Extracellular dissolved organic carbon (DOC) concentrations in axenic and xenic cultures of Thalassiosira gravida in response to varying temperatures and photoperiods

This dataset comprises dissolved organic carbon (DOC) concentrations from axenic and xenic cultures of Thalassiosira gravida that were cultivated at the Alfred-Wegener-Institute (Bremerhaven, Germany) in March, 2023. After a cell density of ~ 15.000 cells * mL-1 was reached, cultures were filtered through a 0.2 µm polycarbonate (PC) filter (Whatman) that was cleaned by soaking in 10 % hydrochloric acid (HCl, Merck suprapure) for at least 12 h and subsequently rinsing with ultrapure water (Merck Millipore MilliQ). DOC was quantified by high temperature catalytic oxidation with a Shimadzu TOC analyzer (VCPN-TOC, Shimadzu) according to Garzón-Cardona et al. 2024; doi: 10.1016/J.JMARSYS.2023.103893. Cultures were grown under two temperatures (9 °C, 13.5 °C) and two photoperiods (16:8 h, 24:0 h light:dark). The aim was to investigate responses of algal extracellular release and bacterial DOC transformation to marine heatwave-like conditions.