Wednesday, January 29, 2025

Climate change reshuffles species like a deck of cards, new study finds

Entire species could vanish and ecosystems collapse if trend continues, researchers say

University of California - Santa Cruz

Intertidal assemblage — image:
An intertidal species assemblage in Davenport Landing, California, USA. Species are being rapidly replaced in assemblages like this as temperatures change around the world.
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Credit: Photo by Michael Kowalski

Santa Cruz, Calif. – A new study led by an ecology and evolutionary biologist at UC Santa Cruz finds that temperature changes due to climate change have a doubly detrimental impact: Not only do they destabilize animal populations, but the impacts accelerate as temperatures change more rapidly.

In the study, published on January 29 in Nature, the international team of researchers found that changing temperatures—either warming or cooling—drive changes in the composition of species in an ecosystem. The results also suggest that behavioral adaptation and changing species interactions are not enough to preserve species composition in the face of higher rates of temperature fluctuations.

“It's like shuffling a deck of cards, and temperature change now is shuffling that deck faster and faster,” said lead author Malin Pinsky, associate professor of ecology and evolutionary biology at UC Santa Cruz. “The worry is that eventually you start to lose some cards.”

The study’s findings are unique because the impacts of temperature change have often not been clear on land or in freshwater ecosystems. While impacts on ocean species have been more overt, and therefore easier to measure, plants and animals on land adapt in subtler ways, the researchers said.

Unlike ocean animals, those on land can often move short distances to find new locations that better suit their temperature needs. Though this can mitigate the effects of temperature change a bit, this research finds that terrestrial creatures are still susceptible to destabilization and replacement due to temperature change. In their paper, the researchers focus on the rates of species replacement, which refers to the loss and gain of species over time. While this happens naturally, they found that the rate of replacement is increasing due to faster temperature changes.

If that trend continues, species could be lost and ecosystems could begin to break down, the study concludes. The most effective ways to avoid these outcomes are to avoid further global warming, preserve landscapes with a diversity of temperatures, and reduce the alteration of natural environments. Benefits could include more abundant wildlife, clean water, and clean air.

“Temperature affects everything from how fast the heart beats to how flexible and porous our cell membranes are; from how much food animals eat to how fast plants grow,” said Pinsky. “Temperature is in many ways the metronome for life.”

Why diverse environments are important

In addition, the researchers found that species in ecosystems with less-varied habitats were more sensitive to temperature change than those with more diverse temperatures nearby. For example, if a person stood in an open field during summer and started to overheat, there would be nowhere cooler to hide. But if a forest were nearby, one could simply move into the shade of a tree to cool down. The paper concludes that plants and animals take advantage of habitat variation to buffer themselves against major temperature swings. Living near these temperature escapes allows organisms to move nearby for relief, rather than going extinct or being replaced entirely.

Whether due to natural conditions or human interference, not all environments have a diversity of temperatures to help protect the species that live in them. It is these animals that are most at risk due to faster temperature changes. Understanding the differing needs of species living in more or less varied environments can help society identify which ecosystems need the most attention and protection, the study concludes.

“Establishing this explicit link between rates of climate change and rates of species turnover allows us to better understand how changing temperatures can impact different ecosystems,” said senior author Shane Blowes, from Germany's Centre for Integrative Biodiversity Research (iDiv) and Martin Luther University Halle-Wittenberg. “Pinpointing factors that impact the rate of local species replacement can help prioritise conservation actions.”

How human activity impacts turnover

Importantly, the researchers found that human impacts like land use, pollution, and introduction of invasive species exacerbate the impacts of temperature change on species replacement. This is possibly due to human activity reducing the diversity of landscapes and increasing stress on species that are already near their temperature limits.

To conserve ecosystems and their benefits to people, humans can help by “preserving more natural habitats, reducing pollution, and reducing the spread of invasive species,” Pinsky said. “In the ocean, factors like reduced fishing pressure and protecting habitats are important and helpful.”

The paper's other authors include Helmut Hillebrand at the University of Oldenburg in Wilhelmshaven, Germany; Jonathan Chase, also from iDiv and Martin Luther University Halle-Wittenberg; and researchers from the Institute of Biodiversity at Friedrich Schiller University in Jena, Germany, the Research Centre for Ecological Change at the University of Helsinki, and the Scottish Association for Marine Science in the UK.

Main funders for the study, "Warming and cooling catalyse widespread temporal turnover in biodiversity," include the National Science Foundation, iDiv, and the Helmholtz Institute for Functional Marine Biodiversity.

Journal

Nature

DOI

10.1038/s41586-024-08456-z

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Warming and cooling catalyse widespread temporal turnover in biodiversity

Article Publication Date

29-Jan-2025

Princeton Chem discovers that common plastic pigment promotes depolymerization

Researchers have shown that a common plastic additive called carbon black can depolymerize polystyrene and polyvinyl chloride (PVC), two of the least recycled plastics in the planet’s waste stream

Peer-Reviewed Publication

Princeton University

Depolymerization of polystyrene — image:
Depolymerizing polystyrene
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Credit: Graphic courtesy of the Stache Lab

It turns out that the black plastic lid atop your coffee cup has a superpower. And the Stache Lab at Princeton Chemistry, which uncovered it, is exploiting that property to recycle at least two major types of plastic.

Their startling mechanism for promoting depolymerization relies on an additive that many plastics already contain: a pigment called carbon black that gives plastic its black color. Through a process called photothermal conversion, intense light is focused on plastic containing the pigment that jumpstarts the degradation.

So far, researchers have shown that carbon black can depolymerize polystyrene and polyvinyl chloride (PVC), two of the least recycled plastics in the planet’s waste stream. Through a process called photothermal conversion, intense light is focused on plastic containing the pigment that jumpstarts the degradation.

Two recent papers highlight the potential. First, in ACS Central Science at the end of last year, there was a proof-of concept for the depolymerization of polystyrene using a common Fresnel lens to focus photonic energy. Then, earlier this month, the lab published their method to upcycle PVC in the Journal of the American Chemical Society (JACS).

In both cases, carbon black serves as the trigger of the breakdown, a quality Assistant Professor of Chemistry Erin Stache discovered recently and that even industrial partners she has spoken with were unaware of. The lab’s method has since been tried out on such post-consumer waste as PVC pipes, black construction pipes, trash bags, credit cards, even those ubiquitous yellow rubber duckies.

“The surprising thing, especially with the black polystyrene depolymerization, is that they’ve been manufacturing these materials for decades and it seems no one recognized that this was possible,” said Stache. “Under ambient sunlight, the energy is not sufficient to break down these polymers. But if you increase the light intensity enough, then you start seeing the depolymerization.

“We can certainly change our habits to help alleviate the amount of plastic we use. But we’re not going to get rid of our dependence on plastic. So can we think of it instead as a resource? Can we turn it into other commodity chemicals that we have to make anyway? We have found that we can.”

In their ACS paper, researchers showed that unmodified post-consumer black polystyrene samples were successfully depolymerized to a styrene monomer without adding catalysts or solvent. Simple, focused radiation on the plastic provided monomer yields of up to 80% in just five minutes.

“I think this marriage between photothermal and depolymerization strategies is really groundbreaking. Black colored plastic accounts for ~15% of all plastics, and we found that 10-weight percent of black polystyrene in plastic mixture is enough to give good yield,” said Hanning Jiang, co-first author on the paper.

“Carbon black absorbs all the way from UV to IR, and that’s great because what we want is for this agent to take as much light as possible and transform light into heat.”

Next, the lab adapted their method to PVC and received strong results. They extended the process by adding polystyrene into the PVC-carbon black mixture—“We basically spatula it in,” said Stache—and were able to upcycle the material and then derivatize it into a couple of common consumer products.

Part of the challenge of recycling PVC is that the material has carbon-chlorine bonds that generates hydrochloric acid (HCl) whether it’s being recycled mechanically or chemically. Hydrochloric acid is corrosive and highly toxic.

“We used carbon black to initiate the thermal degradation of PVC, generate HCl with an acceptor for HCl that reacts to make an adduct,” Stache explained. “So you can basically access a new commodity chemical from the process. We take advantage of what is normally a bad process - the HCl - and add it to another commodity chemical, and then we get a new product.”

Recycling of Post-Consumer Waste Polystyrene Using Commercial Plastic Additives was authored by Sewon Oh, Hanning Jiang, Liat Kugelmass, and Erin Stache and appeared in the Nov. 25, 2024 edition of ACS Central Science.

Upcycling Poly(vinyl chloride) and Polystyrene Plastics Using Photothermal Conversion was authored by Hanning Jiang, Erik Medina, and Erin Stache and appeared in the Jan. 13, 2025 edition of the Journal of the American Chemical Society.

Upcycling PVC.
Credit
Graphic courtesy of the Stache Lab