat dichloride and insecticide ; buthylphenylmethylcarbamate (BPMC) and deltamethrin with variations of the following concentrations: 5ppm, 10ppm, 20ppm and 40ppm. Microalgae growth observations showed that all three strains are able to survive up to 24 hours in media containing pesticides tested. After 24 hours, the three began to show signs of decline. At the 96-hour observation of all micro algae die. The amount of pesticide concentrations ranged from 10-20ppm concentration which is critical to the durability and adaptability of microalgae. Of the overall treatment and observation can be drawn a conclusion that some micro algae have tolerance to pollutants (heavy metals or pesticides) that enter the aquatic environment. Adsorption capacity and adaptation of micro algae can be used as bio-indicators in monitoring and evaluation of marine environmental impacts of the heavy metal pollutants and pesticides.
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Judul: Pemanenan Energi Listrik dari Kincir Angin Vertikal
Abstrak: Usaha pemanenan energi angin di Indonesia masih sedikit. Sampai Tahun 2016 hanya 3.54 MW alat pemanenan energi angin yang sudah terpasang. Kendala utamanya ialah dibutuhkan investasi yang besar untuk membuatnya. Pembuatan kincir angin dengan ukuran yang lebih kecil dengan bahan yang dapat dibeli di pasar lokal menjadi solusi agar pembuatan kincir angin lebih ekonomis. Pembuatan kincir vertikal tipe Savonius dapat menjadi solusinya. Kincir vertikal Savonius dapat beroperasi pada kecepatan < 3 m/s dan ketinggian < 50 m. Kincir angin ini terdiri dari tiga sistem, yaitu generator, rotor kincir dan transmisi pulley-belt. Generator dibuat dari modifikasi motor AC dan magnet neodymium. Rotor kincir dibuat dari pipa PVC 4”, pipa alumunium ¾”, dan papan polikarbonat. Transmisi pulley-belt dibuat dari plastik dan karet. Kincir ini membutuhkan gaya minimal 3 N untuk dapat berputar atau torsi minimalnya 0.75 Nm. Kecepatan angin yang dibutuhkan untuk merotasikannya sebesar 1.9 m/s. Daya maksimal yang dapat dihasilkan ialah 5.76 watt berupa tegangan sebesar 36 volt dan arus 160 mA.
Keyword: energi terbarukan, generator, motor AC, sudu Savonius