Text 1: One hypothesis about sponges filtering water more slowly during heat waves in reef sponges is metabolic stress. Because pumping rates fall in heated tanks with normal sediment levels, the author concludes that heat directly slows sponge pumping. Text 2: A second hypothesis is particle clogging. Because pumping remains normal in warm filtered water but slows in warm particle-rich water, the author concludes that heat waves stir fine particles that clog sponge canals. Which follow-up test would be most useful for deciding between the two hypotheses?