Liqi Chen
Key Lab of Global Change and Marine Atmospheric Chemistry(GCMAC), Third Institute of Oceanography(TIO), SOA, PR China
E-mail: chenliqi@tio.org.cn
The ocean acidification (OA) in the 21 st century has obviously speeded up in comparison to earlier periods. The averaged surface pH of the world ocean has decreased 0.1 units since the industrial revolution and is projected to decrease 0.3-0.4 pH units by the end of this century, equal to increasing 1-1.5 times in ocean acidity. Due to its cold water temperature, low alkalinity and rapid sea ice decline, the Arctic Ocean and subarctic Pacific Ocean
(AOPO) have absorbed massive amounts of atmospheric CO
2
and changed the CaCO
3
system to an aragonite unsaturated state. Between 1994 to 2005, the unsaturated state of aragonite was found to extend from the continental shelf and slope into the upper surface waters of the Canada Basin from the south of 77°N with surface water of 0-30 m to 84°N with the middle water of 75-250 m, respectively. By 2010, the unsaturated aragonite state region continued to expand northward and to shallower depths in the Arctic. This is the first time that aragonite undersaturation was observed at shallow depths (50 m) this far north (to 84°N) in the Canada
Basin. OA in AOPO will be greatly changed in marine chemical environment to affect marine ecosystem.
Therefore, it is important to develop an Ocean Acidification Observation Network for the Arctic and sub-Arctic
Pacific Oceans linked with GOA-ON, AMAP-AOA etc.