By Jennifer Langston , TheTyee.ca
Despite a history of overfishing and pollution from pulp mills and mining, Howe Sound is a richly bio-diverse fjord. Home to more than 650 different species of fish and invertebrates, the 800-foot deep sound has maintained an incredible ecological balance over the past 60 years, though it has been more overfished than any other part of the Strait of Georgia.
Today, oceanic ecosystems are facing a new and potentially catastrophic trend - acidification - a changing of the ocean's chemistry brought on by carbon dioxide absorption. Coupled with concerns about rising ocean temperatures and continued industrial pollution, it could seem as if our small slice of paradise in the greater Pacific Northwest marine system is doomed - but it isn't, not yet.
While ocean acidification is predicted to be a great threat to marine ecosystems, and dropping pH levels (indicating rising acidity) have been documented in Howe Sound over the past 60 years, the region's overall biodiversity has remained stable. However, the impacts of acidification trends have not been isolated from other climate impacts such as El Niño winters or climate regime shifts and acidification as an independent influence has not been thoroughly examined by marine biologists in our area.
Vancouver Aquarium seawater records reveal that ocean acidification has steadily occurred throughout the last half of the 20th Century, with the range of pH in Vancouver Harbor shifting from pH 7.8 - 8.1 from 1954-1974, and increasingly varying to lower pH levels ranging from pH 7.3-7.9 leading up to 2001. Yet the biodiversity has remained very stable in the Straight of Georgia (including Howe Sound) - more stable than in adjacent areas. Despite our best efforts to mess things up, marine biodiversity is demonstrating incredible resilience in the face of documented fisheries exploitation, climate change and ocean acidification.
But concern over the issue must remain especially in light of a new Canadian study released this month, which suggests that the greatest mass extinction on the planet -which wiped out about 90 per cent of all species 250 million years ago- appears to be linked to ocean acidity.
By Susan Hollis
Five years ago, many scientists probably thought they'd never see large pools of corrosive water near the ocean's surface in their lifetimes.
Basic chemistry told them that as the oceans absorbed more carbon dioxide pollution from cars and smokestacks and industrial processes, seawater would become more acidic. Eventually, the oceans could become corrosive enough to kill vulnerable forms of sea life like corals and shellfish and plankton.
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