Transport and transformation of intrinsic material within the Indonesian Seas
Faisal Hamzah (a*), Zhimian Cao (b), Minhan Dai (b)

a) Research Center for Oceanography, The National Research and Innovation Agency, Indonesia
* faisal.hamzah[at]brin.go.id
b) State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, China

Abstract

The Indonesian Seas is the only low-latitude gateway of water movement between the Pacific and Indian Oceans and plays a significant role in global climate change and freshwater balance. Much less known is the material transport (i.e., nutrient and carbon) along the Indonesian throughflow (ITF) and how material transformation would affect the regional seawater chemistry and subsequently ecosystem health. We observed that the ITF water supply from the Pacific had lower nutrient levels than what is required for sustainable biodiversity and marine productivity. In contrast, nutrient flux at the main outflow passage of ITF showed a slightly higher and act to enrich the nitrate to phosphate ratio of the Indian Ocean. The net nitrate flux associated with the ITF is estimated to be significant. Physical processes i.e., vertical diffusion and advection, exerted predominant controls and contributed to located elevated nutrients in the upper 100 m of Indonesian Seas. Other contributions to the Indonesian nutrient budget should be considered, including riverine runoff, upwelling, sediment, atmospheric deposition, and nitrogen fixation.

Keywords: nutrient flux, Indonesian throughflow, transport, transformation

Topic: Ocean-Atmosphere Dynamics