Abstract
The carbon metabolism of two marine sponges,
Haliclona oculata and Dysidea avara, has been studied
using a 13C isotope pulse-chase approach. The sponges
were fed 13C-labeled diatoms (Skeletonema costatum) for
8 h and they took up between 75 and 85%. At different
times, sponges were sampled for total 13C enrichment, and
fatty acid (FA) composition and 13C enrichment. Algal
biomarkers present in the sponges were highly labeled after
feeding but their labeling levels decreased until none was
left 10 days after enrichment. The sponge-specific FAs
incorporated 13C label already during the first day and the
amount of 13C label inside these FAs kept increasing until
3 weeks after labeling. The algal-derived carbon captured
by the sponges during the 8-h feeding period was thus
partly respired and partly metabolized during the weeks
following. Apparently, sponges are able to capture enough
food during short periods to sustain longer-term
metabolism. The change of carbon metabolic rate of fatty
acid synthesis due to mechanical damage of sponge tissue
was studied by feeding sponges with 13C isotope–labeled
diatom (Pheaodactylum tricornutum) either after or before
damaging and tracing back the 13C content in the damaged
and healthy tissue. The filtration and respiration in both
sponges responded quickly to damage. The rate of respiration
in H. oculata reduced immediately after damage, but
returned to its initial level after 6 h. The 13C data revealed
that H. oculata has a higher metabolic rate in the tips where
growth occurs compared to the rest of the tissue and that
the metabolic rate is increased after damage of the tissue.
For D. avara, no differences were found between damaged
and non-damaged tissue. However, the filtration rate
decreased directly after damage.
Original language | English |
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Pages (from-to) | 9-20 |
Journal | Marine Biology |
Volume | 158 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2011 |
Keywords
- fatty-acids
- stable-isotopes
- organic-carbon
- demospongiae
- growth
- lipids
- invertebrates
- regeneration
- biomarkers
- porifera