Resumé
Sponges are sessile filter-feeders, and the basic principles for water pumping and particle retention are the same among all demosponges. Phytoplankton cells smaller than the inhalant openings (ostia) are retained and phagocytosed in the inhalant canal system before the water is sieved through the collar filter of the choanocytes, which efficiently retain bacteria. However, the importance of bacteria versus phytoplankton as the main diet is unclear. Sponges must cope with seasonal changes in food availability in temperate waters, and during winter, low phytoplankton and bacterial biomasses may result in starvation. In this study, the lower threshold of suspended biomass resulting in starvation of the demosponge Halichondria panicea was determined. We measured the seasonal changes in phytoplankton and bacterial biomasses along with the sponge condition index (CI, the ratio of organic to inorganic matter). A low CI during winter reflected starvation, and based on total available carbon concentrations (phytoplankton plus bacterial carbon), we conclude that a concentration of ca. 30 µg C l−1 was not sufficient to cover the maintenance costs of H. panicea. Bacteria constitute a minor, but consistent part of the diet, around 20%. A field growth experiment revealed a positive correlation between CI and sponge weight. Measured volume-specific clearance rate of sponges, density of choanocyte chambers and inter-choanocyte chamber-distance were not significantly different in low and high CI sponges, and it remains unknown how sponges withstand long periods with low suspended food particle concentrations.
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Marine Ecology Progress Series |
| Vol/bind | 608 |
| Sider (fra-til) | 119-132 |
| ISSN | 0171-8630 |
| DOI | |
| Status | Udgivet - 3. jan. 2019 |
Fingeraftryk
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Seasonal changes in bacteria and phytoplankton biomass control the condition index of the demosponge Halichondria panicea in temperate Danish waters. / Lüskow, Florian; Riisgård, Hans Ulrik; Solovyeva, Vita; Brewer, Jonathan R.
I: Marine Ecology Progress Series, Bind 608, 03.01.2019, s. 119-132.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
TY - JOUR
T1 - Seasonal changes in bacteria and phytoplankton biomass control the condition index of the demosponge Halichondria panicea in temperate Danish waters
AU - Lüskow, Florian
AU - Riisgård, Hans Ulrik
AU - Solovyeva, Vita
AU - Brewer, Jonathan R.
PY - 2019/1/3
Y1 - 2019/1/3
N2 - Sponges are sessile filter-feeders, and the basic principles for water pumping and particle retention are the same among all demosponges. Phytoplankton cells smaller than the inhalant openings (ostia) are retained and phagocytosed in the inhalant canal system before the water is sieved through the collar filter of the choanocytes, which efficiently retain bacteria. However, the importance of bacteria versus phytoplankton as the main diet is unclear. Sponges must cope with seasonal changes in food availability in temperate waters, and during winter, low phytoplankton and bacterial biomasses may result in starvation. In this study, the lower threshold of suspended biomass resulting in starvation of the demosponge Halichondria panicea was determined. We measured the seasonal changes in phytoplankton and bacterial biomasses along with the sponge condition index (CI, the ratio of organic to inorganic matter). A low CI during winter reflected starvation, and based on total available carbon concentrations (phytoplankton plus bacterial carbon), we conclude that a concentration of ca. 30 µg C l−1 was not sufficient to cover the maintenance costs of H. panicea. Bacteria constitute a minor, but consistent part of the diet, around 20%. A field growth experiment revealed a positive correlation between CI and sponge weight. Measured volume-specific clearance rate of sponges, density of choanocyte chambers and inter-choanocyte chamber-distance were not significantly different in low and high CI sponges, and it remains unknown how sponges withstand long periods with low suspended food particle concentrations.
AB - Sponges are sessile filter-feeders, and the basic principles for water pumping and particle retention are the same among all demosponges. Phytoplankton cells smaller than the inhalant openings (ostia) are retained and phagocytosed in the inhalant canal system before the water is sieved through the collar filter of the choanocytes, which efficiently retain bacteria. However, the importance of bacteria versus phytoplankton as the main diet is unclear. Sponges must cope with seasonal changes in food availability in temperate waters, and during winter, low phytoplankton and bacterial biomasses may result in starvation. In this study, the lower threshold of suspended biomass resulting in starvation of the demosponge Halichondria panicea was determined. We measured the seasonal changes in phytoplankton and bacterial biomasses along with the sponge condition index (CI, the ratio of organic to inorganic matter). A low CI during winter reflected starvation, and based on total available carbon concentrations (phytoplankton plus bacterial carbon), we conclude that a concentration of ca. 30 µg C l−1 was not sufficient to cover the maintenance costs of H. panicea. Bacteria constitute a minor, but consistent part of the diet, around 20%. A field growth experiment revealed a positive correlation between CI and sponge weight. Measured volume-specific clearance rate of sponges, density of choanocyte chambers and inter-choanocyte chamber-distance were not significantly different in low and high CI sponges, and it remains unknown how sponges withstand long periods with low suspended food particle concentrations.
KW - Chlorophyll a
KW - Choanocyte chambers
KW - Clearance rate
KW - Free-living bacteria
KW - Growth
KW - Porifera
KW - Starvation
U2 - 10.3354/meps12785
DO - 10.3354/meps12785
M3 - Journal article
VL - 608
SP - 119
EP - 132
JO - Marine Ecology - Progress Series
JF - Marine Ecology - Progress Series
SN - 0171-8630
ER -