CO2 outgassing suppressed by enhanced biological pump in the Eastern Tropical Pacific

Abstract

Contractors are licensed by the International Seabed Authority to explore manganese nodule resources in the Eastern Tropical Pacific (ETP). Upwelling in the ETP reportedly contributes up to 50% of new biological production in the global oceans and thus plays a critical role in Earth's carbon cycle. The Pacific Decadal Oscillation (PDO) is the dominant source of sea surface temperature (SST) variability in the Pacific on low-frequency timescales (Newman et al., 2003) and influences the physical and biological conditions of the ETP (Peterson and Schwing, 2003). During the early 2000s, the PDO was linked to a warming ‘hiatus’ when the time-series of global average SSTs showed little increase or even a slightlynegative trend. It is important to understand how biological processes and CO2 outgassing in the ETP are influenced by the PDO. The biological response to natural climate variability in the ETP is poorly understood because of the paucity of long-term observations. The ETP underwent a switch from a positive PDO to a negative phase in the late 2000s (Litzow and Mueter, 2014) (Figure 1). Frequent La Ni