SEP 30, 2020 11:11 AM PDT

Iron levels limit coral resiliency and growth

A new study from Penn State researchers reports that corals’ resiliency to climate change depends on environmental iron levels, suggesting that low iron levels limit coral growth and repair. Their findings are published in the Journal of Phycology.

There are concerns that environmentally available iron will decrease as ocean temperatures warm from climate change. For that reason, the team wanted to investigate how iron levels would influence the heat tolerance of corals, and more specifically, the microalgae that live in corals.

"In this study, we found that limiting the available iron lowered the heat tolerances of two species of microalgae, which potentially could have cascading effects on the coral and on the reef ecosystem," said author Hannah Reich.

It has been previously noted that the photosynthetic microalgae that live within coral cells require high concentrations of iron. These microalgae are crucial to corals’ wellbeing because they provide up to 90 % of the coral's nutritional needs through photosynthesis.

"Corals are the foundation for one of the most important ecosystems in the world. They support significant amounts of biodiversity, protect our shorelines from storms, provide habitat for our fisheries, and boost our economies with their opportunities for tourism. Climate change affects not only the coral, but also their symbiotic microalgae and the partnership between them,” commented said Todd LaJeunesse, professor of biology at Penn State. “In this study, we explored two aspects of climate change--warming waters and altered amounts of trace metals like iron--on the algae."

The study found that under conditions of high temperatures and limited iron, both coral species grew poorly compared to conditions of moderate temperatures and normal iron levels. "High temperatures increase metabolic demands, which forces the microalgae to work harder function properly," said Reich. "It also increases dependence on processes that require iron, like photosynthesis and assimilating other nutrients. We found that under high temperatures, the microalgae needed more than five times as much iron to reach typical, exponential growth rates."

Photo: Pixabay

The team also discovered that limited iron availability at high temperatures additionally adversely impacts the photosynthetic ability of the algae by decreasing their efficiency and ultimately their growth.

The researchers hope to continue their investigations in order to better understand how trace metal requirements change in different conditions in the field. "While it is important to understand how access to iron supplies can impact the ability of corals to respond to climate change stressors, there is still a dire need to reduce carbon dioxide emissions to combat the climate crisis," concluded Reich.

Sources: Journal of Phycology, Eureka Alert

About the Author
  • Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.
You May Also Like
AUG 19, 2021
Plants & Animals
The Hobbit's feeding biomechanics were similar to humans
AUG 19, 2021
The Hobbit's feeding biomechanics were similar to humans
New research suggests that the feeding biomechanics of Homo floresiensis (aka, the Hobbit) are similar to modern humans.
AUG 24, 2021
Plants & Animals
Flanged male orangutans experience more severe early life stress
AUG 24, 2021
Flanged male orangutans experience more severe early life stress
Linear enamel hypoplasia, or LEH, occurs when tooth enamel fails to develop correctly during growth. When the enamel sto ...
AUG 27, 2021
Earth & The Environment
Reducing our Waste Problem
AUG 27, 2021
Reducing our Waste Problem
The generation of waste in most of our lives is astounding. We throw much of what we use in the garbage. On average, Ame ...
AUG 31, 2021
Microbiology
How Cow Stomachs Might Help Us Reduce Plastic Waste
AUG 31, 2021
How Cow Stomachs Might Help Us Reduce Plastic Waste
Plastic is a long-lasting material that has many uses, which has led to a proliferation of plastic packaging that is pol ...
OCT 05, 2021
Chemistry & Physics
Researchers Propose Pathway to Plastics Free of Carbon Emissions
OCT 05, 2021
Researchers Propose Pathway to Plastics Free of Carbon Emissions
Plastics may, in general, be a product of fossil fuels like petroleum, but that has not stopped an international team of ...
OCT 06, 2021
Chemistry & Physics
2021's Nobel Prize in Physics Recognizes Foundational Work in Climate Science
OCT 06, 2021
2021's Nobel Prize in Physics Recognizes Foundational Work in Climate Science
The 2021 lineup for one of the world’s most prestigious awards has been announced, and the medal for physics has b ...
Loading Comments...