Figure 5. Scanning electron micrographs of the sponge, Ianthella basta in control (0 mg L⁻¹) (A, C, E) and acute siliciclastic sediment exposure (B, D, F).

(A) Mucus (m) production in a control sponge, trapping a diatom (arrow). Mucus sloughing cleaned an area of pinacoderm (p) (Scale = 10 µm). (B) Mucus (m) production in I. basta from the high sediment (135 ± 30 mg L⁻¹) treatment after 48 h exposure and 1 h recovery. Sediments (arrows) were trapped in mucus (m). Mucus sloughing cleaned sediments off an area of pinacoderm (p) (Scale = 10 µm). (C) Choanocyte chambers (C) in the control treatment after 24 h (Scale = 10 µm). (D) Choanocyte chamber (C) from the high sediment treatment after 24 h of exposure to sediments (Scale = 10 µm). (E) Surface and ostia (O, incurrent pores) from a control after 24 h of exposure to control conditions (Scale = 20 µm). (F) Surface and ostia (O) from the medium sediment treatment (42 ± 8 mg L⁻¹) after 24 h of exposure to sediment (Scale = 20 µm, arrows indicate sediment particles blocking ostia).