The oceans function as a carbon sink and have already consumed more than 40% of anthropogenic carbon emissions. The vast majority of this CO2 has been taken up by the Southern Ocean, making these waters hotspots of ocean acidification (OA).
Lead author of the paper revealed in Nature Climate Change, Dr. Katherina Petrou from the University of Technology Sydney, mentioned that though changes in ocean pH have been shown to impact marine calcifying organisms, the consequences for non-calcifying marine phytoplankton are less clear.
“Earlier studies reported a range of responses to OA in phytoplankton but rarely considered how environmental pH shifts may affect silicification rates in diatoms,” she says.
Diatoms are unique phytoplankton in that they require silicic acid to provide silica cell walls. Beneath the microscope, they seem like beautiful glass jewelry boxes, however importantly, this dense, glass-like armor promotes sinking, which makes diatoms an essential conduit for transport of carbon to the deep ocean where it may be stored for millennia.
Diatoms are liable for around 40% of ocean productivity, which means they play a vital role in supporting marine food webs, sustaining life for millions of creatures, including humans.
The research was conducted the Australian Antarctic base, Davis station, by a team of scientists from a different university like the University of Technology Sydney, Southern Cross University, the Australian Antarctic Division and the University of Tasmania. Using massive 650 L experimental tanks, temperature-controlled 40-foot container and natural coastal water; their analysis was designed to analyze the effects of predicted future changes in ocean acidity on the community structure of the Antarctic phytoplankton.
“We have been alarmed to find that diatoms were so negatively affected, with some species likely to have diminished silica production before the tip of this century,” states Dr. Petrou.
In the context of global climate change, these findings are essential because they reveal that OA can alter not only phytoplankton community composition but also reduce diatom ballast (sinking skill), adds SCU primarily based Kai Schulz. Loss of silica production and thus ballast might imply that fewer diatoms end up on the ocean floor, leading to less atmospheric CO2 being removed from our atmosphere and transported for storage in the deep ocean.