Monday, December 15, 2025

Moss and symbionts offer a promising solution for removing metals from mining and forestry-impacted waters

University of Oulu, Finland

Mosses and their microbial partners — image:
In the climate room at the University of Oulu, mosses and their microbial partners are cultivated to study how microbes support plant survival in diverse environmental conditions. Image Kaisa Lehosmaa / University of Oulu
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Credit: Image Kaisa Lehosmaa / University of Oulu

New findings shed light on the mechanisms behind a natural purification process and identify the key microbial “teammates” that enable mosses to remove metals from water. A promising moss species was discovered in abandoned mine sites where few other plants survive. Upcoming tests will evaluate their performance in iron-rich forest drained ditches.

Across northern regions, climate change is accelerating the release of metals into waterways. Forest ditching and abandoned mines also leave behind sites that need sustainable water purification solutions. Conventional water treatment methods often fail in cold environments. Researchers at the University of Oulu, Finland are therefore developing alternative, nature-based purification systems that operate without energy input and function reliably in remote conditions.

The project began when researchers discovered abundant stands of Warnstorfia fluitans moss growing in acidic, metal-laden waters near the Pyhäsalmi Mine in Finland. To their surprise, the moss appeared to flourish in conditions where high acidity increases metal solubility.

“Growing evidence shows the crucial role of microbes in helping plants to survive in extreme environments,” explains Professor Anna-Maria Pirttilä. Her research group has previously studied, for example, how gold accumulates in spruce needles and how microbial diversity in bilberries varies between northern and southern Finland.

The new study reveals that mosses do not remove metals alone. The key is the cooperation between the moss and its microbial symbionts.

Microbes live in all organisms, and those inhabiting plants in symbiosis are called endophytes. Mosses collected from metal-rich sites hosted more endophytes that enhance metal tolerance. Two species stood out: Phialocephala bamuru and Hyaloscypha hepaticola, both abundant in metal-contaminated waters. Both were also successfully cultivated in the laboratory.

The results suggest that these symbionts help mosses to precipitate dissolved metals inside their cells. “The moss acts like a sponge that binds and transforms metals into a safer, solid form,” says Postdoctoral Researcher Kaisa Lehosmaa. “The microbes modify conditions inside the moss tissue so that harmful dissolved metals can be converted into manageable particles. And there is always a possibility to remove metal-rich mosses.” The study examined iron as well as cadmium, copper, zinc, nickel, and arsenic.

The research, carried out with international partners, involved collaboration with Pyhäsalmi Mine and Outokumpu steel producer. Moss samples were also collected from the closed Saattopora Mine in Finland and Adakgruvan Mine in Sweden. Mosses from metal-rich waters were compared with those from clean environments.

Pirttilä’s group is also exploring commercial applications. “We are developing microbial strains and products for use across different sectors,” she says.

Previous tests have shown that mosses can remove nutrients from water within three weeks. Metal removal is estimated to take several weeks, and ongoing research aims to evaluate purification efficiency further.

“In forest drainage management, mosses should not be seen as debris that blocks water flow,” Lehosmaa emphasizes. The team will next test moss-microbe purification in the iron-rich Kalimenjoki catchment near Lake Jäälinjärvi in northern Finland.

The study, “Aquatic moss precipitates metals in the presence of a specific endophytic microbiome,” was published in October 2025.

Learn more

Golden spruce trees: Gold forms nanoparticles in the needles – bacteria show the way

New approach gives nature a boost in wastewater treatment

Climate change and forest management can threaten blueberry microbes – differences between northern and southern blueberries

A promising moss species was discovered in abandoned mine sites where few other plants survive. Image Kaisa Lehosmaa / University of Oulu

Credit

Image Kaisa Lehosmaa / University of Oulu

Journal

iMetaOmics

DOI

10.1002/imo2.70061

Article Title

Aquatic moss precipitates metals in the presence of a specific endophytic microbiome

Tapping into whale talk

Open-source bio-logger captures underwater cetacean conversations

Harvard John A. Paulson School of Engineering and Applied Sciences

CETI_sperm_whales — image:
Swimming sperm whales.
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Credit: Patrick Dykstra

Key Takeaways

Harvard engineers, as part of Project CETI, have built an open-source bio-logger that adheres to sperm whales and records high-fidelity, multi-channel audio plus rich behavioral and environmental data.
The data are tailored for machine learning analysis so that researchers can better understand whale communication.
The technology and methods are open source and designed to be shared widely to inspire further studies in cetaceans and other species.

Say you want to listen in on a group of super-intelligent aliens whose language you don’t understand, and whose spaceship only flies by Earth once an hour. It’s not unlike what Harvard scientists and others are doing, except their target species, sperm whales, thankfully live here on Earth.

As part of the nonprofit Project CETI (Cetacean Translation Initiative), an ambitious, multi-institutional endeavor to discern the language of sperm whales, engineers in the John A. Paulson School of Engineering and Applied Sciences (SEAS) and others have led the development of a powerful listening device that adheres to whales and records high-fidelity audio and other information that’s later analyzed by machine learning models.

The device, called a bio-logger, collects large, high-quality datasets of whale sounds called codas, which to human ears sound like a series of rhythmic clicks, along with contextual clues like physical behavior and ocean depth. The bio-logger is among the first to be explicitly designed to capture data for interpretation by machine learning algorithms. Modern machine learning techniques can help uncover structured, non-human communication by identifying patterns and frequencies in the whale codas that humans can’t readily perceive.

The bio-logger has so far been deployed in whales off the Caribbean coast of Dominica during numerous deep-sea dives. The details of the device's design and the inspiration behind it are published in PLOS One.

“When we were looking to decode the language of whales, a key value was to have the mics placed at the best spots, for the best audio recording possible,” said Daniel Vogt, lead Harvard SEAS engineer for Project CETI and first author of the bio-logger paper. “We looked at the state of the art, what was available out there, and there was nothing that really matched what we were looking for. So we made our own.”

Open-source technology

The Harvard-designed bio-logger and all its components and software are open-source, available to anyone in the marine biology or scientific communities. The researchers hope this structure will give rise to crowd-sourced innovation and possibly expand to other species.

“This really democratizes and opens up the field of marine science, to biologists across the world,” said David Gruber, founder and lead scientist of the five-year-old Project CETI, a National Geographic Society Program. Gruber’s work on whale communication began when he was a 2017-2018 Radcliffe Fellow.

The non-invasive bio-logger attaches to the skin of sperm whales via suction cups that were also designed by Harvard robotics researchers. It includes three synchronized, high-bandwidth hydrophones – underwater microphones – that can record sound from multiple whales talking to each other at different distances. Other features include GPS logging and transmission equipment, as well as sensors for depth, movement, orientation, temperature, and light.

Whales can dive a mile down and stay underwater for an hour, surfacing for only a few minutes to breathe; the bio-logger is built to withstand those conditions, with battery life of about 16 hours, and audio sensitivity that picks up higher frequencies than humans can hear.

Legacy whale tagging technologies have in the past recorded many whale vocalizations and formed the basis for the field of cetacean communication. The CETI bio-logger builds on those foundational technologies but captures a richer array of data, including the ability to differentiate between different whales speaking by measuring their sounds’ origin. The datasets are helping researchers interpret the sounds and make sense of them, rather than just listening in.

Recent results have already proven out their methods. One published study used data from bio-loggers to show that sperm whales have their own alphabet; another reports a version of vowels and diphthongs in sperm whales’ language, similar to how humans speak.

Project CETI goals

Founded in 2020, Project CETI is the world’s largest interspecies communication initiative, involving eight institutions and 50 scientists who work in artificial intelligence, natural language processing, cryptography, linguistics, marine biology, and robotics. Harvard researchers have played key scientific roles; Vogt works in the lab of Robert Wood, the Harry Lewis and Marlyn McGrath Professor of Engineering and Applied Sciences, who leads the robotics component of Project CETI and whose lab designed the clingfish-inspired suction cups that adhere the bio-logger onto the whale’s skin. Stephanie Gil, assistant professor in computer science, designed a reinforcement learning framework with autonomous drones that are used to find whales and predict when they will surface so they can be tagged. In addition, the project’s lead linguist, Gašper Beguš, received his Ph.D. at Harvard.

Adhering a microphone to a sperm whale is a 10-out-of-10 challenge across multiple fronts: Using drones to tag the animals without bothering or hurting them. Getting the tags to stick amidst a salty, wavy ocean. Retrieving the devices. Extracting and interpreting the data. The Project CETI team has reached milestones on each of these endeavors. Bringing the bio-logger to many other labs and teams should edge the project even closer to its goal of understanding how sperm whales and other cetaceans communicate, and maybe one day, answering back in their language.

“This technology could now be expanded to the millions of other species we share the planet with” Gruber said. “I see this as a massive moment, because the field of bioacoustics and artificial Intelligence can now vastly expand.”

Learn more about Project CETI: https://www.projectceti.org/

Detail view of the Project CETI bio-logger.