Sutrisno Anggoro

Waves Induce Sediment Transport at Coastal Region of Timbulsloko Demak

Waves have variation of length and period. This influenced by seasonal variation. Impacts of seasonal variation related to wave is playing important roles in sediment transport mechanism and coastal changes. This condition not only treats coastal area but also decreases economic capacity of community. This research aim to determine different seasonal based on Indonesia Northwest-Northeast monsoon and Southeast-Southwest monsoon and theirs relation to sediment transport. Area of study is suffered by 938.73 H of abrasion. Conducted by CERC methods, transforming BMKG Ahmad Yani wind database (2005-2015) into wave’s data of seasonal variation and using field measurement recorded by ADCP. Definitely, maximum speed of wind is reached at 23 knots from December to February, wind direction predominantly from North West direction. Range of significant Wave Height (Hs) all season is 24.66-30.32 cm and Significant Wave period (Ts) count at 3.64-3.78 sec. Net of sediment volume annual 72,353.40 m3 year -1 and sediment movement pattern is forwarding from west to east direction. Correlation between breaking waves and sediment transport is linier.

Mapping of trophic states based on nutrients concentration and phytoplankton abundance in Jatibarang Reservoir

Jatibarang Reservoir is one of the Indonesian Reservoirs, which used for human activities such as tourism and agriculture. These activities will provide input of organic matter and nutrients into the water. These materials will impact water quality and eutrophication process. Eutrophication is the water enrichment by nutrients, especially nitrogen and phosphorus which can promote the growth of phytoplankton. Some indicators of eutrophication are increasing nutrients, trophic states, and change of phytoplankton composition. The relationship between water quality and phytoplankton community can be used as an indicator of trophic states in Jatibarang Reservoir. The aim of this study was to analyze the effect of nutrients concentration and phytoplankton abundance to the trophic states and mapping trophic states based on nutrients concentration and phytoplankton in Jatibarang Reservoir. This study was conducted in June and July 2017 at 9 stations around Jatibarang Reservoir. The results showed that average concentration of nitrate, phosphate, and chlorophyll-a in Jatibarang Reservoir was 0.69 mg/L, 0.27 mg/L, and 1.66 mg/m3, respectively. The phytoplankton abundance ranged 16-62,200 cells/L, consists of 21 genera of four classes, i.e. Chlorophyceae, Cyanophyceae, Bacillariophyceae, and Dinophyceae. Cyanophyceae was a dominant phytoplankton group based on the composition of abundance (>80%). High nutrient concentrations and phytoplankton dominated by Anabaena (Cyanophyceae) which indicated that the waters in Jatibarang Reservoir were eutrophic.

MJO (Madden-Julian Oscillation) Analysis of the Chlorophyll-a Distribution in Western Waters Bengkulu

The global phenomenon Madden-Julian Oscillation (MJO) is one of the dominant oscillation in the equatorial region of the Indian Ocean that oscillates between 30-60 days and experience the process of convection movement from west to east. MJO has a correlation of high intensity rainfall of the area in its path. During his journey eastward, the MJO is influenced by the position of the sun. When the sun in the equatorial MJO moves straight east. Meanwhile, when the position of the sun in the south of the equator, MJO shifted slightly to the south of the equator, known as the propagation of the south-east (south-eastern propagation). When the position of the sun is in the north of the equator, MJO shifted slightly to the north of the equator, known as the propagation of the north-east (north-east of propagation). Waters west of Bengkulu has a huge potential in the fisheries sector, which is situated overlooking the Indian Ocean. The phenomenon MJO influence on rainfall, sea surface temperature, and the concentration of chlorophyll-a. This study aims to look at the temporal distribution of sea surface temperature and chlorophyll-a and decide how MJO relationship with SST and precipitation conditions and increasing the amount of chlorophyll during the phase of the MJO in Bengkulu waters. The dataset used is data of chlorophyll-a which download in oceancolor.gfsc.nasa.gov , sea surface temperature data is used is a model of Kaplan Extended V2, RMM1 index data and RMM2 on www.bom.gov.au and rainfall data of Bengkulu region. The method used is descriptive statistical methods, Conditional Probability and logistics regression. From the above explanation can be said that there is a relationship between the incidence of MJO by the number of chlorophyll-a. Odds the addition of chlorophyll-a have a linear relationship with the duration of the incident MJO in Bengkulu, odds increase the amount of chlorophyll-a in Bengkulu region reaches a threshold value of 0.5, it means that the length occurrence MJO able to identify increasing the number of chlorophyll-a in Bengkulu.

The Dynamics of Sea Surface Height and Geostrophic Current in the Arafura Sea

The aim of this research is to analyze the dynamics of sea surface height and geostrophic current in relation to upwelling and downwelling phenomenon. The climatic factor such as monsoon are also calculated to understand dynamic of all parameters. The location of this research is in the waters of Arafura Sea waters. The data used in this research include sea surface height anomaly and geostrophic current. The method used in this research is done by analyzing the relation of sea surface height and geostrophic current with the eddy current flow. Spatial and temporal analysis using Surfer will be used in this research to visualize the parameters. The result showed that the upwelling (downwelling) phenomenon occurs when the geostrophic current rotate with the cyclonic (anticyclonic) flow followed by higher (lower) sea surface height. The upwelling event mostly occurred during the Southeast Monsoon and downwelling event mostly occurred during Second Transitional Monsoon until Northwest Monsoon.

Analysis of heavy metal content of Pb in ballast water tank of commercial vessels in port of Tanjung Emas Semarang, Central Java province

Commercial vessels that do not conduct ballast water exchange, in accordance with International Convention Ballast Water Management, will endager the environment of ports. This research is aimed to know the metal content in ballast water tank of commercial vessels that have not performed ballast water exchange, in accordance with regulations of International Maritime Organization (IMO). The research about the heavy metal content of ballast water of commercial vessels, both passenger or cargo vessels, berthing in Port of Tanjung Emas Semarang (PTES), has been conducted by using method of AAS (Atomic Absorption Spectroscopy). Sample was gathered from vessels berthed in PTES, dated on December 18th 2014 to October 21st 2015. Results of the research show that the mean content of Pb in ballast water tank is 0.37192 mg/l. Based on the Decree of Minister of Environment Number 51/2004, the heavy metal content of Pb in ballast water tank has exceeded the quality standards of port waters.Commercial vessels that do not conduct ballast water exchange, in accordance with International Convention Ballast Water Management, will endager the environment of ports. This research is aimed to know the metal content in ballast water tank of commercial vessels that have not performed ballast water exchange, in accordance with regulations of International Maritime Organization (IMO). The research about the heavy metal content of ballast water of commercial vessels, both passenger or cargo vessels, berthing in Port of Tanjung Emas Semarang (PTES), has been conducted by using method of AAS (Atomic Absorption Spectroscopy). Sample was gathered from vessels berthed in PTES, dated on December 18th 2014 to October 21st 2015. Results of the research show that the mean content of Pb in ballast water tank is 0.37192 mg/l. Based on the Decree of Minister of Environment Number 51/2004, the heavy metal content of Pb in ballast water tank has exceeded the quality standards of port waters.

Pesticides Usage in the Soil Quality Degradation Potential in Wanasari Subdistrict, Brebes, Indonesia

Uncontrolled application of pesticides can contaminate soil and may kill other nontarget organisms. This study aims to determine the usage pattern of pesticides by farmers in Wanasari Subdistrict and study the soil quality degradation potential. This study was a quantitative and qualitative research. Sources of data were collected from observation, questionnaire, and in-depth interview methods. The respondents were shallot farmers who planted shallot during 2013–2016 ( ). In-depth interview was done with three respondents from the local agricultural extension center (BPP). This study found that there were some different types of insecticides and fungicides that were used in every planting season. The farmers applied pesticides in large amount once every three or four days. They mixed minimally three insecticides and fungicides types about 30–40 ml for each type. Organophosphate residues that were found in soil samples were methidathion residue about 0.014 mg/kg, malathion residue ranging around 0.1370–0.3630 mg/kg, and chlorpyrifos residue in the range of 0.0110–0.0630 mg/kg. The excessive application of pesticides showed the land degradation potential. Soil quality laboratory testing is recommended to ensure the agricultural land condition. Routine assessment of soil quality and pesticide usage control is recommended to keep sustainable ecosystem.