A multi-species investigation of sponges’ filtering activity towards marine microalgaeA multi-species investigation of sponges’ filtering activity towards marine microalgae Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2023-08-292022enThis work was implemented in the framework of the research project SPINAQUA (Grant No 239) funded by the Hellenic Foundation for Research and Innovation (HFRI) and the General Secretariat for Research and Technology (GSRT) under the “1st call for H.F.R.I. Research Projects for the support of Post-doctoral Researchers.Chronic discharge of surplus organic matter is a typical side effect of fish aquaculture, occasionally leading to coastal eutrophication and excessive phytoplankton growth. Owing to their innate filter-feeding capacity, marine sponges could mitigate environmental impact under integrated multitrophic aquaculture (IMTA) scenarios. Herein, we investigated the clearance capacity of four ubiquitous Mediterranean sponges (Agelas oroides, Axinella cannabina, Chondrosia reniformis and Sarcotragus foetidus) against three microalgal substrates with different size/motility characteristics: the nanophytoplankton Nannochloropsis sp. (~3.2 μm, nonmotile) and Isochrysis sp. (~3.8 μm, motile), as well as the diatom Phaeodactylum tricornutum (~21.7 μm, nonmotile). In vitro cleaning experiments were conducted using sponge explants in 1 L of natural seawater and applying different microalgal cell concentrations under light/dark conditions. The investigated sponges exhibited a wide range of retention efficiencies for the different phytoplankton cells, with the lowest average values found for A. cannabina (37%) and the highest for A. oroides (70%). The latter could filter up to 14.1 mL seawater per hour and gram of sponge wet weight, by retaining 100% of Isochrysis at a density of 105 cells mL−1, under darkness. Our results highlight differences in filtering capacity among sponge species and preferences for microalgal substrates with distinct size and motility traits.http://creativecommons.org/licenses/by/4.0/Marine Drugs201Varamogianni-Mamatsi_et_al_Mar. Drugs_20(1)_2022.pdfChania [Greece]Library of TUC2023-08-29application/pdf1.9 MBfree Varamogianni- Mamatsi Despoina Βαραμογιαννη--Μαματση Δεσποινα Anastasiou Thekla I. Vernadou Emmanouela Papandroulakis Nikos Kalogerakis Nikos Καλογερακης Νικος Dailianis, Thanos Mandalakis Manolis MDPI Mediterranean sponges Microalgae Filtering capacity Bioremediation Integrated aquaculture Cell retention