Dataset: TriCo Lim Particulate Organic Phosphorus
Deployment: AT39-05

Shipboard incubation experiments were carried out at 15 stations in the tropical Atlantic with trace metal clean-collected bulk seawater to examine iron (Fe) and phosphorus (P) co-limitation of dinitrogen (N2) fixation (see TriCoLim Station coordinates metadata). Treatments were: Co-limited control (no additions, “Colimit”), + 2nM Fe (“Fe”), + 50 nM P (“P”) and Replete (+Fe+P, “Rep”). All incubations were carried out at ambient (“Lo”) temperature and ambient temperature +3C (“Hi”) for 2-4 days on deck before measuring 15N2 and 13CO2 fixation rates and particulate organic carbon (POC), nitrogen (PON) and phosphorus (POP). See related datasets.

POP measurements were conducted as follows: ~500 ml of bulk water were filtered onto pre-combusted GFF filters and rinsed two times with 2 ml each of 0.17M sodium sulfate (Na2SO4). Filters were placed in pre-combusted borosilicate vials capped a combusted aluminum foil cap and soaked in 2 ml of 0.017M magnesium sulfate (MgSO4) and left to dry in an oven at 60 deg C for 2-3 days.