Suspension-feeding in Marine Sponges Halichondria-panicea and Haliclona-urceolus - Effects of Temperature on Filtration-rate and Energy-cost of Pumping

Filtration rate (measured as clearance of algal cells) was measured at different temperatures in the sponge Halichondna panicea. An increase in water temperature from 6 to 12 "C caused the mean flltration rate to increase 4.3 * 2.3 tlmes. Thls value was higher than previously found for other marine ciliary suspension-feeding anlmals. Filtration rate at 12 "C was also measured in Haliclona urceolus by means of an indirect clearance method In addition to a direct technique for measuring pumping rate. It was found that the 2 sponge specles had near-identical flltration rates, with maximum rates of approximately 60 m1 m ~ n ' (g dry weight).' at 12 T. The normal pump pressure, or operating point 0,, of a standard sponge (based on our own measurements and calculat~ons from l~tera ture data for a 0.1 g dry weight Haliclona sp.) was estimated as the sum of maln contributions to head losses along the flow path from entry (ostia) to exit (osculum) The head losses were as follows: ostia 0.0373 mm H,O, inhalant canal