Unprecedented ocean acidification from greenhouse gases putting Canadian waters at risk, says report
OTTAWA – Canada’s Atlantic waters may be “particularly vulnerable” to increased carbon dioxide emissions in the atmosphere that are causing “unprecedented” acidification of the planet’s oceans, says a report by scientists at the Department of Fisheries and Oceans.
Quoting from numerous scientific publications, the government report, posted on a website without a formal announcement or news release, noted that the world’s oceans have absorbed a significant amount of carbon dioxide emissions from the atmosphere since the industrial revolution, with profound effects on marine ecosystems that could damage the Canadian economy.
The report, which focused on the Scotian Shelf region of Atlantic Canada, says that “adaptive measures coupled with a reduction in carbon dioxide emissions to the atmosphere will have to be pursued to protect ecosystems and human livelihoods against this phenomenon,” since it is not easy to reverse ocean acidification and its effects.
Carbon dioxide emissions — a byproduct of consuming fossil fuels such as oil, gas or coal — also trap heat in the atmosphere and can contribute to global warming.
Co-authors Kristian Curran and Kumiko Azetsu-Scott, from the department, wrote that marine ecosystems might be able to adapt to changes in their acidity over time periods greater than 10,000 years, but would have difficulty with emerging changes that are equivalent to a 30 per cent increase in acidity since the industrial revolution.
“Today’s concern regarding ocean acidification resides in its unprecedented rate of occurrence, due to the significant amount of carbon dioxide that has been added to the atmosphere over the past 250 years,” said the “Ocean Acidification” report, dated October 2012.
The study also noted that there was limited research about potential biological effects, but that many of those “could be severe” in the North Atlantic Scotian Shelf, due to its “exceptional capacity to uptake atmospheric carbon dioxide.”
It said that the compounding effects of climate change, including acidification and warming, posed the greatest uncertainty, “although it is is believed ocean acidification alone will be enough of a driver to alter species composition and dominance in a manner that could profoundly alter marine ecosystem and functioning.”
Giving her first major interview on the report since its release in October 2012, Azetsu-Scott told Postmedia News she was now studying how lobsters respond to the combined effects of different ocean temperatures and acidity levels.
Dr. Kumiko Azetsu-Scott of the Department of Fisheries and Oceans says there’s a direct link between carbon dioxide emissions and ocean acidification.
“To adapt to the changing environment we have to identify where the most vulnerable area is and try to reduce that added stress like pollution (and/or) overfishing,” said Azetsu-Scott, who has a PhD in oceanography and works at the department’s Bedford Institute of Oceanography in Dartmouth, N.S. ”But still a lot of work needs to be done for adaptation.”
She added that there was a direct link between atmospheric carbon dioxide emissions and ocean acidification, which she described as an “urgent and serious problem” particularly for the polar marine environment around Canada.
Azetsu-Scott also said that some recent studies, looking at oysters and mussels on the United States west coast, have demonstrated those species are negatively affected by chemical changes underway in the oceans, which also has impacts on the local shellfish industries.
The Fisheries and Oceans report described the North Atlantic as a “global hotspot” for carbon dioxide absorption, accounting for 23 per cent of the ocean’s total uptake of the gas between 1800 and 1994, even though it only constitutes 15 per cent of the global ocean’s surface area.
The department’s research also quoted recent peer-reviewed research that concluded climate change threatened to cause “numerous local extinctions and simultaneous species invasions likely to affect a range of marine ecosystem services.” In Atlantic Canada, the report said that some shellfish — including scallop, lobster and crab — worth hundreds of millions of dollars and responsible for thousands of jobs, may be “particularly vulnerable.”
Azetsu-Scott said she was expecting to complete her experimental research on lobsters, including examining survival of babies in different conditions, by the end of the summer.
Luke Gaulton, a department spokesman, said the federal government didn’t issue a news release when it published the report. But he noted that it was posted on the website of a network with representation from government, industry, academia and non-governmental organizations allowing for “widespread exposure” among those groups.
Mike De Souza, Postmedia News, 2 July 2013. Article.