An ‘invasive’ marine organism has become an economic resource in the eastern Mediterranean

Skeletons and shells from an invasive species of foraminifera are helping build beaches in the eastern Mediterranean Sea

University of South Florida

 

image: 

Sand sample from Elafonisos, Greece, with abundant A. lobifera shells, as well as shells and shell fragments from snails and other organisms.

view more 

Credit: Olga Koukousioura

KEY TAKEAWAYS:

• A species of single-celled organisms called foraminifera (forams) is increasing in warm, alkaline waters of the eastern Mediterranean, building beaches with their calcium carbonate skeletons.
• In regions like Turke, forams are creating sandy shorelines where there used to be rocky terrain, benefiting tourism.
• Forams thrive in warm waters with high CO2, suggesting they might continue growing as climate change accelerates.
• This species of foram, once native to the Mediterranean, is returning as human activities make their preferred environment suitable again.

TAMPA, Fla. (Sept. 13, 2024) – Pamela Hallock, a biogeological oceanographer and distinguished university professor at the University of South Florida College of Marine Science, typically finds little comfort in climate change.

Hallock has spent her career studying the ocean. She leads USF’s Reef Indicators Lab and is no stranger to the impacts of human activities on marine environments.

Still, she couldn’t help but notice a bright spot in the results of her recent paper on a species of single-celled organisms called foraminifera (forams), published in the Journal of Foraminiferal Research.

“These forams have been increasing in numbers in suitable environments,” Hallock said. “Now they’re so prolific that they’re becoming an economic resource in regions with warm waters and high alkalinity because they’re building beaches.”

The foram species in question, Amphistegina lobifera, found favorable conditions in the warm, nutrient-poor waters of the Mediterranean Sea after traveling north through the Suez Canal 60-80 years ago. A. lobifera populations have since proliferated in the eastern Mediterranean and spread westward, raising concerns about its invasive potential in the region.

Despite these concerns, A. lobifera may be boon for tourism in countries like Turkey, Hallock said. Their calcium carbonate skeletons make excellent beach sand. Shorelines once covered in jagged volcanic and limestone rock have accumulated a half meter or more of sand comprised of dead foram skeletons and other shells.

“The rate at which these forams are building beaches in the region is comparable to the rate of sea level rise,” Hallock said.

There’s reason to believe A. lobifera may continue to flourish in a warming world replete with atmospheric CO2. The genus Amphistegina emerged on Earth during a period of higher atmospheric CO2 concentrations, Hallock noted in her paper, and warm waters with elevated alkalinity increase their rates of metabolism and shell formation.

While A. lobifera may currently be considered invasive in the Mediterranean Sea, its presence in the region is really a return to ancestral waters.

“These are a kind of critter that previously inhabited the region,” she said. “Now, through our influence on the environment, we’re making the habitat once again suitable for them.”

The recent study offers a unique perspective about the impacts of humans on marine environments, and vice versa.

As Hallock and her co-authors state in the study, “Might this return of prolific shallow-water carbonate production ultimately prove at least locally beneficial as climate change progresses?”

Amphistegina lobifera.

This figure shows alkalinity in the Mediterranean. Note the high alkalinity in surface waters in the eastern basin.

The coastal areas of the Mediterranean Sea shown in yellow indicating regions where A. lobifera can live abundantly if water quality is suitable.

Credit

Olga Koukousioura

 

About the University of South Florida

The University of South Florida, a high-impact research university dedicated to student success and committed to community engagement, generates an annual economic impact of more than $6 billion. With campuses in Tampa, St. Petersburg and Sarasota-Manatee, USF serves approximately 50,000 students who represent nearly 150 different countries. U.S. News & World Report has ranked USF as one of the nation’s top 50 public universities for five consecutive years, and this year USF earned its highest ranking ever among all universities public or private. In 2023, USF became the first public university in Florida in nearly 40 years to be invited to join the Association of American Universities, a prestigious group of the leading universities in the United States and Canada. Through hundreds of millions of dollars in research activity each year and as one of the top universities in the world for securing new patents, USF is a leader in solving global problems and improving lives. USF is a member of the American Athletic Conference. Learn more at www.usf.edu. 

---

Method of Research

Observational study

Subject of Research

Animals

Article Title

Why Amphistegina lobifera, a tropical benthic foraminiferal species, is thriving at temperate latitudes in the Mediterranean Sea