MEPS 128:239-246 (1995)  -  doi:10.3354/meps128239

Growth and energetics of the sponge Halichondria panicea

Thomassen S, Riisgård HU

The filtration rate (F, ml min-1 measured as clearance of algal cells) and maintenance respiration rate (Rm, ml O2 h-1 measured as starvation respiration rate) as a function of Halichondria panicea colony size (dry weight DW, g) were described by: F = 28.35DW0.914 and Rm = 0.632DW0.927, respectively. At the maximum specific growth rate of 4% d-1 the net growth efficiency was about 30%. The specific respiration rate (Rs) as a function of the specific growth rate (mu) was described by the equation: Rs = n mu + a where n is the energy cost per unit of growth and a is Rs at zero growth rate. It was found that the energy cost of growth constituted 139% of the biomass increase. This showed that sponges apparently have a higher energy demand for growth than other invertebrates. When sponge colonies were transferred to filtered sea water, a near linear decrease of chlorophyll a (chl a) was seen during the first 24 h. A similar decrease was observed in sponges transferred directly from the field to filtered sea water. The reduction constants (r) in the 2 cases were 3.3 and 2.8% h-1, respectively. The estimated filtration rates, using the equation Fest = (r x S)/chl a, where S is the steady-state chl a content, were almost identical to filtration rates measured as clearance. It is stressed that sponges have a low water pumping capacity compared with other filter-feeding invertebrates, but compensate for this by a high retention efficiency for small particles >0.1 um.

Filtration rate . Respiration rate . Energy cost of growth . Net growth efficiency . Suspension feeding

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