Smaller Size Fractions Research Articles

Improved separation and quantification method for microplastic analysis in sediment: A fine-grained matrix from Arctic Greenland

Microplastic analysis requires effective separation and purification methods, which greatly depend on the matrix and target particle size. Microplastics-sediment extraction usually involves intermediate steps, increasing processing time and particle loss, particularly for particles <100 μm. Here, we propose an improved separation and quantification method for fine-grained sediment that minimizes microplastic loss by reducing intermediate steps. First, the sample is treated with CH3COOH, KOH and NaClO, and only transferred for the density separation (ZnCl2). The extraction efficiency, visually evaluated on spiked samples, was higher than 90% for particles >100 μm and 83% for 63‐75 μm particles. This indicates that a sequential extraction method reduces the risk of particle loss, particularly of the small size fraction. Comparatively, the extraction of ABS particles (20‐100 μm) was low (30%) but the recovery, assessed via μFTIR, was higher (55%). Additionally, the proposed method can be adapted to other sediment types and environmental matrices.

Potential seamount effect on the distribution of the hydrographic features and community structure of pelagic ciliates at the Caroline seamount (tropical western Pacific) in late (2017) and early summer (2019)

Seamounts are ubiquitous features in the world ocean with potential for increasing plankton biodiversity and abundance, and providing important habitats for aquatic predators. Although ecological importance of seamount is well known, the mechanisms for supporting seamount-associated microzooplankton (e.g., pelagic ciliates) communities remains to be substantiated. In this study, pelagic ciliate community structure variations and their relationship with environmental variables were investigated in the Caroline seamount in late (2017) and early summer (2019). Above the seamount in 2019, ciliates exhibited higher abundance and biomass than off the seamount, which supported the classic hypothesis of seamount effect. Aloricate ciliate small size-fraction (10–20 μm) was dominant in bathypelagic (>1000 m) zone. Although relative abundance of small size-fraction was similar in both 2017 and 2019, the absolute abundance in 2019 seamount-effect stations were obviously higher than that in 2017. All abundant tintinnids were classified into surface- and DCM (deep Chl a maximum layer)-peak groups. Among them, four abundant tintinnids (Acanthostomella conicoides, Eutintinnus hasleae, Salpingella curta and S. minutissima) had higher abundance at DCM and might uplifted to shallower waters by upwelling at 2019 seamount-effect stations. The multivariate biota-environment analysis showed that environmental variables have significant impacts on the ciliate community structures in 2017 and 2019. Higher Chl a and nutrient concentrations, and sustained upwelling might be two potential mechanisms for microzooplankton seamount effect. Our study constitutes a rather solid foundation for quantitative and functional study of microzooplankton populations over oligotrophic tropical seamounts.

Concentration of mercury and other metals in an Arctic planktonic food web under a climate warming scenario

Arctic marine ecosystems act as a global sink of mercury (Hg) and other metals, and high concentrations of these have been measured in higher trophic-level organisms. Nevertheless, the concentrations of metals at the basis of the marine food web in the Arctic is less known despite the likelihood of biomagnification from dietary sources. We investigated the concentrations of mercury (Hg) and other metals in different size fractions of plankton in West Greenland. All size fractions contained detectable levels of Hg (ranging from 4.8 to 241.3 ng g dw−1) at all stations, although with high geographic variability, likely reflecting the sources of mercury (e.g., meltwater). In many cases, the concentrations in the larger-size fractions were lower than in the smaller-size fractions, suggesting depuration through the metabolic activity of mesozooplankton. Concentrations of Cd, Pb, V, Ni, and Cr were higher than previously reported elsewhere in the Arctic.

Hydrocarbons in size-fractionated plankton of the Mediterranean Sea (MERITE-HIPPOCAMPE campaign)

Aliphatic and polycyclic aromatic hydrocarbons (AHs and PAHs, respectively) were analyzed in the dissolved fraction (<0.7 μm) of surface water and in various particulate/planktonic size fractions (0.7–60, 60–200, 200–500 and 500–1000 μm) collected at the deep chlorophyll maximum, along a North-South transect in the Mediterranean Sea in spring 2019 (MERITE-HIPPOCAMPE campaign). Suspended particulate matter, biomass, total chlorophyll a, particulate organic carbon, C and N isotopic ratios, and lipid biomarkers were also determined to help characterizing the size-fractionated plankton and highlight the potential link with the content in AHs and PAHs in these size fractions. Ʃ28AH concentrations ranged 18–489 ng L−1 for water, 3.9–72 μg g−1 dry weight (dw) for the size fraction 0.7–60 μm, and 3.4–55 μg g−1 dw for the fractions 60–200, 200–500 and 500–1000 μm. AH molecular profiles revealed that they were mainly of biogenic origin. Ʃ14PAH concentrations were 0.9–16 ng L−1 for water, and Ʃ27PAH concentrations were 53–220 ng g−1 dw for the fraction 0.7–60 μm and 35–255 ng g−1 dw for the three higher fractions, phenanthrene being the most abundant compound in planktonic compartment. Two processes were evidenced concerning the PAH patterns, the bioreduction, i.e., the decrease in concentrations from the small size fractions (0.7–60 and 60–200 μm) to the higher ones (200–500 μm and 500–1000 μm), and the biodilution, i.e., the decrease in concentrations in plankton at higher suspended matter or biomass, especially for the 0.7–60 and 60–200-μm size fractions. We estimated the biological pump fluxes of Ʃ27PAHs below 100-m depth in the Western Mediterranean Sea at 15 ± 10 ng m−2 day−1, which is comparable to those previously reported in the South Pacific and Indian Ocean.

Pelagic ciliate (Ciliophora) communities in the Southern Ocean: Bioindicator to water mass, habitat suitability classification and potential response to global warming

Although the pelagic ciliate (microzooplankton) play important role in carbon flux of marine ecosystems, their ecological function, habitat suitability classification and response to global warming were poorly documented in the Southern Ocean (SO). During summer of 2020/2021, ciliate (including aloricate ciliates and tintinnids) communities in waters from surface to 1000 m were investigated in the SO. Rapid attenuation of ciliate abundance and biomass occurred at 100 m depth in most stations. According to distinctive hydrographic features, five water masses were identified in the SO with unique ciliate community structure. Aloricate ciliate small size-fraction (10–20 μm) was dominant in water masses deeper than 200 m. Tintinnids showed distinctive regional and vertical distribution characteristics, and their habitat suitability characterized by the Bio-index exhibiting different optimum survival zones. Variations in tintinnid habitat can be regarded as indicators for future SO climate change. Correlation between environment factors and biota revealed that depth, Chl a and dissolved oxygen were main factors determining ciliate composition. Combining tendency of phytoplankton and meso-/macro-zooplankton to rapid global warming, ciliates may become smaller and more prominent in the future SO marine pelagic ecosystem. Our study has laid a foundation for recognizing the ciliate community and reinforcing the ideas about tintinnid indication for the change of future SO marine ecosystem.

Zooplankton biomass, size structure, and associated metabolic fluxes with focus on its roles at the chlorophyll maximum layer during the plankton-contaminant MERITE-HIPPOCAMPE cruise

Recent studies have demonstrated that plankton can be a key pathway for the uptake and transfer of contaminants entering the marine environment up to top predators.The plankton-contaminant MERITE-HIPPOCAMPE cruise was devoted to quantifying contaminants in water and the whole plankton size range (10 size fractions) at 10 stations along a north-south transect in the western Mediterranean Sea from the French to the Tunisian coasts through the Provençal and Algerian basins. Pumping and filtering devices and net sampling have been used for collecting very high amounts of small particles and planktonic organisms in the chlorophyll maximum layer (CML). The present paper characterizes the zooplankton components for which the contaminant measurements were carried out. At each station, a horizontal towed Hydro-Bios net with a 60 μm mesh-size net was used to discriminate 5 size-fractions from 60 μm to a few mm. For each size-fraction, one part of the sample was used for dry weight measurements and the other one for estimating the contribution to biomass of detritus, phytoplankton, and among zooplankton of the major taxonomic groups based on the imagery tools ZOOSCAN and FLOWCAM. In each zooplankton size fraction, metabolic rates were calculated from the size spectrum to estimate trophic and excretion fluxes flowing through this fraction. These observations were compared to a similar analysis of tows in the upper layer (vertical) and the surface layer (horizontal).The total sampled biomass concentration at the CML was higher than in the water column (COL) and much higher than at the surface (SURF) in most of the stations, but in the CML and COL a substantial contribution was due to detritus mostly concentrated in the smallest size-fractions (60–200 μm and 200–500 μm). Absolute values of zooplankton biomass show neither a clear spatial pattern nor a significant difference between strata. The CML layer was dominated by copepods similarly to COL and SURF, but presented a higher contribution of nauplii and a near absence of appendicularians. At some stations, crustaceans and gelatinous plankton could be important contributors to CML. The zooplankton biomass composition of the two smallest fractions (<500 μm) was dominated by nauplii, small copepods and, occasionally, by small miscellaneous organisms (mostly pteropodes). In contrast, clear differences between stations appeared for the largest fractions (>500 μm) due to large crustaceans, gelatinous organisms, and chaetognaths. These changes in biomass composition according to size fractions suggest a progressive trophic shift from dominant herbivory in the smallest fractions to more contrasted trophic structure (including carnivory) in the largest fractions.The daily carbon demand and the N and P excretion of zooplankton were on average higher at the CML but with no significant difference with COL. The zooplankton grazing represented 2.7 to 22.7 % of the phytoplankton stock per day, whereas its excretion represented a daily N and P recycling compared to dissolved inorganic nitrogen and phosphorus stocks ranging respectively from 0.2 to 19 % and from 0 to 21 %. This information should help in the interpretation of the content of various contaminants in zooplankton fractions.

Size-fractioned zooplankton biomass in the Barents Sea ecosystem: changes during four decades of warming and four capelin collapses (1980–2020)

Abstract Zooplankton in the Barents Sea has been monitored by the Institute of Marine Research in Norway on autumn cruises since 1986, using a standardized procedure with determination of dry weight biomass in three size fractions following splitting of the sample in two halves. Along with summer data for the early 1980s, we can now describe changes of zooplankton biomass over four decades. The biomass of the central Barents Sea has fluctuated inversely with collapses and recoveries of the Barents Sea capelin stock, which is a major planktivore. Zooplankton biomass in the central Barents Sea was low in 1983 and 1984, driven by low abundance of Calanus finmarchicus, followed by a pronounced peak in 1987 associated with a “first” collapse of the capelin stock. Biomass showed another pronounced peak in 1994, driven by the small size fraction and interpreted to reflect an advective signal from the adjacent Norwegian Sea. In the two most recent decades, there have been divergent trends, with a relatively high biomass in the inflowing Atlantic water, reflecting a second summer generation of C. finmarchicus, and decreased biomass in the central area, reflecting a lower abundance of Calanus glacialis driven by a combined effect of capelin predation and climate.

Late Holocene pteropod distribution across the base of the south-eastern Mediterranean margin: the importance of the &gt; 63 µm fraction

Abstract. Euthecosomata pteropods were analysed in core sediments collected in the framework of the 2016 EUROFLEETS2 SEMSEEP cruise, offshore of Israel, in the eastern Mediterranean Sea. The investigated cores were retrieved in a deep-sea coral area at 690 m depth, an actively methane-seeping pockmark area at 1038 m depth, and a deep-sea channel area at 1310 m water depth. We identified and documented the pteropod species belonging to the families Heliconoididae, Limacinidae, Creseidae, Cavoliniidae, Cliidae, and Hyalocylidae and to some heteropods. Our study highlights the importance of investigating pteropods in the size fractions &gt; 63 µm instead of the &gt; 125 µm only. In particular, neglecting the small size fraction may result in a remarkable (up to 50 %–60 %) underestimation of the relative abundance of the epipelagic species Creseis acicula and Creseis conica and the mesopelagic species Heliconoides inflatus. This may significantly affect palaeoenvironmental reconstructions. The observed presence of tropical species supports the suggestion that the eastern Mediterranean is a refugium for these species. This study provides a basic benchmark for the late Holocene evolution of pteropod and heteropod distribution over 5800–5300 cal BP across the base of the south-eastern Levantine margin.

Global Trends in the Distribution of Biogenic Minerals in the Ocean

AbstractThe cycling of marine particulate matter is critical for sequestering carbon in the deep ocean and in marine sediments. Biogenic minerals such as calcium carbonate (CaCO3) and opal add density to more buoyant organic material, facilitating particle sinking and export. Here, we compile and analyze a global data set of particulate organic carbon (POC), particulate inorganic carbon (PIC, or CaCO3), and biogenic silica (bSi, or opal) concentrations collected using large volume pumps (LVPs). We analyze the distribution of all three biogenic phases in the small (1–53 μm) and large (&gt;53 μm) size classes. Over the entire water column 76% of POC exists in the small size fraction. Similarly, the small size class contains 82% of PIC, indicating the importance of small‐sized coccolithophores to the PIC budget of the ocean. In contrast, 50% of bSi exists in the large size fraction, reflecting the larger size of diatoms and radiolarians compared with coccolithophores. We use PIC:POC and bSi:POC ratios in the upper ocean to document a consistent signal of shallow mineral dissolution, likely linked to biologically mediated processes. Sediment trap PIC:POC and bSi:POC are elevated with respect to LVP samples and increase strongly with depth, indicating the concentration of mineral phases and/or a deficit of POC in large sinking particles. We suggest that future sampling campaigns pair LVPs with sediment traps to capture the full particulate field, especially the large aggregates that contribute to mineral‐rich deep ocean fluxes, and may be missed by LVPs.

Characteristic of Molecular Weight-Fractions of Soil Organic Matter from Calcareous Soil and Yellow Soil

Soil organic matter (SOM), along with the rock weathering, originating from the residues of animals, plants and microorganisms involved in soil formation and evolution. The stability of SOM could directly produce an effect on carbon sequestration. To elucidate the stability characteristics of SOM in karst areas at the molecular structure level, in this study, the humic acids (HA), as the major proxy of SOM, were extracted, purified, and ultra-filtrated. The HA from calcareous soil were fractionated into five size fractions, while the HA from yellow soil were separated into eight size fractions. Via the analysis of potentiometric titration, FTIR, and CPMAS 13C NMR, the results showed some common features, whereby compared with the bigger size fractions, the smaller size fractions have much lower contents of aliphatic carbon, but have higher contents of aromatic carbon, carboxyl groups, ketonic groups, phenolic hydroxyl groups, and total acidity, which indicates that the smaller size fractions are more soluble as well as more degradable than the bigger ones. It was distinct that, in the size fractions of HA from calcareous soil, negative correlations between the acidic functional groups’ contents and the oxygen contents were found, suggesting that the oxygen was mainly located in the hydroxyl group of carbohydrates instead of carboxyl and hydroxyl groups in aromatic rings, and confirming that the bigger size fractions have much higher contents of carbohydrate subunits. According to the analysis, comparing with the HA in yellow soil, we presumed that the HA from calcareous soil were more polar and degradable. However HA from calcareous soil had a larger molecular size than that of HA from yellow soil, as well as, calcareous soil had a higher content of SOM than that of the same layer of yellow soil which suggests that the conservation mechanism of HA in calcareous is not only the organic molecular structure resistance but also the chemical protection from forming complexes with calcium or/and physical protection from enclosing by hypergene CaCO3 precipitation.

Coexistence of savanna and rainforest on the ice-age Sunda Shelf revealed by pollen records from southern South China Sea

Exposure of the presently submerged continental shelf of Southeast Asia during low sea-level stands of the Quaternary is thought to be deeply involved in the biogeographic evolution of this biodiversity hotspot. Inland proxy records are mounting to argue grassland expansions over Southeast Asia during glacial periods, lending supports to the existence of a transequatorial “savanna corridor” as hypothesized. However, pollen records retrieved from marine sediments have indicated widespread rainforests on the exposed northern Sunda Shelf. To reconcile these seemingly conflicting observations, here we present new, multisite marine pollen records from the southern South China Sea focusing on the Last Glacial Maximum (LGM) time interval. It is found that the sites in front of the Sunda Shelf palaeo-rivers contain substantially more Poaceae pollen, in particular a smaller size fraction, than the site offshore North Borneo. Among the sites, abundant lowland tree pollen with similar major taxa is also observed. The co-occurrence of grass and rainforest pollen suggests a longitudinal climate gradient with increasing aridity toward the interior of glacial Sundaland. Combining our results with various palynological evidence from marine sediments seems to indicate that the vegetation on the exposed Sunda Shelf might not be fully recognized by previous studies. This is likely due to an admixture of pollen from other source regions, particularly Borneo where the rainforest was retained during glacial periods. Therefore, the extant vegetation records, from both terrestrial and marine archives, support the hypothesis of a “savanna corridor” over the LGM sundaland.

Processing of coal gasification fine slag by different physical separation methods: Fate of typical heavy metals and comparison analysis on products

The separation of carbon-mineral components in coal gasification fine slag (CGFS) is an important prerequisite for achieving large-scale utilization of the CGFS resources. This study aims to reveal the influence of three physical separation methods on the distribution features, occurrence modes, and environmental risk of typical heavy metals (i.e., V, Cr, Mn, Ni, Cu, Zn, Ba, and Pb) in the CGFS. The results show that all three physical separation methods can separate carbon-rich or mineral-rich fractions from the CGFS at different enrichment levels. Thereinto, froth flotation has a high balance between high yields and excellent separation performance. Furtherly, Ni, Cu, Zn, and Pb are more concentrated in the two carbon-rich fractions obtained by froth flotation while other heavy metals are mostly enriched in the mineral-rich fractions. Density separation is possible to obtain carbon-rich fractions with a fairly high fixed carbon content (68.29 %, dry basis). In addition, a rough separation of the carbon-mineral fractions in CGFS can be performed by particle size classification. The various concentrations and distribution features of typical heavy metals in different separated products are associated with their specific structures. The carbon particles derived through the froth flotation have a higher specific surface area than those produced from the density separation and size classification. It is found a high correlation between mineral content and typical heavy metal concentrations, while porous carbon particles with a high specific surface area and particle size effect could reduce the dependence of some heavy metals (e.g., semi-volatile or volatile heavy metals Ni, Cu, Zn, and Pb) concentrations on mineral content. In addition, the typical heavy metals in separated fractions with a high content carbon particles as well as small-sized particles tend to have a high proportion of mobile fractions. Moreover, the eco-risk assessment code (RAC) analysis results indicate that priority attention should be given to the potential environmental impacts of Mn, Ni, Cu, Ba, and especially Zn in high-carbon content products and small-sized fractions during their resource utilization process.

Distribution and export of particulate organic carbon in East Antarctic coastal polynyas

Polynyas represent regions of enhanced primary production because of the low, or absent, sea-ice cover coupled with the proximity of nutrient sources. However, studies throughout the Southern Ocean suggest elevated primary production does not necessarily result in increased carbon export. Three coastal polynyas in East Antarctica and an off-shelf region were visited during the austral summer from December 2016 to January 2017 to examine the vertical distribution and concentration of particulate organic carbon (POC). Carbon export was also examined using thorium-234 (234Th) as a proxy at two of the polynyas. Our results show that concentrations and integrated POC stocks were higher within the polynyas compared to the off-shelf sites. Within the polynyas, vertical POC concentrations were higher in the Mertz and Ninnis polynyas compared to the Dalton polynya. Similarly, higher carbon export was measured in the diatom-dominated Mertz polynya, where large particles (>53 μm) represented a significant fraction of the particulate 234Th and POC (average 50% and 39%, respectively), compared to the small flagellate-dominated Dalton polynya, where almost all the particulate 234Th and POC were found in the smaller size fraction (1–53 μm). The POC to Chlorophyll-a ratios suggest that organic matter below the mixed layer in the polynyas consisted largely of fresh phytoplankton at this time of the year. In combination with a parallel study on phytoplankton production at these sites, we find that increased primary production at these polynyas does lead to greater concentrations and export of POC and a higher POC export efficiency.

How do biochar size fractions and organic fertilizers interactively influence nitrous oxide emission from a tropical vertisol?

AbstractBackgroundNitrous oxide (N2O) emission from agriculture is increasing alarmingly due to intensive application of inorganic and organic fertilizers. Recently, biochar has been identified as a promising additive to improve agriculture by enhancing soil function and mitigate greenhouse gas emission. However, it is unclear how biochar of different size fractions influences N2O emission from agricultural soil.AimsThe current experiment aims to understand how the size of biochar (BC) and organic fertilizers interactively influence N2O emission from a tropical vertisol.MethodsBC was prepared using pigeon pea (Cajanus cajan) stalks and further processed to obtain two size fractions (&lt;0.25 mm or 0.25–2.00 mm). Organic fertilizers (vermicompost [VC], poultry manure [PM], or farmyard manure [FYM]) and BC were added to soil to evaluate N2O emission potential. BC was added to soil at 10% (w/w), whereas the organic fertilizers were added at 80 kg N ha–1. Emission of CO2 and the abundance of 16S rRNA and amoA gene copies were estimated after incubation period. The interactive effect of BC size fractions and organic fertilizers were statistically evaluated.ResultsBoth BC and organic fertilizers stimulated N2O emission in soil. BC of larger size stimulated N2O emission (µg N2O produced g–1 soil day–1) more than smaller size. Of the three organic fertilizers, PM resulted highest N2O (0.380) emission followed by FYM (0.240) and VC (0.210). BC (0.25 mm) + PM produced least N2O. Abundance of heterotrophic bacterial 16S rRNA gene copies and ammonia‐oxidizing bacterial (AOB) amoA gene copies were highest in PM + BC and lowest in control. Significant relation (p &lt; 0.0001) existed among N2O emission, CO2 emission, and microbial abundance.ConclusionsBC of small size fraction along with organic fertilizers can be an effective strategy to mitigate N2O emission from tropical vertisol.

NUTRITIONAL COMPOSITION, CONSTITUENTS, AND ANTIOXIDANT ACTIVITY OF POWDER FRACTIONS OF FICUS DICRANOSTYLA MILDBREAD LEAVES

Background and objective: The research on nutritional and health-benefiting compounds has increased in leafy vegetables such as Ficus dicranostyla.The current study was conducted to evaluate the effect of sieved-based fractionation on nutrient content, polyphenolic components, and antioxidant activities of Ficus dicranostyla leaves powder.&#x0D; Methods: Dried leaves powder was sieved at three size classes (&lt;125 µm, between 250 and 125µm, ≥ 250 µm) and unsieved powder was produced and characterized for proximate composition, minerals, total phenolic, and flavonoids contents, as well as antioxidant activity. Nutrient quantities were expressed in g/100g of crude leaves. &#x0D; Results: Statistics resultsrevealed a significant difference among fractions composition, as well as antioxidant activity with DPPH and FRAP. Proteins (19.60-26.08), lipids (5.33-10.40), and ash (11.44 16.60) contents were increased in small size fractions, while carbohydrates (40.19-50.88) and fibers (9.08–15.04) contents were lowered. Similarly, minerals namely iron, copper, magnesium, and zinc increased (3.26-9.68, 9.09-24.41, 1.38-2.33, and 3.79-8.55 g/100 g, respectively). In addition, phenolic compounds and flavonoids, as well as antioxidant activity were also higher in smaller powder particles. The powder fraction of &lt; 125 µm (smaller particle) showed the highest phenolic content and antioxidant activity, demonstrating the importance of sizing in the profitability of functional food ingredients.&#x0D; Conclusion: Data analysis clearly demonstrates that Ficus dicranostyla leaf powder could be recognized as a source of nutritive compounds and antioxidants. Ficus dicranostyla derived functional ingredients could be prepared for the nutritive purpose and oxidative stress-related disease prevention.&#x0D; &#x0D; Peer Review History: &#x0D; Received: 3 July 2022; Revised: 13 August; Accepted: 8 September, Available online: 15 September 2022&#x0D; Academic Editor: Dr. Marwa A. A. Fayed, University of Sadat City, Egypt, maafayed@gmail.com&#x0D; UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. &#x0D; Received file: Reviewer's Comments:&#x0D; Average Peer review marks at initial stage: 6.5/10&#x0D; Average Peer review marks at publication stage: 7.0/10&#x0D; Reviewers:&#x0D; Dr. Sangeetha Arullappan, Universiti Tunku Abdul Rahman, Malaysia, sangeetha@utar.edu.my&#x0D; Ahmad Najib, Universitas Muslim Indonesia, Makassar, Indonesia, ahmad.najib@umi.ac.id&#x0D; Dr. Marwa A. A. Fayed, University of Sadat City, Egypt, maafayed@gmail.com&#x0D; Similar Articles: &#x0D; ANTI-INFLAMMATORY AND ANTI-OXIDANT ACTIVITIES OF METHANOL EXTRACT OF BAPHIA NITIDA &#x0D; STORAGE EFFECT ON THE GC-MS PROFILING AND ANTIOXIDANT ACTIVITIES OF ESSENTIAL OILS FROM LEAVES OF ANNONA SQUAMOSA L.

Reuse of aluminium-based water treatment sludge for phosphorus adsorption: Evaluating the factors affecting and correlation between adsorption and sludge properties

Equilibrium phosphorus (P) adsorption was investigated for nine aluminium-based water treatment sludges (WTS) from four water treatment plants in Victoria, Australia. Four WTS, one from each location, were characterised in-depth to unpack the P adsorption trends observed from the nine WTS. Morphology, surface area, porosity, mineralogy, and acid-digestible aluminium were measured. In a key finding resolving longstanding uncertainty on this topic, results indicate that the age of the sludge does not account for differences in P adsorption. However, there was a strong correlation between the acid-digestible Al content of the sludge, the surface area of the sludge and the P adsorption. Acid-digestible Al concentration may serve as a simple proxy to help identify WTS batches best suited to reuse for P adsorption. One of WTS was investigated in further detail to identify suitable conditions for use in adsorption. The highest P adsorption was observed at pH 4 (the lowest pH tested), with negligible release of Fe & Al at this pH. The second smallest fractions (1.18 mm) which showed the highest adsorption. We hypothesise that the smallest size fraction (0.6 mm) is composed of inert materials that do not participate in P adsorption. All WTS released organic content ranging from 1.63 mg/L to 9.7 mg/L into the solution in experiments and it was influenced by the pH and P concentration which supports that ligand exchange is the driving force. This study of provide useful information for water treatment plant operators to identify potential reuse applications for water treatment sludge. • Trends of P adsorption with WTS age do not correlate across multiple sites. • Acid digestible Al shows a strong correlation with surface area and P adsorption. • The particle size fraction less than 0.6 mm appears to be less active in P adsorption. • Organic release is influenced by pH and quantity of P adsorbed but not the sludge age.

Phytoplankton Sources and Sinks of Dimethylsulphoniopropionate (DMSP) in Temperate Coastal Waters of Australia.

The ecologically important organic sulfur compound, dimethylsulfoniopropionate (DMSP), is ubiquitous in marine environments. Produced by some species of phytoplankton and bacteria, it plays a key role in cellular responses to environmental change. Recently, uptake of DMSP by non-DMSP-producing phytoplankton species has been demonstrated, highlighting knowledge gaps concerning DMSP distribution through the marine microbial food web. In this study, we traced the uptake and distribution of DMSP through a natural marine microbial community collected from off the eastern coastline Australia. We found a diverse phytoplankton community representing six major taxonomic groups and conducted DMSP-enrichment experiments both on the whole community, and the community separated into large (≥8.0 µm), medium (3.0–8.0 µm), and small (0.2–3.0 µm) size fractions. Our results revealed active uptake of DMSP in all three size fractions of the community, with the largest fraction (>8 µm) forming the major DMSP sink, where enrichment resulted in an increase of DMSPp by 144%. We observed evidence for DMSP catabolism in all size fractions with DMSP enrichment, highlighting loss from the system via MeSH or DMS production. Based on taxonomic diversity, we postulate the sources of DMSP were the dinoflagellates, Phaeocystis sp., and Trichodesmium sp., which were present in a relatively high abundance, and the sinks for DMSP were the diatoms and picoeucaryotes in this temperate community. These findings corroborate the role of hitherto disregarded phytoplankton taxa as potentially important players in the cycling of DMSP in coastal waters of Australia and emphasize the need to better understand the fate of accumulated DMSP and its significance in cellular metabolism of non-DMSP producers.

Size-fractioned zooplankton biomass in the Barents Sea: Spatial patterns and temporal variations during three decades of warming and strong fluctuations of the capelin stock (1989–2020)

Zooplankton biomass has been monitored on joint Norwegian-Russian surveys in late summer and autumn since the 1980s. We report here on zooplankton biomass in three size fractions (<1, 1–2, and > 2 mm in screen mesh opening) obtained with WP-2 plankton net (180 μm mesh size) hauled vertically over the water column from near bottom to the surface for the period 1989–2020. The number of samples (stations) collected each year has been about 100–200, with a total number of 4543 stations for the whole data set. The size composition of zooplankton reflected by the three fractions has shown remarkable stability, with about 50% of biomass contained in the medium fraction (made up largely of Calanus species), about 1/3 in the small fraction (36%), and 16% in the large fraction. The depth integrated biomass was generally larger in basins compared to shallower bank areas. The temporal (interannual) pattern of change was characterized by a marked peak in biomass in 1994 and 1995 with values up to >20 g dry weight (dw) m−2, driven to large extent by the small size fraction. Subsequently the biomass decreased to lower values but with a divergence of relatively high values (10–15 g dw m−2) in the inflow area of Atlantic water in southwest, and low values (2–6 g dw m−2) in the central area. The difference is interpreted to reflect an increase in a second summer generation of Calanus finmarchicus in the Atlantic water and a decrease of C. glacialis in the central area. The zooplankton biomass fluctuated inversely with the biomass of the Barents Sea capelin (Mallotus villosus) stock, reflecting a top-down predation effect. However, biomass was also negatively correlated with temperature of the Atlantic water, suggesting an additional and confounding effect of climate variability and change. The decrease in biomass of the central area used as a forage area by capelin, was associated with a shift to dominance by the small size fraction. This is likely an effect of predation and could be associated with a lower trophic conversion efficiency from phytoplankton to planktivorous fish and higher trophic levels by smaller zooplankton (smaller copepods such as Pseudocalanus and others) compared to the larger Calanus species.

Appendicularia in the Bering, Okhotsk, Chukchi Seas and North Pacific and their significance for feeding of nekton

Significance of larvaceans (class Appendicularia) for plankton community and feeding of nekton in the Far-Eastern Seas and North Pacific is underestimated, this group of species is poorly represented in scientific literature. The total biomass of larvaceans is below the stocks of dominant groups in the large-sized zooplankton, as copepods, euphausiids, arrowworms, amphipods, and coelenterates, but accounted together with their shells (called «houses») they form a comparable stock. In the studied area, the class Appendicularia is represented by four species: widely distributedOikopleura vanhoeffeni,O. labradoriensis, andFritillaria borealisandF.sp. (perhapsF. pacifica) in the southern periphery of this area. Larger and more numerous oikopleurids dominate by both abundance and biomass and are presented in all size fractions of zooplankton, whereas fritillarids are presented mostly in the small-sized fraction. Larvaceans distribute mainly in the upper epipelagic layer (55–97 %), i.e. in the layer of their prey concentration; their density is the highest in the coastal zone with the depth &lt; 50 m and decreases in deeper areas. They are a significant portion in the diet of many nekton species (41 out of 151 species in the Trofology database of TINRO), including basic commercial fishes, as pollock, salmons, herring, polar cod, mackerels, sardine and some others. Their mucus houses glowing at night, with the animal inside, whose tail vibrates constantly providing movement and nutrition, are attractive for many plankton-eaters. Appendicularia have a high occurrence in the food of all size-classes of nekton, though it decreases for larger-sized fish of such mass fish species, as walleye pollock and pink and chum salmons.

The Geochemical and Textural Transition between the Reef Package and its Hanging Wall, Stillwater Complex, Montana, USA

Abstract The highest grade Pd-Pt deposit on Earth, the J-M Reef, is hosted in coarse-grained to pegmatoidal cumulates called the Reef Package. Decades of mine development of the J-M Reef have revealed that a distinct discontinuity in rock fabric marks the top of the rock unit that hosts economic-grade sulfide mineralization. Mine geologists refer to this discontinuity as the hanging wall contact. This contact is the top of the Reef Package and is always locatable—either by the change in rock fabric or by distinctive hanging wall textures of silicate minerals—even when the reef sulfide mineralization is absent. This rather subtle textural feature is used reliably by mine geologists to follow the Reef during exploration and mine development. Although some high tenor sulfides (&amp;gt;1000 ppm Pd in 100% sulfide) are found sporadically in the hanging wall cumulates, these accumulations are too small to be economically viable. We present quantitative rock fabric data for four Reef Package and hanging wall intersections collected by electron back-scattered diffraction (EBSD). Plagioclase fabrics in the hanging wall are characterized by low variance in grain sizes and a strong point maximum concentration of (010) and a perpendicular girdle distribution of [100] consistent with an axial B-type fabric. These fabrics are indicative of either compaction of the crystal mush or crystal settling of nucleated crystals, the bulk magma in a chamber. Conversely, the fabrics of the Reef Package show higher variance grain in size distributions and weak to undeveloped preferred orientation of plagioclase crystals that did not undergo significant alignment or textural equilibration of plagioclase grains. The absence of foliation in the Reef Package stands in contrast both to hanging wall fabrics and to other reported EBSD datasets of plagioclase crystals orientations from the Bushveld Complex, the Skaergaard Intrusion, and the Rum Intrusion. Furthermore, plagioclase crystal size distributions for the Reef Package show flatter slopes and convex profiles with fewer crystals at small size fractions indicating the dissolution of small crystals during partial melting and textural coarsening (i.e. Ostwald ripening) and crystal growth. Crystal growth was favored over the nucleation of new crystals during prolonged interaction with a hot infiltrating melt into the resident mush resulting in the coarse-grained textures of the Reef Package cumulates. The hanging wall contact represents a boundary between partially remelted crystal mush of the Reef Package, where sulfide mineralization formed and accumulated, and an overlying essentially barren cumulate pile. The hanging wall cumulates formed following the cessation of footwall erosion and the resumption of crystal accumulation by normal magma chamber processes.