"Hydraulic action" takes place when the air in a joint is suddenly compressed by a wave closing the entrance of the joint. This then cracks it. "Wave pounding" is when the sheer energy of the wave hitting the cliff or rock breaks pieces off. "Abrasion" or "corrasion" is caused by waves launching sea load at the cliff. It is the most effective and rapid form of shoreline erosion (not to be confused with "corrosion"). "Corrosion" is the dissolving of rock by carbonic acid in sea water. Limestone cliffs are particularly vulnerable to this kind of erosion. "Attrition" is where particles/sea load carried by the waves are worn down as they hit each other and the cliffs. This then makes the material easier to wash away. The material ends up as shingle and sand. Another significant source of erosion, particularly on carbonate coastlines, is boring, scraping and grinding of organisms, a process termed "bioerosion".