I Wayan Nurjaya

Seasonal distribution and geochemical fractionation of heavy metals from surface sediment in a tropical estuary of Jeneberang River, Indonesia

Lead (Pb) and zinc (Zn) concentrations from surface sediments were determined at 17 stations in riverine, estuarine, and marine environments during the wet and dry seasons. The geochemical fractionations were obtained by a sequential extraction procedure in five geochemical forms: exchangeable, bound to carbonate, iron-manganese oxide, organic, and residual fractions. The concentrations of Pb and Zn in the water were higher during the wet season than the dry season and higher in the riverine and marine samples than the estuarine samples. Following geochemical fractionation, the metals were found mainly in the residual fraction. The results indicated that the concentrations were influenced by season, with the sources of Pb and Zn derived mainly from rivers and natural sources. The contamination status in the estuary of the Jeneberang River was classified as weak to moderate pollution and the risk level to aquatic biota attributed was no risk to low risk.

An assessment of a coastal altimetry data product in the Indonesian Waters

We analyzed the percentage of valid coastal altimetry Jason-2 X-TRACK-SLA data by Center for Topographic Studies in Sea and Hydrosphere (CTOH) and the waveforms from the Sensor Geophysical Data Record (SDGR) that are distributed by NOAA National Ocean Data Center around the Indonesian waters. In general, the percentage of valid data after the first point of the shoreline is greater than 90%. The percentage of valid data in steeper waters (86%) is higher than sloping waters (34%). The waveform types formed in coastal waters are peaky and Brown. However, spatially there is a difference where in a steep coast at a distance of > 5 km from the coastline the type of waveform is identified Brown, while on the sloping coast the brown type is found at a distance > 10 km. The SLA time series indicate seasonal variations in which the SLA is negative during the Southeast Monsoon (May-October) and positive during Northwest Monsoon (November-April).

ANALISIS PERUBAHAN GARIS PANTAI DI PANTAI BARAT DAYA PULAU TERNATE, PROVINSI MALUKU UTARA

Research is a Shoreline Change Analisis along the South West Coast Ternate Island, North Molucas Province. This study aims to assess the shoreline changes from 2001 to 2011. The research was motivated by the reality on the Southwest Coast Ternate Island, accured abrasion and sedeimentasi to residential areas. There has been no comprehensive study on the extent of shoreline change is happening, and what are the factors that cause these changes. The purpose of this study was to analyze shoreline changes that occur in the Southwest Coast Ternaet island. Shoreline change analysis is done using two approaches that use DHI MIKE LITPACK models and digitized images using Landsat 7 ETM+. The results of image analysis used as a benchmark to validate the model output DHI MIKE LITPACK. Mixed model analysis results collated with the results of image analysis showed patterns of changes in the contour of the same coastline. Based on the analysis model, showed the highest abrasion occurs distasiun C (Sasa Coast) as far as 83.67 m and sedimentation occurred at station B as far as 45.69 m, based on the results of image analysis the highest abrasion occurred at station C of 27.14 m and sedimentation occurred at station E of 24.09 m . The amount of abrasion and sedimentation is affected by wave action that occurs and sand mining activities by the community in Southwest coast of the island of Ternate.