New research shows that as the world’s waters acidify because of carbon dioxide levels in the atmosphere, the pink salmon (Oncorhynchus gorbuscha) could become smaller and less likely to survive.
Previous studies have repeatedly and consistently explored potentially problematic consequences of change in the pH value of the world’s oceans. The higher the carbon dioxide concentrations in the air as a consequence of the burning of fossil fuels, the greater the change in oceanic acidity levels.
Researchers at the University of British Columbia, Vancouver, and colleagues looked freshwater fish, which represent 40% of all fish, testing embryos in water at acidity levels expected at the end of this century, and observing them for 10 weeks.
The salmon were smaller, and their ability to smell was reduced, which could signify problems in returning to their spawning grounds or for scenting and responding to danger.
They were also less able to use oxygen in their muscles during migration.
Research in Australia found that common pesticides and industrial contaminants washed into rivers were more toxic at higher water temperatures, putting fish such as rainbow trout, silver perch, rainbowfish and western carp gudgeon at risk.
The 5°C average warming in global atmospheric temperatures predicted by 2100 means that many fish are likely to migrate away from their existing habitats considerably faster than they are doing now.
Jean-Pierre Gattuso, of the Oceanological Observatory in Villefranche, France, and colleagues looked at the evidence on a global scale and report in Science journal, that without attempts to mitigate global warming, the oceans and the creatures in them will be seriously affected by temperature changes and acidification.
“On a positive note, we still have options to substantially reduce these impacts now, but the longer we wait the fewer and fewer options we have,” warns co-author William Cheung, of the fisheries center at Canada’s University of British Columbia.
Source: Tim Radford. Climate News Network. Read the full article here.