Ocean acidification compromises a planktic calcifier with implications for global carbon cycling

Area of Science:

• Marine biology
• Oceanography
• Climate change science

Background:

• Calcifying plankton are crucial for marine ecosystem functioning and carbon cycling.
• Anthropogenic changes in ocean chemistry, particularly pH, pose a threat to marine life.

Purpose of the Study:

• To investigate the physiological and calcification responses of the foraminifer Globigerina bulloides to a range of ecologically relevant seawater pH levels.
• To understand the implications of these responses for marine carbon cycling and paleoceanographic reconstructions.

Main Methods:

• Culturing of Globigerina bulloides under controlled pH conditions (7.5 to 8.3).
• Measurement of multiple metrics of calcification, physiological performance (respiration), and spine repair.
• Analysis of the relationship between seawater pH and biological responses.

Main Results:

• Calcification increased at pH > 8.0 without increased respiration.
• Calcification and oxygen consumption decreased as pH declined from 8.0 to 7.5, indicating metabolic depression.
• Spine repair was reduced at pH < 7.7.

Conclusions:

• Foraminifera, like Globigerina bulloides, are likely to be negatively impacted by future ocean acidification.
• Changes in foraminifera physiology and calcification can alter the vertical transport of carbon, affecting marine carbon cycling.
• Ocean acidification impacts on foraminifera have significant implications for their use as paleoceanographic indicators.