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Abstrak :

Penelitian mengenai struktur komunitas fitoplankton di perairan Danau Sunter Selatan, Jakarta Utara telah dilakukan pada bulan April – Mei 2019. Penelitian bertujuan untuk mengetahui struktur komunitas fitoplankton seperti menghitung indeks kelimpahan, keanekaragaman, kemerataan, dominansi, dan saprobik (pencemaraan air). Metode penelitian yang digunakan yaitu dengan mengambil sampel secara horizontal dan vertikal pada bagian permukaan tiga stasiun (inlet, midlet, dan outlet), selama dua kali pada tanggal 3 dan 21 April 2019. Struktur komunitas fitoplankton di analisis berdasarkan kelimpahan, indeks keanekaragaman, kemerataan, dominansi dan saprobik (pencemaraan air). Keanekaragaman fitoplankton di perairan Danau Sunter Selatan, Jakarta Utara ditemukan 4 kelas dari 12 marga fitoplankton. Fitoplankton terdiri dari Bacillariophyceae (Chaetoceros, Pinnularia, Synedra), Chlorophyceae (Closterium, Cosmarium, Staurastrum, Oocytis, Scenedesmus, Pediastrum) Cyanophyceae (Microcystis, Tetraedron), Euglenophyceae (Euglena). Berdasarkan nilai indeks keanekaragaman fitoplankton secara horizontal dan vertikal berkisar 1,494 - 1,717 dikategorikan tingkat keanekaragaman sedang, indeks kemerataan berkisar 0,701 – 0,764 dikategorikan cukup sampai hampir merata, dan indeks dominansi berkisar 0,238 – 0283 dikategorikan tidak adanya dominasi marga tertentu di perairan Danau Sunter Selatan, Jakarta Utara. Indeks saprobik atau pencemaran air pada setiap stasiun berkisar 0,066 – 0,366 hal tersebut menunjukan perairan Danau Sunter Selatan, Jakarta Utara tercemar sedang, dimungkinkan karena pembuangan sampah dari kegiatan diarea danau.

 

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Research on community structure of phytoplankton in Danau Sunter Selatan, North Jakarta was conducted in April - May 2019. The purpose of this research was to specify the community structure of phytoplankton such as abundance, diversity index, equitability, dominance, and saprobic index (water pollution). The research method used was taking samples horizontally and vertically on the surface of three stations (inlet, midlet, and outlet), for two times on 3^rd and 21^th of April 2019. The community structure of phytoplankton was analyzed based on abundance, diversity index, equitability, dominance, and saprobic index (water pollution). For the diversity of phytoplankton in Danau Sunter Selatan, 4 classes of 12 phytoplankton genera were found. Phytoplankton consists of Bacillariophyceae (Chaetoceros, Pinnularia, Synedra), Chlorophyceae (Closterium, Cosmarium, Staurastrum, Oocytis, Scenedesmus, Pediastrum), Cyanophyceae (Microcystis, Tetraedron), and Euglenophyceae (Euglena). The phytoplankton diversity index by horizontal and vertical method, ranged from 1,494 - 1,717 categorized as moderate diversity index, equitability index ranged from 0.701 - 0.764 categorized as sufficient to almost even, and dominance index ranged from 0,238 – 0283, categorized as no predominance of certain genera in Danau Sunter Selatan. The saprobic index or water pollution at each station ranged from 0,066 – 0,336, indicated that the waters of Danau Sunter Selatan, North Jakarta, are moderately polluted, which may be caused by garbage disposal from activities in the lake area.

 

Abstrak :
Mae Teang District is home to many tributaries of the Ping River. Each tributary is associated with different geographical characteristics and uses. This study is the first report on benthic diatom diversity in the designated water bodies and the first comparison of benthic diatom distribution in the Ping River and its tributaries, including the Mae Hao and Mae Luang Streams in Mae Taeng District of Chiang Mai Province, Thailand. The benthic diatom distribution and physico-chemical properties were investigated in August and November 2015 at three locations in each water body. The highest abundance of benthic diatoms was found in the Ping River (143 species), followed by Mae Hao (132 species) and Mae Luang Streams (90 species). The most abundant species found in the Ping River were Planothidium lanceolatum, Nitzschia palea, Navicula cryptotenella and Seminavis strigosa. The most abundant species found in the Mae Hao Stream were Nitzschia palea, Seminavis strigosa, Surirella splendida and Sellaphora pupula. The most abundant species found in the Mae Luang Stream were Navicula cryptotenella, Diadesmis contenta, Karayevia oblongella and Achnanthes brevipes. Additionally, Amphipleura lindheimeri Grunow was identified as a newly recorded species for Thailand. This study revealed that the Ping River and Mae Hao Stream are similar bodies of water when compared with the Mae Luang Stream in terms of benthic diatom diversity and water quality. In addition, indicator species of tolerance and sensitivity to organic pollution were found. In conclusion, the areas of utilization were found to have affected the distribution of benthic diatoms in these water bodies, along with the water quality of the Ping River and its tributaries.

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ABSTRAK
Penelitian tentang keanekaragaman dan pendugaan kepadatan stok ikan demersal dengan metode sapuan di perairan Aru, Propinsi Maluku, dilakukan sejak tanggal 4 sampai 9 Nopember 2006, menggunakan pukat dasar (bottom trawl). Pengambilan data dilakukan melalui survei pukat dasar menggunakan KR. Bawal Putih dengan lokasi pengambilan contoh ditetapkan sebanyak 36 stasiun. Penelitian ini bertujuan untuk mengetahui indeks keanekaragaman (H?), indeks dominansi spesies (C), indeks kemerataan (J), komposisi hasil tangkapan, laju tangkap, pendugaan kepadatan stok, dan biomassa spesies ikan demersal. Hasil penelitian menunjukkan bahwa komposisi hasil tangkap ikan demersal adalah 65,9 % (6.065,9 kg) dari total hasil tangkap, yang terdiri dari 132 spesies dan 56 famili. Ikan demersal yang banyak tertangkap adalah famili Leiognathidae (50,8%) diikuti Apogonidae (16,5%) dan Mullidae (8,3%). Tiga spesies yang banyak tertangkap yaitu Leiognathus bindus (26,3%) Apogon sp.(16,5%) dan Leiognathus leusiscus (15,8%) yang umumnya tertangkap pada dasar perairan dengan kedalaman 20-30 m. Kisaran indeks keanekaragaman (H?) adalah 0,4940-2,5138 dengan nilai tertinggi pada kedalaman 40-50 m, indeks dominansi (C) adalah 0,0618-0,8041 dengan nilai tertinggi pada kedalaman 10-20 m, dan indeks kemerataan (J?) adalah 0,0553-0,4236 dengan nilai tertinggi pada kedalaman 40-50 m sehingga dapat dikatakan bahwa keanekaragaman spesies ikan demersal di perairan Aru adalah sedang dengan tidak ada spesies yang mendominasi dan penyebarannya tidak merata. Nilai laju tangkap ikan demersal adalah 173,2 kg/jam dengan nilai laju tangkap tertinggi pada perairan di kedalaman 20-30 m, (Leiognathus bindus 27,1 kg/jam tertinggi pada kedalaman 20-30 m, Apogon sp. 18,8 kg/jam tertinggi pada kedalaman 50-60 m, dan Upeneus sulphureus 8,9 kg/jam pada kedalaman 20-30 m; Arius thalassinus 87,4 kg/jam tertinggi pada kedalaman 30-40 meter, Lutjanus malabaricus 12,2 kg/jam, kedalaman 50-60 meter tertinggi, dan Epinephelus sexfaciatus 6,9 kg/jam, tertinggi di kedalaman 40-50 meter). Dugaan kepadatan stok ikan demersal di perairan Aru adalah 4,4±0,2 ton/km2 (Leiognathus bindus, 0.7 ton/km2, Apogon sp. 0,5 ton/km2, dan Upeneus sulphureus 0,2 ton/km2; Arius thalassinus 2,4 ton/km2, Lutjanus malabaricus 0,3 ton/km2, dan Epinephelus sexfaciatus 0,2 ton/km2). Total biomassa ikan demersal di Perairan Aru diduga adalah sebesar 193.975±257 ton (Leiognathus bindus, 29.076 ton, Apogon sp. 20.769 ton, dan Upeneus sulphureus 10.138 ton; Arius thalassinus 0,2 ton, Lutjanus malabaricus 0,1 ton, dan Epinephelus sexfaciatus 0,1 ton).

Abstrak :
Tujuan dari studi ini adalah untuk menganalisa: pertama, hubungan antara board diversity index (BDI) terhadap performa perusahaan; kedua, hubungan non-linear antara kepemilikan keluarga terhadap performa perusahaan; ketiga, pengaruh moderasi kepemilikan keluarga terhadap pengaruh BDI yang diberikan kepada performa perusahaan. Dengan menggunakan PBV sebagai cerminan kinerja perusahaan, hasil studi menunjukkan terdapat hubungan positif dan signifikan antara BDI dan performa perusahaan. Selanjutnya terdapat hubungan positif dan signifikan antara kepemilikan keluarga terhadap performa perusahaan dan tidak ditemukan hubungan non-linear pada kepemilikan keluarga. Selanjutnya terdapat pengaruh positif dan signifikan yang diberikan kepemilikan keluarga dan mendukung dampak positif board diversity ke performa perusahaan dimana hal tersebut menandakan adanya alignment effect antara kepentingan pemilik dan kepentingan dewan ke perusahaan dan bukan entrenchment effect. Dengan demikian, kontribusi studi ini adalah kepemilikan keluarga memberikan dukungan positif pada dampak positif yang diberikan board diversity yang akan meningkatkan performa perusahaan. ......The purpose of this study is to analyze: firstly, the relationship between the board diversity index (BDI) on company performance; secondly, the non-linear relationship between family ownership and firm performance; thirdly, the moderating effect of family ownership on the impact of the BDI given to the company's performance. Using the PBV as a reflection of company performance, the study results show a positive and significant relationship between BDI and company performance. Furthermore, there is a positive and significant relationship between family ownership and company performance; no non-linear relationship was found in family ownership. Furthermore, the moderating variable of family ownership has positive and significant impact of board diversity on the company's performance where it indicates an alignment effect between the interests of the owner and the interests of the board to the company and not an entrenchment effect. Thus, the contribution of this study is that family ownership provides positive support for board diversity's positive impact, which will improve company performance.

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Parameters abserved in research of the Effect of the wood fire on the under trees dynamics in North Sumatera were...

Abstrak :
The condition of ecosystem mangrove of tambak wedi has poluted. Molluscs as one of bioindicator of polution. Observation on molluscs on Tmbak Wedi mangrove ecosystem, Madura Strait was conducted on June 2005....

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Salah satu jenis lebah tidak bersengat yang dapat dijumpai di kampus Universitas Indonesia adalah Tetragonula aff. minor. Penelitian mengenai lebah tersebut perlu dilakukan untuk menunjang upaya konservasi. Penelitian yang dilakukan bertujuan untuk mengetahui keanekaragaman polen yang menjadi pakan leba Tetragonula aff. minor yang dibiakkan di kampus Universitas Indonesia, Depok. Proses pengambilan sampel dilakukan pada bulan November 2019 pukul 09.30--13.30. Sampel polen dikoleksi dari korbikula lebah yang sedang melakukan perjalanan kembali ke sarang. Preparasi sediaan polen dilakukan dengan metode asetolisis. Sediaan polen kemudian diamati dan dihitung di bawah mikroskop cahaya pada perbesararan 10x10 dan 10x40. Hasil penelitian menunjukkan bahwa lebah Tetragonula aff. minor mengoleksi polen dari 10 jenis kelompok tumbuhan yaitu Asystasia gangetica (rumput israel), Caesalpinia pucherrima (kembang merak), Carica papaya (Pepaya), Cocos nucifera (kelapa), Dendrophthoe pentandra (benalu), Mimosa sp. (putri malu), Morinda citrifolia (mengkudu), Lagestroemia sp. (bungur), famili Cyperaceae, dan famili Poaceae. Nilai indeks keanekaragaman Shannon-Wiener adalah 1,431 dan nilai kemerataan 62,1%, menunjukkan keanekaragaman dan kemerataan sedang. Berdasarkan data tersebut diketahui bahwa lebah Tetragonula aff. minor memiliki spektrum diet polilekti dan menunjukkan perilaku konsisten dalam pemilihan bunga selama satu kali perjalanan pencarian makan. ......One of stingless bee that can be found in University of Indonesia campus is Tetragonula aff. minor. Therefore, research about T. aff. minor has to be done to support conservation action. Research conducted to gather information about the diversity of pollen that collected by T. aff. minor in University of Indonesia, campus Depok area. Sample collected in November 2019 at 09:30--13:30. Pollen samples collected from the corbicula of stingless bee that traveling back to the hives. Pollen preparation has done by acetolysis method. After preparation, pollens are observed and counted under light microscope in 100x and 400x magnifications. Result shows that T. aff. minor collected pollens from 10 kind of plants; Asystasia gangetica (chinese violet), Caesalpinia pulcherrima (peacock flower), Carica papaya (papaya), Cocos nucifera (coconut), Dendrophthoe pentandra (mistletoe), Mimosa sp. (mimosa), Morinda citrifolia (noni), Lagerstroemia sp. (crape-myrtle), family of Cyperaceae, and Poaceae. Shannon-Wiener diversity index value is 1,431 and evenness value is 62,1%, classified as moderate diversity and evenness. Based on this research, it is known that T. aff. minor has polilecty diet spectrum and show individual floral constancy during a foraging trip.