Aggregate characteristics and aggregate-associated soil organic carbon and carbohydrates of soils under contrasting tree land use

<p><span>Protection of soil organic carbon and acid-hydrolyzable carbohydrates in aggregate-size fractions is important for appraising soil degradation and aggregation under land use types. Aggregate-associated soil organic carbon (SOC) and acid-hydrolyzable carbohydrates (R-CHO) in bulk soils and aggregate-size fractions of a sandy loam soil under Alchornea bush, Rubber, Oil palm and Teak plantations in southern Nigeria were studied. Results revealed significant differences in aggregate-associated SOC and R-CHO, bulk densities, total porosity, soil organic carbon stock and aggregate stability among the land use types. Greater SOC was stored in macro-aggregates &gt;0.25 mm, while greater R-CHO was occluded in micro-aggregates &lt;0.25 mm (p&lt;0.05). The highest mean weight diameter (MWD) was 1.01 mm in Alchornea soils and 0.92 mm in Oil palm plantation at 0-15 cm topsoil. Soil organic carbon stock in 0-15 cm topsoil was 77.7, 81.8, 92.2, and 67.5 kg C ha^-1 in Alchornea, Rubber, Oil palm, and Teak soils, respectively. Relationships showed a positive linear correlations between MWD and SOC (r = 0.793, p &lt; 0.05) and R-CHO (r = 0.789. p &lt; 0.05). Alchornea bush and Oil palm plantation increased macro-aggregate formation and macro-pores &gt;5 µm, therefore they have greater potentials to boost protection of SOC in soil macro-aggregates.</span></p>

Bazı Tescilli Nohut Çeşitlerinin Elek Analiz Değerleri

Chickpea is consumed after passing through different processes both in fresh and dry forms. Consumers generally prefer large kernels and a kernel size of below 6 mm is not preferred. In the present study, grain size fractions (above 9, 8, 7, 6 mm sieves and below 6 mm sieve) of different chickpea cultivars were determined. Experiments were conducted in randomized blocks design with 3 replications over the experimental fields of the Agricultural Research and Implementation Center of Erciyes University in 2018 and 2019 vegetation seasons without the use of chemical and organic fertilizers. In present experiments, 27 chickpea cultivars registered in Turkey between the years 1991 – 2013 were used. In both years, the greatest size ratios (41.21% in the first year and 35.41% in the second year) were observed for the 8 mm sieve and the second for the 7 mm sieve.

Mechanical Disintegration and Particle Size Sieving of Chondrus crispus (Irish Moss) Gametophytes and Their Effect on Carrageenan and Phycoerythrin Extraction

To better understand the migration properties of hybrid carrageenan from the seaweed tissue during carrageenan extraction, the effect of increasing the seaweed surface area by the mechanical disintegration of gametophyte Chondrus crispus chips was studied under various temperature and time extraction conditions. Dried Chondrus crispus seaweed chips were milled by a rotor beater mill and classified into eight different size fractions by sieving with varying mesh sizes from 50 to 2000 μm. During extraction at 22 °C, the red color of the filtrate increased significantly with the decreasing particle size of the fraction, correlating with the increasing phycoerythrin concentration (from 0.26 mg PE/g dry seaweed in the >2000 μm size fraction to 2.30 mg PE/g dry seaweed in the <50 μm size fraction). On the other hand, under the same extraction conditions, only a small increase in carrageenan precipitate was obtained with the decreasing size fractions (from no recovery in the >2000 μm size fraction to 2.1 ± 0.1 g/kg filtrate in the <50 μm size fraction). This yield was significantly lower than the ones from extractions at 45 °C (5.4 ± 0.1 g/kg) or at 90 °C (9.9 ± 2.1 g/kg) for the same particle size and time conditions. It could be concluded that hybrid carrageenan extraction is not surface area dependent, while phycoerythrin is. Therefore, it seems that phycoerythrin and carrageenan extraction follow different mechanisms. This creates potential for the selective extraction of each of those two compounds.

Survey of residential indoor Particulate Matter measurements 1990-2019

We surveyed literature on measurements of indoor particulate matter in all size fractions, in residential environments free of solid fuel combustion. Data from worldwide studies from 1990-2019 were assembled into the most comprehensive collection to date. Out of 2,752 publications retrieved, 538 articles from 433 research projects met inclusion criteria and reported unique data, from which more than 2,000 unique sets of indoor PM measurements were collected. Distributions of mean concentrations were compiled, weighted by study size. Long-term trends, the impact of non-smoking, air cleaners, and the influence of outdoor PM were also evaluated. Similar patterns of indoor PM distributions for North America and Europe could reflect similarities in the indoor environments of these regions. Greater observed variability for all regions of Asia may reflect greater heterogeneity in indoor conditions, but also low numbers of studies for some regions. Indoor PM concentrations of all size fractions were mostly stable over the survey period, with the exception of observed declines in PM2.5 in European and North American studies, and in PM10 in North America. While outdoor concentrations were correlated with indoor concentrations across studies, indoor concentrations had higher variability, illustrating a limitation of using outdoor measurements to approximate indoor PM exposures.

An 18S V4 rRNA metabarcoding dataset of protist diversity in the Atlantic inflow to the Arctic Ocean, through the year and down to 1000 m depth

Arctic marine protist communities have been understudied due to challenging sampling conditions, in particular during winter and in deep waters. The aim of this study was to improve our knowledge on Arctic protist diversity through the year, in both the epipelagic (< 200 m depth) and mesopelagic zones (200–1000 m depth). Sampling campaigns were performed in 2014, during five different months, to capture the various phases of the Arctic primary production: January (winter), March (pre-bloom), May (spring bloom), August (post-bloom), and November (early winter). The cruises were undertaken west and north of the Svalbard archipelago, where warmer Atlantic waters from the West Spitsbergen Current meet cold Arctic waters from the Arctic Ocean. From each cruise, station, and depth, 50 L of seawater was collected, and the plankton was size-fractionated by serial filtration into four size fractions between 0.45–200 µm, representing picoplankton (0.45–3 µm), small and large nanoplankton (3–10 and 10–50 µm, respectively), and microplankton (50–200 µm). In addition, vertical net hauls were taken from 50 m depth to the surface at selected stations. The net hauls were fractionated into the large nanoplankton (10–50 µm) and microplankton (50–200 µm) fractions. From the plankton samples DNA was extracted, the V4 region of the 18S rRNA-gene was amplified by polymerase chain reaction (PCR) with universal eukaryote primers, and the amplicons were sequenced by Illumina high-throughput sequencing. Sequences were clustered into amplicon sequence variants (ASVs), representing protist genotypes, with the dada2 pipeline. Taxonomic classification was made against the curated Protist Ribosomal Reference database (PR2). Altogether, 6536 protist ASVs were obtained (including 54 fungal ASVs). Both ASV richness and taxonomic composition varied between size fractions, seasons, and depths. ASV richness was generally higher in the smaller fractions and higher in winter and the mesopelagic samples than in samples from the well-lit epipelagic zone during summer. During spring and summer, the phytoplankton groups diatoms, chlorophytes, and haptophytes dominated in terms of relative read abundance in the epipelagic zone. Parasitic and heterotrophic groups such as Syndiniales and certain dinoflagellates dominated in the mesopelagic zone all year, as well as in the epipelagic zone during the winter. The dataset is available at https://doi.org/10.17882/79823 (Egge et al., 2014).