Researchers have long suspected that massive volcanic eruptions undersea caused carbon dioxide (CO₂) increases, global warming and depleted oxygen (called anoxia) in the ocean during the Mesozoic Period. Now, an international team of researchers, including Northwestern University Earth scientists, determined the precise timing of the volcanic eruption and OAE1a, which started 119.5 million years ago. The work adds to a growing volume of evidence that volcanic CO₂ emissions directly triggered the anoxic event.

The new study also determined that OAE 1a lasted for just over 1.1 million years. This new information helps scientists better understand how the Earth’s climate and ocean system operates and responds to stress — especially as it relates to current warming.

The study was published late last month in the journal Science Advances. It marks the most detailed and highly resolved dating of an ocean anoxic event ever achieved.

“Ocean anoxic events occur in part as a consequence of climatic warming in a greenhouse world,” said Northwestern’s Brad Sageman, a senior author of the study. “If we want to make accurate predictions about what we will see in the decades ahead with human-caused warming, this information is invaluable. The best way to understand the future is to look at data from the past.”

An expert on ancient climates, Sageman is a professor of Earth, Environmental and Planetary Sciences at Northwestern’s Weinberg College of Arts and Sciences and a co-director of the Paula M. Trienens Institute for Sustainability and Energy.

A Northwestern connection

The Cretaceous Period experienced two major and several minor ocean anoxic events, with OAE 1a as one of the two largest. The most likely cause: volcanic eruptions rapidly injected massive amounts of CO₂ into the ocean and atmosphere. These aren’t ordinary volcanoes but large igneous provinces that erupt up to a million cubic kilometers of basalt over several millions of years. When CO₂ reacts with seawater, it forms a weak carbonic acid, which literally dissolves sea creatures’ shells. The acid, combined with low oxygen levels, has significant consequences for sea life.

Researchers first began pondering ocean anoxic events in the mid-1970s, after a discovery by Northwestern geologist Seymour Schlanger and Oxford professor Hugh Jenkyns. When examining sediment samples from the Pacific Ocean floor, Schlanger and Jenkyns discovered black, organic carbon-rich shales that matched samples — in composition and age — from both the Atlantic Ocean and rock formations in Italy.

Widespread lack of oxygen was the most likely explanation for these deposits. Anoxia prevents the breakdown of organic matter from dead plants and animals, leading to a global pattern of organic enrichment. Instead of decomposing, the settling plankton and other fossils accumulated to form organic carbon-rich strata scattered around the globe.

“How were black shales forming at the same time in the deep oceans and up on land?” Sageman asked. “Schlanger and Jenkyns realized there must have been a massive global event that caused oxygen to decrease from the ocean surface all the way down to the seafloor.”

History solidified in stone

In the new study, researchers looked not to the depths of the oceans but to ancient strata along the northwest edge of a mountain on Japan’s Hokkaido Island. The rocks, or tuffs, formed from volcanic ash that settled and solidified over time. Tectonic activity lifted these layers above sea level during formation of the Japanese islands, leaving them exposed and accessible where streams carve through the temperate rainforest of Hokkaido. By collecting and analyzing the tuffs, Sageman, his Ph.D. student, Luca Podrecca, and their collaborators gained a glimpse into geologic history.

“Magma comes out of a volcano in liquid form and then begins to cool,” Sageman said. “During this process, crystals start to form. By the time the tuff solidifies, the crystals become a tiny closed system. They lock in atoms, and some of those atoms, like uranium, start to decay, meaning they convert from one isotope to another. That provides a tool to date the eruption, and, thus, date a specific layer within a stack of sedimentary rock. While the expertise of team members from Tohuku University in Japan, Durham University in the U.K. and Northwestern focuses on the characterization and global correlation of the strata, our collaborators at the University of Wisconsin-Madison and Boise State University are experts in the geochronological analyses.”

The researchers also used other types of isotopes, such as carbon, which tracks synchronous changes in the carbon cycle, and osmium, which tracks volcanic activity and changes in ocean chemistry.

“These isotope systems provide tools for correlating the OAE1a interval between sites in Hokkaido, southern France and other sites all around the globe,” Sageman said. “They give us markers for instants in geologic time.”

Pinpointing the exact timeline

According to this evidence, an abrupt shift in carbon isotope ratios — caused first by the spike in volcanic CO₂added to the carbon cycle (and later by the excess burial of organic matter) — occurred in the early Cretaceous at the beginning of OAE 1a. A concurrent shift in the isotopic ratios of osmium reflects a massive input of volcanic material into ocean waters. The timing of these events corresponds to eruption of the Ontong Java Nui complex, an enormous igneous province about the size of Alaska located in the southwestern Pacific Ocean.

Now that researchers know it took the oceans 1.1 million years to recover from the sharp increase in CO₂, they have more insight into how long the effects of CO₂-driven warming events might last and what the associated effects, such as ocean anoxia, may be.

“We’re already seeing zones with low oxygen levels in the Gulf of Mexico,” Sageman said. “The main difference is that past events unfolded over tens of thousands to millions of years. We’re driving roughly similar levels of warming (or more) but doing so in less than 200 years.”

In a paper published in the journal Neuroscience of Consciousness psychology researchers from the University of Technology Sydney (UTS) worked with 54 participants to examine the effects of surveillance on an essential function of human sensory perception — the ability to detect another person’s gaze.

Lead author, Associate Professor of neuroscience and behaviour Kiley Seymour, said previous research has established the effects on conscious behaviour when people know they are being watched, but the new study provided the first direct evidence that being watched also has an involuntary response.

“We know CCTV changes our behaviour, and that’s the main driver for retailers and others wanting to deploy such technology to prevent unwanted behaviour,” Associate Professor Seymour said.

“However, we show it’s not only overt behaviour that changes — our brain changes the way it processes information.

“We found direct evidence that being conspicuously monitored via CCTV markedly impacts a hardwired and involuntary function of human sensory perception — the ability to consciously detect a face.

“It’s a mechanism that evolved for us to detect other agents and potential threats in our environment, such as predators and other humans, and it seems to be enhanced when we’re being watched on CCTV.

“Our surveilled participants became hyper aware of face stimuli almost a second faster than the control group. This perceptual enhancement also occurred without participants realising it.”

Associate Professor Seymour said that given the increasing level of surveillance in society and the ongoing debates around privacy reform, the study’s findings suggested the need for closer examination of the effects of surveillance on mental processes and on public health more broadly.

“We had a surprising yet unsettling finding that despite participants reporting little concern or preoccupation with being monitored, its effects on basic social processing were marked, highly significant and imperceptible to the participants.

“The ability to rapidly detect faces is of critical importance to human social interactions. Information conveyed in faces, such as gaze direction, enables us to construct models of other people’s minds and to use this information to predict behaviour.

“We see hyper-sensitivity to eye gaze in mental health conditions like psychosis and social anxiety disorder where individuals hold irrational beliefs or preoccupations with the idea of being watched.

“Whilst this investigation was specifically focussed on unconscious social processes, future investigations should explore effects on the limbic system more broadly, which would have more general implications for public mental health and the importance of privacy.”

Now, new research from NYU Tandon faculty including Professor of Electrical and Computer Engineering Davood Shahrjerdi; Herman F. Mark Professor in Chemical and Biomolecular Engineering Elisa Riedo; and Giuseppe de Peppo, Industry Associate Professor in Chemical and Biomolecular Engineering and who was previously at Mirimus, shows it’s possible to develop and build microchips that can not only identify multiple diseases from a single cough or air sample, but can also be produced at scale.

“This study opens new horizons in the field of biosensing. Microchips, the backbone of smartphones, computers, and other smart devices, have transformed the way people communicate, entertain, and work. Similarly, today, our technology will allow microchips to revolutionize healthcare, from medical diagnostics, to environmental health” says Riedo,

“The innovative technology demonstrated in this article uses field-effect transistors (FETs) — miniature electronic sensors that directly detect biological markers and convert them into digital signals — offering an alternative to traditional color-based chemical diagnostic tests like home pregnancy tests,” said Shahrjerdi. “This advanced approach enables faster results, testing for multiple diseases simultaneously, and immediate data transmission to healthcare providers” says Sharjerdi, who is also the Director of the NYU Nanofabrication Cleanroom, a state-of-the-art facility where some of the chips used in this study were fabricated. Riedo and Shahrjerdi are also the co-directors of the NYU NanoBioX initiative.

Field-effect transistors, a staple of modern electronics, are emerging as powerful tools in this quest for diagnostic instruments. These tiny devices can be adapted to function as biosensors, detecting specific pathogens or biomarkers in real time, without the need for chemical labels or lengthy lab procedures. By converting biological interactions into measurable electrical signals, FET-based biosensors offer a rapid and versatile platform for diagnostics.

Recent advancements have pushed the detection capabilities of FET biosensors to incredibly small levels — down to femtomolar concentrations, or one quadrillionth of a mole — by incorporating nanoscale materials such as nanowires, indium oxide, and graphene. Yet, despite their potential, FET-based sensors still face a significant challenge: they struggle to detect multiple pathogens or biomarkers simultaneously on the same chip. Current methods for customizing these sensors, such as drop-casting bioreceptors like antibodies onto the FET’s surface, lack the precision and scalability required for more complex diagnostic tasks.

To address this, these researchers are exploring new ways to modify FET surfaces, allowing each transistor on a chip to be tailored to detect a different biomarker. This would enable parallel detection of multiple pathogens.

Enter thermal scanning probe lithography (tSPL), a breakthrough technology that may hold the key to overcoming these barriers. This technique allows for the precise chemical patterning of a polymer-coated chip, enabling the functionalization of individual FETs with different bioreceptors, such as antibodies or aptamers, at resolutions as fine as 20 nanometers. This is on par with the tiny size of transistors in today’s advanced semiconductor chips. By allowing for highly selective modification of each transistor, this method opens the door to the development of FET-based sensors that can detect a wide variety of pathogens on a single chip, with unparalleled sensitivity.

Riedo, who was instrumental in the development and proliferation of tSPL technology, sees its use here to be further evidence of the groundbreaking way this nanofabrication technique can be used in practical applications. “tSPL, now a commercially available lithographic technology, has been key to functionalize each FET with different bio-receptors in order to achieve multiplexing,” she says.

In tests, FET sensors functionalized using tSPL have shown remarkable performance, detecting as few as 3 attomolar (aM) concentrations of SARS-CoV-2 spike proteins and as little as 10 live virus particles per milliliter, while effectively distinguishing between different types of viruses, including influenza A. The ability to reliably detect such minute quantities of pathogens with high specificity is a critical step toward creating portable diagnostic devices that could one day be used in a variety of settings, from hospitals to homes.

The study, now published by the Royal Society of Chemistry in Nanoscale, was supported by Mirimus, a Brooklyn-based biotechnology company, and LendLease, a multinational construction and real estate company based in Australia. They are working with the NYU Tandon team to develop illness-detecting wearables and home devices, respectively.

“This research shows off the power of the collaboration between industry and academia, and how it can change the face of modern medicine,” says Prem Premsrirut, President and CEO of Mirimus. “NYU Tandon’s researchers are producing work that will play a large role in the future of disease detection.”

“Companies such as Lendlease and other developers involved in urban regeneration are searching for innovative solutions like this to sense biological threats in buildings.” says Alberto Sangiovanni Vincentelli of UC Berkeley, a collaborator on the Project. “Biodefense measures like this will be a new infrastructural layer for the buildings of the future”

As semiconductor manufacturing continues to advance, integrating billions of nanoscale FETs onto microchips, the potential for using these chips in biosensing applications is becoming increasingly feasible. A universal, scalable method for functionalizing FET surfaces at nanoscale precision would enable the creation of sophisticated diagnostic tools, capable of detecting multiple diseases in real time, with the kind of speed and accuracy that could transform modern medicine.

The international research, led by The University of Queensland’s Professor Peter Mumby, measured the success of a natural spawning event in March this year.

“In what came as a surprise, we saw that corals needed to be within 10 metres of one another, and preferably closer than that for fertilisation to take place,” Professor Mumby said.

“We knew corals couldn’t be too far apart, but we found they need to be closer than we’d expected.

“Climate change impacts like bleaching are killing and reducing the density of corals, so we’re concerned that individuals may end up too far apart to reproduce successfully.”

To quantify reproduction success, the team placed containers above 26 coral colonies on a reef in Palau, Micronesia during a time when the mostly hermaphroditic corals released eggs and sperm.

“The containers captured some of each corals’ eggs and drifted to the surface where they followed the tide,” Professor Mumby said.

“Although the eggs could not escape, sperm could enter the container and fertilise the eggs.

“After an hour of drifting, the proportion of fertilised eggs was noted for each type of coral along with the distance to similar established corals.”

Fertilisation averaged 30% when corals were very close, but it declined to less than 10% at a separation of 10 metres and was virtually zero by 20 metres.

Co-author Dr Christopher Doropoulos of the CSIRO, Australia’s national science agency, said coral reproduction was fundamental to population resilience and evolution.

“In the future we may need to help corals continue this key part of their lives,” Dr Doropoulos said.

“Understanding the importance of local neighbourhoods provides tangible targets for interventions like coral restoration.

“Ideally, the density of corals would be monitored at important locations and restoration carried out to return the density back to the levels required for successful reproduction.”

Professor Mumby has been working on efforts to repair damaged coral reefs.

“Our work over the past 5 years on the Great Barrier Reef through the Reef Restoration and Adaptation Program is also helping to define these critical thresholds to help restoration practitioners set targets for density to help maintain coral populations,” he said.

The study was funded by the McCusker Foundation and the Australian Government’s Reef Restoration & Adaptation Program.

The research is published in the Proceedings of the National Academy of Sciences USA (PNAS).