{"id":85835,"date":"2022-10-10T02:45:00","date_gmt":"2022-10-10T00:45:00","guid":{"rendered":"https:\/\/www.sonnenseite.com\/?p=85835"},"modified":"2022-10-09T11:46:05","modified_gmt":"2022-10-09T09:46:05","slug":"arctic-ocean-greater-future-acidification-in-summer","status":"publish","type":"post","link":"https:\/\/www.sonnenseite.com\/en\/science\/arctic-ocean-greater-future-acidification-in-summer\/","title":{"rendered":"Arctic Ocean: Greater Future acidification in summer"},"content":{"rendered":"\n

A new study predicts that climate change could shift and intensify the seasonal acidification of the Arctic Ocean, with consequences for its ecosystem.<\/p>\n\n\n\n

Over the past 200 years, our planet\u2019s oceans have absorbed more than a quarter of all anthropogenic carbon dioxide from the atmosphere. As a result, their acidity has increased by nearly 30 percent their acidity has increased by nearly 30 percent since the beginning of the Industrial Revolution. In this regard, the water\u2019s pH value isn\u2019t constant; it varies both seasonally and regionally. The lowest values naturally occur in winter. But that could soon change, since they could be shifted to the summer by climate change, as an international team including experts from the Alfred Wegener Institute recently demonstrated. If this comes to pass, it could have far-reaching consequences for life in the ocean, as they report in the journal Nature.<\/p>\n\n\n

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The Arctic polar cod Boreogadus saida \u00a9 Hauke Flores | awi.de<\/figcaption><\/figure>\n<\/div>\n\n\n

The biological activity of marine organisms normally reaches its zenith in summer, as the season is normally characterised by optimal conditions for survival, finding food and reproducing. However, climate change is now threatening this status quo by shifting the point at which the pH values are lowest from winter to summer, as experts from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) and France\u2019s Laboratory for Sciences of Climate and Environment (LSCE, part of the CEA); LOCEAN \u2013 Laboratory of Oceanography and Climatology; and Institute Pierre-Simon Laplace (IPSL) recently determined. In a new study, they conclude that summer acidification could intensify by up to 25 percent by the end of the century. Some organisms living in the Arctic Ocean would be severely affected by this change, reducing their ability to cope with more intensive summertime warming.<\/p>\n\n\n\n

This seasonal shift is due to the more intense rise in CO2<\/sub> in warmer water. In summer, atmospheric temperatures rise in the Arctic, more sea ice melts, and the surface water grows warmer. This warming process becomes so intense that the acidification of the seawater increases much more rapidly and can no longer be compensated for by the photosynthesis of marine algae. \u201cThese new findings spell trouble for some types of Arctic fish, like the polar cod, which are already threatened by climate change,\u201d says co-author Hans-Otto P\u00f6rtner, a biologist and climate researcher at the AWI. \u201cThe projected high temperatures will push Arctic fauna to their thermal limits or even beyond, particularly with regard to life stages in which they\u2019re more fragile.\u201d First author James Orr from the LSCE and IPSL adds: \u201cWho would have thought that climate change could shift the time of maximum acidification by six months, when studies on seasonal biological rhythms only projected shifts of up to roughly a month?\u201d \u201cThe fascinating thing about this study is the fact that the chemical winters will actually become chemical summers,\u201d says Lester Kwiatkowski, a co-author from LOCEAN and the IPSL.<\/p>\n\n\n\n

In their study, the experts analysed simulations of 27 Earth system models and prepared future climate scenarios. While doing so, for the first time they assessed the potential for seasonal shifts in acidification, including all related variables. Why? Because the degree of acidification isn\u2019t determined by just one factor; it\u2019s a complex interplay of physical and biological processes, influenced by the more intense warming of surface water in summer. These changes were more pronounced in scenarios with moderate and high greenhouse-gas emissions and were far milder in those with lower emissions. In the researchers\u2019 eyes, this represents a glimmer of hope that key elements of the Arctic Ocean\u2019s ecosystem can be preserved if mean global warming can be kept below 2\u00b0C.<\/p>\n\n\n\n