No abstract

Apriadi T, Pratama G, Putra RD, Jumsurizal, Jaya YV, Firdaus M, Arpas HD, Suryanti A. 2018. Comparative study on the fish diversity from natural and bauxite post-mining in wetland system of Bintan Island, Indonesia. Biodiversitas 19: 967-973. In this study, the fish populations between two different wetland systems in Bintan Island, Indonesia, i.e., bauxite post-mining (Kijang) and natural wetland (Toapaya) were compared and to propose a newly index namely Environomic of Fishes Index (EFI) to their respective ecosystems. The purposive random sampling at six stations, each of three stations representing bauxite mining (Kijang) and three stations representing a natural wetland (Toapaya) were used in this research. The numbers of fish species and the abundance were enumerated. The new index derived from the value of diversity index (Shannon), similarity index (Evenness), dominance index (Simpson's), conservation status, and economic value were also evaluated. The natural wetland has higher fish diversity than bauxite post-mining. The total species found were twenty-four. The same seven species were found in both areas. Twelve species were obtained from bauxite post-mining, and nineteen species were obtained from natural wetland. Puntius tetrazona and Rasbora heteromorpha were the common species in area study. The diversity and dominance index was at low category, Evenness index was at high category in all stations, except in tidal swamp station at bauxite post-mining. The EFI in natural wetland was higher than bauxite post-mining. The three community index value, economic value, and conservation status of natural wetland were higher than bauxite post-mining.

Salah satu peran penting ekosistem lamun yaitu sebagai penyerap karbon yang berasal dari atmosfer. Pulau Bintan merupakan salah satu pulau dengan hamparan padang lamun yang cukup luas. Penelitian ini bertujuan untuk mengestimasi kandungan karbon pada padang lamun yang berasal dari seluruh jenis lamun dan sedimen yang berada di perairan Berakit dan Dompak Pulau Bintan. Penentuan potensi cadangan karbon dilakukan dengan melihat estimasi cadangan karbon di dalam sedimen dan biomassa lamun meliputi bagian atas (daun dan pelepah daun) dan bagian bawah lamun (rhizome dan akar). Pengukuran stok karbon pada sedimen lamun dilakukan dengan menggunakan metode pengabuan kering atau Loss on Ignation (LOI) dan kandungan karbon pada biomassa lamun diukur menggunakan metode konversi dengan konstanta. Hasil penelitian menunjukkan pada stasiun Berakit estimasi total cadangan karbon sedimen sebesar 91 Mg Corg ha-1 dan 10,58 Mg C/m2 untuk estimasi kandungan karbon lamun, sedangkan stasiun Dompak nilai estimasi total cadangan karbon pada sedimen berkisar103,80 Mg Corg ha-1 dan 3,34 Mg C/m2 untuk estimasi kandungan karbon bagian lamun. Kandungan karbon pada substrat dipengaruhi oleh komposisi sedimen dan kandungan karbon pada lamun dipengaruhi oleh kerapatan lamun.

Abstract. Coral reefs are one of the most highly productive marine ecosystems, with the largest transfer of energy attributed to the trophic interaction between herbivores and algae. Rapid demographic growth, leading to transmigration to small islands such as Natuna Island where located on outer Island Indonesia.The aim of the present study is to test for significant associations between herbivore fish species traits and Habitat complexity was derived from coral reef cover. Method to record each observed herbivore fish species with UVC (Underwater Visual Census) using SCUBA diving equipment along modification line transects. A total of 39 different fish species belonging to 3 families" herbivore fish were identified. Total biomass of herbivorous fish correlated with Dead Coral Algae (DCA). Biplot of the first two axes for the nonmetric multidimensional a scaling (NMDS) analysis for family and grazer showed the dominance of herbivore fish grazer.

<strong>Primary Productivity on Abandoned Bauxite Mining Pits of Tanjungpinang City, Riau Islands.</strong> The abandoned bauxite mining pits in Bintan Island have a good opportunity to be developed, especially as an aquaculture area. The objective of this study was to determine the primary productivity of the waters, phytoplankton ecological index, and physical and chemical parameters of the bauxite post-mining ponds in Tanjungpinang City, Riau Islands. The study was conducted in April-August 2018 in two bauxite post-mining ponds (station 1 and 2) in Senggarang, Tanjungpinang City. The parameters observed were the abundance and ecological index of phytoplankton, aquatic primary productivity, physical and chemical parameters of the waters, and nutrients, N and P. From the study it was found that there were three phytoplankton divisions, consisted of three classes and eight genera. Mougeotia sp. was the dominant species of phytoplankton. The abandoned bauxite mining pits were classified as labile and the phytoplankton communities were under environmental stress due to the dominance of certain species. The abandoned bauxite mining pits were classified as young (inundation &lt;5 years), low primary productivity, as well as oligotrophic waters. Net primary productivity in station 2 was higher than station 1, i.e. 1,23 mgC L-1 day-1 and 0,25 mgC L-1 day-1, respectively. The physical and chemical parameters of the bauxite post-mining ponds studied met the quality standards for freshwater aquaculture activities, except for pH and ammonia.

Bauxite is one of the mining activities, which can lead to the phenomenon of Acid Mine Drainage (AMD). Activities developed by bauxite mining, since the beginning of operations are able to degrade environmental conditions and cause modifications to the main structure of the environment. Alternative to reducing the negative impact of bauxite mining production with re-utilize abandoned bauxite which forms puddles. The puddle of water on bauxite post-mining have potential for Aquaculture. Each sampling site is located in 5 (five) site based on post bauxite mining activities and determine the heavy metal concentraion of Pb and Cr. Soil and sediment samples were collected to analyze the grain size. Total heavy metal concentrations using Atom Flame Absorption Spectrophotometer (AAS). Analysis of heavy metal concentration (Pb dan Cr) with enrichment factor (EF) value of heavy metals Pb indicates extremely high enrichment for post-mining bauxite site at Simpang Dompak, Dompak and Wacopek (EF> 40). Enrichment Factor (EF) Cr on post-mining bauxite post in Simpang Dompak and Sei.Carang site have EF value > 5 indicating this site contamination with Cr. Index Value, Igeo > 5 indicating very strongly contaminated Pb and Cr with Igeo <5 is contaminated moderately. Water quality in Post-mining bauxite shows good condition of water. In general, the post-mining area of ​​bauskit have potential for aquaculture activities although there is high Pb contamination on the substrate but the water quality parameter can utilized for dynamic organisms such as fish. Proper aquaculture techniques to manage the post-mining bauxite in order to be optimally utilized for cultivation activities.

The floating breakwater is a protective structure that can absorb waves and can be used effectively in coastal areas with moderate wave environmental conditions. The stability of the floating breakwater is affected by the tension of the mooring line and the weight of the anchor. This research was conducted experimentally with a model scale of 1:10 on a floating breakwater with mooring systems and concrete anchor blocks with three types of configurations. The experiment was carried out on irregular waves with the following variations: wave height and period, mooring angle, structure width, and anchor weight. The results of this study indicate that at a wave steepness of 0.02–0.025 floating breakwater, which is installed with a mooring angle of 45 deg, configuration 3 has the largest stability parameter among other configurations. However, if the structure is installed at a mooring angle of 90 deg and cross, configurations 2 and 3 have almost the same stability. The test results also show that the relative width will affect the stability parameters. Configuration 3 (B = 30 cm) has the largest stability-parameter value among other configurations (B = 10 cm and 20 cm).

Perairan Pengudang, memiliki sumberdaya kelautan perikanan yang beragam. Salah satu potensi yang ada yaitu ekosistem terumbu karang dan ikan yang berasosiasi di ekosistem tersebut. Penelitian ini bertujuan untuk memperoleh informasi persentase terumbu karang hidup dan kelimpahan ikan indikator Chaetodontidae beserta hubungannya. Pengambilan data dilakukan dengan menggunakan metode Underwater Photo Transeck (UPT) untuk kondisi terumbu karang dan Underwater Visual Cencus (UVC) untuk ikan chaetodontidae, selanjutnya data karang diolah dengan aplikasi CPCe 4.0. Untuk data ikan Chaetodontidae yang diperoleh dihitung jumlah individu dan diidentifikasi jenis Species yang didapati. Lalu untuk melihat hubungan dari persentase tutupan terumbu karang terhadap kelimpahan ikan indikator Chaetodontidae menggunakan regresi linier sederhana. Persentase karang hidup Perairan Pengudang untuk lokasi pengamatan 1 sebesar 54,14% dengan kategori baik, lokasi pengamatan 2 sebesar 52,57% dengan kategori baik, dan untuk lokasi pengamatan 3 sebesar 35,34% dengan kategori sedang. Adapun untuk jenis ikan Caetodonthidae ditemukan yaitu Chaetodon octofasciatus dengan kelimpahan dan Chelmon rostratus. Untuk keterkaitan diketahui bahwa persentasi karang hidup berpengaruh positif terhadap kelimpahan ikan Chaetodontidae dengan total pengaruh sebesar 7,61% sedangkan 92,39% dipengaruhi oleh faktor lainnya. nilai korelasi ini merupakan nilai korelasi yang sangat rendah