Judul: Karakteristik Habitat dan Kematangan Gonad Kepiting Kelapa (Birgus latro L.) di Pulau Pasoso, Kabupaten Donggala, Sulawesi Tengah
Abstrak: Kepiting kelapa (Birgus latro L.) merupakan fauna pantai yang hampir punah dan dilindungi. Kepiting ini berpotensi ekonomis. Akibat penangkapan yang intensif, dikhawatirkan jumlah populasi di alam akan menurun.
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Judul: Karateristik Habitat dan Beberapa Aspek Reproduksi Kepiting Kelapa (Birgus latro) di Pulau Uta, Propinsi Maluku Utara
Abstrak: Coconut crab (B. latro) is one of crustacea species which has high economic value, but it is considered rare and classified into vulnerable category by the International Union for Conservation of Nature (IUCN). In Indonesia, the status of this animal population has been not exactly identified, but it has tended to decline because of local people consumption and its habitat quality degradation. Regarding importance of the species resources, thus undestanding its biology and ecology aspects can be applied as the proper management stock and effort of preservation. The research was done in Uta Island on May, July and September with the purpose to analyze the habitat characteristic and gonadal maturation of Coconut Crab on that island. The sampling was taken by kuadran method. The parameter which was analized to understand the habitat. Characteristic and its reproduction aspects such as physical – chemical characteristic of soil, gonadal maturation and plant vegetation analysis. The habitat characteristic was analyzed by using cluster analysis. The result analysis showed that the relation of Length – Weight of male crab is W = 1,93 (CP + r)1,17, while the female is W = 1,97 (CP + r)0,97. Each of those sexual species has allometric growth characteristics. The observation showed that the male did not found in TKG I condition but the female can be found on May (30%) and September (25%) of catch. TKG II was mostly found on male which catched on May in South Station (65%), TKG III was mostly found on female which catched on September in West Station (25%) of catched individu. TKG IV (100%) both male and female where mostly found on July. The different of gonadal maturation levels in all catching times showed that gonadal maturation occured different time for broodstock. The smallest crab which is having gonad maturation was found in length of (CP + r) 66,44 mm. The biggest condition factors of male was found on July and decrease on September, while the highest condition factor of female was found on May that decrease on July, but increase again on September. Generally, sex ratio of male and female is 1 : 1 (avoid deviation). The distribution index showed homogen but tend to have random distribution. There is no different on catch both the amount on level of gonadal maturation. Eventhough, there are different habitat characteristic in every station doesn‟t affect to the catch, both the quantity and level of gonad maturity. The habitat condition in all station for coconut crab to support the sustainability of its activities.
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Judul: Sintesis Nanokristal Magnetit Menggunakan Urea sebagai Penjerap Cr(VI)
Abstrak: The study was to synthesize and characterize magnetite nanocrystal. Magnetite powder was synthesized using hydrothermal method from FeSO4 as precursor and sodium hydroxide and urea as the base sources. Characterization of the obtained powder was carried out using X-ray diffraction, scanning electron microscope, and energy dispersive X-ray analyzer. The crystallite size of magnetite by X-ray diffraction was obtained from 18,23 to 67,34 nm. The scanning electron microscope observations showed that magnetite particles underwent agglomeration. Magnetite powder was used as Cr(VI) adsorbent. The results showed that adsorption capacity for urea-based magnetite at pH 1-5 in 2 hours were 1.92; 1.91; 1.59; 1.20; and 1.21 mg/g, respectively. Adsorption capacity for sodium hydroxide-based magnetite (pH 1-5, 2 hours) were 1.74; 1.83; 0.64; 0.69; and 0.77 mg/g. The results indicated that urea-based magnetite is able to increase adsorption capacity.
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