Brissopsis lyrifera is a burrowing heart urchin often dominating soft-bottom biomass at depths between 30 and 200 m along the Swedish West Coast. It is about 5 cm in diameter and burrows through the sediment at about 5 cm depth, while feeding on organic debris, foraminifers, and small organisms within the sediment. The mouth is situated on the underneath side and specialized tubefeets are used for feeding. Burrowing spatangoids constructs ciliary currents around the body for respiration. A more or less well-developed funnel connects the urchin with the sediment surface. Particles that is deposited into the funnel are carried by respiratory currents and transferred to the mouth and ingested. The feeding strategy of B. lyrifera is not fully understood, it seems to be able to feed both from the sedment surface and within the sediment. The response of Brissopsis lyrifera, to organic matter on the sediment surface was investigated in a laboratory experiment, using sediment box-cores. Organic matter was added on the sediment surface and after each addition, one randomly chosen box was video recorded with a time-laps camera. The activity of B. lyrifera on the sediment surface and its response to the added organic matter was studied by measuring emergence behavior, time spent on the surface, locomotion rate on the surface and total reworked surface area. Gonad index, gonad lipid content, gonad water content and intestine lipid content were also measured at the end of the experiment, to evaluate B. lyrifera's ability to utilize the added organic matter. B. lyrifera emerged significantly more frequent in those boxes where organic matter was added, and the total reworked surface area was larger. This indicates that B. lyrifera is able to respond to organic matter and move upward to eat from the sediment surface. Increased gonad index in the fed treatments shows that B. lyrifera is able to utilize the organic matter as food. Lipid content of the intestine remained constant, indicating that assimilated energy is allocated to gonads rather than stored in the gut. B. lyrifera is likely to have a significant impact on the sediment property, reworking of organic matter, and on other infauna down to at least 10 cm depth.