An inverse relationship between moisture and grazing intensity in an arid mountain-basin system

Precipitation has been suggested as a crucial influencing factor in the primary productivity in arid and semi-arid regions, yet how moisture fluctuation in an arid mountain-basin system of the north Qinghai–Tibetan Plateau has affected human activities is poorly understood. Here, we reconstruct the variations of grazing intensity in high elevations and regional humidity based on independent and high-resolution records of Sporormiella-type coprophilous fungal spores and pollen grains in the same well-dated sediment core from Lake Tian’E in the western Qilian Mountains over the past 3500 years. We find that stronger grazing activity was associated with low regional effective moisture, and propose that the drier regional climate pushed people and their livestock into the mountainous areas. A notable exception was a reduction of human and grazing activities in arid region with high mountains during 380–580 CE caused by centennial-length dry and cold conditions. In addition, it is also noteworthy that intensified grazing activity occurred during 580–720 CE and after ∼1920 CE, corresponding to a warmer and wetter climate and diverse subsistence strategies with social developments in the lowlands of the Hexi Corridor. Our findings potentially provide a historical reference for understanding how ancient people adapted to the climate change in arid region with high mountains.

Sporopollenin-inspired design and synthesis of robust materials

Sporopollenin is a mechanically robust and chemically inert biopolymer that constitutes the outer protective exine layer of plant spores and pollen grains. Recent investigation of the molecular structure of pine sporopollenin revealed unique monomeric units and inter-unit linkages distinct from other previously known biopolymers, which could be harnessed for new material design. Here, we report the bioinspired synthesis of a series of sporopollenin analogues. This exercise confirms large portions of the previously proposed pine sporopollenin structural model, while the measured chemical, thermal, and mechanical properties of the synthetic sporopollenins indicate favorable attributes of a new kind of robust material. This study explores a new design framework of robust materials inspired by natural sporopollenins, and provides insights and reagents for future elucidation and engineering of sporopollenin biosynthesis in plants.

A Late Triassic vegetation record from the Huangshanjie Formation, Junggar Basin, China: possible evidence for the Carnian Pluvial Episode

The Carnian Pluvial Episode (CPE; ∼234‒232 million years ago) is characterized by an accelerated hydrological cycle, global warming and a period of elevated biotic turnover. Using spores and pollen, we reconstruct vegetation and climate changes through a Carnian‒Norian (Upper Triassic) interval of the Huangshanjie Formation from the Junggar Basin, China. Four palynofloras were identified, representing distinct vegetation communities. Among these palynofloras, we observed a prominent shift from a conifer-dominated climax forest community, with common ginkgophytes and bennettites, to a fern-dominated community, suggestive of an environmental perturbation. We interpret this change as a regional shift in vegetation, likely caused by increased humidity, consistent with the CPE. Our records represent the first indication of a possible CPE-induced vegetation response in the Junggar Basin and highlight how this event likely affected floral communities of inland Laurasia.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5738637

Tritium Incorporation From Tritium Water as an Index of Metabolism

<p>Part A The metabolism of mustard (Sinapis alba) seeds wet at sub-germination temperatures has been studied using tritium incorporation as an index of metabolism. The theory and scope of the method are discussed. The enzymic reactions known in 1964 are surveyed one by one, suggesting which will, or will not, incorporate tritium from THO into specified metabolites, or cannot be confidently predicted either way. Improvements have been made in the chromatography procedure. At 0°, many of the normal germination chemical reactions proceed, but about one tenth as fast as at 24°. Amino-acids are being metabolised within 2 h of wetting the seeds, and malic and citric acids within 4 h. Within 24 h lipids and fructose are undergoing reactions. An unidentified compound “M”, not reported in normal germination, is being metabolised within 48 h. Another aberration from normal is the absence of detectable succinate metabolism. Labelling of the solid residue (insoluble in ethanol and in water) always occurs, shown to be largely non-metabolic. To explain the non-germination of seeds at temperatures near 0°, it is hypothesized that the Krebs cycle is qualitatively altered, perhaps by “wasting away” of glutamate to 4-aminobutyrate instead of its routing into the Krebs cycle as alpha-oxoglutarate. Part B A method has been developed for studying the metabolism of dry seeds, spores and pollen by exposure to THO vapour. Dry Pinus radiata pollen labels many compounds. A few have been identified and are common metabolites. It may be that the metabolism of dry pollen is not qualitatively different from its germination reactions. Dry mustard seeds and spores of the fungus Pithomyces chartarum give, in contrast to pollen, patterns of incorporation very different from those in early germination.</p>

Tritium Incorporation From Tritium Water as an Index of Metabolism

<p>Part A The metabolism of mustard (Sinapis alba) seeds wet at sub-germination temperatures has been studied using tritium incorporation as an index of metabolism. The theory and scope of the method are discussed. The enzymic reactions known in 1964 are surveyed one by one, suggesting which will, or will not, incorporate tritium from THO into specified metabolites, or cannot be confidently predicted either way. Improvements have been made in the chromatography procedure. At 0°, many of the normal germination chemical reactions proceed, but about one tenth as fast as at 24°. Amino-acids are being metabolised within 2 h of wetting the seeds, and malic and citric acids within 4 h. Within 24 h lipids and fructose are undergoing reactions. An unidentified compound “M”, not reported in normal germination, is being metabolised within 48 h. Another aberration from normal is the absence of detectable succinate metabolism. Labelling of the solid residue (insoluble in ethanol and in water) always occurs, shown to be largely non-metabolic. To explain the non-germination of seeds at temperatures near 0°, it is hypothesized that the Krebs cycle is qualitatively altered, perhaps by “wasting away” of glutamate to 4-aminobutyrate instead of its routing into the Krebs cycle as alpha-oxoglutarate. Part B A method has been developed for studying the metabolism of dry seeds, spores and pollen by exposure to THO vapour. Dry Pinus radiata pollen labels many compounds. A few have been identified and are common metabolites. It may be that the metabolism of dry pollen is not qualitatively different from its germination reactions. Dry mustard seeds and spores of the fungus Pithomyces chartarum give, in contrast to pollen, patterns of incorporation very different from those in early germination.</p>

Distribution of Marine Palynomorphs in Surface Sediments, Prydz Bay, Antarctica

<p><b>Prydz Bay Antarctica is an embayment situated at the ocean-ward end of the LambertGlacier/Amery Ice Shelf complex East Antarctica. This study aims to document thepalynological assemblages of 58 surface sediment samples from Prydz Bay, and tocompare these assemblages with ancient palynomorph assemblages recovered fromstrata sampled by drilling projects in and around the bay.</b></p> <p>Since the early Oligocene, terrestrial and marine sediments from the Lambert Grabenand the inner shelf areas in Prydz Bay have been the target of significant glacialerosion. Repeated ice shelf advances towards the edge of the continental shelfredistributed these sediments, reworking them into the outer shelf and Prydz ChannelFan. These areas consist mostly of reworked sediments, and grain size analysisshows that finer sediments are found in the deeper parts of the inner shelf and thedeepest areas on the Prydz Channel Fan. Circulation within Prydz Bay is dominatedby a clockwise rotating gyre which, together with coastal currents and ice bergploughing modifies the sediments of the bay, resulting in the winnowing out of thefiner component of the sediment.</p> <p>Glacial erosion and reworking of sediments has created four differing environments(Prydz Channel Fan, North Shelf, Mid Shelf and Coastal areas) in Prydz Bay whichis reflected in the palynomorph distribution. Assemblages consist of Holocenepalynomorphs recovered mostly from the Mid Shelf and Coastal areas and reworkedpalynomorphs recovered mostly from the North Shelf and Prydz Channel Fan. Thepercentage of gravel to marine palynomorph and pollen counts show a relationshipwhich may reflect a similar source from glacially derived debris but the percentageof mud to marine palynomorph and pollen counts has no relationship.</p> <p>Reworked palynomorphs consist of Permian to Eocene spores and pollen and Eocenedinocysts which are part of the Transantarctic Flora. Holocene components are avaried assemblage of acritarchs, dinoflagellate cysts (dinocysts), prasinophyte algae,red algae and large numbers of Zooplankton sp. and foraminifera linings. In situdinocysts are dominated by the heterotroph form Selenopemphix antarctica and none of the Holocene dinocyst species found in Prydz Bay have been recorded in theArctic. In contrast acritarchs, prasinophytes and red algae are all found in the Arcticand reflect a low salinity and glacial meltwater environment. Comparison withmodern surface samples from the Arctic and Southern Ocean show there is a strongcorrelation to reduction in the autotroph:heterotroph dinocyst ratio with increasinglatitude.</p> <p>Todays assemblage of marine palynomorphs are more complex than those recordedin ancient assemblages and there is a lower level of reworked material. Acritarchs(Leiosphaeridia spp. Sigmopollis sp.) and prasinophytes (Cymatiosphaera spp.</p> <p>Pterospermella spp. Tasmanites spp.) are recorded in the ancient record in Antarcticaas well as surface sediments in Prydz Bay, but there are very low numbers ofLeiosphaeridia spp. and Sigmopollis spp. present today in comparison to the ancientrecord. Dinocysts in situ and recovered in Prydz Bay are endemic to the Antarcticbut have not been recorded in the ancient record.</p>

Distribution of Marine Palynomorphs in Surface Sediments, Prydz Bay, Antarctica

<p><b>Prydz Bay Antarctica is an embayment situated at the ocean-ward end of the LambertGlacier/Amery Ice Shelf complex East Antarctica. This study aims to document thepalynological assemblages of 58 surface sediment samples from Prydz Bay, and tocompare these assemblages with ancient palynomorph assemblages recovered fromstrata sampled by drilling projects in and around the bay.</b></p> <p>Since the early Oligocene, terrestrial and marine sediments from the Lambert Grabenand the inner shelf areas in Prydz Bay have been the target of significant glacialerosion. Repeated ice shelf advances towards the edge of the continental shelfredistributed these sediments, reworking them into the outer shelf and Prydz ChannelFan. These areas consist mostly of reworked sediments, and grain size analysisshows that finer sediments are found in the deeper parts of the inner shelf and thedeepest areas on the Prydz Channel Fan. Circulation within Prydz Bay is dominatedby a clockwise rotating gyre which, together with coastal currents and ice bergploughing modifies the sediments of the bay, resulting in the winnowing out of thefiner component of the sediment.</p> <p>Glacial erosion and reworking of sediments has created four differing environments(Prydz Channel Fan, North Shelf, Mid Shelf and Coastal areas) in Prydz Bay whichis reflected in the palynomorph distribution. Assemblages consist of Holocenepalynomorphs recovered mostly from the Mid Shelf and Coastal areas and reworkedpalynomorphs recovered mostly from the North Shelf and Prydz Channel Fan. Thepercentage of gravel to marine palynomorph and pollen counts show a relationshipwhich may reflect a similar source from glacially derived debris but the percentageof mud to marine palynomorph and pollen counts has no relationship.</p> <p>Reworked palynomorphs consist of Permian to Eocene spores and pollen and Eocenedinocysts which are part of the Transantarctic Flora. Holocene components are avaried assemblage of acritarchs, dinoflagellate cysts (dinocysts), prasinophyte algae,red algae and large numbers of Zooplankton sp. and foraminifera linings. In situdinocysts are dominated by the heterotroph form Selenopemphix antarctica and none of the Holocene dinocyst species found in Prydz Bay have been recorded in theArctic. In contrast acritarchs, prasinophytes and red algae are all found in the Arcticand reflect a low salinity and glacial meltwater environment. Comparison withmodern surface samples from the Arctic and Southern Ocean show there is a strongcorrelation to reduction in the autotroph:heterotroph dinocyst ratio with increasinglatitude.</p> <p>Todays assemblage of marine palynomorphs are more complex than those recordedin ancient assemblages and there is a lower level of reworked material. Acritarchs(Leiosphaeridia spp. Sigmopollis sp.) and prasinophytes (Cymatiosphaera spp.</p> <p>Pterospermella spp. Tasmanites spp.) are recorded in the ancient record in Antarcticaas well as surface sediments in Prydz Bay, but there are very low numbers ofLeiosphaeridia spp. and Sigmopollis spp. present today in comparison to the ancientrecord. Dinocysts in situ and recovered in Prydz Bay are endemic to the Antarcticbut have not been recorded in the ancient record.</p>

New Oligocene to Early Miocene Palynomorph Zonation of GZ-1 Well, Onshore Western Niger Delta, Nigeria

Palynological studies was carried out on GZ-1 well from the onshore western Niger Delta in order to recognized a new detected developments in the varieties of key pollen and spore taxa that have shorter and more distinguished interval zones to advance stratigraphical delineation. Palynological analysis was carried out using the conventional maceration technique for recovering acid insoluble organic-walled microfossils from sediments. The result yielded rich and diversified palynomorphs. The main assemblage were dominated by angiosperm pollen grain (dominant global flora from Late Cretaceous onwards) followed by pteridophytes/bryophyte spore. Dinoflagellate cysts, on the contrast, were less diverse while the Gymnosperm pollen were scarce. The identified palynomorph were used to establish seven main zones - AF1 Psilatricolporites crassus zone, AF2 Verrucatosporites usmensis zone, AF3 Triplochiton scleroxylon zone, AF4 Crassoretitriletes vanraadshooveni zone, AF5 Acrostichum aureum zone, AF6 Gemmatriporites ogwashiensis zone and AF7 Retitricolporites irregularis zone in this study. Established on quantitative events, the zones were also divided into seven subzones with some having finer subdivisions into (a) and (b) ranging in age from Early Oligocene to Early Miocene. Previous unfiled event trends of important indicator taxa of spores and pollen accredited to Pelliceria, Caesalapinoideae, Stenochlaena palustris, Polypodiaceae, Lygodium microphyllum, Polypodiaceae, Adiantaceae and Amanoa (Euphorbiaceae) have assisted improvement of formerly used palynological zonation schemes in the Niger Delta. It is anticipated that this quantitative zonation scheme erected, will help with imminent palynostratigraphical studies in the onshore Niger delta area.

Construction features of the dwelling at the early Neolithic site Baibek in the North Caspian Sea Region

This work studies construction features of the dwelling discovered at the Neolithic site Baibek. Detailed recorded data made it possible to determine its dimensions, shape and structural components. The layer by layer analysis gave grounds to reconstruct its origin and development. Pottery and stone tools, as well as other materials of the cultural layer found in the dwelling pit are similar to the materials of the Kairshak type of the Neolithic in the Northern Caspian Sea Region. A series of radiocarbon dates establishes the chronological interval of the dwelling functioning: the first quarter of the VI millennium BC. The results of spores and pollen analysis indicate the paleogeographic background at that time. The definition of faunal remains indicates the leading hunting species: onager, red deer, corsac, saiga; fish (sterlet, perch, pike, common carp, pike perch) were caught both in open and in closed reservoirs. Judging by the analysis of the crust on the inner side of the vessels, signs of animal and plant food preparation have been established. The studied dwelling complements the characteristics of the Neolithic culture of the Kairshak type bearers and possibly marks the beginning of the transition of the population to a certain sedentary life. In addition, the information obtained gives reasons to speak about the appearance of dwellings in the region of interest starting from the early Neolithic.

Impact of mid Eocene greenhouse warming on America’s southernmost floras

A major climate shift took place about 40 Myr ago—the Middle Eocene Climatic Optimum or MECO—triggered by a significant rise of atmospheric CO2 concentrations. The biotic response to this MECO is well documented in the marine realm, but poorly explored in adjacent landmasses. Here, we quantify the response of the floras from America’s southernmost latitudes based on the analysis of terrestrially derived spores and pollen grains from the mid-late Eocene (~46–34 Myr) of southern Patagonia. Robust nonparametric estimators indicate that floras in southern Patagonia were in average ~40% more diverse during the MECO than pre-MECO and post-MECO intervals. The high atmospheric CO2 and increasing temperatures may have favored the combination of neotropical migrants with Gondwanan species, explaining in part the high diversity that we observed during the MECO. Our reconstructed biota reflects a greenhouse world and offers a climatic and ecological deep time scenario of an ice-free sub-Antarctic realm.