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- http://www.vancouversun.com/technology/Climate+change+threatens+alter+marine+ecosystem/7050645/story.html
- Climate change threatens to wreak havoc on entire marine ecosystems due to factors such as rising water temperatures, increased acidification, and reduced oxygen levels, according to a report on B.C.'s Pacific coast.
The report by World Wildlife Fund-Canada and the Canadian Parks and Wilderness Society warns that species such as Pacific salmon, southern pink shrimp, Pacific cod, and hake are expected to move northward, along with Humboldt squid, which have arrived in B.C. in large numbers in recent years.
The two environmental groups urge a cautionary and adaptive management approach providing for swift decisions related to human activities such as fishing and pollution in response to climate-induced changes, as well as the creation of refuge areas to help marine species better adapt.
The report, Climate Change Impacts and Vulnerabilities in Canada's Pacific Marine Ecosystems, says climate change threatens to alter the entire marine food web.
Burning of fossil fuels generates car-bon dioxide, which leads to acidification of the oceans. In turn, marine life ranging from shellfish to tiny organ-isms such as coccolithophores and pteropods - a food source for salmon - will have more difficulty building shells and skeletons.
Global warming is also expected to result in rising sea levels and wave heights as well as altered marine life cycles and migrations.
It will also affect ocean currents and upwelling patterns that bring nutrients from the ocean depths to the surface to fuel the marine food chain. Invasive marine species may find conditions favourable to gain a foothold.
Changes could also lead to entire species leaving local waters or becoming extinct, while pushing "marine ecosystems toward or beyond tipping points and into degraded or otherwise altered states from which recovery or return would be unlikely," the report warns.
Especially vulnerable are:
. Areas critical for larval retention and transport such as Dixon Entrance, Queen Charlotte Sound, and Juan de Fuca Strait.
. Sediment shorelines and other nearshore habitats that serve as important fish habitat and are sensitive to erosion and sea-level rise such as Hecate Strait and the Strait of Georgia.
. Coral habitats in Queen Charlotte Sound and the Continental Slope.
. Commercially harvested groundfish species at 250 and 400 metres deep due to oxygen-depleted waters. B.C. is already losing two to three metres of deepwater habitat every year due to oxygen depletion.
. Long-lived species such as Pacific perch, rockfish, and sablefish that cannot adapt as fast as shorter-lived species.
. Areas already under stress from human impacts, including the Strait of Georgia, Queen Charlotte Strait, Johnstone Strait, and Juan de Fuca Strait.
The report notes the exact implications of climate change remain unknown and it is possible that B.C.'s position in an "oceanographic transition zone" between the California Cur-rent and Alaska Coastal Current could make its flora and fauna more resilient to ecological change.
Authors of the study are: Tom Okey, School of Environmental Studies, University of Victoria; Alvaro Montenegro, School of Earth and Ocean Sciences, UVic; Hussein Alidina, marine science planner with WWF-Canada; and oceans manager Sabine Jessen and marine planner Veronica Lo, both with the Canadian Parks and Wilderness Society.
The research of Frank Whitney, an emeritus scientist at the federal Institute for Ocean Sciences in Sidney, also contributed to the report.
