Zooplankton Ecological Baselines in the Eastern Tropical Pacific Amidst Deep-sea Mining Risks - Alexus Cazares, Gabrielle Stedman, Jeffrey C. Drazen, and Erica Goetze

2020 ➢ Manganese nodules contain cobalt, nickel, copper and manganese – all essential for battery production Mining impacts in midwater? Interaction of sediment plumes and oxygen minimum zones Animal distribution and behavior Feeding ecology Buoyancy Clogging of respiratory/feeding structures Release of metals, pollutants Biogeochemical cycling and export Drazen et al. [...] 2023 Zooplankton ecology in the ETP Life is structured around oxygen gradients Oxygen 0 Metridia brevicauda, • Biomass and community composition is structured by Upper oxycline M. [...] princeps, Heterostylites oxygen gradients longicornis/longioperc ulis, etc • Biomass peaks in the upper well-oxygenated layer and in the lower oxycline (LO) • Specialization of species to distinct oxygen OMZ Eucalanus inermis specialists habitats 500 • Epipelagic zooplankton biomass changes seasonally, and is correlated with chlorophyll, primary production, Lucicutia Lower hulsemannae, Disseta pho. [...] 2013, 2018, & 2020; Fernández-Álamo & Färber- Lorda 2006 Depth (m) Establishing ecological baselines prior to impact: ๏Characterize the abundance, biomass, diversity and composition of the zooplankton community from the sea surface to the seafloor ๏Characterize spatial and temporal variability in these assemblages Establishing ecological baselines prior to impact: ๏Characterize the abundance, biom. [...] Popp Zooplankton biomass is higher in spring Seasonality is particularly pronounced within the OMZ Zooplankton Size Fractions 0 ‘****’ 0.0001 ‘***’ 0.001 ‘**’0.01 ‘*’ 0.05 ‘ns’ 1.0 Below OMZ OMZ Upper (700-1500m) (100- (0-100m) 700m) Zooplankton biomass is higher in spring Seasonality is particularly pronounced within the OMZ Zooplankton Size Fractions ๏ Upper 100m: strong seasonality in all size.