Keanekaragaman dan Potensi Pemanfaatan Makroalga di Pesisir Pulau Tunda

Macroalgae is one of the marine biological resources that has a potential to be utilized further by humans. This research aims to study macroalgae diversity and utilization potency by humans in the coastal area of Tunda Island. The study was conducted at 4 stations using the belt transect method. Results of this study indicated that there were 15 species of macroalgae found that came from 3 macroalgae classes, they were chlorophyceae, phaeophyceae, and rhodophycea. Macroalgae species that are often found are Padina minor, Halimeda macroloba, and Gracilaria salicornia. The highest macroalgae diversity was found at station 3 with a value of 2.44. Based on the type of macroalgae found in the field there are several macroalgae species that can be utilized, and the lack of information causes the low macroalgae utilization by the local community. Keywords: Biodiversity, Gracilaria salicornia, Halimeda macroloba, macroalgae, Padina mino

A New Northernmost Distribution Record of the Reef Coral Duncanopsammia axifuga at Bird’s Head Peninsula, West Papua, Indonesia

Duncanopsammia axifuga (Scleractinia: Dendrophylliidae) is reported for the first time from Indonesia. A population was found in 5-m deep, murky water on a sediment-rich, inshore reef at Bird’s Head Peninsula, West Papua. Some corals were attached to dead coral and others were loose fragments living on sediment. One attached specimen was observed to be damaged as a result of direct contact with an adjacent Goniopora coral. Free-living specimens on sand are more likely able to escape competition for space. These observations may help to better understand the northernmost range limit and the natural environment of D. axifuga, a species that is popular in the international aquarium trade, but has not been studied very well in the field

Utilization of Aquatic Weed Salvinia molesta as a Raw Material for Biogas Production

Salvinia molesta is an aquatic weed having very high growth rate. The high abundance of this species biomass could be utilized as a source of alternative energy. This research was aimed to utilize S. molesta as a substrate for biogas production using batch system in order to reduce euthrofication effect in a lake. Cow manure was used as starter for anaerobic process because containing bacteria. Proximate test was conducted to analyze the chemical characteristics of the aquatic weed. Chemical oxygen demand, total solid, and total volatile suspended solid of weed and manure were analyzed according to the APHA 2012 method. Biogas composition was analyzed with gas chromatography. The results showed that the S. molesta contained high lignin content and low C:N ratio. Hydrolisis and acidification process occured very rapid, resulting in an increase of the weed and manure mixture COD. In the other hand, the decreased of COD removal was caused by the massal death of methanogenesis bacteria. The total solid and total volatile suspended solid content were not significantly decreased. Potential biogas production from S. molesta was 58.16 L.kg-1 with 318.29 mL.gram VS-1day-1 of methane production. This production value was still low or compared to that of cow manure which have been established as biogass materials and need modification to improve the biogas production

POLA KEANEKARAGAMAN DAN DISTRIBUSI SPESIES IKAN TERUMBU MENGGUNAKAN ENVIRONMENTAL DNA (eDNA) METABARCODING PADA JARAK LONGITUDINAL DARI TELUK JAKARTA

Keberadaan ikan terumbu tentunya erat kaitannya dengan keberadaan terumbu karang karena ekosistem tersebut merupakan habitat bagi ikan karang. Terumbu karang merupakan ekosistem yang banyak terdapat di pulau-pulau kecil di daerah tropis termasuk Kepulauan Seribu. Kepulauan Seribu adalah sekelompok 110 pulau yang terletak di lepas pantai Jakarta dan hingga 80 kilometer sebelah utara Laut Jawa. Dalam studi ini, kami meneliti distribusi spesies dan keanekaragaman spesies ikan terumbu pada dua lokasi yaitu Pulau Untung Jawa dan Pulau Harapan yang berbeda jarak di Teluk Jakarta menggunakan analisis metabarcoding DNA lingkungan (eDNA). Sebanyak 4 liter sampel air laut dikoleksi pada kedalaman 8-9 meter per lokasi lalu dilakukan analisis menggunakan primer spesifik (MiFish U) dengan marka 12s rRNA. Secara keseluruhan, kekayaan spesies yang lebih tinggi ditemukan di Pulau Harapan (52 spesies) diikuti oleh Pulau Untung Jawa (11 spesies). Indeks Shanon-Wiener juga menunjukkan bahwa Pulau Harapan memiliki keanekaragaman ikan terumbu yang lebih tinggi berdasarkan tiga tingkatan taksonomi (famili, genus, dan spesies). Hanya ada lima spesies ikan terumbu mutual yang ditemukan di dua lokasi tersebut, yakni Atherinomorus aetholepis, Auxis thazard, Cephalopholis sexmaculata, Epinephelus chlorostigma, dan Plectropomus areolatus. Hasil temuan dalam penelitian ini sejalan dengan perbedaan antropogenik dimana Pulau Untung Jawa lebih dekat dengan Teluk Jakarta dibandingkan dengan Pulau Harapan yang letaknya relatif jauh dari Teluk Jakarta.The existence of reef fish is certainly closely related to the existence of reefs coral because the ecosystem is a habitat for reef fish. Coral reefs are ecosystems that are commonly found on small islands in the tropics including the Seribu Islands. The Seribu Islands are a group of 110 islands located off the coast of Jakarta and up to 80 kilometers north of the Java Sea. In this study, we examined the species distribution and diversity of reef fish species on two different distance location in Jakarta Bay using environmental DNA (eDNA) metabarcoding analysis from two sites which are Untung Jawa Island and Harapan Island. The 4L eDNA seawater samples were collected at a depth of 8-9 meters at each site and then analysis using specific primer (MiFish U) of 12S rRNA. Overall, the higher species richness was found on Harapan Island (52 species) followed by Untung Jawa Island (11 species). The Shannon-Wiener Index also showed Harapan Island has higher reef fish diversity based on three taxonomic level (family, genus, and species). There were only five mutual reef fish species found in the two locations, namely Atherinomorus aetholepis, Auxis thazard, Cephalopholis sexmaculata, Epinephelus chlorostigma, and Plectropomus areolatus. The results of these findings in this current study are in line with anthropogenic pressure different where Untung Jawa Island is the closer one to Jakarta Bay than the Harapan Island that located relatively far from Jakarta Bay

The Effects of Reduced Social Security Contributions on Employment: an Evaluation of the 2003 French Reform

In 2003, the French government decided to reform the system managing the different minimum wage regulations and the targeted reductions to employers' social security contributions. The main objective of the reform was to simplify the complex regulations that were created by the progressive introduction of the 35-hour week. The reform incidentally created large variations in labour costs, depending on the type of firm and the wage level within the firm. This paper presents an evaluation of the impact of this reform on employment using a balanced panel of firms with more than five employees, drawn from a matching between several administrative data sources from 2000 to 2005. In both types of firm, significant employment elasticities can be found with respect to labour costs that have the expected signs: a rise of 1% in average labour costs reduces employment by 0.4%. As the majority of firms that remained on the 39-hour week received greater reductions, the Fillon reform allowed them to raise their level of employment. Firms that adopted the 35-hour week experienced the opposite: the reform led to a fall in employment. Ultimately, the Fillon reform has had no clear effect on aggregate employment, measured either in job numbers or full-time equivalents (FTE)

The Effect of CO2 Injection on Macroalgae Gelidium latifolium Biomass Growth Rate and Carbohydrate Content

There are many species of macroalga grow in marine ecosystem and potentially as raw material for bioethanol resource. Bioethanol is a conversion result of carbohydrate, one of macroalgae biomass content. The exploration of macroalgae require information about  growth rate ability to determine availability in the nature. This research analyze growth rate and carbohydrate content of marine macroalga Gelidium latifolium on cultivation using varied injection of carbon dioxide and aeration. The treatments were control (K), 2000 cc CO2 injection and aeration (P1), 3000 cc CO2 injection and aeration (P2), 2000 cc CO2 injection without aeration (P3), and 3000 cc CO2 injection without aeration (P4). Samples weight were 3 gram in early cultivation on laboratorium scale for 42 days observation. The results showed that the daily growth rate Gelidium latifolium during the study ranged from 0.02-1.06%. The highest daily growth rate was 1.06±0.14% (P2). Carbohydrate yield was 18.23% in early cultivation then 19.40% (K and P2), 20.40% (P1), 16.87% (K3), and 16.40% (P4) after cultivation. The high of carbohydrates value may not guarantee the sustainable Gelidium latifolium biomass utilization as raw material for bioethanol production because of the low growth rate, thus it is necessary to modified and encourage cultivation method effectively. Keywords: CO2 injection, growth rate, carbohydrate, macroalgae, Gelidium latifoliu

eDNA metabarcoding of decapod crustaceans across Indonesian seas has implications for biodiversity conservation and fisheries sustainability

Environmental DNA (eDNA) methods are increasingly viewed as alternate or complementary approaches to conventional capture-based surveys for marine conservation and fisheries management purposes, especially at large spatial scales in mega-biodiversity regions such as Indonesia. Decapod crustacean distribution and diversity across Indonesia are still poorly known, even for economically important fisheries commodities. This study assessed coral reef associated decapod diversity and distribution by sampling 40 sites in three regions (West, Central, East), representing 17 provinces and 10 Fisheries Management Areas (FMAs) across Indonesia, with a special focus on the blue swimming crab Portunus pelagicus. DNA sequencing (Illumina iSeq100) data were analysed in mBRAVE (Multiplex Barcode Research And Visualization Environment) yielded 406 OTUs belonging to 32 families, with 47 genera and 51 species identified. The number of families identified was highest in the Central region (25), while the most genera (31) and species (36) were identified in the West region. Alpha diversity did not differ significantly between regions or provinces, while Beta diversity differed significantly between provinces but not between regions. Our results also showed 31 species are possibility native based on the distribution meanwhile 12 species do not appear to have been recorded based of SeaLifeBase or WorMS. While providing a reference for further exploration of Indonesian coastal and small island decapod biodiversity, the high proportion of unidentified taxa calls for concerted efforts to develop and maintain reference specimen and sequence repositories and expand species conservation status assessments. The economically important decapod crustaceans identified in this study included three crabs (Charybdis anisodon, Charybdis japonica, Portunus pelagicus), a freshwater prawn (Macrobrachium nipponense), a lobster (Panulirus stimpsoni) and two penaeid shrimps (Mierspenaeopsis hardwickii and Trachysalambria aspera). For most decapod taxa, observed patterns indicate management under existing provincial and/or FMA level management structures is appropriate. Furthermore, the data can inform science-based fisheries management strategies, in particular for P. pelagicus