Effects of global warming on marine mammals

The effects of global warming on marine mammals are of growing concern. The increase of carbon dioxide and other greenhouse gases into the atmosphere is thought to be the main cause of climate change or global warming. Exactly how this will affect the ocean, which is home to marine mammals, is hard to predict since there are many factors, such as weather events and salinity that affect ocean ecosystems. How all these will interact is highly unpredictable. Using global climate models (GCM)s, scientists can get a general idea of how climate change will impact the ocean environment in the future.

Effects

Marine mammals have evolved to live in the ocean, but the effects of climate change are rapidly altering their habitat.[1][2][3][4] As levels of greenhouse gases in the atmosphere increase they trap heat which causes an overall warming of the planet. During the last century, the global average land and sea surface temperature has increased dramatically.[5] Warming has reached down to about 700 meters[6] and more (per a study which finds that 30% of the ocean warming, over the past decade, has occurred in the deeper oceans below 700 meters).[7][8] Many marine mammal species require specific temperature ranges in which they must live. The warming of the ocean will cause changes in the species migration or area that they inhibit. The species that cannot relocate due to some type of barrier will be forced to adapt to the increasingly warming sea waters or they will face extinction. Many of the species ranges are being pushed further and further north as water temperatures increase and they will soon have nowhere else to go.

The rise in sea level affect the coastal habitat and the species that rely on it.[9] This habitat is often used by pinnipeds as haul out sites. In order to combat rising sea levels in areas inhabited by humans, the construction of sea walls has been proposed, however, these walls may interfere with the migration routes of several marine mammal species. These routes can be very important to some marine mammal species for reaching feeding and breeding grounds.

Changes in the temperature ranges will also change the location of areas with high primary productivity. These areas are important to marine mammals because primary producers are the food source of marine mammal prey or the marine mammals prey themselves. Marine mammal distribution and abundance will be determined by the distribution and abundance of its prey. Migration of marine mammals may also be affected by the changes in primary productivity.

Increased glacier ice melt also impacts ocean circulation because due to the increase of freshwater in the ocean, salinity concentrations in the ocean are changing. Thermohaline circulation may be altered by increasing amounts of freshwater in the ocean. Thermohaline circulation is responsible for bringing up cold, nutrient rich water from the depths of the ocean, a process known as upwelling. This may affect regional temperatures and primary productivity.

Susceptibility to disease is also thought to increase while reproductive success may decrease with increasing ocean temperatures.

The world's oceans absorb a large amount of carbon dioxide from the atmosphere and causes an increase in carbon dioxide concentrations and decreases its overall pH, increasing ocean acidification.

See also

References

  1. ↑ Hardwood, 2001
  2. ↑ Simmonds and Isaac, 2007
  3. ↑ Tynan and DeMaster, 1997
  4. ↑ Learmonth et al, 2006
  5. ↑ Map Shows Vast Regions of Ocean Are Warmer March 30, 2013 Scientific American
  6. ↑ Warming Ocean Threatens Sea Life; Warming down to 700 meters could also affect currents, weather March 30, 2013 Scientific American
  7. ↑ New Research Confirms Global Warming Has Accelerated March 25, 2013 Skeptical Science
  8. ↑ doi:10.1002/grl.50382
  9. ↑ Glick, Patrick; Clough, Jonathan; Nunley, Brad. "Sea-Level Rise and Coastal Habitats in the Chesapeake Bay Region" (PDF). National Wildlife Federation. Retrieved 8 November 2014.

Sources

External links

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