Ario Damar

Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia.

The present application of numerical modelling techniques provides an overview of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay. A hydrological model simulated river discharges with a total of 90 to 377m(3)s(-1) entering Jakarta Bay. Daily total nitrogen and total phosphorus loads ranged from 40 to 174tons and 14 to 60tons, respectively. Flow model results indicate that nutrient gradients are subject to turbulent mixing by tides and advective transport through circulation driven by wind, barotropic and baroclinic pressure gradients. The bulk of nutrient loads originate from the Citarum and Cisadane rivers flowing through predominantly rural areas. Despite lower nutrient loads, river discharges from the urban area of Jakarta exhibit the highest impact of nutrient concentrations in the near shore area of Jakarta Bay and show that nutrient concentrations were not only regulated by nutrient loads but were strongly regulated by initial river concentrations and local flow characteristics.

Pressure on oxygen levels of Jakarta Bay.

Jakarta Bay is subject to inputs of large amounts of dissolved inorganic nutrients and organic matter deriving from the Jakarta Metropolitan Area and its hinterland. As a consequence, inorganic and organic nutrient concentrations in the nearshore area are considerably increased. The hydrographic pattern inside the bay fosters phytoplankton bloom formation due to pronounced vertical density gradients. High Biomass Blooms (HBB) of phytoplankton are observed recurrently, representing an additional source for oxygen consuming degradable organic matter. An oxygen deficiency area of 20km(2) can be identified in the eastern part of Jakarta Bay where oxygen levels decrease to 60% saturation, equaling a noxiously low concentration of 4.0mg·dm(-3) O2. The absolute minimum detected was 51% O2 or 3.2mg·dm(-3) O2. The observed oxygen concentrations fail Indonesian quality standards for seawater.

Net Phytoplankton Community Structure and Its Biomass Dynamics in the Brantas River Estuary, Java, Indonesia

Research on estuarine phytoplankton ecology was conducted from March 2006 till March 2008 in two Brantas river mouths : Wonokromo and Porong, Indonesia, which was aimed to evaluate the phytoplankton ecology and its related environmental condition dynamics. Under water light measured as Secchi depth profiles show a strong influence of rainy season in reducing light availability due to high turbidity derived from the incoming rivers at both estuaries. Nutrient concentration dynamics were observed, showing higher values in the river mouth stations and lower values in the offshore stations. In Porong estuary, lowest nitrate concentrations were found in offshore waters (ranging from 0.72 to 1.21 µM NO3-N), while maximum values prevailed at river mouth stations (ranging from 2.62 to 2.71 µM NO3-N). Typical difference of the two monsoonal seasons on phytoplankton biomass is obviously observed, showing a low average phytoplankton biomass during the rainy season. Annual average of phytoplankton biomass in Porong and Wonokromo estuaries accounted for 4.75 µg Chl a l-1 and 2.51 µg Chl a l-1, respectively (ranging from 0.21 µg Chl a l-1 to 22.23 µg Chl a l-1). Low average of phytoplankton biomass in rainy season is likely due to light inhibition during the very turbid water of rainy period and inversely during the dry season. Phytoplankton biomas dynamics is correlated with that of nutrient concentration.

DAMAGE LEVEL AND CLAIMED VALUE ESTIMATION OF DAMAGE MANGROVE ECOSYSTEM IN BINTAN BAY, BINTAN DISTRICT

ABSTRACT Mangrove ecosystem in some regions of the Bintan Bay has suffered damage due to development of human settlements, developing of land transport infrastructure, and also logging by the community. The aim of this study was to assess the level of damage, factors affecting the damage , and to calculate the estimated value of claims for damaged mangrove ecosystem in the Bintan Bay , Bintan District . The results showed that mangrove vegetation in Bintan Bay consists of 16 species. Based on the analysis of standard criteria and guidelines for mangrove destruction KEPMENLH 201, 2004, the quality of mangroves in Bintan Bay was considered in a good criteria (very dense and medium) and damaged criteria (rare). The observation of satellite images from 1990 to 2013 showed that mangrove area decreased by 501.39 hectares or 27.1%. Contributing factor due to the decrease of mangrove trees was to fuel the manufacture of charcoal, construction of infrastructures such as roads, ports of fishing boats and also the establishment of the fish pond. Based on rehabilitation application scenario for 15 years, the total area of compensated mangrove due to its damage was 1091.727 hectares with rehabilitation cost of about R p 30.372.391.000,00. Meanwhile, for 30 years scenario rehabilitation, the total damage mangrove area that should be compensated was 1743.406 hectares. Keywords : Bintan Bay, mangrove ecosystem, estimated value damage claims

PENGELOLAAN EKOSISTEM MANGROVE BERBASIS SILVOFISHERY DI KECAMATAN CIBUAYA, KABUPATEN KARAWANG

Penelitian ini bertujuan untuk merumuskan pola pengelolaan silvofishery melalui pengoptimalan skenario kelas tambak silvofishery terpilih. Analisis penelitian menggunakan analisis trade off dengan tiga alternatif skenario yaitu (1) tambak silvofishery kelas II (persentase tegakan mangrove dalam tambak (61%-80%), (2) tambak silvofishery kelas III (40%-60%), dan (3) tambak silvofishery kelas IV ( 80%), (2) Class II (61 – 80%), (3) Class III (40% - 60%), dan Class IV (< 40%). The result from trade off analysis showed rangking of score for each class based on 5 criteria, they are (1) class III scenario, in this class the highest average of score is 56,88; (2) class II scenario, in this class average of score is 45,03; (3) class IV scenario, in this class the highest average score is 31,51. Trade off also showed rangking of weight for each class, the rangking are (1) weight of economy criteria is 0,40; (2) weight of ecology criteria is 0,23; (3) weight of bioengineering cultivation criteria is 0,16; (4) weight of institutional criteria is 0,13; (5) weight of social criteria is 0,08. The result from multiplication process be obtained that the first alternative scenario is Class II (with total value 66,68), the second alternative scenario iss Class IV (40,73), and the third alternative scenario is Class II (36,99). Therefore, Perhutani should encourage tenants Silvofishery fourth grade (Class IV) (percentage mangrove <40%) to Class III (mangrove percentage 60%. Thus, tenants are required to replant mangrove farms in fishponds that have been deforested up to 60% and 40% of mangrove fishponds. The ponds class II (percentage 61-80%) can be used as the Pilot Center Silvofishery or education tourism for society.

Distribusi Horizontal Klorofil-a Fitoplankton Sebagai Indikator Tingkat Kesuburan Perairan di Teluk Meulaboh Aceh Barat

The research on horizontal distribution clorophyll-a fitoplankton as indicator the tropic state in waters of Meulaboh Bay conducted on MeiJuly 2014 in Meulaboh Bay. Sampling was done using the method of purposive sampling at 10 sites, which consist of river, mouth river, bay waters, and middle of bay to outer of bay. The purpose of this research is to analyse horizontal distribution of clorophyll-a fitoplankton as the tropic state indicator in the waters and to analyse relationship between clorphyll-a fitoplankton with nutrients availability N and P. The result showed that the horizontal distribution pattern of clorophyll-a fitoplankton dominated by the waters near to teresterial land, likes river, mouth river, and edge of bay, afterward its gradually slightly decrease in the middle of bay and lower in outer of bay. High or low of clorophyll-a was due to the influence of nutirent load N and P in the waters of Meulaboh Bay. The tropic states based on abundance clorophyll-a fitoplankton was categorised in the mesotrofic condition.The research on horizontal distribution clorophyll-a fitoplankton as indicator the tropic state in waters of Meulaboh Bay conducted on Mei-July 2014 in Meulaboh Bay. Sampling was done using the method of purposive sampling at 10 sites, which consist of river, mouth river, bay waters, and middle of bay to outer of bay. The purpose of this research is to analyse horizontal distribution of clorophyll-a fitoplankton as the tropic state indicator in the waters and to analyse relationship between clorphyll-a fitoplankton with nutrients availability N and P. The result showed that the horizontal distribution pattern of clorophyll-a fitoplankton dominated by the waters near to teresterial land, likes river, mouth river, and edge of bay, afterward its gradually slightly decrease in the middle of bay and lower in outer of bay. High or low of clorophyll-a was due to the influence of nutirent load N and P in the waters of Meulaboh Bay. The tropic states based on abundance clorophyll-a fitoplankton was categorised in the mesotrofic condition.

Dinamika Spasial dan Temporal Struktur Komunitas Zooplankton di Teluk Jakarta

Study of spatial and temporal dynamics of zooplankton community structure in the Jakarta Bay. The purpose are analyzing the abundance, distribution, diversity, and dominance index with indicators of water quality spatial and temporal waters of Jakarta Bay. The research was conducted from July-October 2013. Sampling was done four times (July, August, September, and October). The water quality was analysed by Laboratory Productivity and Water Environment at Department of Resources Management, Faculty of Fisheries and Marine Sciences, Bogor Agricultural University. Zooplankton were analyzed using the method of enumeration (census SRC), in Micro Biology Laboratory Faculty. Based on the distribution patterns were its indicates that the landward dissolved oxygen (DO) is increasingly high, especially in August, September, and October, and increase the abundance of zooplankton as much as 1.3106 Ind/m3. DO with a high spatial concentration value reaches the range of 6.2-14.5 mg/L in Muara Marunda (Station 10), and increase the abundance of zooplankton as much as 5.1106 Ind/m3, with a majority composition of crustacea. Results of classification was diversity moderate, stable uniformity, and high dominance index.