A team of researchers from Rice University and Baylor College of Medicine has developed an innovative strategy for identifying toxic compounds in soil, including those that have never been isolated or studied before. The new approach uses machine learning algorithms, theoretical predictions, and light-based imaging techniques to detect polycyclic aromatic hydrocarbons (PAHs) and their derivative compounds (PACs), which are linked to cancer and other serious health problems.

The researchers used surface-enhanced Raman spectroscopy, a light-based imaging technique that analyzes how light interacts with molecules, tracking the unique patterns or spectra they emit. These spectra serve as “chemical fingerprints” for each compound. To refine this method, the team designed signature nanoshells to enhance relevant traits in the spectra.

Using density functional theory, a computational modeling technique, the researchers calculated the spectra of a range of PAHs and PACs based on their molecular structure, generating a virtual library of “fingerprints.” Two complementary machine learning algorithms – characteristic peak extraction and characteristic peak similarity – were then used to parse relevant spectral traits in real-world soil samples and match them to compounds mapped out in the virtual library.

This method addresses a critical gap in environmental monitoring, opening the door to identifying a broader range of hazardous compounds, including those that have changed over time. The researchers tested this approach on soil from a restored watershed and natural area using artificially contaminated samples and a control sample, with results showing the new method reliably picked out even minute traces of PAHs.

The future holds promise for on-site field testing by integrating machine learning algorithms and theoretical spectral libraries with portable Raman devices into mobile systems. This would enable farmers, communities, and environmental agencies to test soil for hazardous compounds without needing to send samples to specialized labs and wait days for results.

Unraveling the Daily Rhythm of Antarctic Krill: A Study on Internal Clocks and Vertical Migration

Antarctic krill (Euphausia superba) may be small, but its impact on the Southern Ocean ecosystem is immense. Billions of these tiny crustaceans form massive swarms that feed countless predators, making them a crucial food source in this polar environment.

A research team from Julius-Maximilians-Universität Würzburg (JMU), in collaboration with the Alfred Wegener Institute and other institutions, has delved into the behavior of Antarctic krill. The study, published in eLife, focused on their daily vertical migration patterns in the water column.

“Antarctic krill use the cover of darkness at night to feed on microscopic algae on the sea surface,” explains Lukas Hüppe, first author and doctoral student at JMU’s Department of Neurobiology and Genetics. “During the day, they seek shelter from predators in deeper, darker layers.”

This periodic migration is essential for the mixing of the water column and the transport of carbon into the deep sea, making it a vital component in regulating the global climate.

To understand this behavior better, researchers developed an activity monitor that allows them to study individual wild-caught animals under different light conditions and times of year. Their observations showed that krill are most active at night, which matches their natural migration patterns in the wild.

What’s more, these nocturnal activity patterns adapted to the changing length of the night throughout the seasons. The krill even maintained a daily rhythm of activity when kept in constant darkness for several days.

The results demonstrate that Antarctic krill exhibit a daily rhythm with increased swimming activity at night, which aligns perfectly with their vertical migration in nature. This is proof that they use an internal clock to adapt their behavior to the day-night cycle.

As the study’s lead researchers conclude, understanding this internal clock and its influence on other important processes in krill, such as reproduction and hibernation strategies, is crucial for predicting future developments in krill populations and their impact on the ecosystem.

The optimal adaptation of krill to its environment is a basic prerequisite for healthy krill stocks. As changes in krill populations can have far-reaching consequences for the entire Southern Ocean ecosystem, unraveling the daily rhythm of Antarctic krill holds significant implications for our understanding of this vital component in regulating the global climate.

Heat and Habitat: Bees Suffer from a Perfect Storm

The world is facing an unprecedented decline in insect numbers, with some studies suggesting that their biomass has almost halved since the 1970s. This alarming trend can be attributed to habitat loss due to agriculture, urbanization, and climate change. While these global change drivers have been well-documented, their interaction and impact on insects are not as well-known.

Researchers at Julius-Maximilians-Universität Würzburg (JMU) conducted a study at 179 locations throughout Bavaria, part of the LandKlif research cluster coordinated by Professor Ingolf Steffan-Dewenter within the Bavarian Climate Research Network bayklif. The results, published in Proceedings of the Royal Society B: Biological Sciences, reveal a complex and concerning relationship between heat, land use, and insect populations.

Bees are particularly affected

The study found that insects from different trophic levels react differently to the combination of higher temperatures and more intensive land use. Bees were particularly affected, with their numbers reduced by 65 percent in urban areas compared to forests. The researchers attribute this decline to not only hot daytime temperatures but also warmer than average nights.

Dr. Cristina Ganuza, a biologist involved in the study, highlights the significance of night-time temperatures: “Precisely because average night-time temperatures rise even faster than daytime temperatures.” This previously unknown effect on insects reveals a new threat that requires further research to uncover the underlying physiological mechanisms.

Key findings

The researchers summarize their findings in three key points:

1. Warmer daytime temperatures lead to higher numbers and diversity of bees, but only in forests and grasslands, the most natural habitats. Therefore, preserving and creating interconnected natural habitats within agricultural and urban areas is crucial.
2. Higher night temperatures lead to lower bee richness across all studied habitat types, highlighting a previously unknown negative effect on insects.
3. Climate change and land use interact, affecting insects at different trophic levels in distinct ways, which could disrupt food webs and important ecosystem functions like pest control and pollination.

The study emphasizes the importance of addressing climate change and land use to protect insect populations, particularly bees. By preserving natural habitats and creating interconnected areas within agricultural and urban landscapes, we can mitigate the negative impacts on these vital pollinators.