Sunday, May 19, 2024

 

Charred stable remains from the Punic War period provide a glimpse into life in the Pyrenees in the Iron Age




UNIVERSITAT AUTONOMA DE BARCELONA





A research led by the UAB discovers the remains of six dead animals burned inside a stable in the Pyrenean village of Bellver de Cerdanya 2,200 years ago. Victims of a violent fire that may have been related to the passage of the Carthaginian army, the animals appeared along with some of the inhabitants’ valuables, such as a gold earring. The finding has made it possible to reconstruct the economic patterns of these inhabitants, with an important livestock breeding in which transhumance was practiced.

 

A research at the Tossal de Baltarga archaeological site, in Bellver de Cerdanya (Lleida Pyrenees), has brought to light the charred remains of a building, called Building G by archaeologists, burned by a fire 2,200 years ago, in the Iron Age. The building had two floors and the fire caused the roof, the support beams and the upper wooden floor to collapse.

 

The researchers, led by Oriol Olesti, lecturer of the Department of Antiquity and Middle Age Studies at the UAB, found the charred remains of a horse, four sheep and a goat, along with valuables such as an iron pickaxe and a gold earring concealed in a pot. From what researchers inferred, the upper floor appeared to have been divided into storage and textile production spaces. Numerous tools were found that could have been used for spinning and weaving the wool of the sheep and goats that lived on the lower floor, such as spindle whorls and loom weights. Archaeologists also found cereals such as oats and barley, and cooking vessels, with residues showing that the people using the building had been consuming milk and cheese and eating pork and lamb stews.

 

Findings show a complex economy

 

 

"The discovery has allowed us to reconstruct the economic patterns of these inhabitants, probably dedicated to transhumance", explains Oriol Olesti. The isotope analysis indicates that some sheep had previously grazed in the lowland pastures, possibly by agreement with other communities.

 

"These mountain communities were not closed in the highlands, but connected with neighboring areas, exchanging products and, likely, cultural backgrounds," said Olesti. The complex economy of these settlers, with farming, agriculture, forest management and mining activities, indicates "an Iron Age society adapted to their environment and taking advantage of their resources in the highlands. But it also shows their contact with other communities," he adds.

 

 

The passing of Hannibal's troops

 

The destruction of Tossal de Baltarga, which occupied a strategic position in the Pyrenees, could have been related to the passage of Hannibal's army through this region to fight against the Romans during the Second Punic War. "The chronological precision in archaeology to speak of the Punic War is not enough to affirm this for sure," says Oriol Olesti, "but we are very clear that it happened at that time in history." He goes on to add that: "It is likely that the violent destruction of the site is related to this war. The general fire points to an anthropic destruction, intentional and very effective, since all the buildings on the site were destroyed. In an adjacent building we also found a burned dog."

 

Tossal de Baltarga was a place of residence and lookout point for the Cerretani community with an important fortified settlement nearby, the Castellot de Bolvir. It seems to have lacked defensive walls, but had an excellent view over the river and the main travel routes. "These valleys were an important territory economically and strategically," Olesti remarks. "We know that Hannibal crossed the Pyrenees fighting against local tribes, also probably against the Cerretani. Not many archaeological remains are preserved from this expedition, but Tossal de Baltarga is probably one of the best examples."

 

A hidden gold earring

 

According to Olesti, "our reconstruction implies a sudden destruction, with no time to open the stall and save the animals". "This could just be an unexpected local fire. But the presence of a hidden gold earring indicates the anticipation by the local people of some kind of threat, likely the arrival of an enemy. Also, the keeping of such a high number of animals in a little stall suggests the anticipation of a danger."

 

Archaeologists do not know what became of the inhabitants of Tossal de Baltarga, but it was eventually reoccupied and used by the Romans. A part of the community likely survived the conflagration, and later lived alongside the Romans at the site. The most significant element of this new occupation is the impressive watchtower that remains at the site.

 

The research, published today in Frontiers in Environmental Archaeology, was led by Oriol Olesti, researcher of the UAB Department of Antiquity and Middle Age Studies, with the participation of Jordi Morera, Joan Oller and Jose M. Carrasco, researchers of the same department, as well as by researchers of the UAB Department of Prehistory Anna Berrocal, Oriol López Bultó, Laura Obea, Nadia Tarifa and Joaquim Sisa López de Pablo; Lídia Colominas, from the Catalan Institute of Classical Archaeology (ICAC-CERCA); Marta Portillo, from the Institució Milà i Fontanals of the CSIC; Paula Tàrrega, from the University of Heidelberg; and Chiara Messana, from the Catalan Institute of Human Palaeoecology and Social Evolution (IPHES-CERCA).

 

Zombie cells in the sea: Viruses keep the most common marine bacteria in check




MAX PLANCK INSTITUTE FOR MARINE MICROBIOLOGY

Helgoland 

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SUNSET OVER THE ISLAND OF HELGOLAND IN THE GERMAN BIGHT, WHERE THE RESEARCHERS FROM THE MAX PLANCK INSTITUTE FOR MARINE MICROBIOLOGY OBTAINED THEIR SAMPLES.

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CREDIT: JAN BRÜWER/MAX PLANCK INSTITUTE FOR MARINE MICROBIOLOGY




The ocean waters surrounding the German island of Helgoland provide an ideal setting to study spring algae blooms, a focus of research at the Max Planck Institute for Marine Microbiology since 2009. In a previous study, the Max Planck scientists observed a group of bacteria called SAR11 to grow particularly fast during these blooms. However, despite their high growth rates, the abundance of SAR11 decreased by roughly 90% over five days. This suggested that the cells were quickly decimated by predators and/or viral infections. Now, the Max Planck researchers investigated what exactly lies behind this phenomenon.

Finding the phages infecting SAR11

“We wanted to find out if the low numbers of SAR11 were caused by phages, that is viruses that specifically infect bacteria”, explains Jan Brüwer, who conducted the study as part of his doctoral thesis. “Answering this seemingly simple question was methodologically very challenging”.

How does phage infection work? Phages infect bacteria by introducing their genetic material into them. Once there, it replicates, and utilizes the bacterial ribosomes to produce the proteins it needs. Researchers from Bremen used a technology that enabled them to “follow” the phage’s genetic material inside the cell. “We can stain the specific phage genes and then see them under the microscope. Since we can also stain the genetic material of SAR11, we can simultaneously detect phage-infected SAR11 cells”, explains Jan Brüwer.

While this might seem straightforward, the low brightness and small size of the phage genes made it challenging for researches to detect them. Nonetheless, thousands of microscope images were successfully analyzed, bringing some exciting news.  

“We saw that SAR11 bacteria are under massive attack by phages”, says Jan Brüwer. “During periods of rapid growth, such as those associated with spring algae blooms, nearly 20% of the cells were infected, which explains the low cell numbers. So, phages are the missing link explaining this mystery.”

Zombie cells: A global phenomenon

To the surprise of the scientists, the images revealed even more. "We discovered that some of the phage-infected SAR11 cells no longer contained ribosomes. These cells are probably in a transitional state between life and death, thus we called them 'zombie' cells”, Brüwer explains.

Zombie cells represent a novel phenomenon observed not only in pure SAR11 cultures but also in samples collected off Helgoland. Furthermore, analysis of samples from the Atlantic, Southern Ocean, and Pacific Ocean revealed the presence of zombie cells, indicating this phenomenon occurs worldwide.

“In our study, zombie cells make up to 10% of all cells in the sea. The global occurrence of zombie cells broadens our understanding of the viral infection cycle”, Brüwer emphasizes. “We suspect that in zombie cells, the nucleic acids contained in the ribosomes are being broken down and recycled to make new phage DNA.”

Brüwer and his colleagues hypothesize that not only SAR11 bacteria, but also other bacteria, can be turned into zombies. Thus, they want to further investigate the distribution of zombie cells and their role in the viral infection cycle.

“This new finding proves that the SAR11 population, despite dividing so fast, is massively controlled and regulated by phages”, stresses Brüwer. “SAR11 is very important for global biogeochemical cycles, including the carbon cycle, therefore their role in the ocean must be redefined. Our work highlights the role of phages in the marine ecosystem and the importance of microbial interactions in the ocean”.

Infected cells and zombie cells 

 

Human activity over natural inputs determines the bacterial community in an ice core from the Muztag ata glacier


SCIENCE CHINA PRESS

The location of Muztag ata glacier and the ice core sampling strategy. 

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THE LOCATION OF MUZTAG ATA GLACIER ON THE TIBETAN PLATEAU AND THE INFLUENCE OF WESTERLY JET AND INDIAN MONSOON ARE SHOWN IN PANEL A. THE ICE CORE SAMPLING STRATEGY IS ILLUSTRATED IN PANEL (B). BRIEFLY, THE 74 M ICE CORE WAS CUT INTO 10 TO 15 CM SECTIONS AND DATED, THEN SECTIONS WITH ENVIRONMENTAL PROXIES AVAILABLE ARE USED FOR DNA EXTRACTION AND BACTERIAL 16S RRNA GENE AMPLICON SEQUENCING.

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CREDIT: ©SCIENCE CHINA PRESS




This study is led by Dr. Yongqin Liu (Institute of Tibetan Plateau Research, Chinese Academy of Sciences). The Tibetan Plateau (TP) has the third-largest number of glaciers after the Antarctic and Greenland. Bacteria, deposited on glacier surfaces through dry and wet deposition, undergo in-situ growth and are subsequently preserved in ice cores following environmental selection pressures such as UV radiation and low temperatures. Since glacier bacteria are largely transported from distant or local sources by atmospheric circulation, changes in source ecosystems can also affect the composition of surface glacier bacteria. Therefore, the characteristics of bacterial communities in ice cores can serve as indicators of past climates and human activities.

The team investigated the bacterial community from a 74 m ice core of Muztag ata glacier on the Tibetan Plateau to link biological indicators with past climate and anthropogenic activities. They observed an increase in bacterial richness throughout the ice core, which was associated with higher NH+4, an indicator of agricultural development. Meanwhile, the evenness demonstrated negative correlations with DOC and MAP, and positive correlation with δ18O, Na+, K+, Mg2+, Ca2+, Cl, SO42-, and NO3-. These indicators collectively offer promising insights for inferring past climate and environmental changes.

The researchers further investigate the composition of bacterial communities in ice cores. Cluster analysis at the bacterial family level indicates three distinct groupings of samples. Through cluster analysis at the bacterial family level, they uncovered three distinct groupings of samples. Cluster A encompasses the years 1953 to 1991, Cluster B consists of 11 samples from 1933 to 1951, while the majority of samples in Cluster C are dated between 1907 and 1930. It was found that the bacterial community composition was shaped by a combination of human activity, natural inputs, and air temperature, with a pronounced human influence becoming evident after the 1950s. Furthermore, the relative abundance of animal gut-associated bacteria, including Aerococcaceae, Nocardiaceae, Muribaculaceae, and Lachnospiraceae, was associated with livestock number changes in the Central Asian region. Together with other bacterial lineages, they jointly explained 59.8% of the livestock number changes.

"These new findings not only quantify the relationship between bacterial diversity and community composition with past climates and human activities but also highlight how changes in land use, driven by agriculture and livestock, intensify the presence of potentially harmful bacteria on glaciers.  This enhances our understanding of regional climate and human activities." Dr. Liu says.

This study provides a comprehensive analysis of the century-long dynamics of bacterial communities in the Muztag Ata ice core. The identified bacterial markers offer valuable insights into past environmental conditions and human activities in the source regions, underscoring the microbial potential in ice core climate studies.

Liu Y, Jiao N, Ji M, Liu K, Xu B, Guo B, Yao T. 2024. Human activity over natural inputs determines the bacterial community in an ice core from the Muztag ata glacier. Science China Earth Sciences, 67(5): 1489–1499, https://doi.org/10.1007/s11430-022-1282-x

 

From leaf elements to biomass across forest biomes in the Himalayas




SCIENCE CHINA PRESS

Biomass as a function of the elevation and multi-element traits based functional diversity. 

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EXPERIMENTAL DESIGN, INCLUDING (A) THE LOCATION OF THE KANGCHENJUNGA LANDSCAPE IN THE EASTERN HIMALAYAS, NEPAL, (B) THE SITUATION OF FOREST PLOTS ALONG THE WHOLE ELEVATIONAL GRADIENT, AND (C) HYPOTHETICAL FRAMEWORK OF ELEMENT-BASED TRAIT DIVERSITY AND (D) DECLINING BIOMASS ALONG THE STUDY GRADIENT. THE FRAMEWORK SHOWS MASS-RATIO (FOCUSING ON COMMUNITY WEIGHTED MEAN, CWM, WHERE TRAIT VALUE OF DIFFERENT SPECIES WAS SYMBOLIZED AS ARROWS POINTING UPWARD) AND COMPLEMENTARITY EFFECTS (FOCUSING ON FUNCTIONAL DIVERGENCE, FD, WHERE E1 TO E5 INDICATE 5 ELEMENTS IN TREE LEAVES AND REPRESENT NICHE PARTITIONING IN THE TRAIT SPACE. THE ELEVATION GRADIENT IS CHARACTERIZED BY: LOW (ELEVATION < 1000 M), MID (ELEVATION 1000-3000 M), AND HIGH-ELEVATION SITES (ELEVATION > 3000 M).

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CREDIT: ©SCIENCE CHINA PRESS




The growth, development, and functioning of plants in various environments depend on multiple elements. However, our understanding of how the element concentrations in leaves that are associated with plant functioning and adaptation affect biomass in tree communities along elevation has been limited. A study led by Prof. Eryuan Liang (Institute of Tibetan Plateau Research, Chinese Academy of Sciences), and Dr. Nita Dyola (Institute of Tibetan Plateau Research, Chinese Academy of Sciences and Université du Québec à Chicoutimi), together with the co-authors, demonstrated the linkages of ten leaf element (carbon, nitrogen, phosphorus, potassium, calcium, magnesium, zinc, iron, copper and manganese) contents in 1,859 trees from 116 species in shaping biomass accumulation from tropical forests (80 m asl) to alpine treeline (4200 m asl) in the Kangchenjunga Landscape, located in the eastern Nepal Himalayas, which is one of the most diverse regions in the world.

The study, published in the Science China Earth Sciences, explored the mechanisms regulating forest biomass by assessing the relative change in the mass-ratio effect (i.e., indicating dominant trait affecting biomass) and complementarity effect (i.e., indicating partitioning of resources) based on multiple leaf elements. The study highlighted that elevation plays a crucial role in regulating trait diversity among plant species and their biomass accumulation in the Himalayas (see the figure below).

The study revealed that a combination of elements and elevation better explained the variation in biomass, accounting for 52.2% of the variance, compared to the individual elemental diversity, which accounted for 0.05% to 21% of the variance in biomass. The findings highlighted the significance of resource partitioning at low elevations and competition in the middle elevations, both of which were positively associated with forest biomass. Although high variation in leaf nutrients improves species’ adaptability to changing environments, it also poses challenges by reducing biomass accumulation in stressful sites at higher elevations.

This study provides a roadmap to comprehend and predict the effect of elevation-dependent environmental shifts, on the functional diversity of elemental traits that shape biomass accumulation across biomes. This knowledge presents a new approach to explore the range of chemical traits that modulate biomass and ecosystem functioning, which is crucial for conserving and managing biodiversity in mountain ecosystems.

See the article:

Dyola N, Liang E, Peñuelas J, Camarero JJ, Sigdel SR, Aryal S, Lin W, Liu X, Liu Y, Xu X, Rossi S. 2024. Linking leaf elemental traits to biomass across forest biomes in the Himalayas. Science China Earth Sciences, 67(5): 1518-1528. https://doi.org/10.1007/s11430-023-1271-4

 

Furry thieves are running loose in a Maine forest, UMaine research shows



UNIVERSITY OF MAINE
Small-mammal-study-news-feature 

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A MOUSE SITS ON A MOSSY LOG IN A MAINE FOREST. 

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CREDIT: PHOTO COURTESY OF BRIGIT HUMPHREYS





Scattered across the Penobscot Experimental Forest are veritable treasure troves for its denizens, each containing riches beyond comprehension. These caches do not contain gold or jewels — they’re filled with eastern white pine seeds and were placed by a team of researchers at the University of Maine for one purpose: to catch furry thieves red-handed. 

Brigit Humphreys, a UMaine graduate student studying ecology and environmental science, has been working in the forest, which sits about 10 miles north of Bangor, for the past two years in an effort to determine which animal personalities are predisposed to pilfering. 

As part of a National Science Foundation-funded research project, Humphreys has been studying the behavior of small mammals in the wild. Her research adds to a growing body of knowledge showing that the unique personalities of individual small mammals play a critical role in forest regeneration by impacting seed dispersal. It also complements a larger project that has been eight years in the making and is nearing completion. 

“The point of the project was to figure out how small mammal personality and animal personality in general influence different ecological processes,” Humphreys said. “We’re focused on small mammals because they’re a great study system. They’re abundant, we get a really good sample size and we can actually conduct experiments on them in the forest. Seed dispersal is a super important aspect to Maine’s economy, recreation and aesthetics. A lot of research focuses at the species or community level, but many of the individual aspects have been ignored in science. The idea is to bring more attention to the individual and how variation and personality at the individual level is actually really important for ecosystems, tree growth and forest regeneration.”

Humphreys has worked under the direction of professor Alessio Mortelliti of the Department of Wildlife, Fisheries, and Conservation Biology. From June-October 2022, Humphreys and a team of researchers set traps for small mammals, including squirrels, chipmunks, mice, voles and shrews. They worked in a six-grid system, slowly moving about 150 traps from one grid to another. Upon catching the animals, the team collected data about their personality traits and tagged each of them. 

Once a grid was cleared of traps, Humphreys and her team planted artificial seed caches across the area, equipping each with a circular antenna buried around the cache. The caches contained eastern white pine seeds, which are an economically important species in Maine and a consistently preferred seed species among the small mammals involved in the study. Game cameras were also set up to observe pilferers in the act. 

“The idea is when an individual that we have tagged crosses over the antenna, the antenna picks up on their unique tag, so we know what the personality of that individual was,” Humphreys said. 

Her findings indicate that small mammal personality determines the effectiveness of pilferage in mice and voles, with some individuals being more successful at stealing seeds than others. The most accomplished thieves: deer mice. 

“We found that more exploratory deer mice were more likely to find caches to pilfer, which makes a lot of sense because they’re likely moving around more and they don’t consider predation risk as much, so they’re able to find these caches and steal them. Those were our main personality results,” Humphreys said. “We found that individuals with a lower body condition, so skinnier animals, were more likely to pilfer because they were desperately hungry. We also found a sex effect. Female voles were more likely to pilfer, which aligns with past research on the same species of voles.”

Humphreys and her team observed many other curious and hungry species over the course of the study as well. 

“We had over 10 different species come and pilfer the caches,” Humphreys said. “Some of them were unexpected, like raccoons came and took some of the seeds, which was interesting. The other common pilferers were American red squirrels, eastern chipmunks, Sorex shrews and jumping mice. For the jumping mice there were only a few individuals that we caught, but the ones that were present in our areas were very effective. They got like 10 caches in a night.”

Humphreys’ findings were recently published in the Journal of Animal Ecology as part of the special feature: “Intraspecific Variation in Ecology and Evolution.” She’s currently working on the last piece of the overall project, which focuses on comparing behavioral diversity in areas with varying styles of forest management. 

“The take-home message of all the research we are doing is that individuals are important,” Humphreys said. “There’s a big push in the science community to conserve biodiversity, but beyond biodiversity, we have to be conserving behavioral diversity within a species if we truly want to have fully functional ecosystems.”