The Role of Equatorial Oceanic Waves in the Activation of the 2006 Indian Ocean Dipole

Observations and a linear wave model were used to evaluate the role of equatorial oceanic wave processes in affecting the evolution of the 2006 positive Indian Ocean Dipole (IOD), focusing on the activation phase of the event. The observations indicate the presence of upwelling equatorial waves and westward near-surface zonal currents along the equator during the activation phase of the event in August 2006. These upwelling equatorial waves (negative sea surface height anomalies) and westward zonal current anomalies contributed to significant sea surface cooling in the eastern equatorial Indian Ocean. The model results reveal that the upwelling equatorial waves and westward nearsurface zonal currents were mainly generated by wind-forced Kelvin waves associated with the easterly wind anomalies. On the other hand, anomalous easterly winds along the equator during June caused downwelling waves (positive sea surface height anomalies) in the off-equatorial region which propagated westward and elevated sea levels in the western region. The model further shows that a complex interplay of wind-forced and boundary-generated Rossby waves elevated sea levels in the western equatorial Indian Ocean during the activations phase of the 2006 IOD event

El Niño Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and the Rise of Extreme Temperatures in Eastern Sumatra: Exploring Climate Change Dynamics

The Indonesian region is affected by the monsoon system, which leads to a rainy season in December-March and a dry season in June-September. Global warming caused by human activities is increasing the risk of extreme climate events like floods, droughts, etc. The study aims to analyze the trends and correlations of extreme temperatures in the South Sumatra coastal area and its relationship with the DMI and Nino 3.4 indices. The four-stage research methodology includes data collection, extreme temperature index calculation, trend detection and correlation analysis with ENSO. Results indicate that the region has seen a rise in temperature, with hot day/night temperatures increasing by 0.26-0.29°C per decade and cold day/night temperatures by 2-3°C per 100-1000 years. A strong correlation was found between the DMI index and daily maximum/minimum temperatures, as well as between the Nino 3.4 index and the Diurnal Temperature Range (DTR). The study projects that nighttime temperatures will increase faster than daytime temperatures in the future, with a proportional correlation between the Nino 3.4 index and extreme temperature

RESTORASI HUTAN MANGROVE TERDEGRADASI BERBASIS MASYARAKAT LOKAL

Mangrove forests are the main ecosystem of life support in coastal areas that have important ecological functions.Although the mangrove forests have many important functions in the coastal areas but excessive used and not oriented to sustainabilitycause degradation of mangrove forest ecosystems. The main cause of mangrove forests degradation in the world is due to anthropogenic influences such as agricultural activities, plantations, fish and shrimp ponds, settlements, loggings (legal logging and illegal logging), pollution, mining and salt ponds. Therefore, local community participation is needed tocontrolthe utilization of mangrove forests. In addition, local people living in coastal areas are at the forefront in mangrove forests restoration because they require the existence of sustainable mangrove forest and have local wisdom that has been tested. Ecological functions and economic functions of mangrove forest ecosystems can be maintained through increasing public awareness of the importance of preservation, in order to reach the optimization and sustainability of the mangrove forests. The local communityparticipation should be supported by government, NGOs and researchers/academics.Hutan mangrove merupakan ekosistem utama pendukung kehidupan di wilayah pesisir yang memiliki fungsiekologisyang penting. Walaupun hutan mangrove memiliki banyak fungsi penting di wilayah pesisir namun sering kali pemanfaatan yang berlebihan dan tidak berorientasi pada keberlanjutan telah menyebabkan degradasi terhadap ekosistem hutan mangrove. Penyebab utama degradasi hutan mangrove di dunia adalah akibat pengaruh antropogenik berupa aktivitas pertanian, perkebunan, tambak ikan dan udang, pembangunan pemukiman, penebangan kayu (legal logging dan illegal logging), pencemaran, pertambangan dan tambak garam.Oleh karena itu peran serta masyarakat lokal sangat diperlukan dalam upaya mengontrol laju penggunaan hutan mangrove. Disamping itu, masyarakat lokal yang hidup di wilayah pesisir merupakan ujung tombak dalam merestorasi kawasan hutan mangrove karena mereka membutuhkan keberadaan hutan mangrove yang lestari serta memiliki kearifan lokal yang telah teruji. Fungsi ekologis dan ekonomis ekosistem hutan mangrove dapat dipelihara melalui peningkatan kesadaran masyarakat akan pentingnya pelestarian, sehingga tercapai optimalisasi dan keberlanjutan pengelolaan kawasan tersebut. Peran masyarakat tersebut harus pula didukung oleh peran pemerintah, LSM dan peneliti/akademisi

Simulated Interannual Modulation of Intraseasonal Kelvin Waves in the Equatorial Indian Ocean

Outputs from a high-resolution ocean general circulation model (OGCM) for the period of 1990-2003 indicate an interannual modulation of intraseasonal Kelvin waves along the equatorial Indian Ocean. During normal conditions without IOD event, the first mode explains about 30-40% of the total variance in the western (60-65ºE) and central (75-80ºE) basin, while the second mode contributes up to 45% to the total variance in the central basin around the longitude of 82ºE. In contrast, during the 1997/98 IOD event, the fourth mode caused about 40% of the total variance in the central and eastern basin. During the 1994 IOD event, the contribution from the fourth baroclinic mode in the eastern basin caused 45% of the total variance. In the central basin, the second and the fourth baroclinic mode caused almost the same variance (~40%). The variations in the characteristics of the intraseasonal Kelvin waves are related to variations in the vertical stratification. During the IOD event, the pycnocline in the eastern basin was raised by about 50 m and the stratification at the upper level is strengthened, while it is weakened at lower levels. These changes lead to an increase in the contribution of higher-order baroclinic modes

Analisis Pemodelan Data Pasang Surut Menggunakan Model TPXO 7.1 di Pelabuhan Tanjung Priok, Jakarta Utara

Aktifitas pembangunan dan pelayaran di Pelabuhan Tanjung Priok sangat tinggi sehingga membutuhkan informasi pasang surut guna mendukung perencanaan pembangunan, alur keluar masuk kapal untuk bongkar muat barang, serta keselamatan pelayaran. Oleh karena itu, penelitian ini bertujuan untuk membandingkan karakteristik pasang surut observasi dengan karakteristik pasang surut prediksi model TPXO 7.1 dari perangkat lunak Tidal Model Driver (TMD) serta menganalisa keakurasian data pasang surut model TPXO 7.1. Metode penelitian yang digunakan untuk mengolah data observasi pasang surut menggunakan metode admiralty dan data prediksi pasang surut didapat dari model TPXO 7.1. Validasi data pasang surut dilakukan dengan menghitung Root Mean Square Error (RMSE) dan korelasi dari kedua data. Penelitian ini dilaksanakan bulan Maret 2018. Hasil analisis menunjukkan bahwa tipe pasang surut dari data prediksi model TPXO 7.1 dan data pengamatan langsung memiliki tipe pasang surut campuran dominan ke tunggal. Akurasi data pasang surut model TPXO 7.1 memiliki nilai RMSE sebesar 0.14 dan korelasi sebesar 0.73, dengan demikian data prediksi Model TPXO 7.1 dapat digunakan untuk menggantikan data observasi pada wilayah yang tidak diukur langsung

COMMUNITY-BASED MANGROVE FORESTS CONSERVATION FOR SUSTAINABLE FISHERIES

The mangrove forests are a type of salt tolerant vegetation, living in tidal zones in tropical and subtropical coastalareas with unique ecosystem that have a strategic function as a connector and counterweight of terrestrial and marineecosystems. Mangrove forests are a productive ecosystem and they have complex functions, such as physical functions,biological functions and socio-economic functions. Fishery resources of mangrove forests are very productive, bothquantitatively and qualitatively, because the mangrove forests act as the natural habitat (spawning, nursery and feedinggrounds) for various species of fish, shrimps and crabs, as well as a source of germplasm and genetic pool. Mangroveforests also provide valuable ecosystem services to coastal communities, tourist attractions, nature conservation,education and research. However, these ecosystems are fragile because it is very sensitive to environmental changes,usually because anthropogenic influences; therefore, it is difficult to be restored. In addition, these ecosystems are soopenly accessible that easily exploited by humans; this can reduce its quality and quantity. Local communities who usemangrove forests and their resources may have considerable botanical and ecological knowledge about their forests.Silvofishery techniques in aquaculture are very suitable for community-based mangrove forests conservation efforts.Silvofishery is an integrated model that considers both economically benefit and conservation.Key words: mangrove conservation, sustainable fisheries, community-base

The Rapid Changes of the Landscape Structure of the Meranti-Dangku Tropical Lowland Forest in the South Sumatra Province, Indonesia

The fragmentation of forest vegetation cover can be measured quantitatively, using tools that can characterize the geometry and spatial properties of the patch or patches of mosaic, which depicts the forest loss and the changes in the temporal pattern.   The aims of this paper are to observe the process of the forest fragmentation, to find out the changes of spatial patterns of habitat continuum by applying the spatial dynamics change analysis of the forest fragmentation phases, and to provide the comprehensive approach in determining the rapid change of the forest landscape structure in the spatial transformation process, based on the decision tree models.  We find three phases of the forest fragmentation were identified, namely dissection, dissipation, and attrition.  This study shows that the production forest area and a wildlife conservation area that contiguous or borders, has the same phases in the process of fragmentation of the forest, but both have a difference of the magnitude of forest loss.  We find there are at least five effects of forest fragmentation to the landscape structure, those are  increasing in a number of habitat patches, decreasing in a size of habitat patches, reduction in a habitat amount, increasing in a dispersion and interspersion of patch types, and reduction in a size of spatial connectedness between patches.Keywords: fragmentation, landscape metrics, spatial transformation

Molecularly Imprinted Polymers (MIP) Based Electrochemical Sensor for Detection of Endosulfan Pesticide

The use of endosulfan pesticides in agriculture can cause environmental problems, such as pollution in aquatic environments that can lead to destruction of fishery resources and drinking water. So, it has become imperative to detect and separate the hazardous pesticide endosulfan from contaminated water. In this work, molecularly imprinted membrane has been fabricated for the specific recognition by using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethyl acrylate (EGDMA) as cross linker. The molecular imprinting of endosulfan on membrane matrix was confirmed by Scanning Electron Microscopy (SEM). This was followed by sensing of the endosulfan by voltammetry. The electrochemical potential is additional information enhancing the selectivity of the sensor. It can be concluded that MIP-based voltammetric sensors are very promising analytical tool for the development of highly selective analytical sensor. The test results of electrode performance indicated that MIP endosulfan-based aluminum-carbon sensor had detection limit of 0.02 mM, sensitive in the concentration range from 0.02 to 0.12 mM with Nernst factor > 0.059 V/decade and had good stability.

Long-term shift and recent early onset of chlorophyll-a bloom and coastal upwelling along the southern coast of Java

Long-term change in the timing of coastal upwelling due to climate variations alters the heat budget and biogeochemical balance in the regional ocean and is an important issue in local fisheries. In this study, we investigated decadal changes in the onset of coastal upwelling along the southern coast of Java over the past two decades (2003–2020) based on the timing of chlorophyll-a (Chl-a) bloom. We estimated the bloom from satellite Chl-a concentration data. On average, the onset of coastal upwelling observed (the first Chl-a bloom of the year) was around mid-June. In the most recent decade (2011–2020), earlier-onset upwelling (before early June) was observed frequently, and the linear trend for the onset date during 2003–2020 was about 2 weeks earlier/decade. To explore the causes of the change in the timing of the upwelling, we focused on the season (April–June) during which these earlier upwelling onsets occurred, and investigated decadal changes in atmosphere and ocean conditions associated with climate change. While sea surface temperature (SST) trends reflected a basin-wide warming pattern in the Indian Ocean, warming was not significant in the southeastern Indian Ocean. During the onset period of coastal upwelling, significant SST warming trends were also observed west of Sumatra. In association with the SST warming pattern, enhanced convective activity and convergent zonal winds around Sumatra were observed. Atmospheric forcing revealed trends favoring Ekman downwelling in the equatorial eastern Indian Ocean and upwelling in the southeastern Indian Ocean, which was consistent with the trends in thermocline depth. This study provides the first results regarding the recent decadal shift in the onset timing of coastal upwelling. Ongoing monitoring is needed to better understand the long-term change of the upwelling system in the eastern tropical Indian Ocean