As climate warming increases and greenhouse gases such as carbon dioxide continue to rise, scientists continue to look to the Pacific Ocean along the West Coast as a model of how other areas of the ocean will respond to the coming decades of environmental change. If oceans continues to undergo acidification and low-oxygen zones keep expanding, coastal oceans from British Columbia to Mexico are the most ideal areas to look for early warning signals.
Recently, scientists from the University of Washington examined the impacts of ocean acidification and low-oxygen conditions on fish and invertebrate physiology and how these stressors impact various organisms such as shellfish and squid. The results point to serious negative effects from these stressors and hightlight the importance of realizing the continued challenges that they will pose to marine life.
"Our research recognizes that these climate change stressors will co-occur, essentially piling on top of one another," Terrie Klinger, co-author of the study, said in a press release. "We know that along the West Coast temperature and acidity are increasing, and at the same time, hypoxia is spreading. Many organisms will be challenged to tolerate these simultaneous stressors, even though they might be able to tolerate individual stressors when they occur on their own."
With carbon dioxide emissions on the rise, so too does the acidity of the ocean due to the absorption of this greenhouse gas. This increase in acidity is stressing organisms due to the change in chemistry of the seawater, especially organisms that have calcium carbonate shells or skeletons such as oysters and corals. Alternatively, low-oxygen conditions, or hypoxia, can cause massive fish and shellfish die-offs due to the expansion of areas that possess these conditions.
"Along this coast, we have relatively intensified conditions of ocean acidification compared with other places. And at the same time we have hypoxic events that can further stress marine organisms," Klinger said. "Conditions observed along our coast now are forecast for the global ocean decades in the future. Along the West Coast, it's as if the future is here now."
The findings were published in the Jan. 1 issue of BioScience.