The material origin of the particulate organic matter (POM) in the Eastern Indonesian waters

Abstract

Particulate organic matter (POM) is formed by the organism’s fecal pellets, phytodetritus of sinking plankton, and marine snow aggregates. It is exported downward from the euphotic zone. This process is an essential factor in the biological pump of aquatic ecosystems. It has been known that the coastal and open sea POM properties are different due to the origin of the materials. For instance, the terrestrial organic matter will strongly affect the composition of POM in coastal water compared to the open sea. However, some studies indicated that the physical and chemical processes in the marine environment alter that general pattern. Since the Indonesian water has unique features, i.e. water mass from other waters (the South China Sea, Pacific, and the Indian Ocean), upwelling and the existence of Indonesian Through Flow (ITF), the POM properties will be greatly transformed. There are few studies about POM spatial distribution and its isotopic profile in the Indonesian marine waters. This study used stable isotope in term of profiling the POM, especially to elucidate its organic matter origin. The sampling sites represent the eastern Indonesian waters (RCO-IOCAS cruise tract). This study can enhance the POM properties of the Indonesian waters which have never been studied before. The preliminary result shows that POM within 1000 m depth is stratified as the marine-end member (up to 100m) and mixed composition (up to 300m). This finding indicates that the vertical profile of the water mass relates to the biological pump through the vertical flux of POM.