Judul: Estimation of CO2 Flux and Carbon Stock in Mangrove (Rhizophora stylosa) and Sentigi (Pemphis acidula) Vegetation
Abstrak: Penyerapan dan penyimpanan karbon oleh tumbuhan menjadi sangat penting dalam upaya mengurangi jumlah karbon dioksida (CO2) di atmosfer yang berasal dari aktivitas industri. Penelitian ini bertujuan untuk mengetahui fluks CO2 melalui dynamic chamber, mengetahui hubungan fluks CO2 dengan suhu dan intensitas cahaya, mengetahui kandungan klorofil, serta mengestimasi cadangan karbon pada vegetasi mangrove (Rhizophora stylosa) dan sentigi (Pemphis acidula) di area kegiatan penghijauan PT Kangean Energy Indonesia (PT KEI). Fluks CO2 dihitung melalui dynamic chamber serta cadangan karbon diperoleh dari perhitungan biomassa atas permukaan dan biomassa bawah permukaan. Hasil penelitian menunjukkan fluks CO2 dipengaruhi oleh intensitas cahaya ketika pengukuran berlangsung. Pengamatan yang dilakukan pada siang hari akan menyebabkan nilai fluks yang tercatat lebih rendah dibandingkan pada pagi dan siang hari karena pengaruh Photosintesis Photon Flux Density (PPFD). Fluks CO2 memiliki hubungan yang linear dan positif dengan PPFD. Kandungan klorofil yang terdapat pada sentigi lebih sedikit dibandingkan mangrove. Kandungan klorofil yang tinggi pada kedua vegetasi menunjukkan nilai PPFD yang lebih tinggi tinggi dan fluks CO2 yang tercatat di dalam chamber lebih kecil karena digunakan untuk fotosintesis. Cadangan karbon pada spesies R. stylosa lebih tinggi daripada P. acidula karena luas daun, diameter pohon, dan umur R.stylosa lebih besar nilainya. Nilai cadangan karbon di areal penghijauan PT KEI akan terus meningkat seiring dengan pertumbuhan tanaman., The absorption and storage of carbon by plants are very important to reduce the amount of carbon dioxide (CO2) in the atmosphere that comes from industrial activities. This study aims to determine CO2 flux through a dynamic chamber, determine the relationship between CO2 flux and temperature and light intensity, determine chlorophyll content, and estimate carbon stocks in mangrove (Rhizophora stylosa) and sentigi (Pemphis acidula) vegetation in PT Kangean Energy's reforestation area Indonesia (PT KEI). The CO2 flux is calculated through the dynamic chamber and carbon stock is obtained from the calculation of above-ground biomass and sub-surface biomass. The results showed that the CO2 flux was affected by the light intensity when the measurement took place. Observations made during the day will cause the recorded flux value to be lower than in the morning and afternoon due to the influence of Photosynthesis Photon Flux Density (PPFD). CO2 flux has a linear and positive relationship with PPFD. The chlorophyll content in sentigi is less than in mangroves. The high chlorophyll content in both vegetations indicated higher PPFD values and the CO2 flux recorded in the chamber was smaller because it was used for photosynthesis. The carbon stock of R. stylosa species was higher than that of P. acidula because the leaf area, tree diameter, and age of R.stylosa were higher. The value of carbon stocks in PT KEI's reforestation area will continue to increase along with plant growth.
Keyword: carbon stock, CO2 flux, photosynthesis, Pemphis acidula, photosynthesis photon flux density, Rhizophora stylosa, carbon uptake

Judul: Estimation of Carbon Content in Mangrove Stands in the Karangsong Mangrove Ecotourism Area, Indramayu Regency
Abstrak: Hutan mangrove mempunyai potensi mitigasi perubahan iklim karena kemampuannya dalam menyerap dan menyimpan karbon dalam waktu lama dan dalam jumlah besar. Adanya alih fungsi lahan dapat merubah komposisi vegetasi hutan mangrove dan mengurangi simpanan karbon. Penelitian ini bertujuan untuk mengetahui komposisi vegetasi pada kawasan ekowisata mangrove Karangsong dan mengetahui kemampuan mangrove dalam menyerap serta menyimpan karbon. Metode dalam penelitian ini yaitu jalur garis berpetak pada 10 titik stasiun pengamatan yang dianggap mewakili keseluruhan karakteristik vegetasi dengan total intensitas sampling sebesar 5%. Analisis kandungan karbon dilakukan menggunakan persamaan alometrik. Dari hasil analisis vegetasi terdapat 4 jenis mangrove, yiatu Avicennia marina, Avicennia alba, Rhizophora stylosa, Rhizophora mucronata. Total biomassa, kandungan karbon dan simpanan karbon dioksida seluruh kawasan seluas 20 ha yaitu beturut-turut sebesar 99,14 ton/ha; 46,6 tonC/ha; 171 tonCO2 /ha. Besarnya kandungan karbon yang tersimpan di kawasan ekowisata Mangrove Karangsong dipengaruhi oleh faktor lingkungan yang terbentuk pada tegakan mangrove., Mangrove forests have the potential to mitigate climate change because of their ability to absorb and store carbon for a long time and in large quantities. The existence of land use change can change the composition of mangrove forest vegetation and reduce carbon sequestration. This study aims to determine the composition of vegetation in the Karangsong mangrove ecotourism area and to determine the ability of mangroves to absorb and store carbon. The method in this study was a line transect plot at 10 points of observation stations which are considered to represent the overall characteristics of the vegetation, the total sampling intensity is 5%. Carbon content analysis was carried out using allometric equations. From the results of the vegetation analysis, there were 4 types of mangroves, namely Avicennia marina, Avicennia alba, Rhizophora stylosa, and Rhizophora mucronata. The total biomass, carbon content, and carbon dioxide uptake in the entire area of 20 ha are 99.14 tons/ha; 46.6 tonsC/ha; and 171 tonsCO2/ha, respectively. The amount of carbon stored in the Karangsong Mangrove ecotourism area was influenced by environmental factors formed in the mangrove stands.
Keyword: biomassa, karbon, mangrove, vegetasi

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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