Judul: Struktur Komunitas Ikan di Ekosistem Padang Lamun Pulau Karang Congkak, Taman Nasional Kepulauan Seribu
Abstrak: Padang lamun memiliki fungsi sebagai daerah asuhan bagi beraneka ragam spesies ikan sehingga memiliki peran penting dalam menunjang sumber daya ikan di perairan pantai. Penelitian ini bertujuan untuk mengungkap struktur komunitas ikan di perairan lamun Pulau Karang Congkak, baik secara spasial maupun temporal. Sampling dilakukan setiap bulan dari November 2018 sampaiMaret 2019 menggunakan metode purposive sampling. Contoh ikan dikumpulkan menggunakan pukat tarik yang dioperasikan di empat stasiun yakni utara, timur, selatan, dan barat Pulau Karang Congkak. Analisis contoh ikan meliputi identifikasi, pengukuran panjang dan bobot tubuh ikan dilakukan di laboratorium. Data yang dikumpulkan dianalisis secara deskriptif. Selama penelitian terkumpul sebanyak 10.069 ekor ikan, 46 spesies, 26 famili, dan 9 ordo. Komposisi ikan didominasi oleh ikan pada stadia yuwana dengan jumlah 95% dari total ikan yang tertangkap dan sebanyak 77% dari yuwana yang terkumpul tersebut merupakan ikan komersial. Tidak ada perbedaan struktur komunitas secara spasial, namun berbeda secara temporal. Perubahan kondisi lingkungan perairan, jumlah spesies, dan kelimpahan ikan menyebabkan struktur komunitas ikan berfluktuasi tiap bulan.
Keyword: Daerah asuhan, ikan, lamun, struktur komunitas

Judul: Struktur Komunitas Ikan Pada Lamun Jenis Enhalus Acoroides Dan Cymodocea Rotundata Di Pulau Pari, Kepulauan Seribu
Abstrak: Ekosistem lamun mempunyai peranan yang penting bagi kehidupan ikan. Penelitian ini bertujuan mengetahui struktur komunitas ikan dan hubungannya dengan lamun Enhalus acoroides dan Cymodocea rotundata. Penelitian ini dilakukan pada bulan Mei 2015 di empat Stasiun Pulau Pari dengan metode swept area menggunakan jaring mini beach seine untuk menangkap ikan. Analisis struktur komunitas ikan menggunakan perhitungan indeks ekologi. Analisis koresponden digunakan untuk mengetahui hubungan ikan dengan sebaran jenis lamun. Kondisi kualitas perairan Pulau Pari secara umum dalam keadaan baik untuk menunjang kehidupan lamun dan ikan. Berdasarkan hasil penelitian, ikan yang ditemukan di ekosistem padang lamun terdiri atas 10 spesies dari 8 famili. Struktur komunitas ikan di ekosistem padang lamun di Pulau Pari dalam kondisi yang stabil. Famili Apogonidae memiliki asosiasi erat dengan sebaran lamun jenis Enhalus acoroides sedangkan famili Atherenidae dan Gerridae memiliki asosiasi erat dengan sebaran lamun jenis Cymodocea rotundata.
Keyword: ikan, lamun, Pulau Pari, Enhalus acoroides, Cymodocea rotundata

Judul: Enhancement of photon absorbtion on BaxSr1-xTiO3 thin films semiconductor using photonic crystals.
Abstrak: In this research, has been conducted BaxSr1-xTiO3 (BST) thin films manufacturing for mole fraction x = 0.25, 0.35, 0.45, and 0.55; and concentration of 1 molar using chemical solution depositon (CSD) method. The materials, which are used in this research, are barium acetate [Ba(CH3COO)2, 99%], strontium acetate [Sr(CH3COO)2, 99%], titanium isopropoxide [Ti(C12O4H28), 97.999%], gallium trioxide [Ga2O3], 2-methoxyethanol [H3COOCH2CH2OH, 99%] and 1 x 1 cm of transparent conductive oxide (TCO) glass as substrate. Two BST thin films are made that for BST thin films which are doped by 10% galium (BGST) as p-type layer and pure BST solution as n-type. BST solution is made by reacting barium acetate [Ba(CH3COO)2, 99%], strontium acetate [Sr(CH3COO)2, 99%] and titanium isopropoxide [Ti(C12O4H28)] into 2-methoxyethanol solvent [H3COOCH2CH2OH, 99%] in accordance with mass gram for each x value. While, BGST solution is made in the same way as BST solution, plus adding gallium at 10% of the mass of BST. Once all materials are reacted, then vibrated using ultrasonic for 90 minutes, and followed by coating BGST / BST on the TCO substrate. Once the layer is formed, then annealed for 15 hours at temperature of 500 °C with increasing rate of 1.67 oC/minute. Characterizations of BST thin films with or without photonic crystals include the absorbance and transmittance in the visible light spectrum, as well as the electrical photoconductivity characterizations. From BST thin films without photonic crystals indicate that our thin films have light absorption area on almost the entire range of the visible light spectrum even to the infrared range with absorption value over than 67.6%, in addition, it can be seen that the maximum absorbance of BST thin films for all mole fractions lie in blue to green light spectrum region, 457 nm ≤ λ ≤ 570 nm and the minimum in yellow to red light spectrum region, 570 nm ≤ λ ≤ 678 nm. The largest absorbance is found at x = 0.25 with average absorbance value of 92.04% and maximum and minimum absorbance peaks at wavelength of 500.89 and 657.72 nm, respectively. At x = 0.35, average absorbance value decreased to 83.55% with maximum and minimum peaks at 505.73 and 613.68 nm, respectively. Then increased to 91.16% at x = 0.45 with maximum and minimum peaks at 506.04 and 618.56 nm, respectively. At x = 0.55, average absorbance value decreased to 80.12% with maximum and minimum peaks at 507.85 and 608.79 nm, respectively. Moreover, it can be seen that the addition of barium mole fraction leads to wider maximum absorbance or minimum transmittance peaks and narrower minimum absorbance or maximum transmittance peaks in the same range of the green and blue & red light spectrums, respectively. BST thin films with photonic crystals show increasing in absorption for all x values in the range of 3.04 into 13.33%. At x = 0.25, average absorbance percentage increased 3.96% from 92.4 into 95.68%, for x = 0.35 average percentage increased 7.07% into 89.45 from 83.55%. Furthermore, average absorbance of BST thin films at x = 0.45 increased 3.04% from 91.16 into 93.93% and x = 0.55 has
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