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From left: Aaron Bugaj, research technologist and media producer at Biosphere 2; Diane Thompson, director of marine research at Biosphere 2; and Samantha King, a doctoral candidate in the Department of Ecology and Evolutionary Biology, in the Biosphere 2 ocean biome during the coral transplantation on Feb. 4.
Chris Richards/University Communications
Diane Thompson adjusts her scuba mask and checks her air gauge, then steps off the pier and splashes into the water. Being the director of marine research at the University of Arizona’s Biosphere 2, she has dived in the Ocean Habitat underneath the expansive dome enclosure of white steel and glass many times, but today’s underwater outing is a very special one: for the first time in more than 30 years, Biosphere 2’s Ocean Habitat will be home to corals.
Thompson teamed up with Samantha King, a coral ecologist and doctoral student in the U of A’s Department of Ecology and Evolutionary Biology, for a two-hour dive in the 25-foot-deep saltwater basin, with Biosphere 2’s iconic space frame soaring above. Their mission: attach 108 living coral onto two “Coral Arks” – custom-engineered, spherical support structures consisting of triangular lattices of PVC piping – suspended just beneath the water surface. The project opens a new chapter in Biosphere 2’s history. The goal: help coral reefs across the world recover and become more resilient to environmental challenges.
A team of researchers has introduced, for the first time, corals into the ocean biome at the University of Arizona’s Biosphere 2. The team transplanted the coral on Feb. 4 as part of an experiment designed to better understand how coral respond under predicted higher future temperature conditions.
Chris Richards/University Communications
To prepare the habitat for the corals, Thompson’s team installed a scaffold of steel beams traversing the ocean, a lighting truss system mimicking the natural sunlight that would dance across a coral reef on a sunny day in nature. Stocking the ocean with coral marked a very special day and the beginning of a new chapter of ecosystem research at Biosphere 2.
“This has been a long time coming, and it is so exciting to finally be putting corals in the ocean,” said King, who is part of a research team that includes experts from a variety of disciplines, including oceanography, molecular biology, geochemistry and engineering. Researchers can track how corals grow their calcium carbonate skeletons much like how trees add rings as they age, King explained. Over time, their skeletons amass to formidable reefs, while the living animals themselves – tiny polyps forming colonies of varying sizes – are often overlooked.
In a healthy coral reef, the polyps harbor algae in their tissues that use sunlight to assemble nutrients in a process called photosynthesis. The corals provide a home for the algae to thrive, and the algae produce nutrients in an otherwise nutrient-poor, tropical open water environment – a mutually beneficial relationship that requires a delicate balance among many factors. When excessive water temperatures or changes in water chemistry affect this balance, coral reefs suffer.
The corals introduced into the Ocean Habitat are part of a temperature-resilience experiment designed to better understand how two specific coral groups respond under predicted higher temperature conditions. Recent upgrades – including a new heat exchanger, circulation pump, water-turbulence devices and the lighting structure – were critical in enabling this type of experiment, according to Thompson. The coral experiment involves strong collaboration with several external institutions, further strengthening the scientific value of the Biosphere 2 facility and highlighting its unrivaled capacity for large-scale, controlled ecosystem research.
The coral transplants are part of a temperature-resilience experiment designed to better understand how corals respond under predicted higher future temperature conditions.
Chris Richards/University Communications
By analyzing core samples collected from coral reef structures, living or fossilized, researchers can gather clues about what the conditions were like when the polyps built their stony homes and how they impact coral growth.
“Studying coral skeletons allows us to reconstruct past climate conditions that we wouldn’t know about otherwise,” said King, whose research focuses on understanding how and why environmental conditions cause biological changes in how corals build their skeleton.
“I want to find out what genes are getting turned on and off when corals are stressed,” she added. “Or how it affects the relationship with their symbionts. We want to understand the mechanisms for the changes we’re seeing in coral reef core samples that give us clues about past climates, but more importantly, how they impact corals growing today, as climate change persists into the future.”
King has partnered with another doctoral student, Mikayla Deigan in the Department of Geosciences, who will focus on how environmental stress impacts the chemistry in coral skeletons. Identifying geochemical markers in coral samples could help scientists identify times of stress in the past, with the goal of making paleoclimate reconstructions more reliable.
The research is critically needed, Thompson says, pointing out that over the past 10 years, the coral reef community has come together through a series of workshops and identified Biosphere 2 as the hub for testing solutions for coral reefs across the world.
“That’s because at that time, and increasingly each year, people have realized that corals are in really critical condition,” she said. “Climatic stressors are causing yearly coral mortality events across the globe.”
Through her research drilling deep into the history of coral reefs, Thompson discovered that corals have recovered from decimating events in Earth’s past.
“We know that reefs can bounce back, as long as they have enough time to recover in between such events, but now those events are becoming almost annual in frequency,” she said. “That’s why the community is almost desperate to come up with innovative solutions, moving from understanding the process, which we’ve been focused on for decades, to applying what I like to think of as the building blocks of resilience to intervene to help reefs.”
Diane Thompson, director of marine research at Biosphere 2, gets ready to dive in the ocean habitat.
Daniel Stolte/University Communications
Before they could be moved into their new home, the corals selected for this project – collected from reefs in the Florida Keys and the Flower Garden Banks National Marine Sanctuary in the Gulf of Mexico – were carefully tended to in a holding room specifically constructed for this purpose.
Corals are fickle creatures, as Campbell McPeak knows – she’s a research intern working with Biosphere 2’s Ocean team and a junior in the Department of Ecology and Evolutionary Biology and well-versed in coral husbandry. On a given day, she can be found in the raceway testing various water parameters and inspecting the corals for any parasites or dirt that may have settled on them. She feeds them powdered shrimp and even uses a mascara wand to gently brush off any algae that may otherwise smother the delicate polyps.
Meanwhile, the divers have finished planting the first batch of corals and bob on the surface, awaiting the next round. Their team members hand them a new set of trays loaded with panels holding the precious cargo, and they slip back under the surface. After two hours, they have successfully deployed all coral fragments on the Coral Ark structures.
“It took a few tries to get it right,” King said. “Because the water is cold, so my fingers weren’t working great. There was a little bit of juggling trying to keep the panels in place and not dropping all those washers and nuts.”
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