Picophytoplankton Phenology in the Global Ocean Addressed by Quantitative Niche Models

FLOMBAUM, PEDRO; VISINTINI, NATALIA

San Diego, California

Congreso; Ocean Science Meeting 2020; 2020

AGU-ASLO-TOS

Understanding seasonal cycles is key to evaluate the impact of future climates. Lineages withinpicophytoplankton were projected to increase or remain unchanged in future climates, althoughseasonal variation remains unclear. Our objective was to describe the global abundance anddistribution seasonal cycle for the main lineages of picophytoplankton: Prochlorococcus (PRO),Synechococcus (SYN) and picoeukaryotic phytoplankton (PEUK). Abundance was calculated usingquantitative niche models for each lineage and environmental data on PAR (Ocean Color),temperature and nitrate (World Ocean Atlas). Cells/ml were projected globally in a 1-degree gridfrom surface to 200m depth with a monthly time step. For each lineage we dened highabundance as the cell concentration >90th percentile, 15.5, 3.1 and 1.3 x104 cells/ml for PRO, SYNand PEUK respectively. We observed that seasonal variation was higher for PEUK>SYN>PRO. Thepeak with maximum abundance did not coincide corresponding to May, March and September forPRO, SYN and PEUK, respectively. For PRO, areas with high abundance showed an extended regionof high prevalence (>7 months) in the band 25 N-S. For SYN, regions with high abundance showeda similar area with high and low (