No abstract

Padang lamun memiliki peran penting sebagai sumber utama produktivitas primer atau penghasil bahan organik, habitat untuk berbagai biota, tempat asuhan, tempat memijah, sumber makanan bagi biota langka dan penyokong keanekaragaman jenis-jenis biota laut serta bernilai ekonomis dari jasa ekosistem lamun. Aktivitas pembangunan di wilayah pesisir yang terus meningkat telah mengakibatkan kerusakan padang lamun di perairan timur pulau Bintan. Saat ini kajian terbaru terkait dengan kondisi lamun belum tersedia. Kajian ini dilakukan pada Mei dan September (2015-2016) dengan tujuan untuk mengetahui dampak perubahan tutupan lahan terhadap kondisi lamun di perairan timur pulau Bintan. Kondisi lamun ditentukan berdasarkan persentase tutupan lamun. Analisis perubahan penggunaan lahan menggunakan perangkat lunak ENVI 5.1 dan ArcGIS 10.1. Pengukuran debit sungai dan penanganan sampel air dilakukan di lapangan dan laboratorium P2O-LIPI Jakarta. Hasil penelitian menunjukkan bahwa perubahan penggunaan lahan menjadi lahan terbuka, perkebunan dan semak belukar pada DAS Kawal telah memberikan dampak menurunnya kondisi lamun khususnya di sekitar muara Sungai Kawal. Secara umum kondisi lamun di perairan timur Pulau Bintan menurun ditunjukkan dengan persentase tutupan lamun yaitu 46 % (2006) dan 41 % (2015). Dalam penelitian ini ditemukan tujuh spesies lamun, antara lain Enhalus acoroides, Thalassia hemprichii, Cymodocea rotundata, Cymodocea serrulata, Halophila ovalis, Halodule uninervis dan Syringodium isoetifolium.

Hypoxia is one of the aquatic phenomena caused by natural and/or anthropogenic factors. Eutrophication is the main trigger of hypoxia in coastal waters throughout the hemisphere. Hypoxia that occurs in aquatic ecosystems refers to the low concentration of dissolved oxygen in the water column to less than 2 mg/L. Hypoxia causes a double effect, low oxygen supply for biotic physiological process, and triggers ocean acidification. Prolonged hypoxic conditions will have a significant impact on the food webs in coastal waters and sea waters, further conditions will ultimately have an impact on capture-based fishing activities. The case of hypoxia in Indonesian coastal waters has not been widely revealed and has not been a concern to be understood or traced to its existence. Retrospective as well as actual traces of hypoxia were revealed, especially in the waters of Jakarta Bay. The retrospective study was carried out using proxies that have been used in various tropical and subtropical countries, the Ammonia-Elphidium (A-E) index (Foraminifera). The results show that several places in the coastal waters of Jakarta Bay and Semarang have experienced episodic hypoxic events for several centuries. A brief review of phenomenal hypoxic events in other parts of the world and preliminary information on recorded events in several Indonesian coastal waters are expected to open stakeholder awareness about further threats of hypoxia in Indonesian waters.

Coastal area is the most vulnerable area to climate change. Cirebon coastal land inWestern Java, Indonesia is low-lying coastal area which is one of the potential areal for fish culture and farming. There are also major transportation facilities for western Java province to the whole area in the island (Java) Keywords:vulnerability, coastal, climate change, sea level rise ABSTRAK Wilayah Pesisir adalah daerah yang paling rentan terhadap perubahan iklim. Wilayah pesisir Cirebon di Jawa Barat, Indonesia adalah dataran rendah daerah pantai yang merupakan salah satu areal potensial untuk budidaya ikan dan pertanian. Melalui daerah ini terdapat juga sarana transportasi utama propinsi Jawa Barat untuk seluruh wilayah di pulau Jawa. Sebagai kota yang terletak di dataran rendah dengan penduduk yang padat dan kota berkembang, Cirebon sangat rentan terhadap kenaikan permukaan air laut. Studi geomorfologi, geo-listrik, dan penginderaan jauh dilakukan selama tahun 2008 dan 2009 di wilayah pesisir Cirebon. Hasil penelitian menunjukkan bahwa sebagian besar wilayah pesisir di Cirebon telah longsor pada berbagai skala mulai dari kondisi rentan menjadi buruk. Air laut telah menembus sampai beberapa kilometer kedaratan. Kerugian nilai penggunaan lahan diproyeksikan sekitar Rp. 1.295.071.755.150/ha/ tahun akibat naiknya air laut sebesar 0,8 meter yang akan membanjiri berbagai lahan seperti: tambak udang, ikan, garam kolam, sawah, dan pemukiman.Kata kunci: kerentanan, pesisir, peribahan iklim, kenaikan air laut I. PENDAHULUANIndonesia adalah Negara kepulauan yang sangat rentan terhadap dampak perubahan iklim. Dampak berskala luas dari perubahan iklim terjadi di lautan karena mencakup perubahan yang bersifat fisis, biologis dan kimiawi.

<p>Jakarta bay is a unique water since there are hydrological and ecological complexity. In general, the feature of these water consist of three ecological elements that are estuaries, coral reefs and open sea. Each of these ecological element has different hydrology, ecology as well as biological characteristics. As a form of meiobenthic community, foraminifera has adaptive behavior to each of ecological element of the waters. The observation on foraminiferal adaptive behavior due to the hydrological condition of Jakarta Bay was conducted from 2003 to 2009. The result showed that foraminiferal distribution was tend to pursue to the degradation water conditions and constructed a specific pattern. Coastal water and estuary were found dominated by Ammonia beccarii, Calcarine and other larger benthic foraminifera were common in coral reef area, Elphidium and Nonion depressulum were common in open waters area. Based on the diversity indices, the foraminifera in Jakarta Bay has a higher diversity compared to foraminifera in the coastal water of Semarang and Cirebon and among the ecological element of Jakarta Bay, reef area has the highest diversity index than coastal nor open sea area.</p><p>Keywords: Foraminifera, Calcarine, Jakarta Bay</p>