Understanding the potential impact of the global climatic events on organic carbon input to the deep-sea sediment of the Northeast equatorial Pacific

Abstract

Long-term environmental monitoring surveys have been conducted in the Clarion-Clipperton fracture zone of the northeast equatorial Pacific for the last 10 years by the deep-sea program at Korea Ocean Research and Development Institute. In order to understand the impact of the environmental changes, such as major climatic disturbances (i.e. El-Niño, La-Niño), on the organic matter flux in the equator, various physical, chemical, and biological parameters (temperature, salinity, nutrients, chlorophyll, zooplankton biomass, etc.) and surface sediment’s organic carbon and nitrogen content have been measured for the last 10 years during these surveys. Organic carbon content in surface sediments ranged from 4.0 to 6.5 mg/g-wet wt. with significant annual variations. Especially, in 1998, known as El-Niño year, and in 1999, known as La-Niño year, organic carbon contents of surface sediments appear lower and higher than normal years, respectively. The similar trend is also found in other parameters. This result suggests that global climate disturbances could be one of significant factors to affect the carbon flux in the northeast equatorial Pacific even though episodic and local environmental changes could also influence the organic carbon inputs to the deep-sea sediments.