Abstract
Hypoxia is one of the aquatic phenomena caused by natural and/or anthropogenic factors. Coastal areas such as Jakarta Bay are experiencing a lot of environmental pressures due to the continued increase in quality or/and quantity of human activities. Thus, the bay is highly susceptible to the threat of hypoxia triggered by eutrophication. Hypoxia in aquatic leads to a double impact, i.e. low oxygen supply for the biotic respiration process, also increases the toxicity of some metals. This study used the index of benthic foraminifera of Ammonia and Elphidium as hypoxic proxies in the western part of Jakarta Bay (Tangerang). Sampling was conducted in 2016 using short core samples. Scanning with (210)pb was performed to measure the age of sediment deposition. The result showed that there was an increase of index during the period of the late 1970s to the early 1990s. In the same period, four metals Cu, Pb, Ni and Zn concentration increased.