Effects of global warming on marine mammals

The effect of global warming on marine mammals is a growing concern. Many of the effects of climate change are currently unknown due to its unpredictability, but many are becoming increasingly evident today. Some effects are very direct such as loss of habitat, temperature stress, and exposure to severe weather. Other effects are more indirect such as changes in host pathogen associations, changes in body condition because of predator–prey interaction, changed in exposure to toxins, and increased human interactions. These are just a few examples of what marine mammals are dealing with as a result of rapid climate change.[1] There are a number of marine mammals that have been affected by climate change including walruses, seals, penguins, and polar bears.[2]

Effects

Marine mammals have evolved to live in oceans, but the effects of climate change are rapidly altering their natural habitat.[3][4][5][6] We can learn about the consequences of global warming on arctic marine mammals by studying the difference in their habitat, distribution, abundance, movement and migration, body conditions, behavior, and their sensitivity. Climate is rapidly changing, which makes it hard for certain species to adapt fast enough. Immense pressure and stress due to global warming are imposed on marine mammals, which can lead to their potential extinction.[7]

During the last century, the global average land and sea surface temperature has increased dramatically due to increased greenhouse effect linked to human activities.[8] Warming has even reached depths of more than 700 meters[9] (30% of ocean warming over the past decade has occurred in the deeper oceans below 700 meters).[10][11] Many marine mammal species require specific temperature ranges to survive. Ocean warming will therefore lead to increased species migration, as endangered species look for a more suitable habitat. If a species cannot successfully migrate to a suitable environment, unless it learns to adapt to rising ocean temperatures, it will face extinction. Sea level rise is also of utter importance when assessing the impacts of global warming on marine mammals. The rise in sea level also affects coastal environments that marine mammals species rely on to survive.[12]

Primary productivity

Changes in temperatures changes the location of areas with high primary productivity. Primary producers, such as plankton, are the main food source for marine mammals such as whales, or their preys. Species migration will therefore be directly affected by locations of high primary productivity. Water temperature changes also affect the ocean turbulence which has a major impact on the dispersion of plankton and other primary producers.[13] Due to global warming and increased glacier melt, Thermohaline circulation patterns may be altered by increasing amounts of freshwater released into oceans and therefore changing ocean salinity. Thermohaline circulation is responsible for bringing up cold, nutrient-rich water from the depths of the ocean, a process known as upwelling.

Turtles

Coastal erosion is an important risk for turtles, as it affects their reproduction habits by modifying the conditions under which they can lay their eggs. The temperature of sand also determines the sex of the eggs, and warmer conditions favour the reproduction of female turtles. Many places are having a 90% production of females and if the temperature rises by just one degree, there could potentially be no more male turtles.

Penguins

Penguins are very easily affected by climate warming, and they are in the International Union for Conservation of Nature's Red List. Penguin species such as adelie, chinstrap or gentoo are affected by global warming and changes in sea ice levels.[14] The breeding process is particularly affect are warm temperatures can decrease the number of chicks.[15]

Polar bears

Polar bears are one of the marine mammals that are most at risk due to climate change. The biggest issue for polar bears related to climate change is the melting of ice as a result of increasing temperatures. When the ice melts, polar bear lose their habitat and food sources. Although polar bears have been known to eat more than 80 species of animals, most of their diet consists of seals, another species endangered by global warming.[16] There have been an increasing number of polar bear drownings due to becoming exhausted by having to swim farther to find ice or prey.[17]

References

  1. ↑ Burek, Kathy. "Effects of Climate Change on Arctic Marine Mammal Health". Ecological Society of America. JSTOR 40062160.
  2. ↑ "Pollution, habitat loss, fishing, and climate change as critical threats to penguins". Conservation biology.
  3. ↑ Hardwood, J. (2001). "Marine mammals and their environment in the twenty-first century". Journal of Mammalogy. 82 (3): 630–640.
  4. ↑ Simmonds, Mark P.; Isaac, Stephen J. (5 March 2007). "The impacts of climate change on marine mammals: early signs of significant problems". Oryx. 41 (1): 19–26. doi:10.1017/s0030605307001524.
  5. ↑ Tynan, Cynthia T.; DeMaster, Douglas P. (1997). "Observations and Predictions of Arctic Climatic Change: Potential Effects on Marine Mammals" (PDF). Arctic. 50 (4): 308–322.
  6. ↑ Learmonth, JA; Macleod, CD; Santos, MB; Pierce, GJ; Crick, HQP; Robinson, RA (2006). "Potential effects of climate change on marine mammals". In Gibson, RN; Atkinson, RJA; Gordon, JDM. Oceanography and marine biology an annual review. Volume 44. Boca Raton: Taylor & Francis. pp. 431–464. ISBN 9781420006391.
  7. ↑ Laidre, Kristin L.; Stirling, Ian; Lowry, Lloyd F.; Wiig, Øystein; Heide-Jørgensen, Mads Peter; Ferguson, Steven H. (January 1, 2008). "Quantifying the Sensitivity of Arctic Marine Mammals to Climate-Induced Habitat Change". Ecological Applications. 18 (2): S97–S125. JSTOR 40062159.
  8. ↑ Map Shows Vast Regions of Ocean Are Warmer March 30, 2013 Scientific American
  9. ↑ Warming Ocean Threatens Sea Life; Warming down to 700 meters could also affect currents, weather March 30, 2013 Scientific American
  10. ↑ New Research Confirms Global Warming Has Accelerated March 25, 2013 Skeptical Science
  11. ↑ "Distinctive climate signals in reanalysis of global ocean heat content". Geophysical Research Letters. 40: 1754–1759. doi:10.1002/grl.50382.
  12. ↑ Glick, Patrick; Clough, Jonathan; Nunley, Brad. "Sea-Level Rise and Coastal Habitats in the Chesapeake Bay Region" (PDF). National Wildlife Federation. Retrieved November 8, 2014.
  13. ↑ Castilla, Juan Carlos. "Marine Ecosystems, Human Impacts on". Encyclopedia of Biodiversity (2 ed.). Academic Press. pp. 56–63.
  14. ↑ Boersma. "Penguins as marine sentinels".
  15. ↑ "Pollution, habitat loss, fishing, and climate change as critical threats to penguins".
  16. ↑ Derocher, Andrew. Polar Bears: A Complete Guide to Their Biology and Behavior. Johns Hopkins University Press. p. 84.
  17. ↑ Parsons, Edward; Milmoe, B.J.; Rose, Naomi. "Polar Bears". Encyclopedia of Global Warming & Climate Change (2 ed.). SAGE Reference. p. 1114.
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