Judul: Comparison of Spat Bivalvia Recruitment in Rehabilitated Mangrove Ecosystems with Natural Mangroves Rangsang Island, Riau Province
Abstrak: The life cycle found in mangrove bivalves in their growth into adult shells are spat. Spat is a juvenile that has settled on the bottom of the water in an area that is still small with a shell shape resembling an adult shell and will grow and develop in that area. Spat growth until it becomes an adult clam, takes place in the mangrove ecosystem area in brackish waters. The importance of the economic value of bivalves makes the availability of seeds very important. Knowing the type, abundance and life cycle of bivalves is the right step in estimating the ideal time for spacing bivalves. The research was conducted in a natural and rehabilitated mangrove ecosystem on Rangsang Island, Meranti Islands Regency, Riau Province, for 4 (months) months, starting from October to January 2021. The sampling location for A. granosa bilvalvia spat was determined by purposive sampling, which consisted of 2 (two) subzones and each subzone is located in the intertidal zone, namely at the highest high tide and highest low tide point in the mangrove ecosystem area, namely Subzone 1 is located in the lower subzone (Upper) in the highest tide area. Subzone 2 is located in the Upper (Lower) subzone at the lowest ebb and is on the beach. The distance between subzones is 50 meters. The results showed that the distribution of the abundance and spat length of A. granosa bivalves in the natural and rehabilitation mangrove ecosystems on Rangsang Island differed each month (November, December and January). The highest average abundance and length were found in December in rehabilitation mangroves of 79100 ind/100 m2 and 7.67 (±3.94) mm in length and in natural mangroves of 107100 ind/100 m2 and 4.25 (±3.60) in length and with an average mangrove density of 2,283.33 ind/ha and 42,33.33 ind/ha. The species found in the rehabilitated and natural mangrove ecosystems consist of Avicennia alba and Avicennia marina. Comparison of the abundance of Bivalve spats between the rehabilitation mangroves and natural mangroves did not show significant differences either between time periods or between zones. Spat length of A. granosa bivalves was affected (strong category) by pH and temperature. The relationship between mangrove density and A. granosa abundance was in the very strong category in December 2020 and January 2021, while the relationship between mangrove density and A. granosa abundance in November 2020 was in the strong category. The condition factor results showed that Bivalvia A. granosa in the rehabilitation mangrove ecosystem ranged from -5.41 to -1.34 and in natural mangrove ecosystems it ranged from -1.90 to -1.4. From these results the analysis of condition factors in both ecosystems described environmental conditions that were not good enough for A. granosa. So if viewed from these results, the rehabilitation and natural mangrove ecosystem on Rangsang Riau Island is a habitat that is not good for A. granosa to grow.
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Judul: Hubungan Antara Gastropoda dan Mangrove di Ekosistem Mangrove Rehabilitasi Pantai Indah Kapuk Jakarta
Abstrak: Ekosistem mangrove Pantai Indah Kapuk Jakarta merupakan ekosistem hasil rehabilitasi yang sebelumnya telah mengalami kerusakan akibat pengalihan fungsi lahan menjadi tambak. Kegiatan antropogenik Sungai Angke diduga mempengaruhi karakteristik lingkungan dan kerapatan mangrove. Kerapatan mangrove sebagai penyusun utama ekosistem, diduga mempengaruhi keberadaan biota asosiatif, termasuk gastropoda. Gastropoda berperan penting dalam fungsi ekologi dan siklus rantai makanan pada ekosistem mangrove. Kelimpahan dan distribusi gastropoda pada ekosistem mangrove dipengaruhi oleh lingkungan, makanan, dan predator. Kerapatan mangrove yang tinggi akan menghasilkan serasah yang lebih banyak yang selanjutnya menjadi sumber makanan gastropoda. Penelitian ini dilaksanakan pada bulan November 2019 di ekosistem mangrove rehabilitasi Pantai Indah Kapuk Jakarta. Penentuan stasiun penelitian menggunakan metode purposive sampling berdasarkan keberadaan vegetasi mangrove. Pengambilan data gastropoda, vegetasi mangrove, dan karakteristik lingkungan dilakukan dengan menggunakan metode transek kuadrat. Variasi karakteristik lingkungan antar stasiun penelitian dianalisis dengan menggunakan analisis komponen utama (Prnicipal Component Analysis / PCA). Hubungan antara gastropoda dan mangrove dianalisis dengan menggunakan analisis koresponden (Correspondence Analysis / CA). Hasil penelitian menunjukkan bahwa ekosistem mangrove rehabilitasi Pantai Indah Kapuk Jakarta memiliki 3 Genus gastropoda (Cassidula, Melampus, Salinator) dan 10 spesies (Cassidula angulifera, C. aurisfelis, C. rugata, dan C. vespertilionis, C. nucleus, Melampus luteus, M. olivaceus, M. globulus, M. monile, dan Salinator takii). Rata-rata keanekaragaman gastropoda di lokasi penelitian masuk kedalam kategori sedang. Gastropoda memiliki keterkaitan dengan variasi karakteristik lingkungan dan mangrove. Gastropoda berukuran besar, sedang, dan kecil dari Genus Cassidula terutama spesies C. aurisfelis dan C. vespertilionis banyak ditemukan di habitat yang didominasi oleh mangrove Avicennia marina dengan kerapatan pohon lebih dari 15 ind/100 m2 dan substrat (sedimen) berfraksi liat. Hasil penelitian ini dapat digunakan untuk kebijakan pengelolaan lebih lanjut bagi ekosistem mangrove rehabilitasi Pantai Indah Kapuk Jakarta yang berbasis pada sumber daya moluska.
Keyword: Gastropoda, Mangrove, Pantai Indah Kapuk, Sungai Angke

Judul: Sintesis dan Pencirian Kompleks Fe(III)-Kuersetin
Abstrak: Quercetin belongs to flavonols which is able to chelate metal ions. Quercetin may chelate metal ions at 3’,4’-catechol, 3- or 5-hydroxycromone sites. In this study, quercetin was complexed with Fe(III). The complex with Fe(III) ions from FeCl3·6H2O was more stable than the complex derived from Fe(NO3)3·9H2O. The quercetin was yellow in color and showed maximum wavelengths (λ􀭫􀭟􀭶) at 250 and 370 nm. The Fe(III)-quercetin complex from Fe(NO3)3·9H2O was yellowish green with 􀟣􀭫􀭟􀭶 at 280 and 420 nm, whereas that from FeCl3·6H2O was dark green with 􀟣􀭫􀭟􀭶 at 280 and 430 nm. The 􀟣􀭫􀭟􀭶 shift indicated that the complex was formed at 3-hydroxychromone site. The Fe(III)- quercetin complex was formed with 1:1 metal-ligand mole ratio based on atomic absorption spectrophotometry analysis and the X-ray diffractogram showed that the crystallinity of the complex was 37%.
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