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.

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Pollutants in Europe’s Soil and Water: A Growing Threat to Sustainable Agriculture and Health

A recent study conducted in Europe has shed light on two significant areas of concern: metals in fertilized agricultural soils and oestrogens (hormone-disrupting substances) in aquatic systems, including the Scheldt estuary. This research focused not only on the presence of these pollutants but also on their behavior and interaction with environmental factors such as pH, redox potential, and dissolved organic carbon.

From Manure to Metal Mobility

One key aspect of this study involved investigating the impact of fertilizers on the mobility and bioavailability of metals in agricultural soils. The use of a novel technique called DGT (Diffusive Gradients in Thin Films) allowed researchers to measure the fraction of metals that are truly available for plant uptake, which is crucial for food safety and long-term sustainable agriculture policy.

“Fertilizers are a source of heavy metals in agricultural soils,” explains Professor Yue Gao of VUB’s Analytical, Environmental and Geo-Chemistry (AMGC) research group. “The application of the passive DGT sampler is essential for assessing the bioavailable fractions of metals in soil, as this directly affects plant uptake.”

Using innovative analytical techniques, researchers compared three types of fertilizers: phosphate fertilizer, sewage sludge, and animal manure. The findings indicate that animal manure is a preferable option when it comes to limiting metal contamination.

Oestrogens in the Scheldt: A Declining Trend

In parallel with these studies on metals, researchers also investigated the presence of oestrogens (hormone-disrupting compounds) in the Scheldt estuary. These substances can affect the endocrine systems of aquatic organisms and ultimately human health.

Through bioassays, researchers demonstrated that oestrogenic activity in the water column decreases downstream, and sediment concentrations show a general decline over a period of four decades. “These results demonstrate the impact of investment in wastewater treatment and the effect of European regulations such as the Water Framework Directive,” says Professor Emeritus Willy Baeyens.

However, continued monitoring remains essential, particularly in light of emerging chemical substances and changing industrial and urban discharge patterns.

An International Dimension

Yuwei Jia’s research underscores the importance of integrated environmental policy at the intersection of soil quality, water management, and food safety. Her work highlights the need for a comprehensive approach to addressing these interconnected issues, which are expected to become even more prominent on the policy agenda in the coming years.

The production of green hydrogen, a clean and renewable energy source, has long been hampered by its high cost. However, researchers from the Australian Research Council Centre of Excellence for Carbon Science and Innovation (COE-CSI) and the University of Adelaide have made significant strides in developing two innovative systems that harness the power of urea found in urine and wastewater to generate hydrogen efficiently.

Unlike traditional water-splitting electrolysis, which is energy-intensive and costly, these new pathways use significantly less electricity. The researchers’ breakthroughs address several limitations associated with existing urea-based systems, such as low hydrogen yields and the generation of toxic nitrogenous by-products (nitrates and nitrites).

The COE-CSI team, led by Professor Yao Zheng and Professor Shizhang Qiao, has successfully developed two separate systems that overcome these issues. The first system utilizes a membrane-free electrolysis process with a novel copper-based catalyst, while the second employs a platinum-based catalyst on carbon supports to generate hydrogen from urine.

One of the most exciting aspects of this research is the use of human urine as an alternative source for urea production. This green and cost-effective approach has the potential to significantly reduce the cost of making hydrogen, while also remediating nitrogenous waste in aquatic environments.

As Professor Zheng notes, “We need to reduce the cost of making hydrogen, but in a carbon-neutral way.” The researchers’ innovative systems are designed to produce harmless nitrogen gas instead of toxic by-products, and they use between 20-27% less electricity than traditional water-splitting systems.

The University of Adelaide team is committed to building on this fundamental research by developing carbon-supported, non-precious metal catalysts for constructing membrane-free urine-wastewater systems. This will achieve lower-cost recovery of green hydrogen while remediating the wastewater environment.

This breakthrough has far-reaching implications for the global energy crisis and the pursuit of sustainable energy solutions. As we continue to push the boundaries of innovation, it is essential that we develop technologies that not only address our energy needs but also minimize their environmental impact. The COE-CSI team’s work on green hydrogen production from urine and wastewater is a shining example of this vision, and its potential to transform the industry cannot be overstated.