<
https://theconversation.com/as-ocean-surfaces-acidify-a-deep-sea-acidic-zone-is-expanding-marine-habitats-are-being-squeezed-215672>
"In the deepest parts of the ocean, below 4,000 metres, the combination of high
pressure and low temperature creates conditions that dissolve calcium
carbonate, the material marine animals use to make their shells.
This zone is known as the carbonate compensation depth – and it is expanding.
This contrasts with the widely discussed ocean acidification of surface waters
due to the ocean absorbing carbon dioxide from the burning of fossil fuels.
But the two are linked: because of rising concentrations of carbon dioxide in
the ocean, its pH is decreasing (becoming more acidic), and the deep-sea area
in which calcium carbonate dissolves is growing, from the seafloor up.
The transition zone within which calcium carbonate increasingly becomes
chemically unstable and begins to dissolve is called the lysocline. Because the
ocean seabed is relatively flat, even a rise of the lysocline by a few metres
can rapidly lead to large under-saturated (acidic) areas.
Our research showed this zone has already risen by nearly 100 metres since
pre-industrial times and will likely rise further by several hundreds of metres
this century.
Millions of square kilometres of ocean floor will potentially undergo a rapid
transition whereby calcareous sediment will become chemically unstable and
dissolve."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
