World Ocean Systems Undermined by Climate Change by 2100

"Oct. 15, 2013 — An ambitious new study describes the full chain of events by which ocean biogeochemical changes triggered by humanmade greenhouse gas emissions may cascade through marine habitats and organisms, penetrating to the deep ocean and eventually influencing humans."

Previous studies have focused on ocean warming and ocean acidification while not taking into consideration the biological consequences of climate change in the ocean. A new study, led by Camilo Mora and Craig Smith, now suggests that by 2100, no part of the world will be untouched by the climate change. One of the following consequences of the climate change is the deficiency of dissolved oxygen in seawater and a decline in oceanic ecosystems. "The consequences of these co-occurring changes are massive -- everything from species survival, to abundance, to range size, to body size, to species richness, to ecosystem functioning are affected by changes in ocean biogeochemistry," says the lead author of the study, Camilo Mora. There are large human consequences to this as well. 470 – 870 million of the world’s poorest people depend on seafood. With the possible decline of seafood, this can affect several jobs, the lives of people, and food chains.

The researchers used the newest and strongest models that project climate change to form their analysis. They ran two different models; the first model is the way the world would be in 2100 if we continue to release CO2 the way that we release it now, the second model is the way that the world would be in 2100 if we were to start intervention now. They found that most of the ocean surfaces around the world would have a synchronous effect in terms of “ocean warming, acidification, oxygen depletion, or shortfalls in productivity”. Nowhere in the oceans will there be cooling or pH increase and a very small part of the oceans, mostly in the polar areas, “will face the opposing effects of increases in oxygen or productivity”. This is bad because some intrusive animals will continue to migrate to these areas and threaten the species that live there and the people that depend on them says a co-author of the study.

Ocean warming and the effects on coral reefs

By 2100, the global average of the surfaces of ocean could experience a temperature increase of 1.2 to 2.6°, a dissolved oxygen concentration decrease of about 2% to 4% of the current value, and a pH decline of 0.15 to 0.31. Primary producers, such as phytoplankton, will produce about 4 to 10% from what they are producing now. But, the seafloor was projected to go through a less drastic change with very small changes in temperature and pH levels but would undergo through the same reduction in dissolved oxygen. Coral reefs, sea grass beds, and shallow soft-bottom benthic habitats would experience the most change while species that live in the deep-sea would experience lesser effects. Deep-sea communities, like coral reefs, would have a lower resilience because of the slightest changes in the environment, says a co-author Lisa Levin. Nonetheless, every part of the ocean will experience the effects of the climate change.

The study was published on October 15, 2013 in the scientific journal PLOS Biology.

Sources:

http://www.sciencedaily.com/releases/2013/10/131015191401.htm

http://d1jqu7g1y74ds1.cloudfront.net/wp-content/uploads/2010/01/globalwarming.jpg

http://centerforoceansolutions.org/climate/wp-content/uploads/2009/12/Acid_pH_graph.jpg

http://www.noaanews.noaa.gov/stories2007/images/co2coral2.jpg