During R/V Sonne cruise SO254, we conducted ex-situ experiments with shallow- and deep-water demo- and hexactinellid sponges from New Zealand. Over a period of 5 hours, the sponges were incubated at in-situ temperature in the light (shallow-water incubation) or in the dark (deep-water incubation), and water samples for dissolved organic carbon (DOC), total dissolved nitrogen (TDN), and fluorescing dissolved organic matter (FDOM) were taken every hour. At the end of the incubations, samples for (biogeochemical) tissue analyses (including fatty acid analyses) were taken of the sponges together with samples for microbial analyses of the bacterial community living inside the sponges. Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) fluxes in the shallow- and deep-water sponge incubations were calculated by linear regression analyses of concentrations of DOC and TDN in seawater that were measured every hour over an incubation period of 5 hours.