Search

Diatomite deposits of the lacustrine Truckee Formation near Hazen, Northern Nevada, are of Miocene age (ca. 10.3 million years old) and consist of varved deposits within commercial mines. These exposed deposits have been primary source of paleontological samples of stickleback fish fossils (Gasterosteous doryssus) spanning 100,000 years. These samples have revealed stasis, rapid morphological and genetic evolution, and local extinction of G. doryssus against a background of changing diatom communities. Here, we draw on geological, limnological, anthropogenic, and bibliographical data to illustrate the geographic and paleontological context of the Hazen diatomite deposits. We include a stratigraphic section describing lithology and stickleback specimen frequency at a 1 mm resolution. This paper should help researchers identify patterns in fossil site distribution and better understand the geological processes that have shaped the area, spurring new sampling and future research.

The ecosystem services and immense biodiversity of Amazon rainforests are threatened by deforestation and forest degradation. A key goal of modern archaeology and paleoecology in Amazonia is to establish the extent and duration of past forest disturbance by humans. Fossil phytoliths are an established proxy to identify the duration of disturbance in lake sedimentary and soil archives. What is not known, is the spatial scale of such forest disturbances when identified by phytoliths. Here we use phytolith assemblages to detect local-scale forest openings, provide an estimate of extent, and consider long-term forest recovery. We use modern phytolith assemblages of 50 Amazonian lakes to i) assess how phytolith assemblages vary across forest cover at 5 spatial scales (100 m, 200 m, 500 m, 1 km, 2 km), ii) model which phytolith morphotypes can accurately predict forest cover at 5 spatial scales, and iii) compare phytoliths with pollen to quantify their relative ability to detect forest cover changes. DCA results show phytolith assemblages could be used to differentiate low, intermediate, and high forest cover values, but not to distinguish between biogeographical gradients across Amazonia. Beta regression models show Poaceae phytoliths can accurately predict forest cover within 200 m of Amazonian lakes. This modern calibration dataset can be used to make quantitative reconstructions of forest cover changes in Amazonia, to generate novel insights into long-term forest recovery. Combining phytoliths and pollen provides a unique opportunity to make qualitative and quantitative reconstructions of past vegetation changes, to better understand how human activities, environmental and climatic changes have shaped modern Amazonian forests.

Recent studies suggest that in Upper Mesopotamia during the Late Neolithic period, specifically between 6400 and 5900 BCE, simple cereal flour doughs were baked in domed ovens using ceramic pans, commonly known as husking trays. Adopting an integrated approach that investigates various types of evidence, such as use-wear, phytoliths, and organic residues, we further refined and explored this hypothesis. Analysis of a sample of 13 sherds belonging to these trays from Mezraa Teleilat, Akarçay Tepe, and Tell Sabi Abyad provides evidence that a limited number of them could have been used to bake 'focaccia'-like products with ingredients such as lard or oil. This research project not only further strengthens the theory that husking trays could have been used for baking, but also provides insights into the variety and elaboration of food practices that existed amongst early agricultural communities, demonstrating the existence of a number of different 'recipes' for a particular dish. Furthermore, from a methodological perspective, this study highlights how only an integrated approach can contribute to the knowledge of the various culinary traits and traditions of ancient communities. [ABSTRACT FROM AUTHOR]

Summary Here, we developed and applied models to quantitatively reconstruct forest cover and biomass changes at three lakes in northwestern Amazonia over the past > 1500 yr. We used remotely sensed data and a modern dataset of 50 Amazonian lakes to develop generalized linear models that predict aboveground biomass, using phytolith morphotypes and forest cover as predictor variables. Also, we applied a published beta regression model to predict forest cover within 200 m of each lake, using Poaceae phytoliths. Charcoal and maize phytoliths were analysed to identify past land use. Results showed forest cover and biomass changes at our study sites ranged between 48–84% and 142–438 Mg ha−1, respectively. Human occupation was discontinuous, with major changes in forest cover and biomass coinciding with periods of land use. Forest cover and biomass decreased notably after fire (at all sites) or cultivation events (Lakes Zancudococha, Kumpaka). The timing and ecological impact of past land use were spatially and temporally variable. Our results suggest past human impact was small‐scaled and heterogenous in northwestern Amazonia, with a significant impact of fire on forest cover and biomass changes. [ABSTRACT FROM AUTHOR]

The existence of vegetation of open environments with a predominance of grass–forb meadow associations and the participation of pine–oak forests was reconstructed on the basis of study of microphytofossils from the Lower Pleistocene deposits of the Taurida cave in central Crimea. These results are consistent with data on the composition of land vertebrates from the Taurida locality. The studied spectrum demonstrates similarity with the spore–pollen assemblage of the Berezan horizon of Ukraine with a maximum age of about 1.8 Ma. Based on the abundance of trichomes and plant fibers similar to those of Ficus carica Linnaeus, 1753 in the coprolites, it is assumed that the extinct hyenas Pachycrocuta brevirostris (Gervais, 1850) ate fig fruits in certain seasons. [ABSTRACT FROM AUTHOR]

Simple Summary: The potato is the most important non-cereal food crop worldwide. Silicon (Si) fertilizers have been reported to improve potato growth and yield. We used results from two field experiments in the temperate zone to gain insight into silica accumulation in potato plants as well as corresponding long-term potato yield performance. We found relatively low Si contents in potato plants grown in soils with different concentrations of plant-available Si (field experiment 1). Moreover, potato yield was not correlated to plant-available Si concentrations in soils in the long term (1965–2015, field experiment 2). Based on our results, we ascribe the reported positive effects of Si fertilization on potatoes rather to effects of the used Si fertilizers than to silica accumulation in potato plants. While Si fertilizers applied directly to the leaves can prevent fungal infections, soil-applied Si fertilizers can enhance phosphorus and water availability in agricultural soils. With our study, we aim to inspire further research on Si fertilization–potato relationships. The corresponding results will help to derive practice-oriented recommendations for potato growers worldwide to cope with the challenges of climate change. The potato is the most important non-cereal food crop, and thus improving potato growth and yield is the focus of agricultural researchers and practitioners worldwide. Several studies reported beneficial effects of silicon (Si) fertilization on potato performance, although plant species from the family Solanaceae are generally considered to be non-Si-accumulating. We used results from two field experiments in the temperate zone to gain insight into silica accumulation in potato plants, as well as corresponding long-term potato yield performance. We found relatively low Si contents in potato leaves and roots (up to 0.08% and 0.3% in the dry mass, respectively) and negligible Si contents in potato tuber skin and tuber flesh for plants grown in soils with different concentrations of plant-available Si (field experiment 1). Moreover, potato yield was not correlated to plant-available Si concentrations in soils in the long term (1965–2015, field experiment 2). Based on our results, we ascribe the beneficial effects of Si fertilization on potato growth and yield performance reported in previous studies mainly to antifungal/osmotic effects of foliar-applied Si fertilizers and to changes in physicochemical soil properties (e.g., enhanced phosphorus availability and water-holding capacity) caused by soil-applied Si fertilizers. [ABSTRACT FROM AUTHOR]

Abstract Recent studies suggest that in Upper Mesopotamia during the Late Neolithic period, specifically between 6400 and 5900 BCE, simple cereal flour doughs were baked in domed ovens using ceramic pans, commonly known as husking trays. Adopting an integrated approach that investigates various types of evidence, such as use-wear, phytoliths, and organic residues, we further refined and explored this hypothesis. Analysis of a sample of 13 sherds belonging to these trays from Mezraa Teleilat, Akarçay Tepe, and Tell Sabi Abyad provides evidence that a limited number of them could have been used to bake ‘focaccia’-like products with ingredients such as lard or oil. This research project not only further strengthens the theory that husking trays could have been used for baking, but also provides insights into the variety and elaboration of food practices that existed amongst early agricultural communities, demonstrating the existence of a number of different ‘recipes’ for a particular dish. Furthermore, from a methodological perspective, this study highlights how only an integrated approach can contribute to the knowledge of the various culinary traits and traditions of ancient communities.

The Ecuadorian Amazon holds more biodiversity than most other places on Earth. Palms are a particularly dominant component of the vegetation; however, it remains unknown to what degree the pattern has persisted through time. Here, we investigate the persistence of palm dominance through time and the degree to which past human activities (e.g., fire, cultivation, and forest opening) have affected changes in palm abundances across five regions of the Ecuadorian Amazon. We analyzed soil cores (40–80 cm depth) from each region for charcoal (evidence of past fire) and phytoliths (evidence of past vegetation change). The timings of fires (based on 14C radiocarbon dates), the occurrence, recurrence, and number of fires (based on charcoal presence and abundance in samples), and the amount of change in palm abundances (based on phytoliths) varied within and between the studied regions. The charcoal and phytolith results indicate the presence of low levels of past human activity at all sites. Our results show that patterns of modern palm hyperdominance found in Amazonian forests have not been persistent through time, and that even low levels of past human activities can affect palm abundance. [ABSTRACT FROM AUTHOR]

As a plant kingdom and a biodiversity hotspot, Yunnan is a key region for our understanding of modern and past global changes in biodiversity and environment. As proxies of vegetation and climate, phytoliths have become increasingly important in ecological and paleoecological studies. In this study, phytolith analysis was carried out on samples of surface sediments from 70 lakes in western Yunnan, southwest China. These lakes are surrounded by modern vegetation types including broadleaved and coniferous forests, scrubs, grasslands, meadows, and alpine vegetation. The results of this study show that modern lacustrine phytoliths in western Yunnan are dominated by herbaceous phytoliths, among which Poaceae types are the most abundant. The 70 phytolith samples used can be divided into 4 groups, reflecting the major vegetation types from which samples were collected. The principal component analysis (PCA) and redundancy analysis (RDA) of the phytolith and climatic data of the 70 lacustrine phytolith samples showed that temperature and precipitation are the climatic parameters controlling the spatial distribution of phytolith assemblages in western Yunnan. Phytolith–MAT (mean annual temperature) and phytolith–MAP (mean annual precipitation) transfer functions were developed using weighted averaging partial least squares (WA-PLS), and both the MAT and MAP functions showed good performances (MAT: R2 = 0.67, RMSEP = 0.96 °C, MAP: R2 = 0.64, RMSEP = 140.4 mm). Our results also reveal that phytolith analysis is a useful technique offering reliable vegetation interpretation and climate reconstruction; thus, this study provides a basis for the vegetational and climatic interpretation of fossil lacustrine phytolith records in western Yunnan. [ABSTRACT FROM AUTHOR]

Copyright of Memoria Americana is the property of Memoria Americana, Cuadernos de Etnohistoria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents the results of the first geoarchaeological study of the materials of Christian burials identified in the interior of the Middle Zelenchuk temple of the 10th century in the Nizhne-Arkhyz ancient settlement (Republic of Karachay-Cherkessia). The results of microbiomorphic (phytolith) and total phosphorus content analyses allowed us to reveal previously unknown features of the funeral rites of the multicultural and multi-ethnic Christian population of one of the largest cities of the North Caucasus in the Middle Ages. The differences in funerary practices between the 11th and 13th centuries became evident when studying even a small group of funerary complexes in which people of the same social group – representatives of the social elite of Western Alania – were buried. The geoarchaeological study showed an abundance of plant and animal organic matter in the burials. The complex analysis of archaeological materials and data obtained during the microbiomorphic study allowed us to conclude that members of the urban Christian community had several burial traditions: in stone boxes (tombs), in wooden frames, and a mixed ritual when a wooden structure was placed in a stone box. The presence of wooden bark particles in the burials seems to be related not so much to the material from which the burial structures were made as to the presence in the graves of bark or bast objects (bast caskets or boxes, birch bark amulets, toys, etc.). The tradition known from pagan Alanian burials of placing the head of the deceased on a “stone cushion” (more typical for male burials) was preserved in early Christian burials. In one of the four women’s graves studied, the analysis showed the presence of a “hay pillow.” Probably, before the burial, a ritual of washing the deceased was performed, as evidenced by the presence of diatoms and sponge spicules in the samples.

Phytolith content and its preservation in soils form a robust tool for paleoecological reconstruction. Post-depositional processes, however, influence the preservation of phytolith assemblages in soils thus making the paleoecological inferences biased. Here we evaluated the preservation of phytoliths in a Late Quaternary loess-paleosol sequence (LPS) from Kashmir Valley, northwest Himalaya. The soil micromorphological study, physicochemical parameters, phytolith morphometry, and phytolith translocation rates were employed to assess phytolith preservation and absence (not recorded) in the various litho-units of the Wanihama LPS. The comparison of phytolith content and soil physio-chemical parameters including pH, electrical conductivity, available N, P, K, organic carbon, extractable Fe, Zn, Mn and Cu do not show any significant correlation. This suggests that soil physicochemical parameters have a minor role in regulating the preservation of phytoliths in the LPS. The depth distribution of phytoliths exhibits an inconsistent pattern and phytolith content doesn't decrease systematically with depth. The phytolith content usually follows the loess-paleosol stratigraphy, with low concentrations in loess units and high concentrations in paleosols indicating that phytolith assemblages in the LPS have not been altered or translocated as a result of pedogenic processes. The micromorphological observations suggest weak pedogenesis and the sequence does not seem to be significantly mixed by bioturbation activities. This is augmented by the low translocation rate of

Disturbances in tropical forests can have long‐lasting ecological impacts, but their manifestations (ecological legacies) in modern forests are uncertain. Many Amazonian forests bear the mark of past soil modifications, species enrichments, and fire events, but the trajectories of ecological legacies from the pre‐contact or post‐colonial period remain relatively unexplored. We assessed the fire and vegetation history from 15 soil cores ranging from 0 to 10 km from a post‐colonial Surinamese archaeological site. We show that (1) fires occurred from 96 bc to recent times and induced significant vegetation change, (2) persistent ecological legacies from pre‐contact and post‐colonial fire and deforestation practices were mainly within 1 km of the archaeological site, and (3) palm enrichment of Attalea, Oenocarpus and Astrocaryum occurred within 0, 1, and 8 km of the archaeological site, respectively. Our results challenge the notion of spatially extensive and persistent ecological legacies. Instead, our data indicate that the persistence and extent of ecological legacies are dependent on their timing, frequency, type, and intensity. Examining the mechanisms and manifestations of ecological legacies is crucial in assessing forest resilience and Indigenous and local land rights in the highly threatened Amazonian forests. [ABSTRACT FROM AUTHOR]

Copyright of Revista del Museo de Antropología is the property of Museo de Antropologia - IDACOR and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista del Museo de Antropología is the property of Museo de Antropologia - IDACOR and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phytoliths of biogenic silica play a vital role in the silicon biogeochemical cycle and occlude a fraction of organic carbon. The location, chemical speciation, and quantification of this carbon within phytoliths have remained elusive due to limited direct experimental evidence. In this work, phytoliths (bilobate morphotype) from the sugarcane stalk epidermis are sectioned with a focused ion beam to produce lamellas (≈10 × 10 μm2 size, <500 nm thickness) and probed by synchrotron scanning transmission X-ray microspectroscopy (≈100–200 nm pixel size; energies near the silicon and carbon K-absorption edges). Analysis of the spectral image stacks reveals the complementarity of the silica and carbon spatial distributions, with carbon found at the borders of the lamellas, in islands within the silica, and dispersed in extended regions that can be described as a mixed silica-carbonaceous matrix. Carbon spectra are assigned mainly to lignin-like compounds as well as to proteins. Carbon contents of 3–14 wt.% are estimated from the spectral maps of four distinct phytolith lamellas. The results provide unprecedented spatial and chemical information on the carbon in phytoliths obtained without interference from wet-chemical digestion. [ABSTRACT FROM AUTHOR]

The lower Nhecolândia region, in the south of the Pantanal, contains thousands of shallow freshwater and saline-alkaline lakes isolated by sandy ridges. To understand the paleoenvironment, sediment cores from B02SR (freshwater) and 07SR (saline-alkaline) lakes were analyzed, employing a combination of 14C dating, microfossils, geochemical, elemental, and isotopic analyses. The 07SR core recovered Late Pleistocene sediments (~ 23,440 cal yrs BP), and the B02SR core Middle Holocene sediments (~ 6080 cal yrs BP). The base of the cores consists of bedded sands with no organic matter, sponge spicules, or diatoms. Phytoliths suggest the presence of cerrado vegetation with seasonal floods, suggestive of a periodically inundated distal floodplain. We interpret that the two lakes sustain perennial alkaline geochemical conditions between ~ 3080 and ~ 1330 cal yrs BP. The Lake B02SR transitioned to slightly acidic waters with low electrical conductivity from ~ 1330 cal yrs BP to the present, probably associated with a connection to ephemeral shallow or perennial channels. Lake 07SR maintained consistent water chemistry throughout the record, suggesting that an isolated drainage pattern remained unchanged creating persistent alkaline conditions. Our results suggest that lake chemical changes were spatially variable in lower Nhecolândia in the Holocene, which has implications for ecosystem services. [ABSTRACT FROM AUTHOR]

The study is devoted to the analysis of the morphometric parameters of Crenate phytoliths of the Dactylis glomerata L. leaf epidermis. The use of morphometry for the nomenclature and identification of phytoliths determines the relevance of studying factors that impact on the size of silica bodies. One of the possible reasons for morphometric differences may be the phenophase in which the herbarium material was collected. We collected herbarium material of D. glomerata from its two habitats at the beginning and the end of the growing season. Morphometric data of phytoliths extracted from leaves were processed using descriptive statistics and analysis of variance. The Crenate study of D. glomerata phytoliths at different stages of the growing season shows that some parameters tend to increase, while others remain stable and may have a taxonomic potential. Finally, the increase in the size characteristics of phytoliths at the end of the growing season has been revealed. Such parameters as area, width and equivalent diameter are stable. By the end of the growing season, the phytoliths have a more elongated and irregular shape. The most stable shape parameters are roundness, compactness and aspect ratio.

Abstract Background Terrestrial ecosystems contain significant carbon storage, vital to the global carbon cycle and climate change. Alterations in human production activities and environmental factors affect the stability of carbon storage in soil. Carbon sequestration in plant phytoliths offers a sustainable method for long-term carbon stabilization. Carbon occluded in phytoliths (PhytOC) is a kind of carbon that can be stable and not decomposed for a long time, so it is crucial to conduct more in-depth research on it. Results We undertook a meta-analysis on PhytOC across global terrestrial ecosystems, analyzing 60 articles, encapsulating 534 observations. We observed notable differences in phytolith and PhytOC contents across various ecosystems. Bamboo forest ecosystems exhibited the highest vegetation phytolith and PhytOC content, while soil phytolith content was most prominent in bamboo forests and PhytOC content in croplands. Human activities, such as grassland grazing, had a lesser impact on soil PhytOC transport than actions like cutting and tillage in croplands and forests. Our study separated bamboo ecosystems, analyzing their PhytOC content and revealing an underestimation of their carbon sink capacity. Conclusions Notwithstanding our findings, phytoliths’ intricate environmental interactions warrant further exploration, crucial for refining ecosystem management and accurately estimating PhytOC stocks. This deepened understanding lays the foundation for studying phytoliths and the carbon sink dynamics.

An ash heap is defined as a specific object at an archaeological site, usually in the form of a separate hillock containing a layer of finely-dispersed greyish-yellow or ash-coloured soil. The existing assumptions about the formation and functional purpose of ash heaps, as special archaeological objects found near the Bronze Age pastoral settlements, have so far been poorly supported by scientific data. At the ash heap near the Sintashta fortified settlement of Stepnoye, Chelyabinsk Oblast, for the first time, large-scale and comprehensive studies were carried out on the structure of these deposits, their granulometric and geochemical composition, in combination with the analysis of plant macroremains, paleoparasites, microbiomorphic and palynological complexes, indicative bacterial groups, and keratinophilic fungi. Judging by the archaeological materials, it is patently obvious that this was a multifunctional object that developed over many centuries and played different roles at different stages. The results of the conducted analyses showed that the 45 cm thick “ash” horizon in the Stepnoye ash heap contains a significant proportion of a fine sand fraction, and not a silty fraction. An increase in the biophilic elements (predominantly calcium, as well as phosphorus and sulphur), accumulated mainly in the organic matter of faunal origin, was noted in the upper bench of the ash layer. However, the high concentration of phytoliths in the “ashy” deposits indicates that the layer was formed mainly as a result of the accumulation of a large amount of plant organic matter. The absence of charcoal and the scarcity of charred macroremains indicate that the deposited organic material was not burnt but decomposed naturally. The increased content of saprotrophic bacteria in the “ashy” layer also supports the natural decomposition of an organic matter. The composition of the phyto-lithic and pollen spectrum of the “ashy” horizon is not typical for the steppe of the south of Western Siberia, since it is dominated by a group of mixed herbs with elements of a ruderal flora, and not by cereals. All the data supports the hypothesis that the ash heap is the result of regular practice of cleaning of the floor and interiors of the buildings of the fortified settlement of Stepnoye. This is evidenced by the increase in the number of keratinophilic fungi, which decompose wool and hair and therefore accumulate in the occupational layer of the structures. Based on the results of the study, the hypotheses that the Stepnoye ash heap is a place of consolidated ash removal or composting of stable manure were rejected.

The potato is the most important non-cereal food crop, and thus improving potato growth and yield is the focus of agricultural researchers and practitioners worldwide. Several studies reported beneficial effects of silicon (Si) fertilization on potato performance, although plant species from the family Solanaceae are generally considered to be non-Si-accumulating. We used results from two field experiments in the temperate zone to gain insight into silica accumulation in potato plants, as well as corresponding long-term potato yield performance. We found relatively low Si contents in potato leaves and roots (up to 0.08% and 0.3% in the dry mass, respectively) and negligible Si contents in potato tuber skin and tuber flesh for plants grown in soils with different concentrations of plant-available Si (field experiment 1). Moreover, potato yield was not correlated to plant-available Si concentrations in soils in the long term (1965–2015, field experiment 2). Based on our results, we ascribe the beneficial effects of Si fertilization on potato growth and yield performance reported in previous studies mainly to antifungal/osmotic effects of foliar-applied Si fertilizers and to changes in physicochemical soil properties (e.g., enhanced phosphorus availability and water-holding capacity) caused by soil-applied Si fertilizers.

In 2011, in the Aleksandrov quarry (Kursk oblast, Russia), the Ryshkovo pedolithocomplex of the Mikulino (Eemian) Interglacial (MIS-5e) was studied. It includes three to four soil profiles separated by humified pedosediments. The lower soil is an eroded gray forest soil, the two middle soils ones are meadow soils at the bottom of the ravine and a soddy-podzolic soil on the paleoslope, and the upper soil is an underdeveloped soil with elements of forest pedogenesis. Morphological, physicochemical, and microbiomorphic studies of the pedolithocomplexes on the slope and in the bottom of the buried coastal ravine filled with colluvial and alluvial–colluvial sediments made it possible to reconstruct at least three pedogenic and four morpholithogenic stages in MIS-5e, which significantly detailed the event history of the interglacial. In the profile of the Ryshkovo pedolithocomplex, the buried humus horizon of the lower gray forest soil is clearly visible reflecting warmer climatic conditions of the first half of the last completed interglacial in comparison with its second half. Soil formation in trans-accumulative landscapes was repeatedly interrupted by erosion–accumulation processes, which reflects the instability (rhythmicity) of the climatic situation during the Mikulino interglacial and correlates well with detailed records from other geological archives. [ABSTRACT FROM AUTHOR]

Background: Terrestrial ecosystems contain significant carbon storage, vital to the global carbon cycle and climate change. Alterations in human production activities and environmental factors affect the stability of carbon storage in soil. Carbon sequestration in plant phytoliths offers a sustainable method for long-term carbon stabilization. Carbon occluded in phytoliths (PhytOC) is a kind of carbon that can be stable and not decomposed for a long time, so it is crucial to conduct more in-depth research on it. Results: We undertook a meta-analysis on PhytOC across global terrestrial ecosystems, analyzing 60 articles, encapsulating 534 observations. We observed notable differences in phytolith and PhytOC contents across various ecosystems. Bamboo forest ecosystems exhibited the highest vegetation phytolith and PhytOC content, while soil phytolith content was most prominent in bamboo forests and PhytOC content in croplands. Human activities, such as grassland grazing, had a lesser impact on soil PhytOC transport than actions like cutting and tillage in croplands and forests. Our study separated bamboo ecosystems, analyzing their PhytOC content and revealing an underestimation of their carbon sink capacity. Conclusions: Notwithstanding our findings, phytoliths' intricate environmental interactions warrant further exploration, crucial for refining ecosystem management and accurately estimating PhytOC stocks. This deepened understanding lays the foundation for studying phytoliths and the carbon sink dynamics. [ABSTRACT FROM AUTHOR]

The pedocomplex of a mesodepression with birch grove amid steppe has been studied in Novosibirsk oblast, West Siberia. This pedocomplex consists if the modern soddy solod soil (Planosol) overlying the buried organo-accumulative quasigleyic soil (Umbrisol). Several peaks of the maximum accumulation of phytoliths are seen in the profile of the soddy solod soil. The largest number of phytoliths is confined to the eluvial horizon. A significant part is represented by phytoliths of steppe grasses and rod-shaped phytoliths of dicotyledonous plants (forbs, legumes). The buried soil went through the steppe stage of development, as indicated by the predominance of phytoliths of steppe grasses, which was then replaced by the meadow-forest stage with an increase in the portion of forest and meadow grasses. The presence of diatom shells has been recorded throughout the entire thickness of the soil profile, including the buried soil. Their accumulation is associated with seasonal inundation of the mesodepression. [ABSTRACT FROM AUTHOR]

A displaced paleosol layer presumably used for rice farming was found in the section under a rampart in the Southern Ussuriysk fortress. The paleosol was periodically flooded, as evidenced by diatoms from different environments. Bulliform rice phytoliths were found in the paleosol. The obtained range of radiocarbon dates made it possible to reconstruct the course of events. Based on a finding of B-Tm cryptotephra of the Baitoushan Volcano (946/947 CE), the rice field existed in the period between the middle of the tenth century and the construction of the fortress at the beginning of the twelfth century. The soil was transferred from the floodplain where soil profiles were formed in the Middle–Late Holocene under drier conditions than in the Middle Ages. The moisture increase in the Medieval Warm Period was favorable for the agriculture development, including the rice cultivation. The deposits formed during severe floods overlapped both the cultural layers and the paleosol of the rice field. It was likely one of the reasons for the end of rice cultivation along with the climate change towards cooling and a decrease in precipitation. [ABSTRACT FROM AUTHOR]

Phytoliths are an important component in the cycling of silicon (Si) in rice cultivation, yet little is known about their medium to long-term stability. While it is commonly accepted that phytolith solubility in soil decreases with time, the mechanisms that cause this decrease remain unclear. Most studies on phytolith aging to date have been conducted under laboratory conditions and field studies are rare. Here, we present a comprehensive field study of phytolith aging in paddy and non-paddy fields in the Philippines and Vietnam. Phytoliths extracted from rice straw were placed in mesh bags and exposed to ambient soil conditions for up to 550 days. Following exposure, total mass loss and changes in physical (particle size, specific surface area, ζ potential) and chemical (surface chemical composition by acid digestion and X-ray photoelectron spectroscopy) properties as well as dissolution kinetics (56 days in 0.1 M CaCl2 at pH 6.5) were determined. Phytolith dissolution in the field was rapid (up to 30 % mass loss) and three times faster in paddy than in non-paddy soils. Differences in phytolith properties were unexpectedly little between paddy and non-paddy soils. Laboratory and field-derived dissolution rates decreased with exposure time but were one order of magnitude lower in the field. While laboratory dissolution rates were negatively related to surface Al contents this was not observed for field-exposed phytoliths. Our findings suggest that under natural field conditions, phytolith dissolution is overwhelmingly governed by water regime, while the influence of protective surface coatings is only minor. We conclude that reliable estimates of phytolith dissolution can be best obtained in field experiments.

As a plant kingdom and a biodiversity hotspot, Yunnan is a key region for our understanding of modern and past global changes in biodiversity and environment. As proxies of vegetation and climate, phytoliths have become increasingly important in ecological and paleoecological studies. In this study, phytolith analysis was carried out on samples of surface sediments from 70 lakes in western Yunnan, southwest China. These lakes are surrounded by modern vegetation types including broadleaved and coniferous forests, scrubs, grasslands, meadows, and alpine vegetation. The results of this study show that modern lacustrine phytoliths in western Yunnan are dominated by herbaceous phytoliths, among which Poaceae types are the most abundant. The 70 phytolith samples used can be divided into 4 groups, reflecting the major vegetation types from which samples were collected. The principal component analysis (PCA) and redundancy analysis (RDA) of the phytolith and climatic data of the 70 lacustrine phytolith samples showed that temperature and precipitation are the climatic parameters controlling the spatial distribution of phytolith assemblages in western Yunnan. Phytolith–MAT (mean annual temperature) and phytolith–MAP (mean annual precipitation) transfer functions were developed using weighted averaging partial least squares (WA-PLS), and both the MAT and MAP functions showed good performances (MAT: R2 = 0.67, RMSEP = 0.96 °C, MAP: R2 = 0.64, RMSEP = 140.4 mm). Our results also reveal that phytolith analysis is a useful technique offering reliable vegetation interpretation and climate reconstruction; thus, this study provides a basis for the vegetational and climatic interpretation of fossil lacustrine phytolith records in western Yunnan.

Dinosaurs were the dominant megaherbivores during the Cretaceous when angiosperms, the flowering plants, emerged and diversified. How herbivorous dinosaurs responded to the increasing diversity of angiosperms is largely unknown due to the lack of methods that can reconstruct diet directly from body fossils. We applied dental microwear texture analysis (DMTA), an approach that quantifies microtopography of diet‐induced wear marks on tooth surfaces, to ornithopods, the dinosaur clade that includes taxa with the most sophisticated masticatory system. We found that Late Cretaceous ornithopods have significantly rougher dental microwear texture (DMT) compared to pre‐Late Cretaceous ornithopods, and DMT variation increased in hadrosaurids, a derived Late Cretaceous ornithopod clade. These changes indicate a likely temporal dietary shift towards more abrasive foodstuffs within ornithopods, probably due to the increased ingestion of phytoliths (amorphous silica bodies in plants). Phytoliths are a main source of rough DMT in modern herbivores, along with exogenous dust and grit, and were generally more concentrated in Late Cretaceous angiosperms than in other major plant groups. Our results show that DMTA of the occlusal enamel surface can be used to reconstruct the diets of herbivorous dinosaurs, with a resolution superior to conventional methods. [ABSTRACT FROM AUTHOR]

Silicon-based defenses deter insect herbivores in many cultivated and wild grass species. Furthermore, in some of these species, silicon (Si) uptake and defense can be induced by herbivory. Tropical trees also take up Si and leaf Si concentrations vary greatly across and within species. As herbivory is a major driver of seedling mortality and niche differentiation of tropical tree species, understanding antiherbivore defenses is pivotal. Yet, whether silicon is a constitutive and inducible herbivory defense in tropical forest tree species remains unknown. We grew seedlings of eight tropical tree species in a full factorial experiment, including two levels of plant-available soil Si concentrations (-Si/+Si) and a simulated herbivory treatment (-H/+H). The simulated herbivory treatment was a combination of clipping and application of methyl jasmonate. We then carried out multiplechoice feeding trials, separately for each tree species, in which leaves of each treatment combination were offered to a generalist caterpillar (Spodoptera frugiperda). Leaf damage was assessed. Three species showed a significant decrease in leaf damage under high compared to low Si conditions (by up to 72%), consistent with our expectation of Si-based defenses acting in tropical tree species. In one species, leaf damage was increased by increasing soil Si and in four species, no effect of soil Si on leaf damage was observed. Opposite to our expectation of Si uptake and defense being inducible by herbivory damage, simulated herbivory increased leaf damage in two species. Furthermore, simulated herbivory reduced Si concentrations in one species. Our results showed that tropical tree seedlings can be better defended when growing in Si-rich compared to Si-poor soils, and that the effects of Si on plant defense vary strongly across species. Furthermore, Si-based defenses may not be inducible in tropical tree species. Overall, constitutive Si-based defense should be considered part of the vast array of anti-herbivore defenses of tropical tree species. Our finding that Si-based defenses are highly species-specific combined with the fact that herbivory is a major driver of mortality in tropical tree seedling, suggests that variation in soil Si concentrations may have pervasive consequences for regeneration and performance across tropical tree species. [ABSTRACT FROM AUTHOR]

Copyright of Jangwa Pana is the property of Revista Jangwa Pana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The moisture, ash, and silicon content, as well as the phytolith morphotype and concentration in the tissue-cultured, seed-cultured, and grafted seedling leaves of Dendrocalamus brandisii were determined to investigate the differences in silicon uptake and phytolith morphology in the leaves from different rearing methods. The results showed that ash, silicon content, and phytolith concentration were higher in the mature leaves. Tissue-cultured seedlings had a significantly higher moisture content than grafted seedlings. Ash and silicon demonstrated the same order of grafted seedlings > tissue-cultured seedlings > seed-cultured seedlings. The highest phytolith concentration was found in tissue-cultured seedlings. The phytolith morphotypes in D. brandisii seedling leaves raised by different methods were identical and grouped into eight morphotypes. The phytolith assemblage was characterized by a high frequency of bilobate and saddle, accounting for more than 60%, whereas the morphotypes of elongate, blocky, flabellate, and circular phytoliths accounted for the smallest proportion, normally all below 4.5%. The phytolith size demonstrated an increasing trend in the maturing leaves. The sizes of bilobate, saddle, and acute phytoliths expanded the fastest in tissue-cultured seedling leaves, implying rapid growth of the cell in tissue-cultured seedlings. Accordingly, the tissue-cultured seedlings contained more silicon and phytoliths of larger sizes, which could be a better choice of stock supply for establishing large-scale plantations. If the stock of the seed-cultured and grafted seedlings is to be used, silicon fertilizer application is an optimal option to boost seedling growth. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Tropical forests provide global ecosystem services and harbor much of Earth's terrestrial biodiversity, but the mechanisms driving the patterns of biodiversity remain uncertain. Palms are one of the most abundant and most widely used plant groups, particularly in the Neotropics. Our data highlight how both direct and indirect human influence that occurred decades to hundreds of years ago can affect the abundances of palm species in modern tropical forests. Our results highlight that biodiversity is dynamic, and changes through time, and that human activities can affect species composition for centuries in tropical forests. Summary Human activities over the past decades and centuries, including fire, cultivation, and forest opening, may have left ecological legacies that persist in modern tropical forests, particularly among palms. We investigated whether past human activities affected modern palm abundances in a well‐studied plot located in a tropical semievergreen forest of Panama. We analyzed soil cores for charcoal to reconstruct past fire events and phytoliths to reconstruct past vegetation changes. We dated as many charcoal fragments as possible to place a temporal framework on past fire events. Our analysis documented widespread fires that occurred 600–900 years ago across the plot. Oenocarpus mapora increased in abundance as a result of these fires, though other palms did not. A subsequent increase in O. mapora occurred later in the relative absence of fire and was likely due to game hunting during the construction of the Panama Canal. Our results showed that the enrichment of O. mapora was determined by disturbance characteristics (e.g., timing, type, and intensity), but the persistence of increased abundances was likely determined by traits (life history characteristics). These data highlight the complexity of human–environment interactions and how they can persist for centuries in settings with long‐lived trees such as tropical forests. These data highlight the importance of adding a historical context to further understand modern ecological patterns and processes.

The open research movement has gained momentum in the last decade and no academic can ignore the necessity to make research more open, as it improves reliability, sustainability and reusability of data. In this paper, we present the results of a community-based survey concerning the extent to which open practices are known and applied within the phytolith research community. The survey covered aspects of research including the use of open source/access software and the open publication of data and papers. The answers of 81 participants show that ≥50% use open source/access software in their research, 40.7% know or use open repositories (not necessarily DOI-based), and 37% and 60.5% are predisposed to or have published gold open access and green open access/preprints, respectively. Among respondents with publications (n = 71), 49.3% stated that all their publications included full method descriptions and 53.5% expressed that ≥60% of their publications contained raw data. Overall, the results of the survey indicate that, albeit some misunderstandings about open research are still present, phytolith researchers are positive towards open research and intend to adopt its principles and practices.

Morphometric parameters of phytoliths are effectively applied in identifying fossil remains of cultivated grass species. The research of intraspecific trait variation it phytolith size and shape will expand the possibilities of applying morphometric studies. The aim of the study is to assess the degree of intraspecific variability of D. glomerata crenate phytoliths in response to coenotic and climatic factors. 6 habitats have been studied in the south of Western Siberia (Kulunda lowland and Altai mountains). A high amplitude of intraspecific and intrapopulation variability of morphometric characteristics of crenate phytoliths D. glomerata has been revealed. Most of the parameters correlate with the amount of annual precipitation. According to the totality of all 17 morphometric parameters, phytoliths of forest and herbaceous ecosystems differ from each other. Thus, crenate phytolith size and shape are influenced by climatic and coenotic factors.

Phytoliths are opal silica particles formed within plant tissues. Diatoms are aquatic, single-celled photosynthetic algae with silica skeletons. Phytolith and diatom morphotypes vary depending on local environmental and climatic conditions and because their silicate structures preserve well, the study of phytolith and diatom morphotypes can be used to better understand paleoclimatic and paleoenvironmental dynamics and changes. This article presents original data from an 820cm-deep stratigraphy excavated at the Hazen diatomite deposits, a high-elevation desert paleolake in the Fernley District, Northern Nevada, USA. The site has been studied for an assemblage of fossilized threespine stickleback, Gasterosteus doryssus, that reveal adaptive evolution. For this study, a total of 157 samples were extracted at 20 cm intervals covering approximately 24,500 years. After extraction, the samples were mounted on slides and viewed under 400-1000x light microscopy, enabling classification of 14 phytolith and 45 diatom morphotypes. Our data support paleoenvironmental reconstructions of the Hazen Miocene paleolake.

Cross-cultural models are a useful tool to generate hypotheses about the past using ethnographic data, especially when they can be validated against the archaeological record. In this paper, we propose the use of computer modelling techniques to gain insights into the agricultural history in the northern Horn of Africa of two key staple crops, i.e. finger millet (Eleusine coracana) and sorghum (Sorghum bicolor). To date, our understanding of the role of these cereals in the past economies of the region has been hindered by preservation issues and the limited number of systematic archaeobotanical research programs. By building predictive models that combine published ethnographic literature and environmental datasets on a global level, we can generate hypotheses about past agricultural systems in the northern Horn. The ability of the models to predict local agricultural practices in the area was tested against ethnoarchaeological observations in Gulo Makeda (Tigrai, Ethiopia). Archaeobotanical data from an archaeological site in the area, i.e. Ona Adi (ca. 750 BCE – CE 700), was used to assess the model’s predictions when applied to the archaeological record. According to our results, the rainfed agriculture of finger millet and sorghum was already in place during the Aksumite period (ca. 50 BCE – CE 800) around the main centres of settlement articulation. These results are supported by the phytolith assemblage from Ona Adi, which records the presence of water-stressed Chloridoideae and Panicoideae grasses throughout the occupation of the site.

Phytolith research contributes to our understanding of plant-related studies such as plant use in archaeological contexts and past landscapes in palaeoecology. This multi-disciplinarity combined with the specificities of phytoliths themselves (multiplicity, redundancy, naming issues) produces a wide variety of methodologies. Combined with a lack of data sharing and transparency in published studies, it means data are hard to find and understand, and therefore difficult to reuse. This situation is challenging for phytolith researchers to collaborate from the same and different disciplines for improving methodologies and conducting meta-analyses. Implementing The FAIR Data principles (Findable, Accessible, Interoperable and Reusable) would improve transparency and accessibility for greater research data sustainability and reuse. This paper sets out the method used to conduct a FAIR assessment of existing phytolith data. We sampled and assessed 100 articles of phytolith research (2016–2020) in terms of the FAIR principles. The end goal of this project is to use the findings from this dataset to propose FAIR guidance for more sustainable publishing of data and research in phytolith studies. [ABSTRACT FROM AUTHOR]

Phytoliths are silica bodies formed in living plant tissues, and they can be reliable indicators of their parent plants when they demonstrate characteristic phytolith morphology. As shown by the growing case studies around the globe, phytolith morphology is of significant value for identifying and even quantifying domesticated plants. However, researchers also alert that phytoliths morphology can change, for example, in alkaline solutions or heat, causing the loss of characteristic phytoliths and eventually leading to the over- or under-identification of certain phytoliths. Focusing on the degree to which heat can cause changes to the phytolith morphology of millet, the present study carried out a series of controlled heating experiments on six varieties of modern common millet (Panicum miliaceum) growing in different regions of Northern China. Husked grains were heated following the dry ashing method. Specimens prepared from the dry ashing method were examined under an optical microscope to quantify articulated husk phytoliths, which are characteristic millet phytoliths, and to estimate the surface area of millet grains. We estimated that 30.8% to 59.5% of the common millet phytoliths underwent morphological damage in the heating experiments. Considering our previous heating experiments on foxtail millet, we conclude that compared to foxtail millet phytoliths, common millet phytoliths experience morphological damage more quickly when exposed to heat. This observation may explain (at least partially) the contradictory results between macro- and micro-botanical results. It reminds us that common millet can be underrepresented in the micro-botanical evidence (phytoliths). We conclude the paper by discussing the potential archaeological implications of our heating experiments. [ABSTRACT FROM AUTHOR]

The earliest evidence of agriculture in the Horn of Africa dates to the Pre- Aksumite period (ca. 1600 BCE). Domesticated C3 cereals are considered to have been introduced from the Near East, whereas the origin (local or not) and time of domestication of various African C4 species such as sorghum, finger millet, or t'ef remain unknown. In this paper, we present the results of the analysis of microbotanical residues (starch and phytoliths) from grinding stones recovered from two archaeological sites in northeastern Tigrai (Ethiopia), namely Mezber and Ona Adi. Together, both sites cover a time period that encompasses the earliest evidence of agriculture in the region (ca. 1600 BCE) to the fall of the Kingdom of Aksum (ca. 700 CE). Our data indicate that these communities featured complex mixed economies which included the consumption of both domestic and wild plant products since the Initial Pre- Aksumite Phase (ca. 1600 to 900 BCE), including C3 crops and legumes, but also C4 cereals and geophytes. These new data expand the record of C4 plant use in the Horn of Africa to over 1,000 y. It also represents the first evidence for the consumption of starchy products in the region. These results have parallels in the wider northeastern African region where complex food systems have been documented. Altogether, our data represent a significant challenge to our current knowledge of Pre- Aksumite and Aksumite economies, forcing us to rethink the way we define these cultural horizons. [ABSTRACT FROM AUTHOR]

For the majority of higher plants, silicon (Si) is considered a beneficial element because of the various favorable effects of Si accumulation in plants that have been revealed, including the alleviation of metal(loid) toxicity. The accumulation of non-degradable metal(loid)s in the environment strongly increased in the last decades by intensified industrial and agricultural production with negative consequences for the environment and human health. Phytoremediation, i.e., the use of plants to extract and remove elemental pollutants from contaminated soils, has been commonly used for the restoration of metal(loid)-contaminated sites. In our viewpoint article, we briefly summarize the current knowledge of Si-mediated alleviation of metal(loid) toxicity in plants and the potential role of Si in the phytoremediation of soils contaminated with metal(loid)s. In this context, a special focus is on metal(loid) accumulation in (soil) phytoliths, i.e., relatively stable silica structures formed in plants. The accumulation of metal(loid)s in phytoliths might offer a promising pathway for the long-term sequestration of metal(loid)s in soils. As specific phytoliths might also represent an important carbon sink in soils, phytoliths might be a silver bullet in the mitigation of global change. Thus, the time is now to combine Si/phytolith and phytoremediation research. This will help us to merge the positive effects of Si accumulation in plants with the advantages of phytoremediation, which represents an economically feasible and environmentally friendly way to restore metal(loid)-contaminated sites. [ABSTRACT FROM AUTHOR]

Si availability may be altered by bamboo expansion when other trees are replaced by bamboo due to the influence of plant communities on the quantity of phytoliths and Si accumulation. It has been shown that Si availability can modify nutrient-use efficiency (e.g., N and P) of some Si-accumulating plants. However, it is unclear how Si availability might alter N uptake and assimilation between Si-accumulating plants such as bamboo compared to other species, particularly for different chemical forms such as ammonium (NH4+) and nitrate (NO3−). To explore the influences of Si availability on uptake and assimilation rates for different forms of inorganic N between bamboo and other trees, we selected one-year-old seedlings of bamboo (Phyllostachys pubescens) and three other native subtropical species, namely Phoebe bournei, Schima superba, and Cunninghamia lanceolata. We applied three levels of Si and 15N tracers in a pot experiment and then measured the concentrations of Si (total Si, soluble Si, and exchangeable Si), C, N (total N, NH4+-N, and NO3−-N), and N uptake and assimilation rates for both roots and leaves. We found that there were higher inorganic N root uptake and assimilation rates for bamboo compared to other species, likely due to higher biomass accumulation and quicker turnover of fine roots. Moreover, Si supply did not change the uptake preference for N forms or overall uptake and assimilation rates in most species; however, a high concentration of the Si supply slightly increased NO3−-N uptake and assimilation rates in fine roots and leaves of P. bournei, particularly immediately following the addition of Si. These results have implications for predicting the coexistence and competition between bamboo and other trees through the uptake and assimilation of different forms of inorganic N (i.e., high Si-accumulating plants compared to other plants), particularly when Si availability is altered in ecosystems. [ABSTRACT FROM AUTHOR]

Summary: Phytoliths, microscopic deposits of hydrated silica within plants, play a myriad of functional roles in extant tracheophytes – yet their evolutionary origins and the original selective pressures leading to their deposition remain poorly understood. To gain new insights into the ancestral condition of tracheophyte phytolith production and function, phytolith content was intensively assayed in a basal, morphologically conserved tracheophyte: the foxtail clubmoss Lycopodiella alopecuroides.Wet ashing was employed to perform phytolith extractions from every major anatomical region of L. alopecuroides. Phytolith occurrence was recorded, alongside abundance, morphometric information, and morphological descriptions.Phytoliths were recovered exclusively from the microphylls, which were apicodistally silicified into multiphytolith aggregates. Phytolith aggregates were larger and more numerous in anatomical regions engaging in greater evapotranspirational activity.The tissue distribution of L. alopecuroides phytoliths is inconsistent with the expectations of proposed adaptive hypotheses of phytolith evolutionary origin. Instead, it is hypothesized that phytoliths may have arisen incidentally in the L. alopecuroides‐like ancestral plant, polymerizing from intraplant silicon accumulations arising via bulk flow and 'leaky' cellular micronutrient channels. This basal, nonadaptive phytolith formation model would provide the evolutionary 'raw material' for later modification into the useful, adaptative, phytolith deposits seen in later‐diverging plant clades. [ABSTRACT FROM AUTHOR]

Phytolith analysis is a well-established archaeobotanical tool, having provided important insights into pre-Columbian crop cultivation and domestication across Amazonia through the Holocene. Yet, its use as a palaeoecological tool is in its infancy in Amazonia and its effectiveness for reconstructing pre-Columbian land-use beyond archaeological sites (i.e., 'off-site') has so far received little critical attention. This paper examines both new and previously published soil phytolith data from SW Amazonia to assess the robustness of this proxy for reconstructing pre-Columbian land-use. We conducted the study via off-site soil pits radiating 7.5 km beyond a geoglyph in Acre state, Brazil, and 50 km beyond a ring-ditch in northern Bolivia, spanning the expected gradients in historical land-use intensity. We found that the spatio-temporal patterns in palm phytolith data across our soil-pit transects support the hypothesis that pre-Columbian peoples enriched their forests with palms over several millennia, although phytoliths are limited in their ability to capture small-scale crop cultivation and deforestation. Despite these drawbacks, we conclude that off-site soil phytolith analysis can provide novel insights into pre-Columbian land use, provided it is effectively integrated with other land-use (e.g., charcoal) and archaeological data. [ABSTRACT FROM AUTHOR]

Calcium oxalate phytoliths are one of the most prominent types of Ca speciation in the plant kingdom, and they store extensive amounts of carbon in crystalline form. Ca phytoliths were investigated in the root, trunk, and bark of Vitis vinifera Chasselas from a vineyard in Alsace, France. A multi-analytical approach was used, which included SEM coupled with EDX spectroscopy, XRD, XRF, TGA, and 13C-NMR spectroscopy. These techniques revealed that phytoliths are composed of crystalline calcium oxalate monohydrate (whewellite). The whewellite crystals exhibited mostly equant or short-prismatic habits in all of the three studied grapevine parts, but bipyramidal crystals also occurred. Raphide crystals were only observed in the root, where they were abundant. Instead of using wet chemical procedures to extract the mineral components from the organic parts of the biomass, a thermal treatment via calcination was chosen. The suitable temperature of calcination was determined through TGA experiments. The calcination of the biomass samples at 250 °C enhanced the amounts of Ca phytoliths in the residual chars. The thermal treatment, however, affected the appearance of the Ca oxalate crystals by producing surfaces that displayed macroporosity and by creating fractures. For calcination at both 300 °C and 350 °C, Ca oxalate lost a molecule of carbon monoxide to form Ca carbonate, and the modifications of the original crystal surfaces were more pronounced than those observed after thermal treatment at 250 °C. [ABSTRACT FROM AUTHOR]

Triple oxygen isotopes (17 O-excess) of water are useful to trace evaporation at the soil–plant–atmosphere interface. The 17 O-excess of plant silica, i.e., phytoliths, inherited from leaf water, was previously calibrated in growth chambers as a proxy of atmospheric relative humidity (RH). Here, using a model–data approach, we examine the parameters that control the triple oxygen isotope composition of bulk grass leaf water and phytoliths in natura, at the O 3 HP experimental platform located in the French Mediterranean area. A grass plot was equipped to measure for 1 year, all environmental and plant physiological parameters relevant for modeling the isotope composition of the grass leaf water. In particular, the triple oxygen and hydrogen isotope composition of atmospheric water vapor above the grass was measured continuously using a cavity ring-down spectrometer, and the grass leaf temperature was monitored at plot scale using an infrared (IR) radiometer. Grass leaves were collected in different seasons of the year and over a 24 h period in June. Grass leaf water was extracted by cryogenic vacuum distillation and analyzed by isotope ratio mass spectrometry (IRMS). Phytoliths were analyzed by IR–laser fluorination–IRMS after chemical extraction. We showed that the traditional Craig–Gordon steady-state model modified for grass leaves reliably predicts the triple oxygen isotope composition of leaf water during daytime but is sensitive to uncertainties on the leaf-to-air temperature difference. Deviations from isotope steady state at night are well represented in the triple oxygen isotope system and predictable by a non-steady-state model. The 17 O-excess of phytoliths confirms the applicability of the 17 O-excess phyto vs. RH equation established in previous growth chamber experiments. Further, it recorded average daytime RH over the growth period rather than daily RH, related to low transpiration and silicification during the night. This model–data approach highlights the utility of the triple oxygen isotope system to improve the understanding of water exchange at the soil–plant–atmosphere interface. The in natura experiment underlines the applicability of 17 O-excess of phytoliths as a RH proxy. [ABSTRACT FROM AUTHOR]

Background Silicon and aluminium oxides make the bulk of agricultural soils. Plants absorb dissolved silicon as silicic acid into their bodies through their roots. The silicic acid moves with transpiration to target tissues in the plant body, where it polymerizes into biogenic silica. Mostly, the mineral forms on a matrix of cell wall polymers to create a composite material. Historically, silica deposition (silicification) was supposed to occur once water evaporated from the plant surface, leaving behind an increased concentration of silicic acid within plant tissues. However, recent publications indicate that certain cell wall polymers and proteins initiate and control the extent of plant silicification. Scope Here we review recent publications on the polymers that scaffold the formation of biogenic plant silica, and propose a paradigm shift from spontaneous polymerization of silicic acid to dedicated active metabolic processes that control both the location and the extent of the mineralization. Conclusion Protein activity concentrates silicic acid beyond its saturation level. Polymeric structures at the cell wall stabilize the supersaturated silicic acid and allow its flow with the transpiration stream, or bind it and allow its initial condensation. Silica nucleation and further polymerization are enabled on a polymeric scaffold, which is embedded within the mineral. Deposition is terminated once free silicic acid is consumed or the chemical moieties for its binding are saturated. [ABSTRACT FROM AUTHOR]

Phytoliths are intra and extracellular siliceous deposits present in different plant tissues. Si uptake and transport are mediated by Lsi genes and its concentration is associated with forage quality. Our objective was to determine the phytolith content in seven Eragrostis curvula genotypes at the outbreak and re-growth stages to assess its relationship with the forage quality parameters and perform a genome-wide analysis to detect the presence/absence of Lsi genes. The mean values of the phytolith content of dry matter varied between 1.94–2.26% and 2.72–4.71% at the outbreak and re-growth stages, respectively, with highly significant differences among the genotypes and phenological stages. A highly negative correlation was observed in the phytolith content and in vitro dry matter digestibility and crude protein, revealing its importance as a selection parameter in breeding programs. A positive correlation was obtained between the phytolith content and lignin, neutral detergent fiber, and acid detergent fiber. The main morphotypes of the phytoliths included saddle-shaped, bulliform, and acicular cells. Genes Lsi1, Lsi2, Lsi3, and Lsi6, previously reported in silica uptake, were identified and compared with related species, being the gene sequences highly conserved, meaning that its accumulation is probably due to differences in the gene expression or different allelic variants among cultivars. [ABSTRACT FROM AUTHOR]

Halmyris (Murighiol, Tulcea County, Romania) is one of the most important Roman settlements located in the inferior sector of the Danube Delta, in the easternmost part of Scythia province during the Late Antiquity. Halmyris was the most easterly fort of the Danubian border in Roman times and probably served as a supply centre for the imperial fleet; Roman inscriptions inform on the existence of a 'mariner's village' named vicus classicorum. Given that the written information about this settlement is extremely incomplete, the study of animal and plant remains can answer important questions related to economic life (e.g., human use of biological resources) and the relationship between community and environment. This study contributes to understanding the process of Roman domination in the area (e.g., highlighting the improved type of cattle, brought and reproduced here by the Romans), as well as to the knowledge of environmental changes under anthropic pressure (e.g., animal extinction, such as aurochs). In 2014, extensive archaeological research took place in the extramural area of the fort. During research, a total area of 234 sqm was investigated through five trenches west–east oriented and perpendicular to vallum II but not intersecting with it. Phytolith samples were taken from the habitation levels dated to the 5th–6th centuries AD, and faunal remains were collected from four trenches dated to the 4th–6th centuries AD. Phytolith assemblages from the Halmyris site are composed mainly of grass phytoliths. We noticed important amounts of Elongate dendritic forms and a high proportion of silica skeletons. Phytolith analysis resulting from the processing of 12 samples shows that cereals were a relevant part of the subsistence economy of the site, revealing an important signal of cereal processing. Flax fibers, which are the strongest natural fibers, were also identified in samples from Halmyris. The exploited animal resources are varied, including molluscs, fish, birds, and mammals. Most of the skeletal remains belong to the group of mammals. Animal husbandry represented an important occupation; the identified domestic mammals are cattle, sheep, goat, pig, horse, donkey, and dog. The predominant species were cattle and sheep/goat, both by the number of identified remains and by the minimal number of individuals. Hunting had small importance for the settlement under study, red deer and wild boar having the highest proportion of wild mammals. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Tropical forests provide global ecosystem services and harbor much of Earth's terrestrial biodiversity, but the mechanisms driving the patterns of biodiversity remain uncertain. Palms are one of the most abundant and most widely used plant groups, particularly in the Neotropics. Our data highlight how both direct and indirect human influence that occurred decades to hundreds of years ago can affect the abundances of palm species in modern tropical forests. Our results highlight that biodiversity is dynamic, and changes through time, and that human activities can affect species composition for centuries in tropical forests. Summary: Human activities over the past decades and centuries, including fire, cultivation, and forest opening, may have left ecological legacies that persist in modern tropical forests, particularly among palms. We investigated whether past human activities affected modern palm abundances in a well‐studied plot located in a tropical semievergreen forest of Panama.We analyzed soil cores for charcoal to reconstruct past fire events and phytoliths to reconstruct past vegetation changes. We dated as many charcoal fragments as possible to place a temporal framework on past fire events.Our analysis documented widespread fires that occurred 600–900 years ago across the plot. Oenocarpus mapora increased in abundance as a result of these fires, though other palms did not. A subsequent increase in O. mapora occurred later in the relative absence of fire and was likely due to game hunting during the construction of the Panama Canal.Our results showed that the enrichment of O. mapora was determined by disturbance characteristics (e.g., timing, type, and intensity), but the persistence of increased abundances was likely determined by traits (life history characteristics). These data highlight the complexity of human–environment interactions and how they can persist for centuries in settings with long‐lived trees such as tropical forests. These data highlight the importance of adding a historical context to further understand modern ecological patterns and processes. [ABSTRACT FROM AUTHOR]