Seasonality in Lipid Content of the Demosponges Halichondria panicea and H. bowerbanki at Two Study Sites in Temperate Danish Waters

Abstract

This study relates the lipid content of two marine filter-feeding demosponges, Halichondria panicea and H. bowerbanki to the seasonal availability of their suspended food, mainly free-living bacteria and phytoplankton at two study sites in Danish waters. The aim was to investigate if the lipid content of sponges is linked to food availability and season, and to what extend free-living bacteria are available in starvation periods where the phytoplankton biomass is low. The highest concentrations of bacteria were observed during summer when also chlorophyll a concentrations were high, and therefore bacteria and phytoplankton were available in similar ratio at all seasons. Bacterial cell carbon was estimated to contribute 2.9 and 4.6% compared to phytoplankton cell carbon in the food at the two sites, respectively, and free-living bacteria were available only as a minor food source at all seasons. Highest lipid contents (29.5% of sponge dry weight) were seen in H. panicea at the site with lowest food availability, while the lipid content of H. bowerbanki was 11.5% of dry weight. No seasonal variations in lipid content as fraction of sponge dry weight were observed, and the lipid content was not affected by food availability or starvation. It remains unclear why the lipid-content levels at the two study sites were conspicuously different.

Stability of a dominant sponge‐symbiont in spite of antibiotic‐induced microbiome disturbance

“…The genome of this Alphaproteobacterium displays key features of a sponge-symbiont, for example, its role in ammonia assimilation, vitamin B12 synthesis and antimicrobial peptide production (Knobloch et al, 2019c). The sponge host has been studied in its natural environment (e.g., Barthel, 1986Barthel, , 1988Lüskow, et al, 2019a;Lüskow, et al, 2019b) including the reproductive cycle (Witte et al, 1994). It is amenable to aquarium maintenance and experimentation with adults that spawn in captivity (Amano, 1986;Riisgård et al, 2016), single-osculum explants (Kumala et al, 2021) and primmorphs, that is, cell aggregates from dissociated cells (Lavrov & Kosevich, 2016).…”

Phospholipid fatty acids from Colombian Caribbean sea sponges

“…A study on seasonal variation in the contents of demospongic acids (C24-C28) in sponges from the Sea of Japan, collected between January and July, revealed variability ranging from 24% to 30% for the C24:0 fatty acid contents for the sponge Semisuberites cribrosa. The fatty acids with a chain length of C25:1 in Semisuberites cribrosa, C26:2 in Haliclona (Reniera) cinerea and C28:0 in Suberites domuncula presented a CV<15 %, while other fatty acids had variations ranging from 30% to 100% (Lüskow et al, 2019). However, the seasonal fluctuation of fatty acid composition is also common in marine sponges and is an adaptive response of the sponge to optimize membrane flexibility at different environmental temperatures (Lüskow et al, 2019) which probably partly explains the high FA content variations encountered in our study (Table 4).…”

Oogenesis and lipid metabolism in the deep-sea sponge Phakellia ventilabrum (Linnaeus, 1767)

“…Koopmans et al 67 studied fatty acid (FA) composition in North-East Atlantic/Mediterranean Sea demosponge species of the genera Haliclona Grant, 1841, Halichondria Fleming, 1828 and Aplysina Nardo, 1834 and found a strong correlation between the FA composition in the surrounding dissolved organic matter and the sponge FAs during nutrient blooms in spring-summer 67 . On the other hand, Lüskow et al 68 measuring the lipid content as a fraction of sponge dry weight, found that it remained invariable throughout the year, without being affected by seasonal planktonic blooms or periods of starvation. However, none of these studies linked directly these variations with reproduction.…”