User:Emkmiller100/Effects of climate change on marine mammals

Species impacted
Polar Bears Polar bears are one of many Arctic marine mammals at risk of population decline due to climate change. When carbon dioxide is released into the atmosphere, a greenhouse like effect occurs, warming the climate. For polar bears and other Arctic marine mammals, rising temperature is the changing the sea ice formations that they rely on to survive. In the circumpolar north, the Arctic sea ice is a dynamic ecosystem. The levels of sea ice extent varies by season. While some areas maintain year-round ice, others only have ice on a seasonal basis. The amount of permanent sea ice is decreasing with global temperature increases. Climate change is causing slower formations of sea ice, quicker decline and thinner ice sheets. Polar bears and other Arctic marine mammals are losing their habitat and food sources in result of the sea ice decline.

Polar bears rely on seal s as their main food source. Although polar bears are strong swimmers, they are not successful at catching seal underwater, therefore polar bears are ambush predators. When they hunt seals, they wait at seal breathing hole to ambush and haul out their prey onto the sea ice for feeding. With slower sea ice formations, thinner ice sheets and shorter winter seasons, polar bears are having less opportunity for optimal hunting grounds. Polar bears are facing pressures to swim further to gain access to food. This requires more calories spent to obtain calories to sustain their body conditions for reproduction and survival. Researchers use body condition charts to track polar bear population health and reproductive potential. Trends suggest 12 out of 19 sub populations of polar bears are declining or data deficient.

Polar bears also rely on sea ice to travel, mate and female polar bears usually choose to den up on the sea ice during denning season. The sea ice is becoming less stable, forcing pregnant female polar bears to choose less optimal locations for denning. These aspects are known to result in lower reproduction rates and smaller cub years.

Other Species

Not only are marine mammals impacted by climate change but so is other marine life. An example of this could be coral. When coral is introduced to warming ocean temperatures changes, runoff and pollution, overexposure to sunlight extremely low tides and other stresses, the coral will expel an algae growing on them. They have a symbiotic relationship with the algae. When the coral expels the algae it becomes bleached or "completely white". This is called coral bleaching. The coral then become more vulnerable to disease and death.