Intensification of tropical Pacific biological productivity due to volcanic eruptions

Major volcanic eruptions generate widespread ocean cooling and thus reduce upper ocean stratification. Through this ocean dynamic response, volcanic strong eruptions further have the potential to increase nutrient delivery into the euphotic zone and boost biological productivity. Using three climate/Earth System models (Model for Interdisciplinary Research On Climate (MIROC), Community Earth System Model (CESM), and LOch-Vecode-Ecbilt-CLio-agIsm Model (LOVECLIM)), we test the hypothesis whether large volcanic eruptions intensify nutrient-driven export production. In the historical last millennium simulations in CESM and LOVECLIM, strong volcanic radiative forcing enhances the likelihood of eastern Pacific El Nino-like warming, thereby reducing nutrients and export production in the eastern equatorial Pacific for the first two years. This initial response, however, reverses after about 3 years in associated with the following La Nina onset. The resulting delayed enhancement of biological production resembles the multiyear response in MIROC. In this study, volcanic impacts on tropical Pacific dynamics and biogeochemistry persist for several years, thus providing a new source for potential multiyear ecosystem predictability.