Analysing the way these phytoplankton create their shells can help scientists understand how ocean acidification will affect marine ecosystems.
Credit: Wikimedia
EDINBURGH: Scientists have pinpointed they way the cells of ubiquitous marine algae are affected by ocean acidification.
The discovery, published this week in the journal PLOS biology, represents a breakthrough in understanding in exactly how ocean acidification will impact marine organisms.
The team, led by marine biologist Alison Taylor from the University of North Carolina Wilmington, in the US, investigated the process that single-celled algae called coccolithophores use to generate their chalky scales.
Coccolithophores are a significant part of the phytoplankton that live near the marine surface, and play a role in absorbing carbon from the atmosphere. They create their chalky scales by making limestone utilising the calcium in the ocean.
Acid affects shell-building
But the increasing acidification of the ocean - adding hydrogen ions (protons) to the water and lowering its pH - affects the way the coccolithophores generate these carbonate scales.
"We wanted to understand how coccolithophores manage to generate their calcium carbonate scales (coccoliths) inside their cells", explained marine biologist Glen Wheeler, from Plymouth Marine Laboratory in the UK and a co-author of the study.
"It is very hard to predict what effects lower ocean pH may have on calcifying organisms as we do not know very much about the cellular mechanisms of calcification.
"By identifying a mechanism directly associated with calcification and pH regulation, we can now start to examine how this mechanism may respond to future changes in ocean pH," he said.
Making calcium scales
The armour scales of coccolithophores are formed by transporting calcium and bicarbonate into the cell where they combine to form calcium carbonate and protons (hydrogen atoms with a positive charge, written as H+).
"Protons are a byproduct of coccolith formation. Producing the protons inside the cell will acidify the cell to toxic levels unless you get rid of them very rapidly," said Wheeler.
"We found that there was a massive outward flux of H+ across the cell membrane, and can now start to examine how this mechanism may respond to future changes in ocean pH."
