Inorganic and organic carbon and nitrogen uptake strategies of picoplankton groups in the northwestern Atlantic Ocean

Picoplankton populations dominate the planktonic community in surface oligotrophic ocean. Yet, their strategies acquisition and partitioning of organic inorganic sources nitrogen (N) carbon (C) are poorly described. Here, we measured at single-cell level uptake dissolved C (C-fixation), C-leucine, N-leucine, nitrate (NO3?), ammonium (NH4+), N-urea pigmented nonpigmented picoplankton groups six low-N stations northwestern Atlantic Ocean. Our study highlights important differences trophic between Prochlorococcus, Synechococcus, photosynthetic pico-eukaryotes, prokaryotes. Nonpigmented prokaryotes were characterized by high leucine rates, nonsignificant C-fixation relatively low NH4+, N-urea, NO3? rates. contributed to 7% ± 3%, 2% 2%, 9% 5% NO3?, uptake, respectively. In contrast, displayed NH4+ but lower rates than Synechococcus pico-eukaryotes higher Prochlorococcus ones. Pico-sized accounted for a significant fraction (63% 27%), (47% (62% 49%), (81% 35%). Interestingly, showed greater reliance on C- N-leucine average, suggesting N sources. Taken together, our results decipher wide diversity within marine groups, clear still remains.