Tasas de filtración y retención de bacterias in situ de tres especies de esponjas litorales. Estudio preliminar

Resum

Water-pumping activity and bacterial retention rates in situ, of three species of littoral
sponges. Preliminary study.
Studies using scuba diving techniques were carried out on specimens of three species of Mediterranean littoral sponges (Ircinia fasciculata, Petrosia flciformis and Agelas oroides) to determinate in situ patterns of water-pumping activity. Activity patterns are variable within species and specimens. This variability depends on the oscular area and the biomass in dry weight. Samples of ambient water (inhaland) and oscular stream (exhaland) of three sponges were analyzed for bacteria retention rate. The bacterial retention efficiency was between 84% and 99% Some comments are made on the negative efficiency, particularly when the ambient bacterial concentration is low. The results of bacteria as food or bacteria retention of sponges studied, is discussed in relation with some factors: bacterial association, water-pumping activity and ecological characteristics of coastal waters. When the ambient bacterial concentration is high, bacteria done can satisfy the almost entire food requirement of sponges.