The foundation of life is at risk from climate change
Photosynthesis forms the foundation of life on Earth, yet climate change increasingly threatens this essential process. With advanced tools, scientists can now study how shifts in temperature, humidity, and light impact photosynthesis and, by extension, the future of ecosystems.
For Rakesh Tiwari, a postdoctoral researcher at Uppsala University‘s Department of Ecology and Genetics, uncovering how plants adapt – or fail to adapt – to climate shifts is critical.
“I want to understand how species and ecosystems can function in the future,” said Tiwari, whose research spans tropical forests in Puerto Rico, the Amazon, and even the controlled climate of Uppsala’s Tropical Greenhouse.
Using cutting-edge tools to simulate environmental extremes, Tiwari seeks to understand plants’ adaptability to climate challenges and their potential limits.
Observing photosynthesis under pressure
In the humid atmosphere of Uppsala’s greenhouse, surrounded by towering palms and dense foliage, Tiwari demonstrates his process using a portable greenhouse gas analyzer, designed to simulate various environmental conditions on leaves.
He places a hibiscus leaf into the instrument’s chamber, exposing it to intensified light and heat. The leaf’s reaction offers clues about how plants process sunlight, carbon dioxide, and water to create glucose and oxygen under different stresses.
“Since it’s a portable instrument, I can take it to different places and analyze photosynthetic responses to different environmental conditions for plants,” Tiwari explained.
“For example, I can change the temperature and light levels, and measure how this affects the photosynthesis rate.”
This on-site work parallels studies he’s conducted in natural tropical environments, where he’s observed distinct patterns in how photosynthesis responds to extreme heat.
Life’s foundation in the rainforest
In 2017, Tiwari participated in a research project in the Amazon, where he and his colleagues used similar tools to monitor the health of the rainforest’s photosynthesis system.
“We used a similar fluorometer to monitor when the photosystems started to break down. What we saw was a clear pattern. Trees in one of the Amazon’s hottest sites are already experiencing air temperature conditions that can affect their photosynthesis machinery.”
The researchers discovered that plants in particularly hot and dry areas of the Amazon were already nearing their heat tolerance, with photosynthesis rates dropping during especially high temperatures.
The limits of photosynthetic efficiency
Global photosynthetic efficiency is strikingly low, typically at most 5%, due in part to a process called photorespiration.
During photorespiration, an enzyme called rubisco mistakenly binds oxygen instead of carbon dioxide, a problem exacerbated by high temperatures. This reduces the plant’s ability to produce energy efficiently.
“Another factor is the small openings, or stomata, in the plant’s leaves that regulate carbon dioxide absorption and water exchange,” Tiwari said.
“In extreme heat, they can close to save water. This is a survival strategy, but it also reduces their photosynthesis rate. While in some trees, stomata open at higher temperatures to make use of evaporative cooling as a leaf cooling mechanism.”
Implications for carbon storage
Tiwari’s research at Uppsala, conducted with Bob Muscarella’s team, focuses on understanding temperature-related adaptations in tropical and temperate forests.
His recent findings suggest that temperature sensitivity to photorespiration varies significantly among species, which could inform reforestation strategies aimed at selecting species most resilient to climate change.
“The consequences of such understanding can better inform reforestation projects. For example, we can understand how vegetation could function in warmer futures and how we can adapt our future conservation and afforestation strategies,” Tiwari noted.
However, Tiwari emphasizes that planting trees alone isn’t sufficient to protect the climate. Preserving mature forests offers unparalleled ecological benefits.
“We cannot recreate the complexity of a mature forest. It does more than just capture carbon; it supports biodiversity, regulates water flows, and provides habitats for countless species,” he said.
Preserving the foundation of life
From October 21 to November 1, the UN biodiversity conference COP16 will be held in Cali, Colombia, where leaders will address global conservation challenges.
Tiwari hopes that conference discussions will focus on preserving natural ecosystems, especially forests, as they are irreplaceable in regulating carbon and supporting biodiversity.
“If we lose biodiversity and forest ecosystems, we lose the planet’s best natural carbon capture system,” he said.
“One day there may be technologies that can remove carbon dioxide from the atmosphere, but the more we rely on artificial solutions, the more damage we risk causing the planet. These are risks we cannot afford to take.”
Balancing innovation with natural solutions
In the face of climate challenges, Tiwari’s research highlights the need for both conservation and innovation. While advanced tools are improving our understanding of photosynthesis, preserving existing ecosystems remains essential for achieving true sustainability.
“The best way to protect the environment is to preserve the natural systems that already exist,” Tiwari said. His work highlights a balanced approach: technological advances in plant science coupled with committed efforts to maintain natural habitats.
By investigating the intricate ways plants respond to climate shifts, Tiwari’s research emphasizes the importance of biodiversity conservation in climate action.
Through both preservation and innovation, the scientific community can work towards sustaining the ecosystems that serve as the foundation of life on Earth.
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