Because Prince William Sound contained many rocky coves where the oil was collected, the decision was made to displace it with high-pressure hot water. However, this also displaced and destroyed the microbial populations on the shoreline; many of these organisms (e.g. plankton) are the basis of the coastal marine food chain, and others (e.g. certain bacteria and fungi) are capable of facilitating the biodegradation of oil. At the time, both scientific advice and public pressure was to clean everything, but since then, a much greater understanding of natural and facilitated remediation processes has developed, due somewhat in part to the opportunity presented for study by the "Exxon Valdez" spill. Despite the extensive cleanup attempts, less than ten percent of the oil was recovered.