Uthaya Siva M, Selvakumar P and Sakthivel A
Global warming is progression in which the earth temperature and the temperature on the atmosphere layers that are close to earth rise artificially as a result of the intense increase in some gases that occur in consequence of various human activities and that are qualified as greenhouse gases in the atmosphere. As to global climate change, it is the phenomenon where other climatic factors change as well depending upon global warming. Marine ecosystems are not in a steady state, but are affected by the environment, which varies on many spatial and temporal scales. Generally due to climate change and global warming the small and beneficial microorganism such as algae, bacteria, phyto and zooplanktons are getting disturbed or due to increasing of temperature and sea level raise it powerless to survive in the water surroundings. Detailed information is reported on the main Indian reef areas, including the Lakshadweep Islands, Andaman and Nicobar Islands, and Gulf of Mannar, with limited and largely anecdotal information for reefs elsewhere in the country. A fish population cannot be tolerant of high temperature changes in the area where it is distributed in a certain time interval. If these changes are within a certain temperature boundary and slow, it generally causes migration of fish specifically ornamental clown fishes. Temperature takes important physiological phenomena such as feeding, respiration, osmoregulation, growth and reproduction under control. If the individuals of population cannot adjust themselves according to the sudden and strong changes in temperature, one or some of their metabolism activities may deteriorate and mass deaths may occur and the changes in the sea water level will endanger the coastal habitat and species such as the sea turtle which uses the beaches as reproduction areas and lays eggs there will be unfavorably affected since their reproduction areas will become narrower.