There were few clear patterns of extinction associated with the second extinction pulse. Every region and marine environment experienced the second extinction pulse to some extent. Many taxa which survived or diversified after the first pulse were finished off in the second pulse. These include the "Hirnantia" brachiopod fauna and "Mucronaspis" trilobite fauna, which previously thrived in the cold glacial period. Other taxa such as graptolites and warm-water reef denizens were less affected. Sediments from China and Baltica seemingly show a more gradual replacement of the "Hirnantia" fauna after glaciation. Although this suggests that the second extinction pulse may have been a minor event at best, other paleontologists maintain that an abrupt ecological turnover accompanied the end of glaciation. There may be a correlation between the relatively slow recovery after the second extinction pulse, and the prolonged nature of the anoxic event which accompanied it.