Chilean experts assess climate change impacts on Antarctic marine systems

Santiago — Chilean scientists have installed pH meters in the waters surrounding Antarctica to assess the extent to which increased levels of CO2 in the atmosphere, the main driver of climate change, are affecting ocean acidification.

As part of Antarctic Scientific Expedition #55, carried out between January and March of this year, the specialists plunged a sensor to a depth of 30 meters (98 feet) to measure pH levels (how acidic or alkaline the water is).

The project at South Bay, just off Doumer Island, involved launching a capsule from a boat and keeping it submerged for a period of one year so it can take readings of pH levels at three-hour intervals.

Chilean scientists already have been studying ocean acidification, a phenomenon that occurs when ocean pH levels decrease due to a higher level of CO2 in the atmosphere, for the past three years.

But this new project also allows data to be obtained in the Antarctic winter, when the surrounding ocean water freezes and climactic conditions make expeditions impossible.

Marine biologist Emilio Alarcon, a scientist affiliated with a research center at Chile’s Austral University that studies the dynamics of high latitude marine ecosystems, stressed the importance of “having continuous readings of various oceanographic variables.”

“The pH reading is a measurement of the acidity of sea water and has to do with ... the increase in CO2 in the atmosphere,” the expert said.

This information will help scientists understand the dynamics of the Frozen Continent’s coastal marine ecosystems and gauge changes in water chemistry and variations in the ocean’s biological and physical processes.

“We want to understand the role of the ocean, especially the Southern Ocean, in absorbing CO2, which results in more acidic seawater. That’s why it’s important to monitor pH” levels, Alarcon said.

This information will assist with future analyses of proposals for marine protected areas in Antarctica, since climate change forecasts indicate that the oceans will become increasingly acidic due to increased CO2 levels in the atmosphere.

“Antarctica is one of the systems most susceptible to climate change, and that’s why it’s important to understand what’s happening in the different areas. Reports on ocean acidification in the White Continent are scarce due to the logistical complexities involved in getting there,” the Chilean scientist said.

Changes in the level of acidity in Antarctic seas could have a major impact on organisms that live in those waters and on the ocean floor, scientists say.

Species such as mollusks, for example, are extremely vulnerable to ocean acidification because it reduces the availability of the calcium carbonate they need for shell production.

The scientists involved in this expedition plan to remove the sensors in February 2020 and then compare the results with those obtained in a similar study carried out in the Arctic region.