Potential effects of shoaling of oxygen minimum zone on the population of Acartia (Acanthacartia) tonsa in the Humboldt Current Upwelling System (23°S)

Expansion and shoaling of the Oxygen Minimum Zone (OMZ) in coastal upwelling systems due to climate change can have dire consequences on ecosystem structure productivity. The OMZ restricts habitat range most zooplankton, species with low tolerance hypoxia may suffer physiological stress mortality as a result. During 2013 2014, copepod Acartia tonsa collected off northern Chile was used evaluate how affect its survival vital rates. Exposure gravid females severe (∼0.2 mL L−1 dissolved oxygen) resulted total mortality. Hypoxia at ∼0.5 decreased female ∼20% egg production nil. ∼0.8 ∼50% but no rate compared normoxia treatment. Egg hatching success ∼68% naupliar development time ∼36% lower than normoxia. critical lethal oxygen levels for were estimated be 1.78 0.73 L−1, respectively. Based modeled historical data, 1.5 isopleth has been moving upward 1.3–2.0 m per year Chile, barring interruptions during El Niño events. long-term, gradual is expected significant impacts zooplankton community productivity region.