The effect of global warming on marine mammals is a growing concern. Many of the effects of global warming 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. There are a number of marine mammals that have been affected by climate change including walruses, seals, penguins, and polar bears.
Video Effects of global warming on marine mammals
Effects
Marine mammals have evolved to live in oceans, but the effects of climate change are rapidly altering their natural habitat. 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. The impact in vertebrates is less known from developing countries, where there are the fewest studies; between 1970 and 2012, vertebrates declined by 58 percent, with freshwater, marine, and terrestrial populations declining by 81, 36, and 35 percent, respectively.
During the last century, the global average land and sea surface temperature has increased dramatically due to increased greenhouse effect linked to human activities. Warming has even reached depths of more than 700 meters (30% of ocean warming over the past decade has occurred in the deeper oceans below 700 meters). 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.
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. 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.
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. There have been an increasing number of polar bear drownings due to becoming exhausted by having to swim farther to find ice or prey.
Maps Effects of global warming on marine mammals
References
- Poloczanska, E. S., Babcock, R. C., Butler, A., Hobday, A. J., Hoegh-Guldberg, O., Kunz, T. J., Matear, R., Milton, D. A., Okey, T. A., & Richardson, A. J. 2007. "Climate change and Australian marine life". Oceanography and Marine Biology: An Annual Review, 45, 407-478.
- Marine Climate Change Impacts Partnership. 2006. "Marine Climate Change Impacts Annual Report Card 2006". (Eds. Buckley, P.J., Dye, S.R., & Baxter, J.M..), Summary Report, MCCIP, Lowestoft, 8pp.
External links
- Marine Mammal Commission
- United Nations Environment Programme World Conservation Monitoring Centre
- Intergovernmental Panel on Climate Change
- The Infography about Climate Change and Biodiversity
Source of article : Wikipedia
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