Water column primary production from inorganic carbon uptake for 24h at simulated in situ (SIS) light levels in deck incubators, collected aboard Palmer LTER annual cruises off the coast of the Western Antarctic Peninsula, 1995 – 2023.

Primary Production experiments were led by Vernet from 1995-2008. Schofield is the current lead, beginning in 2009. Methods have been kept consistent as much as possible over the full time series and different Principal Investigators. Primary production is the uptake of inorganic carbon and assimilation of it into organic matter by phytoplankton. Primary production rates, expressed as mgC per m3 per day were measured by the uptake of radioactive (14C) sodium bicarbonate. Water samples are collected throughout the water column at stations along the Western Antarctica Peninsula at regular PAL-LTER grid stations. Water is put into borosilicate bottles, inoculated with 1 uCi of NaH14CO3 per bottle, and incubated in an outdoor deck incubator. The incubator is plumbed to the ship sea water system to maintain ambient seawater temperature and bottles are screened to in situ light levels. The uptake of 14C-bicarbonate by the phytoplankton was measured in a scintillation counter after a 24-hour incubation period. Data is unavailable for the LMG16-01 cruise due to measurement issues. Data is temporarily unavailable for the LMG20-01 cruise. Primary production experiments were not conducted during the 2022 (NBP21-13) nor 2024 (LMG24-01) cruises. There was no cruise in the austral summer of 2021.