Around the world coral reefs  are facing threats  brought by climate change and great changes in sea temperatures. While ocean warming has been the primary focus for scientists and ocean policy managers, cold events can also whiten corals. A new study by scientists compared damaged to corals exposed to heat as well as cold stress. The results show that cool temperatures can cause more damage in the short term, but heat is more destructive  in the long run. Climate change is widely known to produce warming conditions in the oceans, but extreme cold-water events have become more frequent and serious as well. In 2010, for example, coral reefs around the world faced on of the coldest winters and one of the hottest summers on record. During a unique experiment, corals under cold temperatures suffered greater damage in just days compared with heat treated corals. Yet the researchers found that corals were eventually able to adjust to the cold conditions, make their health stable and continue to grow. However, over the long term corals subjected to heat suffered more greatly than those in cold, with evidence of severe whitening and growth stoppage, which leads to death. The coral's ability to adjust to cool temperatures surprised the researchers, who say the study's results show the complexities  of monitoring coral health in response to different environmental factors . "Global warming is associated with increases but also decreases of temperatures," said Deheyn, one of the researchers. "Not much has been known about the comparative effects of temperature decrease on corals. These results are important because they show that corals react differently to temperature differences, which is important for future management of coral reefs in the field of climate change." According to the research,  _  .
corals may continue to grow in cold events after a few days cold events help corals grow more quickly in a short time corals show no response to hot temperatures in the first days corals are whitened mainly because of warm temperatures