Becky Ferreira, Author at ��è��Ƶ

Dark algae could accelerate melting of Greenland ice sheet

Becky Ferreira — Wed, 19 Feb 2025 10:24:42 +0000

Algae on the Greenland ice sheet absorb light and accelerate melting

Laura Halbach

Dark algae that grow on the surface of Arctic ice sheets are likely to expand their range in the future, a trend that will exacerbate melt, sea level rise and warming.

“These algae are not a new phenomenon,” says at the Mediterranean Institute of Oceanography in Marseille, France. “But if they bloom more intensely, or the bloom is more widespread, then it would be an important thing to consider in future projections of sea level rise.”

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Plan to refreeze Arctic sea ice shows promise in first tests

Greenland’s ice sheet, which covers most of the island, is rapidly melting due to rising temperatures, making it the biggest single contributor to sea level rise worldwide.

Ancylonema algae under the microscope

Nature Communications

Ancylonema algal species bloom on ice patches, called ablation zones, which are exposed as the snow line recedes on the ice sheet each summer. The blooms darken the ice, reducing its reflectivity and absorbing more heat, thereby enhancing melt in these areas by an estimated 10 to 13 per cent.

To better understand this feedback loop, Bradley and his colleagues collected Ancylonema samples from the south-west tip of the ice sheet and examined the cells with advanced imaging techniques.

The results revealed that the algae are highly adapted to nutrient-poor conditions, suggesting that they could make inroads into ice at higher elevations, where nutrients are scarce.

Global warming is already causing the snow line to retreat to increased altitudes over time, exposing more ice, which is less reflective than snow and therefore accelerates melt. Ice algae add yet another layer to these interactions that will need to be accounted for in future climate projections.

“We’ve been studying glacier algal blooms for several years now, but one of the big questions remaining has been how they are able to grow to such high numbers in such nutrient-poor ice,” says at the University of Bristol, UK, who wasn’t involved in the project. “One big part of understanding this puzzle is how much nutrient is needed by the glacier algal cells and whether they are able to efficiently take up and store the scarce nutrients available in the system. This study does a great job of demonstrating these things using cutting-edge methodologies.”

Journal reference:

Nature Communications

Hunter-gatherers built a massive fish trap in Belize 4000 years ago

Becky Ferreira — Fri, 22 Nov 2024 19:00:15 +0000

Earthen channels that span more than 640 kilometres show that pre-Mayan Mesoamericans built large-scale fish-trapping facilities earlier than previously thought

Greenland voyage sheds light on little-known ancient Arctic culture

Becky Ferreira — Fri, 06 Sep 2024 14:00:37 +0000

On a recent expedition, researchers braved summer storms in northern Greenland to learn the secrets of the ancient peoples who lived there 4500 years ago

Bronze Age hoards hint that market economies arose surprisingly early

Becky Ferreira — Mon, 29 Jul 2024 15:00:00 +0000

A hoard of Bronze Age metal fragments from Weißig, Germany

J. Lipták/Landesamt für Archäologie Sachsen

Bronze Age Europeans earned and spent money in much the same way as we do today, indicating that the origins of the “market economy” are far more ancient than expected. That is the controversial conclusion of new research that challenges the view that elites were the dominant force in Bronze Age economies, and proposes that human economic behaviour may not have changed much over the past 3500 years – and perhaps even longer.

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The rise and fall of the mysterious culture that invented civilisation

“We often tend to romanticise European prehistory, but the Bronze Age was not a fantasy realm where townsfolk and peasants were merely the background for some great lord providing for their needs,” says at Aarhus University in Denmark. “It was a very familiar world where people had families, friends, a social network, marketplaces and a job, and ultimately had to figure out how to make ends meet.” Europeans of the Bronze Age, a period that spans 3300 to 800 BC, were not meticulous bookkeepers like people of some other ancient societies, such as Mesopotamia. But Ialongo and at the University of Bologna, Italy, suggest that important revelations about their daily lives, and the roots of our own modern economic behaviour, can be found in the troves of metal fragments, known as hoards, that they left behind. Lago and Ialongo analysed more than 20,000 metal objects from hoards buried in Italy, Switzerland, Austria, Slovenia and Germany during the Bronze Age. The pieces appear in many forms, but around 1500 BC, they start to become standardised by weight, a shift that distinguishes them as a form of pre-coinage money. “The discovery of a widespread measurement and weight system makes it possible to model things that have been known about for centuries in a way that they have never been modelled before,” says Ialongo. “This opens up new results to old questions, but also new questions that no one was asking before.” To that end, the team found that the weight values of the huge sample follow the same statistical distribution as the daily expenses of a modern Western household: small everyday expenses, represented by lighter fragments, made up the vast majority of consumption patterns, while larger expenses, represented by heavier fragments, were comparatively rare. This pattern is analogous to what you might find in an average modern wallet, with lots of smaller banknotes and very few high-value ones. Lago and Ialongo interpret the findings as evidence that Bronze Age economic systems were regulated by supply and demand market forces, in which everyone participates proportionally to how much they earn. This hypothesis stands in contrast to an influential view put forth in the 1940s by the anthropologist Karl Polanyi, who cast modern economies based on monetary profit as a new and distinct phenomenon from ancient economies centred around barter, gift exchange and social standing. at Purdue University in Indiana finds the study to be credible. “The argument, I think, will prompt discussion among archaeologists and economic anthropologists, who have been labouring under false assumptions about the antiquity of market economies for decades,” he says. “I think this paper will beneficially add fuel to that kind of critique,” says Blanton. “For me, the paper throws a whole new light on the function of the bronze hoards and their potential for the use of bronze pieces as units of exchange.”

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Amazingly preserved Bronze Age village reveals life in ancient England

However, at Johns Hopkins University in Maryland is sceptical of the team’s conclusions. “It’s risky to assume that ordinary people in pre-modern times used money in ordinary economic ways,” says Schoenberger. “Medieval English peasants, for example, only began selling their produce for money when their lords began demanding money in place of in-kind rents and taxes. The peasants handed most – if not all – of that money directly to the lord. They sold in order to get money, but they did not use it to buy things they needed. We’re still a long way from modern economic behaviour [in the Middle Ages].” Lago and Ialongo hope their research will inspire specialists in other fields to develop similar work on artefacts from different regions and cultures. They suggest that market economies naturally arose across time and cultures, and that such systems are not new or special inventions of Western societies that emerged over the past few centuries. “Technically, we do not prove that the Bronze Age economy was a market economy,” says Ialongo. “We simply find no evidence that it wasn’t. And we simply point out the paradox: why is everyone convinced that the market economy did not exist, if everything we see can be explained by a market economy model? In other words, why should we imagine a more complex explanation, if the simplest one works just fine?”

Journal reference:

Nature Human Behaviour

Mysterious rock art in Venezuela hints at little-known ancient culture

Becky Ferreira — Thu, 27 Jun 2024 12:30:07 +0000

Pictograms and petroglyphs depicting abstract lines and shapes offer a rare glimpse into the culture of people who lived in South America thousands of years ago

Stolen planet could be hiding on the edge of our solar system

Becky Ferreira — Fri, 15 Dec 2023 10:17:39 +0000

When the sun was young, it may have stolen a planet from another nearby star – meaning an exoplanet could be waiting on the outer edges of the solar system for us to discover

Becky Ferreira, Author at ��è����Ƶ

Dark algae could accelerate melting of Greenland ice sheet

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Hunter-gatherers built a massive fish trap in Belize 4000 years ago

Greenland voyage sheds light on little-known ancient Arctic culture

Bronze Age hoards hint that market economies arose surprisingly early

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Mysterious rock art in Venezuela hints at little-known ancient culture

Stolen planet could be hiding on the edge of our solar system

Becky Ferreira, Author at ��è��Ƶ