Growth and energetics of the sponge Halichondria panicea

Abstract

The filtration rate (F, m1 min-' measured as clearance of algal cells) and maintenance respiration rate (R,, m1 O2 h-' measured as starvation respiration rate) as a function of Halichondria panicea colony size (dry weight DW, g) were described by: F = 2 8 . 3 5~~~.~'~ and R, = 0.632DWg2', respectively. At the maximum specific growth rate of 4 % d-l the net growth efficiency was about 30 %. The specific respiration rate (R,) as a function of the specific growth rate (p) was described by the equation: R, = np + a where n is the energy cost per unit of growth and a is R, 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 (I) in the 2 cases were 3.3 and 2.8% h-', respectively. The estimated filtration rates, using the equation F,,, = (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 z0.1 pm.

Experimental silicon demand by the sponge Hymeniacidon perlevis reveals chronic limitation in field populations

“…It is well known that spicule production varies over the year cycle (e.g., Bavestrello et al, 1993) and it could be that these sponges were not at the same stage of their annual growth cycle, therefore having very different DSi demands at the time of the experiments. Differences in DSi affinity could also be related to the fact that these sponges have different spicule (BSi) content (as calculated from dry weight/ash weight ratio) relative to the bulk of their respective soft tissues, accounting for about 34.4% of dry weight in H. panicea (e.g., Thomassen & Riisgård, 1995), 46.5 ± 8.6% in H. peerlevis, and 54.9 ± 11.5% in Axinella spp. .…”

Sponges as important sources of nitrate on an oligotrophic continental shelf

“…Over a much larger size range of sponges, there was a significant relationship between dry weight of sponge and total DIN release (average and maximum) when all species and all specimens sampled were included (n 5 36, excluding one outlier, as explained previously, p 5 0.031 and p 5 0.020 for average and maximum release rates, respectively). However, it is not unexpected that DIN release rates per unit of mass may be lower in larger sponges, given it is well known that other mass-specific rate measurements such as respiration and filtration rates decrease with an increase in sponge weight (Thomassen and Riisgå rd 1997;Ribes et al 1999).…”

The marine sponge Chondrilla nucula Schmidt, 1862 as an elective candidate for bioremediation in integrated aquaculture

“…Despite relatively low pumping rates, sponges can exhibit high retention rates as a function of well-developed aquiferous systems [4,5]. This ability is significant in benthic Á/ pelagic coupling, and suggests the Porifera are able to influence or ameliorate microbial polluting assemblages associated with faecal contamination [6].…”

“…Many different approaches, both direct and indirect, have been applied to investigate filtering efficiencies and particle uptake in sponges. These studies have focused on the energy balance of filtering activity [1,4,13], the effects of temperature [13,14], and on the uptake of microorganisms and/or particles [2,3,15 Á/18].…”