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. The biogeochemical composition of 4 shallow-water and deep-water sponge species were determined after the cruise by measuring the organic and total carbon and nitrogen content of freeze-dried sponge tissue and the stable isotopic composition (δ13C, δ15N) of the tissue. Phospholipid-derived fatty acids (PLFAs) of freeze-dried sponge tissue were extracted using a modified Bligh-Dyer extraction protocol and subsequently the PLFA concentrations were measured using gas chromatography flame ionization detection (GC-FID).

Phospholipid fatty acids: µg C-PLFA g-1 DM spongeω? means that it was not investigated exactly where double bonds exist.