Judul: Relationship between phytoplankton primary productivity and nutrient availability on different levels of clarity in waters off Kendari Bay, Southeast Sulawesi.
Abstrak: The relationship between primary productivity of phytoplankton to the availability of nutrients in the waters of the Bay of Kendari was implemented on April-June 2009 at three sites. The purpose of this research is to examine the relationship between primary productivity of phytoplankton with the abundance and biomass of phytoplankton, and the relationship between primary productivity of phytoplankton with nutrient availability and light intensity at various levels of brightness in the waters of the Bay of Kendari. Based on the data description and laboratory analysis, net primary productivity values during the survey period varied from 2,54 to 11,13 mgC/m3/hour with ranges of average value of NPP from 5,10 to 7,30 mgC/m3/hour. Sampling station located at the middle of the bay had the highest NPP value followed by sampling station positioned at the mouth of the bay and the lowest was found at sampling station located near the river mouth of the upper part of the bay. Relationship between primary productivity and sunlight intensity depicted a strong correlation at the three sampling stations. Relationship of primary productivity to nutrient and light intensity showed that the relationship high on all three stations. The three stations showed similar patterns between the three research stations. At the station mouth of the bay, the three nutrients N (ammonia, nitrate, and nitrite) and light intensity are also factors that provide a real influence on the high and low NPP values while at the middle station and inside the bay, nutrient nitrate with ICM provides a real influence against high and low NPP values in the waters.
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Judul: Relationship of phytoplankton productivity with nutrient availability streaming derived from the river and the sea in Inner Ambon Bay
Abstrak: The development of increasingly rapid development resulted in bay conditions, particularly in Ambon bay gets heavy pressure, resulting in changes in the aquatic environment. These changes further affect marine organisms that live in it. One of the marine organisms playing an important role for productivity is a water plankton community. Plankton community plays great role in marine ecosystems, particularly because phytoplankton are the foundation of the food chain so called primary producers. As primary producers, phytoplankton can form organic matter from inorganic matter through photosynthesis which in turn can be used directly by other living organisms. The purposes of this study were 1) to analyze seasonal changes in the distribution of temperature, salinity and density in the water; 2) to analyze the inter-relationship between the light intensity and the level of turbidity water; 3) to analyze the load level of nutrients in water derived from river and sea; 4) to analyze the spatial and temporal distribution of phytoplankton composition and abundance in the water; 5) to analyze seasonal changes in the level of productivity of phytoplankton in the water; and 6) to examine the inter-relationship between the succession of phytoplankton to changes in N:P ratio in the water of the Ambon bay. The results of this study indicate that temperature, salinity and density were low in East Season. In the Bay of Ambon there was stratification in temperature and salinity, while mixing was not occur either from surface to bottom water. Season were great influence on the distribution of nutrients in the water, again the average ammonia concentration was higher in East Season that indicate domestic sewage polluted water. Average NO3-N concentration of the lowest in the Western season (0.05 μm) and high in East Season (0.55 μm). Average concentration of nitrate in the East Season in Zone-1 was low and Zone-2 was high. In East Season high phosphate concentrations, so that phosphate stimulates rapid growth (blooming) Trichodesmium in water. Average concentration of silica in the East, Transition II, Western and Transition I Season highly significant, with the lowest concentrations in Transition Season I (1.29 μm) and high in East Season (35.61 μm). At the moment there was a high concentration of silica Bacillariophyceae low abundance in the eastern season. In the Transition II, the West, and the Transition I Season occurred increased abundance of Bacillariophyceae, along with decrease in the concentration of silica. Input nitrate and phosphate in East Season was very large from outside Ambon Bay compared to from river. Spatial and temporal waters in the Inner Ambon Bay were found oligotrofik and mesotrofik state. Flushing time were occured in Ambon Bay within 14 days. The average of chlorophyll-a concentration in the East, Transition II, West and Transition I Season were highly significant, the lowest concentration at West season (0.44 μg/l) and high in East season (0.94 μg/l). In the East Season, there was an increase of chlorophyll-a, but the low abundance of phytoplankton. In the East Season, chlorophyll-a negative correlation revealed in nitrate and nitrite, this is due to an increase in chlorophyll-a caused by decrease in nitrate and
Keyword: primary productivity, phytoplankton, nutrients, succession, Inner Ambon Bay

Judul: Konstruksi aritmetika kurva eliptik F(2m) supersingular dan non-supersingular untuk skema kunci publik ElGamal
Abstrak: Algoritme ElGamal adalah salah satu algoritme kunci publik dengan aritmetik modular p yang mempunyai struktur grip siklik Z(p). Tingkat keanaman algoritme ini terletak pada pemecahan masalah logaritme diskret dari Z(p). Akan tetapi, tingkat keamanan tadi tahun ke tahun semakin menurun yang disebabkan kemampuan pemecahan algoritme diskret semakin meningkat. Untuk memenuhi tingkat keamanan yang memadai dibutuhkan p yang cukup besar yang menyebabkan proses enkripsi dan dekripsi menjadi lambat.
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