Unveiling 12,000 Years of European History: The Mont Blanc Ice Core Record

A team of researchers from the Desert Research Institute’s (DRI) Ice Core Lab has made a groundbreaking discovery by analyzing a 40-meter long ice core from the French Alps. This study, published in the June issue of PNAS Nexus, reveals an intact record of atmospheric aerosols and climate dating back at least 12,000 years.

The ice core, collected from Mont Blanc’s Dôme du Goûter, provides a unique insight into Europe’s local climate during different time periods. By using radiocarbon dating techniques, the research team established that the glacier offers an accurate record of past atmospheric aerosols and climate transitions.

Aerosols play a significant role in regional climate through their interactions with clouds and solar radiation. The insights offered by this ice core record can help inform accurate climate modeling for both the past and future.

One of the most striking aspects of this study is that it reveals a temperature difference of about 3 degrees Celsius between the last Ice Age and the current Holocene Epoch. Using pollen records embedded in the ice, reconstructions of summer temperatures during the last Ice Age were about 2 degrees Celsius cooler throughout western Europe, and about 3.5 degrees Celsius cooler in the Alps.

The phosphorous record also tells researchers the story of vegetation changes in the region over the last 12,000 years. Phosphorous concentrations in the ice were low during the last Ice Age, increased dramatically during the early to mid-Holocene, and then decreased steadily into the late Holocene.

Records of sea salt also helped researchers examine changes in historical wind patterns. The ice core revealed higher rates of sea salt deposition during the last Ice Age that may have resulted from stronger westerly winds offshore of western Europe.

The most dramatic story told by this study is the change in dust aerosols during the climatic shift. Dust serves as an important driver of climate by both absorbing and scattering incoming solar radiation and outgoing planetary radiation, and impacts cloud formation and precipitation by acting as cloud condensation nuclei.

During the last Ice Age, dust was found to be about 8-fold higher compared to the Holocene. This contradicts the mere doubling of dust aerosols between warm and cold climate stages in Europe simulated by prior climate models.

This study is only the beginning of the Mont Blanc ice record’s story, as researchers plan to continue analyzing it for indicators of human history. The first step in uncovering every ice core’s record is to use isotopes and radiocarbon dating to establish how old each layer of ice is. Now, with that information, scientists can take an even deeper look at what it can tell us about past human civilizations and their impact on the environment.

The Mont Blanc ice record has the potential to reveal more stories entombed in its layers, and researchers are eager to continue exploring this ancient history for a better understanding of our planet’s climate variability and human history.

The majority of the Earth’s plant species rely on animal pollinators to reproduce, and our modern agricultural industry is heavily reliant on honey bees. Feral honey bees, which are non-native and often escape human management, can perturb native ecosystems when they become abundant. A new study by University of California San Diego biologists is calling attention to the threat posed by these feral honey bees to native pollinators in Southern California.

The researchers found that honey bees remove about 80% of pollen during the first day a flower opens, leaving scant resources for native bees. If the pollen and nectar used to create honey bee biomass were instead converted to native bees, populations of native bees would be expected to be roughly 50 times larger than they are currently.

While public concern often focuses on the plight of the honey bee, researchers say that such a level of honey bee exploitation is not well documented. This can pose an additional and important threat to native bee populations in places where honey bees have become abundant.

The study used pollen-removal experiments to estimate the amount of pollen extracted by honey bees using three common native plants as targeted pollen sources. The researchers found that just two visits by honey bees removed more than 60% of available pollen from flowers of all three species.

One step to address this situation could be increased guidance on whether and where large-scale contract beekeepers are allowed to keep their hives on public lands after crops have bloomed, to limit opportunities for honey bees to outcompete native species for scarce resources provided by native vegetation.

The buzz on bees has long been a topic of interest, but recent research is shedding new light on how environmental change affects their communication and pollination abilities. Scientists have found that high temperatures and exposure to heavy metals can reduce the frequency and pitch of non-flight wing vibrations in bees, which could have significant consequences for their role as pollinators.

Dr. Charlie Woodrow, a postdoctoral researcher at Uppsala University, has been studying the effect of environmental change on bee buzzes. He notes that people often don’t realize that bees use their flight muscles for functions other than flight, such as communication and defense. One important function is buzz-pollination, which involves a bee curling its body around the pollen-concealing anthers of flowers and contracting its flight muscles up to 400 times per second to produce vibrations that shake loose the pollen.

Dr. Woodrow’s experiments involved using accelerometers to measure the frequency of the buzz, which corresponds to the audible pitch. He also used thermal imaging to show how bees deal with the extra heat generated by their buzzing. The research has found that temperature plays a vital role in determining the properties of a bee’s buzz, and exposure to heavy metals can reduce the contraction frequencies of the flight muscles during non-flight buzzing.

The benefits of understanding the impact of environmental change on a bee’s buzz include unique insights into bee ecology and behavior, helping to identify species or regions most at risk, and improving AI-based species detection based on sound recordings. Dr. Woodrow suggests that buzzes could even be used as a marker of stress or environmental change.

The research also has implications for robotics and the future safeguarding of pollination services. Dr. Woodrow is working towards understanding bee vibrations through micro-robotics, so their results are also going towards developing micro-robots to understand pollen release.

Overall, the buzz on bees is more than just a curiosity; it’s an important aspect of their ecology that can provide valuable insights into environmental change and its impact on pollination services.