Nutrient pollution makes ocean acidification worse for coral reefs

A study published this week by a team of researchers, alumni and students from the University of Hawaiʻi at Mānoa‘s School of Ocean and Earth Science and Technology (SOEST) showed that local impacts of humans—nutrient pollution from activities on land—may accelerate the negative impacts of global ocean acidification on coral reefs.

Coral reefs provide critical ecosystem services including food security and shoreline protection to coastal communities. These services largely depend on the highly complex three-dimensional structure of coral reefs.

In order for coral reefs to thrive, calcifying organisms, such as corals, must build the reef faster than bioeroding organisms and natural dissolution break down the reef.

Prior research showed that stressors associated with human-derived carbon dioxide emissions, such as ocean acidification, are shifting coral reefs toward net loss, which would lead to the loss of the three-dimensional framework in the future.

The new study in Proceedings of the Royal Society B: Biological Sciences, led by Nyssa Silbiger, assistant professor at California State University, Northridge and alumna of HIMB, showed that nutrient pollution could make coral reefs more vulnerable to ocean acidification and accelerate the predicted shift from net growth to overall loss.

“Nutrient pollution negatively affects reef growth both directly and indirectly, creating a double whammy for coral reefs already stressed by ocean acidification around the world,” said co-author Megan Donahue, researcher at HIMB. “ Our data indicate that both local management efforts such as reducing nutrient runoff and seepage into groundwater, and global actions, such as reducing global carbon dioxide emissions, are required to protect reefs from rapidly declining.”

Read more on UH News and Big Island Now.