Seasonal changes in bacteria and phytoplankton biomass control the condition index of the demosponge Halichondria panicea in temperate Danish waters

Florian Lüskow*, Hans Ulrik Riisgård, Vita Solovyeva, Jonathan R. Brewer

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Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

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.

OriginalsprogEngelsk
TidsskriftMarine Ecology Progress Series
Vol/bind608
Sider (fra-til)119-132
ISSN0171-8630
DOI
StatusUdgivet - 3. jan. 2019

Fingeraftryk

sponge
phytoplankton
bacterium
biomass
bacteria
starvation
water
winter
carbon
collars
diet
inorganic matter
food availability
filter feeder
clearance rate
index
canal
pumping
filter
food

Citer dette

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title = "Seasonal changes in bacteria and phytoplankton biomass control the condition index of the demosponge Halichondria panicea in temperate Danish waters",
abstract = "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.",
keywords = "Chlorophyll a, Choanocyte chambers, Clearance rate, Free-living bacteria, Growth, Porifera, Starvation",
author = "Florian L{\"u}skow and Riisg{\aa}rd, {Hans Ulrik} and Vita Solovyeva and Brewer, {Jonathan R.}",
year = "2019",
month = "1",
day = "3",
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journal = "Marine Ecology - Progress Series",
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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 -