SCIENCE

Deep Ocean Sounds

Below the surface of the ocean, the waters are anything but silent. 

The sounds uttered by fish, whales and crustaceans are vibrant and informative—they tell us something about each animal, like where they are, what they’re up to and how they communicate.  

Monitoring the sounds of marine life is one of the most comprehensive and least invasive ways for scientists to study these creatures. A simple hydrophone on the seafloor can pick up noises in the pitch black night without the use of boats, lights or divers. 

A group of researchers from around the world have set a goal to create a library of these noises, called the Global Library of Underwater Biological Sounds. They outlined their proposal in a new paper out this month in the journal Frontiers in Ecology and Evolution.

This collection will allow scientists to study how marine ecosystems are affected by climate change, extreme weather events or big infrastructure projects like offshore wind farms. A lot of the ecosystems that the researchers will be looking at are threatened by climate change, said paper co-author Aran Mooney, a researcher at Wood’s Hole Oceanographic Institution, and it’s important to document them before they change entirely. 

“We need to know what a healthy environment is because what we’re going to need to do is to kind of rebuild these habitats,” Mooney said. “And you can’t really rebuild a proper habitat without understanding what it looks like, what it smells like, what it sounds like for the animals.”

The library will also be a place that citizen scientists can submit recordings of marine life that they make while snorkeling or diving in the ocean, and if enough records are collected, the library can be used to train artificial intelligence to identify marine species by their sounds, as a bird can be identified by its song. 

“We think there are thousands of species that make sounds that are not yet in the libraries, because this whole area is pretty new,” said Jesse Ausubel, a scientist at the Rockefeller University who is also involved in the project. “Of course, you start off with things like humpback whales that are obvious or croaker fish that croak. But there are many, many thousands of species probably that are not yet cataloged. So there’s a lot to discover.”

CULTURE

‘Wrapping Our Heads Around’ 1.5 Degrees Celsius 

Will humanity actually be able to keep global warming below 1.5 degrees Celsius?

That’s the question at the center of the fourth season of the podcast Threshold, called Time to 1.5. Host and journalist Amy Martin brings the listener through a narrative of what it will take to achieve this goal outlined in the Paris agreement to avoid the worst effects of climate change. Inside Climate News recently discussed the new season with Martin. This conversation has been lightly edited for length and clarity.

What will you explore in this new season of Threshold?

It’s basically about the time that we have left before we cross 1.5 degrees Celsius of global heating over pre-industrial levels. It’s kind of a technical thing, whenever I say that, I’m always like, “Oh, I feel like I’ve lost people halfway through that sentence.” But that’s kind of the complexity of our time. Like we all have to start wrapping our heads around the fact of this scientific information and what it actually means for us in our lives, and I think most people know at this point that climate change is real, that it’s a huge problem. But I don’t know how many people are actually living with that on a daily basis and grappling with it in a really immediate way, just how high the stakes are. 

Why is the 1.5 degree Celisus threshold important?

There’s a scientific answer and there’s a political answer. And I think sometimes I hear debates talking about 1.5 and it feels like sometimes those two sides of the story are not talking to each other or understanding each other. Because on the science side, it’s not like flipping a light switch. It’s turning a dial. And so it’s not like we hit 1.52 and everything just goes to hell in a handbasket. I think that’s a danger of focusing on 1.5, it can confuse people about that and make them think that way.

On the political side, we have to choose a number somewhere. You can’t form a global regimen for holding each other accountable as countries for reducing emissions by just saying “everybody hold their hands and try to burn less carbon.” They have to choose something, you have to choose a target. And that’s where the science kind of starts to clash with the politics a little bit.

What is the role of storytelling in communicating about climate change?

I really feel like the stories that we tell, the narratives we shape, the mental paradigms that we have as a society are some of the most important things in this whole process. I do not think that stories alone are going to solve the climate crisis. But I don’t think we can solve the climate crisis without good stories, without stories that make people feel like they can see themselves as being part of the solution, without stories that help people understand what’s actually at stake. 

SCIENCE

Two Life Forms Living Symbiotically as One

The organisms that form a flaky, green or blue crust on boulders and tree trunks are known as lichens, and they are actually two different life forms living symbiotically as one—an algae that provides nutrients through photosynthesis and a fungus that provides a greenhouse-like shelter for the algae to comfortably survive. 

Lichens are an incredibly diverse group and can be found in nearly every terrestrial environment. A new study conducted by researchers from the Chicago Field Museum found that the most common species of algae found in lichens around the world, Trebouxia, does not evolve fast enough to keep up with the rapid pace of climate change.

That means that this most common algal species in lichens may find itself in environments that are just too hot, forcing its range to change. 

“It was definitely an ‘Oh, my,’ moment, and definitely surprised me,” Matthew Nelsen, a scientist at the field museum, said of when he first realized what their research was showing. “I feel really silly, because I should have known, especially from reading other papers, but somehow I just didn’t expect it to be quite so striking.”

Lichens are important parts of the ecosystem. In dry environments, they can help retain water. Some help recycle nutrients, sequester carbon and indicate air quality. Others serve as a food source for animals or even a tiny habitat for insects. 

It’s difficult to predict what exactly will happen to lichens as the planet warms, Nelsen said, but even if climate change does alter where certain algae can exist, some fungi may be able to find other algal species to partner with to form lichen, while others may need to shift ranges along with the shifting algae. 

“Symbioses might be very vulnerable to changing environments,” Nelsen said. “The idea being that you’ve got two different organisms involved that each have their own unique niches, they might not be completely in sync with one another. And impacting one of those symbiotes might have a cascading effect.”

SCIENCE

Life Forms in the Atmosphere 

Ecological communities floating in the atmosphere are far less studied than marine and terrestrial ecosystems. These communities of fungi and bacteria swept up into the air by gusts of wind are so small that the laws of gravity don’t apply to them. They float in the sky until they’re knocked to the ground by a raindrop or attached to a settling piece of dust. 

But novel techniques used in a recent study of the fungi and bacteria living up to two miles high in the sky found that temperature is the No. 1 factor determining the composition of microbes in the atmosphere. As global warming drives temperature changes, species composition and distribution of airborne microbes will also change, the study authors project. 

Studying life forms in the atmosphere has evolved over the last century from collecting samples on adhesive surfaces on the sides of early 20th century airplanes, to sophisticated air samplers taking simultaneous measurements at varying altitudes.

“This is a super precise, super high resolution biological sensor that, for the first time, lets you read the biological output as it changes in response to temperature,” said lead author Stephan Schuster of Nanyang Technological University in Singapore. 

Schuster and other researchers from Singapore Centre for Environmental Life Sciences Engineering found that higher temperatures may allow microbes to distribute more widely, possibly globally, increasing the distribution of pathogens that could be potentially harmful to human health and agriculture as the planet warms. Their findings were published this month in the journal Proceedings of the National Academy of Sciences (PNAS).

However, much is still unknown about what the ramifications of a warming climate will be for these communities, Schuster said. 

“This is not like fear mongering,” he said. “What we are saying is that we now understand the mechanisms of how this can work.”