Stratifikasi dan Struktur Massa Air di Utara Kepala Burung Papua

Abstract

Perairan Utara Papua barada di sisi Pasifik Ekuator dan dilintasi oleh sistem Arus Pantai Papua yang membawa massa air Pasifik Selatan dimana massa air ini sebagai bagian dari sumber Arus Lintas Indonesia yang melintasi Laut Halmahera. Penelitian ini bertujuan untuk mendeskripsikan stratifikasi dan jenis massa air di Utara Kepala Burung Papua dengan menggunakan data CTD dari hasil kegiatan survei Kajian Stok Sumber Daya Ikan Nasional Juli 2015 serta keluaran model arus dekat permukaan. Stratifikasi lapisan tercampur dan termoklin dihitung dari gradien vertical suhu terhadap kedalaman dengan gradien 0,05 °C/m. Jenis massa air dianalisis dari diagram TS, TO, dan SO. Hasil penelitian menunjukan lapisan tercampur berkisar 67-109 m, dimana suhu, salinitas, densitas, dan oksigen terlarut relatif homogen di lapisan ini. Ketebalan lapisan termoklin berkisar antara 113-244 m di kedalaman 68-312 m, stasiun sebelah timur cenderung lebih tebal dibandingkan sebelah barat sekitar 17 m. Pengukuran CTD dilakukan sampai kedalaman sekitar 500 m, sehingga jenis massa air yang ditemukan utamanya massa air Subtropis Pasifik Selatan (South Pacific Subtropical Water, SPSW) pada kedalaman 97-188 m dengan kisaran suhu, salinitas, dan oksigen terlarut masing-masing 19,06-26,18 °C, 35,01-35,48 PSU, dan 3,98-4,91 mg/l.

The Northern sea of Papua are on the Pacific side of the Equator and are crossed by the Papua Coastal Current system which carries the South Pacific water mass where this water mass is part of the source of the Indonesian Through Flow that crosses the Halmahera Sea.This study aims to describe the stratification and type of water mass in the North of Papua using CTD data from the results of the July 2015 National Fish Resource Stock Study survey and the output of the near-surface current model. Mixed layer stratification and thermocline were calculated from the vertical gradient of temperature with depth with a gradient of 0.05 °C/m. The type of water mass was analyzed from the TS, TO, and SO diagrams. The results showed that the mixed layer ranged from 67-109 m, where the temperature, salinity, density, and dissolved oxygen were relatively homogeneous in this layer. The thickness of the thermocline layer ranges from 113-244 m at a depth of 68-312 m, the east station tends to be thicker than the west about 17 m. CTD measurements were carried out to a depth of about 500 m, so that the type of water mass found was mainly South Pacific Subtropical Water (SPSW) at a depth of 97-188 m with a temperature, salinity, and dissolved oxygen range of 19,06 -26,18 °C, 35,01-35,48 PSU, and 3,98-4,91 mg/l.