Organic Debris Research Articles

Seasonal Trophic Dynamics of Sinking Particles in the Ulleung Basin of the East Sea (Japan Sea): An Approach Employing Nitrogen Isotopes of Amino Acids

To identify the sources of organic matter, we examined nitrogen isotopes of the amino acids of sinking particles collected from July 2017 to March 2018 at 1000 and 2250 m in the Ulleung Basin, the southwestern part of the East Sea (Japan Sea). Compared to the 1000 m samples, sinking particles at 2250 m were found to contain more resuspended sediment and underwent more microbial degradation. The signature of microbial degradation was significant in winter-early spring than in late summer-autumn. The source amino acids of sinking particles showed a substantial decline in the isotopic ratio during winter at both depths, suggesting changes in the nitrogen source for primary production. The average trophic positions (TPs) of sinking particles were larger at 1000 m (2.3 ± 0.3) than at 2250 m (1.9 ± 0.2), indicating that organic matter was mainly derived from fecal pellet and other organic debris from heterotrophs. In winter, the average TPs of sinking particles at 1000 m decreased below 2.0, which probably reflects the minimum zooplankton grazing in the euphotic layer. Sinking particles near the seafloor (2250 m) showed lower TP values than those at 1000 m, demonstrating that sinking particles at 2250 m are affected by lateral transport, particularly during winter. Our results show that the nitrogen isotope ratios of amino acids in sinking particles reflect the seasonal dynamics of both nitrogen sources and trophic structure in the water column.

Synthesis, characterization, and function of Au nanoparticles within TS-1 zeotypes as catalysts for alkene epoxidation using O2/H2O reactants

A synthetic procedure was developed for the encapsulation of Au nanoparticles within titanium silicalite-1 (TS-1). Encapsulation was achieved via crystallization of TS-1 synthesis gels containing ligated Au cations, resulting in TS-1 framework assembly around Au coordination complexes. X-Ray diffraction and micropore volume measurements indicated that TS-1 could be crystallized at much milder conditions than previously reported, allowing the assembly of TS-1 without concomitant decomposition of added Au complexes. Infrared (IR) and UV–vis spectroscopy showed that Ti was incorporated into the frameworks as tetrahedrally coordinated atoms. Changes to established crystallization procedures for TS-1 included lower temperature (393 K vs. 448 K) compensated by longer time (120 vs 48 h) and the use of seed crystals. Post-synthetic thermal treatments led to the formation of small Au nanoparticles (2.8–3.8 nm) visible in electron micrographs and free of organic debris, as indicated by IR spectroscopy. Such nanoparticles are protected from bulky titrants, and thus reside within TS-1 crystallites (>96% encapsulation). The Au particles were active for propene epoxidation with H2O/O2 even without promotion by alkali cations (e.g., Cs+), though alkali doping led to enhanced rates. These Au/TS-1 systems were less active for epoxidation than Au/TS-1 prepared by deposition–precipitation, likely because the latter contains a disproportionately active minority population of exceedingly small (<1 nm) Au clusters.

Seasonal and Longitudinal Variations in Suspended Load Connectivity Between River Channels and Their Margins

AbstractInput of organic matter into stream channels is the primary energy source for headwater ecosystems and ultimately carbon to the oceans and hence is an important component of the global carbon cycle. Here, we quantify organic‐rich fine sediment mobilization, transport, and storage in a Strahler fourth‐order stream during individual intermediate‐sized storm events. By combining measurements of fallout radionuclides (FRNs) 7Be and 210Pb and stable water isotopes with a conceptual model of suspended load trapping by channel margins, we find that the channel bed was consistently a source of suspended load to the channel margins. Relative to storage on the channel margins, suspended load export increased through the spring and summer, perhaps related to the in‐channel decomposition of organic debris as indicated by its FRN exposure age and changing bulk δ13C composition. Trapping of suspended load by riparian margins limits sediment transport distances, which, given sufficient discharge to fully suspend the load, is nearly independent of stream discharge for sub‐bankfull discharges. Limited data indicate that the fractional size of the channel margins where trapping occurs decreases with increasing watershed area. Increasing transport length and decreasing fractional margin area with increasing watershed area results in a systematic downstream decoupling of the channel from local terrestrial organic matter exchange. These findings provide a framework for understanding suspended load dynamics in formerly glaciated regions where sediment production and fluxes are generally low and thus the annual input of organic debris is a major component of suspended load budget.

The 28 November 2020 Landslide, Tsunami, and Outburst Flood – A Hazard Cascade Associated With Rapid Deglaciation at Elliot Creek, British Columbia, Canada

AbstractWe describe and model the evolution of a recent landslide, tsunami, outburst flood, and sediment plume in the southern Coast Mountains, British Columbia, Canada. On November 28, 2020, about 18 million m3 of rock descended 1,000 m from a steep valley wall and traveled across the toe of a glacier before entering a 0.6 km2 glacier lake and producing &gt;100‐m high run‐up. Water overtopped the lake outlet and scoured a 10‐km long channel before depositing debris on a 2‐km2 fan below the lake outlet. Floodwater, organic debris, and fine sediment entered a fjord where it produced a 60+km long sediment plume and altered turbidity, water temperature, and water chemistry for weeks. The outburst flood destroyed forest and salmon spawning habitat. Physically based models of the landslide, tsunami, and flood provide real‐time simulations of the event and can improve understanding of similar hazard cascades and the risk they pose.

Linking endogenous decay and sludge bulking in the microbial community to membrane fouling at sub-critical flux

This study examined membrane fouling and associated microbial taxa in a membrane bioreactor operating at a sub-critical flux condition using next-generation amplicon sequencing. The membrane was operated at a sub-critical flux, thus, fouling was not observed until endogenous decay. The observed fouling could be attributed to endogenous decay which was driven by nutrient deficiency at high sludge age and low food-to-microorganisms ratio (decreasing from 0.15 to 0.09 gBOD/gMLVSS.d). Endogenous decay resulted in a sharp decrease of the number of species and evenness between different species (49.7 and 58.9% compared to the inoculum, respectively). The release of dissolved organic matters and cell debris from endogenous decay as well as the excessive growth of filamentous bacteria, e.g. Thiotrichales were the main contributors to membrane fouling. The relative abundance of Thiotrichales significantly correlated with TMP (Pearson R = 0.996, p-value <0.001), indicating this order's contribution to membrane fouling. Other dominant orders in the mixed liquor after endogenous decay such as Rhizobiales, Burkholderiales, Rhodospirillales and Myxococcales, Flavobacteriales can produce extracellular polymeric substances and aggravating membrane fouling. Fouling layers possess highly similar microbial composition with the mixed liquor, with some filamentous microbial orders, e.g. Corynebacteriales and Oligoflexales showing increased relative abundance by 6.83 and 5.64 folds, respectively.

Pollen and Spores Recovery in Tunga Buzu Carbonaceous Shale Type Section Member: Significance in Sequence Stratigraphy, Age Dating and Paleoenvironment Deduction of the Early Miocene Gwandu Formation, Sokoto Basin, Northwestern Nigeria

Feld samples were collected from an outcrop at Tunga Buzu with the intention of comparing field relationship between the claystone member and the underlying carbonaceous shale Type Section for palynological study. The study was carried out in order to determine the geologic age relationship of the facies sequence, sequence stratigraphy and paleoenvironment of deposition of the sediments. Lithological description of the beds follows notation of colour, facies composition, texture, fossil content, structure and post depositional diagenetic effects. Laboratory preparation of palynological slides involved decarbonisation, sample digestion using hydrofluoric acid, sieving with 10µm mesh, bleaching of organic debris with nitric acid, maceral separation with zinc bromide, rinsing of separated maceral with ethanol and final mounting of the organomaceral on the slides for microscopic analysis.The carbonaceous shale is light grey in colour, fissile, carbonaceous, slightly bioturbated and ferruginized. Pollen, spores, dinoflagellates and algae were recovered from samples N1-N4. The samples N1-N3 are claystone samples characterised by relatively low assemblage assemblage of miospores with downhole increase in dinoflagellate cysts. The carbonaceous shale (sample N4) is relatively rich in palynomorphs with corresponding high palynomorph population and diversity compared with the claystone facies. Both the claystone and carbonaceous shale contain marker fossils such as Striamonocolpites sp., Retibrevitricolporites obodoensis, Verrutricolporites sp., Praedapollis sp., Belskipollis elegans and Peregnipollis nigericus; indicative of Early Miocene age. The litho-sequence of claystone and carbonaceous shale indicated alternation of continental and marginal marine deposits characterised by paucity and preponderance of peridinacean dinocysts. This suggests eustatic change in sea level of continental Lowstand Systems Tract (LST) and marginal marine Transgressive Systems Tract (TST) deposits respectively. The Tunga Buzu Carbonaceous Shale Type Section constitutes a member of the Early Miocene Gwandu Formation of the Sokoto Basin, Nigeria.

Vegetal Undercurrents-Obscured Riverine Dynamics of Plant Debris.

Much attention has been focused on fine‐grained sediments carried as suspended load in rivers due to their potential to transport, disperse, and preserve organic carbon (OC), while the transfer and fate of OC associated with coarser‐grained sediments in fluvial systems have been less extensively studied. Here, sedimentological, geochemical, and biomolecular characteristics of sediments from river depth profiles reveal distinct hydrodynamic behavior for different pools of OC within the Mackenzie River system. Higher radiocarbon (14C) contents, low N/OC ratios, and elevated plant‐derived biomarker loadings suggest a systematic transport of submerged vascular plant debris above the active riverbed in large channels both upstream of and within the delta. Subzero temperatures hinder OC degradation promoting the accumulation and waterlogging of plant detritus within the watershed. Once entrained into a channel, sustained flow strength and buoyancy prevent plant debris from settling and keep it suspended in the water column above the riverbed. Helical flow motions within meandering river segments concentrate lithogenic and organic debris near the inner river bends forming a sediment‐laden plume. Moving offshore, we observe a lack of discrete, particulate OC in continental shelf sediments, suggesting preferential trapping of coarse debris within deltaic and neritic environments. The delivery of waterlogged plant detritus transport and high sediment loads during the spring flood may reduce oxygen exposure times and microbial decomposition, leading to enhanced sequestration of biospheric OC. Undercurrents enriched in coarse, relatively fresh plant fragments appear to be reoccurring features, highlighting a poorly understood yet significant mechanism operating within the terrestrial carbon cycle.

Factors Determining Suitable Landfill Sites for Energy Generation from Municipal Solid Waste: A Case Study of Jabodetabek Area, Indonesia.

Most municipal solid waste (MSW) is found to be dominated by organic debris, which has excellent potential as an energy source. However, the main problems of this material are poor planning, urban expansion, and lack of management skills. All these problems are presently being encountered by the regional governments of Jakarta, Bogor, Depok, Tangerang, and Bekasi city (known locally as Jabodetabek), Indonesia. In the MSW management system, a vital planning protocol is reportedly assessing suitable landfill sites for energy generation, although this selection process is still a complex task that should consider various factors, such as environmental, social and safety, and economic variables. Therefore, this study aims to examine various factors in determining a suitable location for landfills. It also aims to identify the various factors required for MSW energy generation. Based on this study, a multicriteria decision analysis (MCDA) approach was applied to weigh the factors determining the appropriate location. This approach is popular in decision-making due to evaluating the complexity of multidimensionality factors. The results showed that 3 factors and 14 subfactors were formulated and structured in the MCDA hierarchy, with their information obtained to create pairwise comparisons by 10 involved experts. In this study, the MCDA output was the weight value associated with a systematic priority level, indicating that the environment was the highest factor in determining a suitable landfill site for energy generation. In addition, the weight factors were used for overlay analysis, in determining the suitable site for future energy generation studies.

Submerged hollow-fiber-ultrafiltration for harvesting microalgae used for bioremediation of a secondary wastewater

Microalgae were employed to remove nutrients from a pre-treated wastewater (so-called anaerobic membrane bioreactor effluent, AnMBR effluent) over a 24-day semi-continuous cultivation with varied N:P ratios. NH4+-N reduction percentage ranged from 68 to 94% with average removal rates varying from 8 to 26mgN·L-1d-1 at different stages. Total phosphorus was almost completely removed shortly after inoculation. Biomass productivity ranged from 0.13 to 0.19 g·L-1d-1 during the cultivation. A submerged membrane-based filtration device was used to investigate the formation of biofouling, which occurred on the membrane surface during filtration and is considered as a bottleneck in downstream processing. Results indicated most severe fouling was caused by original microalgal suspension, compared to its individual fractions (cellular resuspensions, supernatant and AnMBR effluent). Irreversible fouling mainly occurred at the beginning of the filtration process; extracellular organic matter and cellular debris in the supernatant changed the fouling behavior more significantly than morphological properties of the algae cells; AnMBR effluent also led to a nonnegligible fouling effect. To minimize biofouling, TOC content in wastewater should be carefully controlled before and during cultivation. The current membrane can be proposed for long-term filtration, as irreversible fouling only occurred at the beginning and reversible fouling can be controlled effectively by backflushing and aeration. The biomass, characterized by relatively high protein and carbohydrate but low heavy metal content, indicated its potential as feeds and feedstock for bioenergy production. The present work provides novel insights into the coupling of wastewater treatment and fouling control, which has been rarely studied.

Hygienic monitoring in long-term care facilities using ATP, crAssphage, and human noroviruses to direct environmental surface cleaning

BackgroundNorovirus and C. difficile are associated with diarrheal illnesses and deaths in long-term care (LTC) facilities and can be transmitted by contaminated environmental surfaces. Hygienic monitoring tools such as adenosine triphosphate (ATP) bioluminescence and indicators of fecal contamination can help to identify LTC facility surfaces with cleaning deficiencies. MethodsHigh-touch surfaces in 11 LTC facilities were swabbed and tested for contamination by norovirus, a fecal indicator virus, crAssphage, and ATP which detects organic debris. High levels of contamination were defined as log ATP relative light unit values or crAssphage log genomic copy values in the 75th percentile of values obtained from each facility. ResultsOver 90% of surfaces tested positive for crAssphage or gave failing ATP scores. Norovirus contamination was not detected. Handrails, equipment controls, and patient beds were 4 times more likely than other surfaces or locations to have high levels of crAssphage. Patient bed handrails and tables and chairs in patient lounges had high levels of both ATP and crAssphage. ConclusionsSurfaces with high levels of ATP and crAssphage were identified. Quantifying levels of contamination longitudinally and before and after cleaning might enhance infection prevention and control procedures for reducing diarrheal illnesses in LTC facilities.

Impact of Pheidole fallax (Hymenoptera: Formicidae) as an Ecosystem Engineer in Rehabilitated Coal Mine Areas

Pheidole fallax is one the most abundant ants in sites where coal mines have undergone rehabilitation and in forests without mine intervention. The impact that this species may have as an ecosystem engineer needs to be assessed. We aimed to test whether P. fallax nests have an effect on soil chemical properties, to characterize the organic debris found in the refuse piles, and to describe nest architecture as proxy of the bioturbation effect. The study was carried out in a coal mine in Colombia, in sites with 16 and 20 years of rehabilitation. Samples were taken from inside the nests, from the external refuse pile, and from a control treatment one meter away from the nest. The three sample types were subjected to chemical analysis and near-infrared spectra (NIRS). The biomass of items from the 20-year site was significantly greater, and P. fallax use food resources of different trophic levels, with arthropods and seeds being the main items in their diet. The NIRS analysis enabled us to distinguish the origin of the sample: refuse pile, interior of nest, or control soil. No statistical differences were found between the soil of the nests and control soil. High contents of organic matter and other parameters contributed to the soil nutrient pool through accumulation of organic debris in the refuse piles. Nest molds presented an asymmetric architecture, with mean volume ranging from 30 to 105.7 cm3 and an average of 11.8 chambers per nest. The construction and maintenance of nests may play an important role in the reestablishment of ecological and hydrological processes, such as bioturbation and water infiltration, respectively.

Extracellular polymeric substance induces biogenesis of vivianite under inorganic phosphate-free conditions

Vivianite is often found in reducing environments rich in iron and phosphorus from organic debris degradation or phosphorus mineral dissolution. The formation of vivianite is essential to the geochemical cycling of phosphorus and iron elements in natural environments. In this study, extracellular polymeric substances (EPS) were selected as the source of phosphorus. Microcosm experiments were conducted to test the evolution of mineralogy during the reduction of polyferric sulfate flocs (PFS) by Shewanella oneidensis MR-1 (S. oneidensis MR-1) at EPS concentrations of 0, 0.03, and 0.3 g/L. Vivianite was found to be the secondary mineral in EPS treatment when there was no phosphate in the media. The EPS DNA served as the phosphorus source and DNA-supplied phosphate could induce the formation of vivianite. EPS impedes PFS aggregation, contains redox proteins and stores electron shuttle, and thus greatly promotes the formation of minerals and enhances the reduction of Fe(III). At EPS concentration of 0, 0.03, and 0.3 g/L, the produced HCl-extractable Fe(II) was 107.9, 111.0, and 115.2 mg/L, respectively. However, when the microcosms remained unstirred, vivianite can be formed without the addition of EPS. In unstirred systems, the EPS secreted by S. oneidensis MR-1 could agglomerate at some areas, resulting in the formation of vivianite in the proximity of microbial cells. It was found that vivianite can be generated biogenetically by S. oneidensis MR-1 strain and EPS may play a key role in iron reduction and concentrating phosphorus in the oligotrophic ecosystems where quiescent conditions prevail.

Diversity and abundance of some insect fauna in Bhawal and Madhupur Sal forests of Bangladesh

The abundance and diversity of insect fauna were studied from two deciduous sal forests of Bhawal and Madhupur located at central part of Bangladesh. A total of 544 individuals of insects of 61 species belonging to 54 genera, 33 families and 11 orders have been identified with Hymenoptera (31%) as the dominant order in species richness followed by Coleoptera (13%), Orthoptera (11%), Diptera (10%), Hemiptera (8%), Lepidoptera (8%), Odonata (8%), Homoptera (3%), Isoptera (3%), Neuroptera (3%) and Dictyoptera (2%). Bhawal scores higher Shannon-Weaver diversity index (Hʹ=3.725) compared to Madhupur (Hʹ=3.340). The Bhawal Sal Forest with the collected 341 (63%) insects and identified 53 (59%) species belonging to 10 orders was found more diverse in species richness than the Madhupur Sal Forest with 37(41%) species belonging to 11 orders identified from the collected 203 (37%) insect samples. Insects of the order Neuroptera were not recorded from Bhawal. Off the 61 species, 29(48%) species were common in both the forests, 24(39%) species were exclusive to Bhawal and eight (13%) species were exclusive to the Madhupur Sal Forest. Apis cerana of Hymenoptera was identified as the dominant species having 9% of the identified samples followed by dipteran species Musca domestica with 6% of the samples. Among the insect species 30 (49%) species were found playing beneficial role as biological control agents, predators, pollinators, honey producers and also organic debris recycler. On the other hand, 31(51%) species were found to be harmful causing damage to forest vegetation as well as human and wildlife at variable degrees. J. Biodivers. Conserv. Bioresour. Manag. 2021, 7(1): 11-24

Larval ecology of Aedes mosquitoes and risk of arbovirus transmission at the port of San-pedro (Côte d’ivoire)

Mosquitoes of the genera Aedes are vectors of arboviruses. Through trade at the entry points, they spread to new areas where they can cause arbovirus epidemics. The lack of vaccine and treatment for most arboviruses makes vector control the only means of prevention. This study aimed to determine the level of infestation of Aedes mosquitoes and the risk of arbovirus by describing their larval ecology. All water containers found in activity and residential areas of the port of San Pedro were inspected for immature mosquitoes once a month from March to July 2018. Out of 227 identified potential breeding sites, 102 (44.93%) contained Aedes larvae. Abandoned containers constituted 53.92% of the sites colonized by Aedes and represented 73.43% of productivity. Sites associated with turbid water, organic debris, and those with vegetation around were more preferred by Aedes for oviposition. The house (20.80%), Breteau (27.20%) and Container (44.93%) Indices indicated a high level of entomological risk on the WHO density scale for both the activity area and the residential area. This study shows that Aedes uses more anthropogenic sites preferably abandoned containers and that its presence constitutes a risk of transmission of arboviruses in the port of San Pedro.

A checklist of wild mushrooms in three urban parks in Kolkata, India

In addition to having nutritional benefits, macrofungi have also been used medicinally. As a result, it is crucial to both the economy and the environment. This study was conducted from May 2020 to June 2022 in three urban parks in Kolkata, a major city in the Indian state of West Bengal. Twenty-eight fungal specimens were identified in this investigation, out of which 99% of the taxa are Basidiomycota, while only 1% is Ascomycota. The taxa belonged to 18 families and eight orders. Sixteen species were discovered in wood, notably over the dry stems of bamboo, and ten were discovered in soil, particularly in grasslands, over rotten dry leaves, and one over organic debris. Eleven of the specimens are edible, whereas the other eight are not. Out of 28 species, 32.14% of species are unknown. Among the three urban parks, viz., Ecopark, Central Park, and Elliot Park, macrofungal diversity was found to be the highest in Ecopark, followed by Central Park and Elliot Park. This study demonstrates the macrofungal diversity in three urban parks in Kolkata. The current study creates new opportunities for the investigation and use of wild mushrooms in urban parks in Kolkata.

Immature stages of the limnephilid caddisfly Verger lutzi (Navás 1918) (Trichoptera: Limnephilidae ): description and larval life-history traits in seasonal forested wetlands of Northwestern Patagonia

The genus Verger Navás 1918 (Trichoptera: Limnephilidae), is a Neotropical genus exclusive to the Andean region, with most of its species distributed from Tierra del Fuego to north central Chile and Argentina. Currently, 20 species of the genus have been described from adults and only six larvae have been associated and diagnosed. The ecology of the species is completely unknown. In this work, we describe and illustrate the immature stages of Verger lutzi (Navás 1918) and study its breeding phenology, larval growth and adult emergence. The main characters that enable the separation of this species are the coloration the body, shape of the anterior ventral apotome, shape and distribution of metanotal setal areas, distribution of tracheal gills and number of accessory teeth in the anal prolegs. Reproduction occurs during the summer and females lay their eggs on the wetland basin formed by humid leaf litter and organic debris, covered by herbaceous vegetation. Larvae hatch after flooding and overwinter in the wetland. Larvae develop fast during spring and emergence begins in December before the wetland dries up. Description of the immature stages is helpful for use of macroinvertebrates biomonitoring, ecological studies and understanding their ecosystem services in seasonal-lentic habitats.

Synthesis of An Amidoximated Acrylic Copolymer Membrane (AACM) Treated with Nano Silver Particles to Study the Antibacterial Efficiency of The Membrane

Polymers with cationic functional groups are proven to be an effective antimicrobial barrier. Particles, organic debris, and microbes can be well removed from drinking water using polymer membrane filtration. A variety of copolymers are utilized in the synthesis of such membranes. In this study, a copolymer membrane was synthesized first, and then Amidoximation was used to convert a portion of the copolymer’s nitrile groups to amidoxime groups. The membrane was treated with HA at 60-80°C in an aqueous solution to obtain an Amidoximated film. After being treated with Nano Silver particles, the efficiency of the prefabricated and particularly produced copolymer film as an antibacterial water disinfectant was analyzed. Various techniques were used to analyse the virgin and Amidoximated Acrylic Copolymer Membranes (AACM), including X-ray diffraction (EDX), Fourier Transform Infrared (FTIR), Scanning Electron Microscope, Transmission Electron Microscope, and Thermogravimetric analysis, Many substantial changes in the copolymer characteristics, including functionality, crystallinity, thermal activity, hydrophilicity, elemental composition, surface morphology, and antibacterial activity, were identified during the Amidoximation phase. It was revealed that an Amidoximated copolymer membrane outperforms an untreated membrane in terms of antibacterial activity.

Tonsillolith – A rare cause of halitosis and odynophagia in a 9-year-old girl

Tonsil stones, also known as tonsilloliths or tonsiliths, areusually tiny white or yellowish mineralized structurespacked with organic debris and bacteria that develop inthe enlarged palatine tonsillar crypt. Tiny tonsillitis is commonlydetected in diagnostic imaging such as computed tomography(CT) and less so in panoramic radiography, with the prevalenceincreasing with age. Giant tonsilloliths are rare and most reportedcases have been in adults, with only a few cases reported in thepediatric population. In this report, we described a 9-year-old girlwho had suffered from halitosis for 6 months and odynophagiawith oropharyngeal foreign body sensation for 2 weeks and waslater diagnosed with a tonsil stone.

Alkane variation in peat reveals palaeohydrological changes since the Little Ice Age in eastern China

The East Asian summer monsoon (EASM) system plays a crucial role in regulating climatic and hydrological variability in East Asia. The hydrological effects of the EASM in eastern China during the Little Ice Age (LIA) remains controversial, however. Here, we established a relatively high-resolution palaeohydrological record over the last 700 years in East China via analyzing n -alkanes from a peat core. Mid- and long-chain (C 21 –C 25 and C 27 –C 31 ) n -alkanes account for more than 95% of the total odd‑carbon-numbered n -alkanes, with short-chain n -alkanes (C 17 –C 19 ) accounting for only 2.3% on average, suggesting that organic matter in the peat core originated primarily from vascular plants. Organic geochemical indices, including P aq (an indicator of contributions from aquatic plants), the average chain length (ACL) of long-chain n -alkanes, and C 31 /C 27 and C 23 /C 29 n -alkane ratios, suggest a transition from dry conditions during the middle LIA to wet conditions in the late LIA. Comparing P aq records from the study profile with previous records from the EASM region, we found that the northern and southern parts of eastern China showed contrasting changes in humidity during the LIA. Specifically, the southern part shifted from mid-LIA dry conditions to late-LIA wet conditions, whereas the northern part shifted from mid-LIA wet conditions to late-LIA dry conditions. This spatial heterogeneity in hydroclimate could be attributed to La Niña-like conditions and intense summer monsoons during the middle LIA and El Niño-like conditions and weak summer monsoons during the late LIA. Our study demonstrates the importance of understanding spatial heterogeneity of hydroclimatic changes to probe the mechanisms whereby EASM modulates regional climatic changes during the LIA. • We analyzed alkane proxies from a peatland in SE China to rebuild palaeohydrology. • Organic debris originate from a mixture of terrestrial and aquatic plants. • Alkanes reveal shifts from moderate wet to dry to wet conditions during the LIA. • Northern and southern parts of the EASM region show humidity contrast in the LIA. • This spatial heterogeneity in palaeohydrology may be linked to EASM and ENSO.

NIR Spectroscopy and Aquaphotomics Approach to Identify Soil Characteristics as a Function of the Sampling Depth

Soil is a very complex medium made of minerals, organic matter, microorganisms, air, and water. Vibrational spectroscopy techniques are exceptionally well-suited to be used with portable and hand-held devices. In this study, NIR spectroscopy was applied using portable instrumentation and the holistic Aquaphotomics approach to identify the differences in three Mediterranean soil profiles from Sardinia (Italy). The soil samples (95) collected from alluvial and loess-sampling sites in the three study areas of North Sardinia (i.e., Arborea, Berchidda, and Ottava) underwent preliminary oven-drying at 40 °C and sieving (mesh size of 2 mm) to remove skeletal particles, large roots, and organic debris. Data on soil spectra were collected in duplicate using the microNIR OnSite-W spectrometer (VIAVI Srl, Italy) in reflectance mode from 900 – 1,600 nm (50 scans; 125 reading points). Then, the data on the absorbance from 1,300 to 1,550 nm were statistically processed to construct the aquagrams and perform a PCA (95% confidence level). The suitability of using a portable instrument to identify the kind of soil in different areas, for example, in areas that have undergone desertification, can help in soil classification and the rapid and non-destructive analysis of its characteristics. The Aquaphotomics approach could detect considerable variation (particularly in the soil from Arborea) associated with the sampling depth.