Soil Microbial Community Based on PLFA Profiles in an Age Sequence of Pomegranate Plantation in the Middle Yellow River Floodplain

Pomegranate (Punica granatum L.) is one of the most important fruit trees in semi-arid land. Previous studies were primarily focused on soil microbial community composition under different pomegranate plantation managements. However, soil microbial community composition under long-term pomegranate plantation has rarely been studied. We investigated pomegranate plantation along with an age sequence (i.e., 1, 3, 5, and 10 years after pomegranate plantation; abbreviated by P1, P3, P5, P10, respectively) in the Middle Yellow River floodplain. Our objectives were to address (1) variations of soil physicochemical properties and (2) changes in soil microbial community composition and the influential factors. The results demonstrated that the soil water content of pomegranate plantation decreased with the increase of pomegranate plantation stand age. Specifically, dissolved organic carbon, ammonium, and available phosphorus increased significantly with stand age both at 0–10- and 10–20-cm soil depths. The P10 had the highest microbial phospholipid fatty acid (PLFA) profiles, including fungi, bacteria, Gram-positive bacteria, Gram-negative bacteria, and arbuscular mycorrhizal fungi. The ratio of fungal PLFAs to bacterial PLFAs increased and the ratio of Gram-positive to Gram-negative bacterial PLFAs decreased along the pomegranate plantation stand age. Dissolved organic carbon was the most important influential factor among the studied variables, which explained 42.2% variation of soil microbial community. In summary, the long-term plantation of pomegranate elevated soil microbial biomass and altered microbial community composition.

Early Neolithic Settlement of the Po Plain (Northern Italy)

Around the mid-19th century, several groups of archaeologists active in northern Italy discovered a few sites characterized by the presence of ‘hut-floors’ or ‘pit-dwellings’ (fondi di capanna), which they attributed to a well-defined period of their Stone Age sequence. Research in the central Po Plain of Lombardy was resumed in the 1970s, allowing one to attribute some of the older discoveries to the Early Neolithic Vhò cultural aspect. The scope of the excavations, which started on one of the Vhò di Piadena sites in 1974, was to interpret the function of the previously discovered features, establish their radiocarbon chronology, and compare the finds with those of the Fiorano culture distributed across the eastern regions of the Po Plain. The main goal of this paper is to provide an international audience with novel information about one of the still poorly known Early Neolithic cultural aspects of northern Italy, namely that of the Vhò.

Biomass and carbon storage in an age-sequence of Acacia mangium plantation forests in Southeastern region, Vietnam

Aim of the study: The major objective of this study was to estimate the biomass increment and carbon (C) storage of the main ecosystem components in an age-sequence of three Acacia mangium plantation stands.Area of study: Chang Riec Historical - Cultural Forest, Southeastern region, Vietnam.Material and methods: In order to assess the biomass of different tree components, 36 trees with diameter at breast height ranging from 13.38 to 22.87 cm were harvested from the different aged stands. Biomasses of understory (shrubs and herbs), and litter were also determined. Carbon storage in the trees and understory biomass, litter, and mineral soil (0-50 cm) were determined by analyzing the C content of each compartment.Main results: The biomass in trees, understory vegetation, litter, and ecosystem increased with stand age. Soil C represented 61.99% of the total, aboveground tree biomass C made up 26.73%, belowground tree biomass C accounted for 7.01%, and litter comprised 2.96%, whereas only a small amount (1.30%) was associated with understory vegetation. The average C content of total tree (47.97%) was higher than those of understory and litter. Soil organic C stock in the top 50 cm depth in 4-, 7- and 11-year-old stands of A. mangium were 86.86, 126.88 and 140.94 Mg. C ha-1 respectively. Soil C concentration decreased continually with increasing soil depth. Total C storage of three planted forests ranged from 131.36 to 255.86 Mg. C ha-1, of which 56.09 - 67.61% of C storage was in the soil and 26.88 - 40.40% in the trees.Research highlights: These results suggest that A. mangium is a promising afforestation tree species with fast growing, high biomass accumulation and high C sequestration potential.Keywords: Acacia mangium plantations; Biomass; Ecosystem carbon storage; Age-sequence; Vietnam.

Experimentation preceding innovation in a MIS5 Pre-Still Bay layer from Diepkloof Rock Shelter (South Africa): emerging technologies and symbols

In southern Africa, key technologies and symbolic behaviors develop as early as the later Middle Stone Age in MIS5. These innovations arise independently in various places, contexts and forms, until their full expression during the Still Bay and the Howiesons Poort. The Middle Stone Age sequence from Diepkloof Rock Shelter, on the West Coast of the region, preserves archaeological proxies that help unravelling the cultural processes at work. This unit yields one of the oldest abstract engraving so far discovered in Africa, in the form of a rhomboid marking on the cortical surface of an ungulate long bone shaft. The comprehensive analysis of the lithic artefacts and ochre pieces found in association with the engraved bone documents the transport of rocks over long distance (>20km), the heat treatment of silcrete, the coexistence of seven lithic reduction strategies (including the production of bladelets and the manufacture of unifacial and bifacial points), the use of adhesives and the processing of ochre. At Diepkloof, the appearance of engraving practices take place in a context that demonstrates a shift in rock procurement and a diversification in lithic reduction strategies, suggesting that these behavioral practices acted as a cultural answer to cope with new environmental and/or socio-economic circumstances. We argue that the innovations later found during the Still Bay and the Howiesons Poort were already in the making during the MIS5 pre-Still Bay, though not all the benefits were yet taken advantage of by the populations.

RADIOCARBON DATING THE 3RD MILLENNIUM BC IN THE CENTRAL BALKANS: A RE-EXAMINATION OF THE EARLY BRONZE AGE SEQUENCE

ABSTRACTLong-standing archaeological narratives suggest that the 3rd millennium cal BC is a key period in Mediterranean and European prehistory, characterized by the development of extensive interaction networks. In the Balkans for instance, the identification of such interactions relies solely upon typological arguments associated with conflicting local terminologies. Through a combination of 25 new radiocarbon (14C) dates and re-examination of the existing documentation, this paper defines the absolute chronology for groups which were previously only broadly framed into the 3rd millennium BC central Balkans (modern-day Serbia and North Macedonia). These absolute dates allow us to establish with greater clarity the chronological relations between different cultural groups that represent the main cultural units of the central Balkans sequence for the 3rd millennium cal BC: Coţofeni-Kostolac, Bubanj-Hum II, Belotić-Bela Crkva, Armenochori, and Bubanj Hum III. When comparing together the chronologies for material culture, funerary treatment of the body, and funerary architecture, there are no easily discernible patterns. We observe instead a complex mix of traits criss-crossing over a wide area encompassing the Pannonian basin, the central Balkans and the Greek peninsula.

High frequency fire drives forest species change: impacts on ecohydrology and ecosystem functioning

<p>Fire as a hydrologic agent has been most frequently examined in terms of erosion and water quality, with studies on the ecohydrology expressed as evapotranspiration/streamflow often focussing on short term perturbation that relaxes with vegetation recovery. Far more dramatic ecohydrologic impacts are possible if repeated fire disturbance leads to species change. Such a scenario occurs in some forests in south-eastern Australia, a region that is among the most flammable in global terms due to the confluence of climatic and stand productivity factors. The most vulnerable of these forests are the “ash” type – mainly Eucalyptus regnans and E. delegatensis. The E.regnans ecology  has evolved with long fire intervals as medium/hot fire kill the trees, which then regenerate as single aged strands. However there have been several large short interval fire events in mountain forests (eg. 1926-1939, 2003-2006-2009-2019) in the past decades that overlap in area. E.regnans, and the other ash-type species, require 15-20 years to develop seed. If re-burnt, the stands cannot naturally regenerate. Frequently acacia and other understorey species colonise the sites, resulting in a dramatic change in forest structure and biomass.</p><p>The implications of this change are significant, with potentially high magnitude changes in ecohydrologic functioning. Further, these areas are the principal water supply catchments the city of Melbourne (> 4 M pop.) and a number of other towns. The impact of high frequency fire that is predicted to increase under climate change therefore has the potential to change ecology, hydrology and essential ecosystem services, in this case, water supply.</p><p>An extensive field experimentation and modelling program set out to (a) investigate the climatic conditions under which these wet forests burn and the sensitivity of these drivers to predicted climate change; and (b) evaluate the eco-hydrologic impact of a species change from E.regnans to acacia species over an age sequence of 80 years.</p><p>Results revealed there is an envelope of dry surface soil and maximum vapour pressure deficit (VPD) within which there is a 50% chance of uncontrolled fire. The most damaging fires occurred when VPD was within the upper 0.01% of values and available surface soil water below 55%. Modelling suggests this conjunction of drivers will increase significantly in the future.</p><p>Stand structure, particularly sapwood area, diverged between the eucalypts and acacias at age 10-20 years, with the difference increasing until acacia death at age 80. This structural parameter scales with ET, with acacias exhibiting a marked decline over time relative to E. regnans. This ET change is principally driven by sapwood area. These differences increase as the stands age, resulting in A.dealbata using around 30% of an E.regnans stand at age 80. This represents a fundamental change in eco-hydrology, and suggests a system pushed to a state of disequilibrium. The stand structural attributes over the age sequence indicate a large change in carbon stocks, resulting in significant alteration of both carbon and water cycles under this disturbance. The results have significant implications for water supply, forest ecosystem services, and system feedbacks of flammability-fire-ecohydrology.</p>

Geochemical Features and Geological Processes Timescale of the Achaean TTG Complexes of the Ingozero Massif and the Pechenga Frame (NE Baltic Shield)

This article provides a geological review and results of the structural, metamorphic, and geochronological studies of the Pechenga frame outcrops located in the NW part of the Central-Kola terrain and the Ingozero massif outcrops situated in the northeastern part of the Belomorian mobile belt of the Kola Region (NW Baltic Shield). As a result of the work, the deformation scales and ages of the geological processes at the Neo-Archaean–Paleoproterozoic stage of the area’s development were compiled, and the reference rocks were dated. The petrochemical and geochemical characteristics of the Ingozero rocks are similar to those of tonalite–trondhjemite–granodiorite (TTG) complexes established on other Archaean shields. The isotope U–Pb dating of individual zircon grains from the biotite gneisses provided the oldest age for magmatic protolith of the Ingozero gneisses, which is 3149 ± 46 Ma. Sm–Nd model ages showed that the gneisses protolite initial melt formed at 3.1–2.8 Ga. Ages of metamorphic processes were determined by using isotope U–Pb dating ID TIMS (isotope dilution thermal ionization mass spectrometry): Biotite gneisses—2697 ± 9 Ma; amphibole–biotite gneisses—2725 ± 2 Ma and 2667 ± 7 Ma; and biotite–amphibole gneisses 2727 ± 5 Ma. Ages of granitoids, which cut the deformed gneisses, are 2615 ± 8 Ma and 2549 ± 31 Ma for plagiogranites and pegmatoid veins in gneisses, respectively. The following age sequence of geological processes was established by using U–Pb zircon dating: 2.8 Ga—The time of the garnet–biotite gneiss metamorphism; 2722 ± 9 Ma—The granodiorite crystallization time; 2636 ± 41 Ma—The aplite emplacement age and 2620 ± 16 Ma—The age of pegmatites origin, which marked final stages of the Archaean evolution; 2587 ± 5 Ma—The age of gabbros emplacement and 2507 ± 7 Ma—The age of gabbros metamorphism; 2522–2503 Ma—The origin time of the iron quartzite interpreted as the age of gabbros and biotite gneiss metamorphism.