Physical properties and nutrients distribution of seawater in the Banda Sea - Indonesia

Abstract

The Banda Sea is a sea in the eastern part of the Indonesian archipelago, connected directly to the Pacific Ocean and surrounded by hundreds of small islands that create its unique characteristics. A large portion of Pacific seawater is passed through the Banda Sea to the Indian Ocean forming an Indonesian through flow (ITF), an ocean current with importance for global climate. The ITF provides a low-latitude pathway for warm, fresh water to move from the Pacific to the Indian Ocean and serves as the upper branch of the global heat conveyor belt. Despite its importance in the global ocean and climate system, detail study and discussion of the Banda Sea are scarce. Here, we discuss the physical properties in term of temperature, salinity and density in conjunction with nutrients distribution in seawater from 17 stations of the Banda Sea using the direct observation data of the research cruises that were gathered by Reid and Mantyla. The available numerical data of the Banda Sea were then visualized using Ocean Data View software. To the best of our knowledge, it is the first report for a detailed discussion of this kind in the Banda Sea. The results show that nutrients concentration depleted in surface water (0 – 500 m) and enriched in deep water (500 m – bottom). The concentrations ranges of phosphate, nitrate and silicate were 0.3 – 3.1, 0.5 – 40 and 1 – 147 μmol l−1, respectively. As shown from temperature, salinity and density profiles, it is known that the inflowing seawater from the Pacific Ocean into the Banda Sea is gradually modified which change the upper water masses (0 – 250 m) characteristics that eventually outflows into the Indian Ocean.