High Organic Matter Research Articles

Searching for drivers of the patchy distribution of sympatric deposit‐feeding sea cucumbers: A multi‐scale monitoring study

AbstractThree sea cucumber species, Holothuria atra, Holothuria leucospilota, and Stichopus chloronotus, are patchily distributed within the coral reefs of Reunion Island, exhibiting locally high densities (> 1 ind m−2). Previous studies stated that these sympatric species have thrived for almost four decades; however, factors involved in their distribution and spatiotemporal dynamics are not well understood yet. The aims of this study are to analyze the fine‐scale spatiotemporal dynamics of these sympatric species and identify the key sedimentary factors (substrate composition and cover) involved in their distribution. Sea cucumber populations and sedimentary factors were monitored along back‐reef and shore‐to‐ocean gradients during four consecutive seasons. Meanwhile, feeding behavior was assessed by measuring motility and excretion rates. Each species presents its own dynamic between the beginning and the end of the monitoring: increase of density for H. leucospilota, stability for H. atra, and decrease for S. chloronotus. Distribution of H. atra was closely related to substrate organic features (high organic matter, chlorophyll a, and ∂13C), H. leucospilota with the occurrence of seagrass and S. chloronotus with none. Results on feeding behavior showed that S. chloronotus emerges as a specialist while the two others appear to be generalists. Conspecific attraction or recruitment pattern may drive the high‐density patchy distribution of both Holothuria species, while the drastic decrease of S. chloronotus could be linked to unstudied factors related to predation or climate change. Water flow regime could also have a significant effect on the patchy distribution of these species, therefore, further studies should pay particular attention to this factor.

A Comparative Analysis of Agriculture in Tropical and Temperate Climates

T he largest agricultural areas in the world are in North America, Euro-Asia, and Central South America. However, agriculture in tropical and temperate climates is very different, mainly because of the environmental conditions. Unlike in temperate climates, there are not four seasons in the tropics. The tropics have only two seasons, rainy and dry, with plants f lowering all year round because air temperatures are not too low in the winter, and crops can grow during this season; thus, some crops may have three cycles per year in the tropics. In most temperate climates, there is only one crop cycle per year due to low winter temperatures, but the yield can be the highest. The low temperatures of a temperate climate, below 0°C, allow soils to be shallow, with high organic matter content and fertility because soil microbial activity and lixiviation are arrested at such temperatures, and organic matter is less degraded than in tropical soils where soil microorganisms and lixiviation continue throughout the year. As a result, yields of major crops in temperate climates are the highest in the world, confirming the efficiency of temperate agriculture, even with only one crop cycle per year. On the other hand, in tropical climates, yields are lower, but crops can be grown several times a year, thus increasing the annual production.

Oceanic anoxic event 3 in Arctic Canada—Arc volcanism and ocean fertilization drove anoxia

The global extent of the Late Cretaceous oceanic anoxic event 3 (OAE 3) remains uncertain. It is not considered to have extended into the Boreal Realm. To test this, we examined Late Cretaceous organic- and metal-rich black mudstones of the Smoking Hills Formation in Arctic Canada. New high-precision U-Pb zircon ages indicate that deposition of the Smoking Hills Formation (88.535−78.230 Ma) was temporally coincident with OAE 3, indicating a much broader global expression of this event than previously thought. OAE 3 was likely manifest throughout the proto−Arctic Ocean (now Arctic Canada). Abundant bentonite layers and cryptotephra within the Smoking Hills Formation have rare earth element (REE) patterns that are consistent with ashfall derived from Cretaceous arc volcanism. Anomalously high organic matter content in the Smoking Hills Formation, as compared to underlying and overlying units, suggests that ocean fertilization led to enhanced productivity and metal drawdown. A peak in arc volcanism may have been a key driver of the OAE 3 event. We also explored the potential use of cadmium as a geochemical marker of volcanism and show that high volcanogenic metal loading could affect the use of Cd and other proxies for marine productivity (e.g., Zn, Cu).

International Biological Flora: Trapa natans†

Abstract This account presents information on all aspects of the biology of Trapa natans L. (water caltrop and water chestnut) that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the International Biological Flora: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, conservation and global heterogeneity. The water caltrop is an annual herbaceous hydrophyte rooted in the sediment of water bodies, forming flexuous underwater stems that create a buoyant, light‐capturing leaf rosette at the water surface. The submerged stem nodes additionally bear linear leaves. These are replaced by photosynthetically active, pinnately branched structures and unbranched adventitious roots early on, which complement previously established roots on the hypocotyl, altogether facilitating anchorage, nutrient and water absorption, aeration and capture of subsurface irradiance. Solitary flowers pollinated primarily through autogamy and incidentally through entomophily give rise to a fully developed edible single‐seeded drupe with two to four barbed horns. Fruits are dispersed with the help of hydrochory, epizoochory and anthropochory. Throughout its lowland, global temperate, subtropical and tropical distribution in Eurasia and Africa, the thermophilic macrophyte is found in shallow, sun‐exposed, nutrient‐rich freshwater bodies with low‐velocity flows and steady water levels. These offer slightly acidic to mildly basic conditions. The accompanying soft substrate is usually characterized by a high organic matter content. Regularly co‐occurring with other macrophytes, some of which are also of conservation concern, such as those in rare stands of the association Trapetum natantis in Europe, the water caltrop has at times been outcompeted, though it may form monodominant stands, due to several competitive features. Formerly widespread in Europe, T. natans is today recognized as a rare, strictly protected macrophyte. It has been introduced to Australia and North America; on the latter continent, its naturalization, spread and aggressive overgrowth have led to extensive control efforts. Having been used as a crop since Neolithic times, it is still exploited in Asia for means of food production, phytoremediation, ornamental purposes, medication and alternative uses.

Soil microbial communities and degradation of pesticides in greenhouse effluent through a woodchip bioreactor

Pesticides, including insecticides and fungicides, are major contaminants in the effluent from intensive agricultural systems, such as greenhouses. Because of their constant use and persistence, some pesticides can accumulate in soil and/or run off into adjacent waterways. Microbial communities in soil can degrade some pesticides, and bioreactors with enhanced microbial communities have the potential to facilitate decontamination before the effluent is released into the environment. In this study, we sampled the soil along a gradient from immediately below greenhouses, into, through and below a bioreactor. Multi-analyte pesticide screening was undertaken along with shotgun metagenomic sequencing, to assess microbial community taxonomic profiles and metabolic pathway responses for functional analysis. Two insecticides (imidacloprid and fipronil) and nine fungicides were identified in the soil samples, with a general decrease in most pesticides with increasing distance from the greenhouses. Diversity indexes of taxonomic profiles show changes in the microbial community along the gradient. In particular, microbial communities were significantly different in the bioreactor, with lower Shannon diversity compared to immediately below the greenhouses, in the channels leading into the bioreactor and further downstream. Metabolic pathway analysis revealed significant changes in a wide range of core housekeeping genes such as protein/amino acid synthesis and lipid/fatty acid biosynthesis among the sampling sites. The result demonstrates that the composition and potential functional pathways of the microbial community shifted towards an increased tendency for phytol and contaminant degradation in the bioreactor, facilitated by high organic matter content. This highlights the potential to use enhanced microbial communities within bioreactors to reduce contamination by some pesticides in sediment receiving run-off from greenhouses.

Integrated Transcriptomic and Proteomic Analysis Reveals Molecular Mechanisms of the Cold Stress Response during the Overwintering Period in Blueberries (Vaccinium spp.).

In China, the Liaodong Peninsula is an important growing area for blueberries because of the high organic matter content in the soil, the abundance of light, and the large temperature difference between day and night. However, the low temperature and relative humidity of the air during the winter and early spring in the Liaodong Peninsula are the main reasons for the damage to blueberry plants. Here, we documented the transcriptome and proteome dynamics in response to cold stress in three blueberry cultivars ('Northland', 'Bluecrop', and 'Berkeley'). Functional enrichment analysis indicated that many differentially expressed genes (DEGs) and differentially abundant proteins (DAPs) were mainly involved in the pathways of protein processing in the endoplasmic reticulum, the glutathione metabolism pathway, and ribosomes. We identified 12,747 transcription factors (TFs) distributed in 20 families. Based on our findings, we speculated that cold tolerance development was caused by the expression of calcium-related genes (CDPKs and CMLs), glutathione proteins, and TFs (NAC, WRKY, and ERF). Our investigation found that three cultivars experienced cold damage when exposed to temperatures between -9 °C and -15 °C in the field. Therefore, the cold resistance of blueberries during overwintering should not only resist the influence of low temperatures but also complex environmental factors such as strong winds and low relative humidity in the air. The order of cold resistance strength in the three blueberry cultivars was 'Berkeley', 'Bluecrop', and 'Northland'. These results provide a comprehensive profile of the response to cold stress, which has the potential to be used as a selection marker for programs to improve cold tolerance in blueberries.

Changes in macroaggregate stability as a result of wetting/drying cycles of soils with different organic matter and clay contents

The wetting–drying (WD) cycles, caused by natural or anthropogenic processes such as rainfall or irrigation, can affect many soil properties. Among these properties, soil aggregate stability has been introduced as a convenient soil health indicator because of its relation to the soil’s primary particles (sand, silt, and clay) and organic matter content (OM). However, previous studies have shown erratic effects depending on soil type and WD cycle setup when measuring aggregate stability. Therefore, this study aimed to characterize the soil primary particles composition and organic matter (OM) content of macroaggregates and measure the effects of WD cycles on aggregate stability. A series of soils with distinctive properties, such as OM and clay contents from five different USDA textural classes (loam, sandy loam, silty clay loam, silty loam, and clay loam) were used. Particle size distribution, OM, and mass fraction were measured in three aggregate size classes (2–1 mm, 1–0.5 mm, and 0.5–0.25 mm), and isolated aggregates were exposed to 3, 6, and 12 wetting and drying cycles. The main results indicate that soils with a high OM content have macroaggregates with finer particles, and the OM in soils is linearly related to the macroaggregate OM content. For 2–1 mm aggregates, a statistically significant reduction (p < 0.05) of water-stable aggregates compared to the control sample (0 cycles) was observed for every cycle, with reduction values between 4.8–7.3 %. An increase was observed only between 6–12 cycles (1.84 %). Additionally, statistically significant reductions were observed after the first three cycles in 1–0.5 mm aggregates and the first six in 0.5–0.25 mm aggregates. Finally, the macroaggregates were more resistant to the WD cycles when their clay and OM contents increased or the soil pH decreased. This study provides high-resolution results of macroaggregate particle size distribution and OM. It relates them to the effects of WD cycles in water-stable aggregates and soils with different land uses.

Photochemical transformation of liquid crystal monomers in simulated environmental media: Kinetics, mechanism, toxicity variation and QSAR modeling

Liquid crystal monomers (LCMs) are a new class of emerging pollutants with high octanol-water partition coefficients; however, their transformation behavior and associated risk to environments with high organic matter content has rarely been reported. In this study, we investigated the photodegradation kinetics, mechanism, and toxicity variation of 23 LCMs on leaf wax models (e.g., organic solvents methanol and n-hexane). The order of the photolysis rates of these LCMs were biphenylethyne LCMs > phenylbenzoate LCMs > diphenyl/terphenyl LCMs under simulated sunlight, while the phenylcyclohexane LCMs were resistant to photodegradation. The phenylbenzoate and biphenylethyne LCMs mainly undergo direct photolysis, while the diphenyl/terphenyl LCMs mainly undergo self-sensitized photolysis. The main photolysis pathways are the cleavage of ester bonds for phenylbenzoate LCMs, the addition, oxidation and cleavage of alkynyl groups for biphenylethyne LCMs, and the cleavage/oxidation of chains attached to phenyls and the benzene ring opening for diphenyl/terphenyls LCMs. Most photolysis products remained toxic to aquatic organisms to some degree. Additionally, two quantitative structure-activity relationship models for predicting kobs of LCMs in methanol and n-hexane were developed, and employed to predict kobs of 93 LCMs to fill the kobs data gap in systems mimicking leaf surfaces. These results can be helpful for evaluating the fate and risk of LCMs in environments with high content of organic phase.

Novel strategy for efficient energy recovery and pollutant control from sewage sludge and food waste treatment

Considering the high organic matter contents and pollutants in sewage sludge (SS) and food waste (FW), seeking green and effective technology for energy recovery and pollutant control is a big challenge. In this study, we proposed a integrated technology combing SS mass separation by hydrothermal pretreatment, methane production from co-digestion of hydrothermally treated sewage sludge (HSS) centrate and FW, and biochar production from co-pyrolysis of HSS cake and digestate with heavy metal immobilization for synergistic utilization of SS and FW. The results showed that the co-digestion of HSS centrate with FW reduced the NH4+-N concentration and promoted volatile fatty acids conversion, leading to a more robust anaerobic system for better methane generation. Among the co-pyrolysis of HSS cake and digestate, digestate addition improved biochar quality with heavy metals immobilization and toxicity reduction. Following the lab-scale investigation, the pilot-scale verification was successfully performed (except the co-digestion process). The mass and energy balance revealed that the produced methane could supply the whole energy consumption of the integrated system with 26.2 t biochar generation for treating 300 t SS and 120 t FW. This study presents a new strategy and technology validation for synergistic treatment of SS and FW with resource recovery and pollutants control.

Cu2(OH)3NO3/γ-Al2O3 catalyzes Fenton-like oxidation for the advanced treatment of effluent organic matter (EfOM) in fermentation pharmaceutical wastewater: The synergy of Cu2(OH)3NO3 and γ-Al2O3

The secondary effluent of fermentation pharmaceutical wastewater exhibits high chromaticity, elevated salinity, and abundant refractory effluent organic matter (EfOM), presenting significant treatment challenges and environmental threats. Herein, Cu2(OH)3NO3/γ-Al2O3 was fabricated through ultrasound-assisted impregnation and calcination to catalyze the Fenton-like oxidation for degrading organic pollutants in this secondary effluent. Under neutral conditions, with 400.00 mg/L H2O2, 8 g/L catalyst, and at 30 ℃, the EfOM and CODCr removal efficiencies can reach 96.90 % and 51.56 %, respectively. The Cu2(OH)3NO3/γ-Al2O3 catalyst possesses ideal reusability, maintaining CODCr, chromaticity, and EfOM removal efficiencies at 44.44 %-64.59 %, 85.45 %-93.45 %, and 61.00 %-95.00 % over 220 h in a continuous-flow catalytic oxidation system operated at room temperatures (15–25 ℃). Electron paramagnetic resonance results and density functional theory calculations indicate that •OOH may be the predominant reactive oxygen species, facilitated by the easier elongation of the OH bond in H2O2 compared to the OO bond. The adjusted electronic structure endows Cu2(OH)3NO3/γ-Al2O3 composite sites with superior catalytic selectivity for H2O2 activation compared to Cu2(OH)3NO3 single crystal sites, with γ-Al2O3 additionally facilitating H2O2 activation through electron donation. This research highlights the efficacy of Cu2(OH)3NO3/γ-Al2O3 in the advanced treatment of complex industrial wastewater, elucidating its catalytic mechanisms and potential applications.

THE STUDY OF SOME PHYSICAL PROPERTIES OF ANDISOLS IN VARIOUS LAND IN JERNIH JAYA VILLAGE, GUNUNG TUJUH DISTRICT, KERINCI REGENCY

ABSTRACT Although Andisols is the best soil type to support plant growth, overuse of Andisols soil type can degrade soil quality. Gunung Tujuh District of Kerinci Regency's Jernih Jaya Village, there is an Andisols land use location. Soil quality is negatively impacted by land management practices, which disregard land sustainability, soil, and water conservation measures. To understand the physical characteristics of Andisolss in various land uses in Jernih Jaya Village, it is vital to examine the effects of different tillages and land uses. The stages were (1) preparation of primary data (taking soil samples) and secondary data (making maps), (2) survey (preliminary survey and main survey), (3) data processing and interpretation of data resulting from analysis of soil samples and surveys. Based on an examination of various physical attributes of Andisols in different land used within Jernih Jaya Village, Gunung Tujuh District, Kerinci Regency, it could be inferred that the physical properties of Andisols were deemed favorable. The results indicated that the area was used for vegetables, plantations, secondary forests, and paddy fields, with slope classes ranging from 0-3%, 3-8%, and 8-15%, sandy loam with a crumb structure in all land used, high water content, moderate to high total pore space, low to medium volume weight, and high organic matter were all present. When compared to other land uses, paddy fields had the highest organic matter content (22.10%), highest moisture content (124.89%), highest total pore space (79.39%), and lowest bulk density (0.57 g/cm3).

Surveying the Distribution and Diversity of Predominant Mycobiota in Cultivated and Uncultivated Soils of Zaria, Northwestern Nigeria

Study’s Novelty/Excerpt This study presents a comprehensive survey of the distribution and diversity of soil fungi in cultivated and uncultivated soils of Zaria, Northwestern Nigeria, highlighting their morphological and microscopic characteristics, frequency, and relationship with physicochemical properties. It identifies and quantifies the presence of eight different fungal species, with Aspergillus niger being the most dominant, providing critical insights into the fungal biodiversity of this region. Additionally, the study correlates the richness of soil mycobiota with specific soil properties such as pH, organic matter content, and moisture levels, suggesting that these factors significantly influence fungal diversity and distribution, and recommending further research to assess their impact on soil productivity. Full Abstract Soil fungi are a crucial component of terrestrial ecosystems, playing a vital role as decomposers in nutrient cycles. The diversity of soil fungi serves as an indicator of soil health (favorable/deficient). Understanding soil biodiversity and its biological functioning will help not only in crop yields but also in a healthier society as it directly or indirectly enters the food chain. This study aimed at surveying the distribution and diversity of predominant mycobiota in cultivated and uncultivated soils of Zaria, Northwestern Nigeria. Focusing on their morphological and microscopic characteristics, percentage frequency, and relationship with physicochemical properties. After removing the surface soil, soil samples were randomly collected from two locations at 0-15 cm depths. Fungi were isolated via the dilution method on PDA. Previously established criteria were used to identify eight different fungal species: Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Fusarium spp., Mucor spp., Penicillium spp., Rhizopus spp., and Trichoderma spp. Aspergillus niger was the most dominant species, with a relative frequency of 26%, followed by Fusarium spp. and Rhizopus spp. With 18% and 17%, respectively. Aspergillus fumigatus was the least abundant (2%). The highest fungal isolation frequency (32%) was observed in L1 cultivated soil, closely followed by L2 uncultivated soil (31%), with the lowest in L2 uncultivated soil (16%). Physicochemical analysis indicated that these soils are rich in mycobiota, attributed to a basic pH range of 7.12-9.15, high organic matter content, and optimal moisture levels. Soils with significant organic matter due to litter accumulation, moist deciduous vegetation, and neutral to alkaline pH levels retain considerable moisture content, fostering a rich qualitative and quantitative mycobiota for recycling dead organic matter making nutrients available for suitable utilization. Further research is recommended to evaluate the impact of these isolated fungi on soil productivity, to determine whether their presence has a positive or negative effect.

A Comparative Study on Soil-Crop Selenium Characteristics in High-Incidence Areas of Keshan Disease in Chinese Loess and Black Soil

With the gradual emphasis on health by people, the research on the pathogenesis of endemic diseases has become increasingly in-depth. Through analyzing the environmental selenium characteristics and conducting a comparative study in typical areas of Chinese loess and black soil in this paper, it is concluded that the environmental selenium in the two regions has different characteristics. The soil in the loess area has the characteristics of high alkalinity, low selenium, and relatively high selenium availability, and the crops are selenium-deficient, while the soil in the black soil area has the characteristics of high organic matter, low selenium availability, and relatively high selenium in crops. The research concluded that the environmental occurrence mechanism of Keshan disease in the loess area and the black soil area is different. Keshan disease can be induced in both low-selenium and sufficient-selenium environments, and environmental selenium should be one of the inducing factors of Keshan disease. This research provides a reference for predicting the areas where Keshan disease occurs and for disease prevention, and it can also serve in the prevention and control of endemic diseases.

Optimal biochar selection for cadmium pollution remediation in Chinese agricultural soils via optimized machine learning

Biochar is effective in mitigating heavy metal pollution, and cadmium (Cd) is the primary pollutant in agricultural fields. However, traditional trial-and-error methods for determining the optimal biochar remediation efficiency are time-consuming and inefficient because of the varied soil, biochar, and Cd pollution conditions. This study employed the machine learning method to predict the Cd immobilization efficiency of biochar in soil. The predictive accuracy of the random forest (RF) model was superior to that of the other common linear and nonlinear models. Furthermore, to improve the reliability and accuracy of the RF model, it was optimized by employing a root-mean-squared-error-based trial-and-error approach. With the aid of the optimized model, the empirical categories for soil Cd immobilization efficiency were biochar properties (60.96 %) > experimental conditions (19.6 %) ≈ soil properties (19.44 %). Finally, this study identified the optimal biochar properties for enhancing agricultural soil Cd remediation in different regions of China, which was beneficial for decision-making regarding nationwide agricultural soil remediation using biochar. The immobilization effect of alkaline biochar was pronounced in acidic soils with relatively high organic matter. This study provides insights into the immobilization mechanism and an approach for biochar selection for Cd immobilization in agricultural soil.

Female oviposition preferences and larval behavior of the Aedes aegypti mosquito (Linnaeus, 1762) exposed to predator cues (Odonata: Libellulidae)

The reproductive success of mosquitoes is heavily influenced by females' ability to select suitable oviposition sites for the proper development of their offspring. Many of these potential habitats may harbor predators, and the detection of these predators is crucial for assessing the risk of predation, which can, in turn, influence the behavior of the prey. However, there are often trade-offs to consider, which can impact the life history of these organisms. In our study, we investigated the oviposition preferences and larval behavioral responses of the Aedes aegypti mosquito when exposed to cues from predators and the actual presence of predation by Libellulidae (Odonata) larvae. We observed the mosquito's choices regarding oviposition with and without predation cues for a duration of ten weeks, following 48 hours of exposure. Additionally, we measured larval behavior across various treatments, including those with predation cues, predator cues, the presence of larvae, and controls with only water. Our findings revealed that the highest preference for oviposition occurred in containers with high organic matter content, regardless the presence of both predator cues and actual predators. Furthermore, we noted significant changes in larval behavior in response to predation cues, including evasive behaviors. When facing the risk of predation, larvae spent more time near the container's edges and exhibited discrete feeding behaviors or avoidance of the risk of predation. Conversely, in the absence of predation risk, larvae explored the entire container, swimming vigorously. These results highlight the significance of anti-predatory behaviors triggered by the recognition of predation cues in the context of Ae. aegypti's reproductive success.

Pedological factors affecting pesticide retention in a series of tropical volcanic ash soils in the French West Indies

Specific pedoclimatic conditions in tropical environments have a considerable impact on pesticide fate. Tropical volcanic soils result from specific pedogenesis processes linked to successive volcanic projections; they are characterised by acidic conditions, high organic matter content, a specific mineralogical composition and the presence of organo-mineral complexes. The retention of pesticides in these soils is therefore often high but variable depending on the associated molecules and soil properties. Nevertheless, knowledge of pesticide sorption in these soils remains limited, and knowledge of the desorption process is scarce. The objectives of this work were to study the variability of the sorption and desorption coefficient of four pesticides currently used in banana and sugarcane crops on a set of representative tropical soils developed on volcanic ash (Guadeloupe, French West Indies). Adsorption and desorption isotherms were analysed for three ionizable pesticides (2,4-D, mesotrione, glyphosate) and a hydrophobic pesticide (difenoconazole) on ten soil samples from five soil profiles: one silandic andosol, one vitric andosol, two nitisols and one ferralsol. For ionizable pesticides, soil pH appears to be a first-order discriminating factor of the sorption capacity, and the organic carbon content appears to have a lesser impact on 2,4-D. For a strongly hydrophobic pesticides such as difenoconazole, the organic carbon content plays a major role in sorption. Desorption hysteresis has been observed regardless of the soils and the molecules considered, and tropical volcanic soils seem to be conducive to adsorption but show low to moderate release. The silandic andosol, which has the greatest sorption, buffers the dissemination of pesticides towards surface and groundwaters but also increases the risk of long-term contamination in the case of molecules that degrade slowly. Moreover, our results highlight that agronomic practices, such as liming, have a major impact on the sorption coefficient of pesticides and must be considered for when predicting sorption in a tropical volcanic context.

Food web attributes to assess spatial–temporal dynamics in estuarine benthic ecosystem

Threatened benthic ecosystems need urgent tools for effective bioassessment and relevant management. EU Marine Strategy Framework Directive (MSFD) obligates member states to achieve GES (Good Environmental Status) for 11 descriptors of environmental state (MSFD; 2008/56/EC). From all of the descriptors, D4 that focuses on Food Webs is the most functional-oriented indicator, but also the most challenging to implement due to our limited knowledge on benthic interactions. Particularly, it is still unclear how spatially and temporally regulated abiotic variables determine the entire benthic food webs, and which benthic food web attributes best respond to these spatially and temporally derived environmental variations. To fill this gap, we measured the natural isotopic ratios (δ13C and δ15N) of macrobenthic organisms and their food sources and build twelve food web topologies across three distinct sites (Navigator, Gambia, Tróia) in summer and winter during two consecutive years. To assess these food web topologies, we applied isotopic metrics, further integrated with univariate and multivariate analysis to find food web-based indicators that best respond to these spatial and temporal variability.We found clear spatial patterns associated to an increase in primary production and quantity and quality of organic matter (OM). Sites with higher organic load and less quality OM (Navigator and Gambia) had simpler food webs, likely associated to high abundance of opportunistic meiobenthic species. Site located inside protected area (Tróia) with high quality OM had the most complex food web characterized by high diversity of specialist consumers that used more efficiently available resources. Similarity metrics were valuable complementary tool that helped to further disentangle the causes of spatial variability, in this case distinguishing between two food webs (Navigator and Gambia) that had similar structures but different resource utilization.The temporal patterns were not so evident than the spatial patterns, although significant differences were reported between sampling occasions for the same metrics (maximum trophic position and the percentage of carnivores and omnivores, p < 0.05). The most complex Tróiás food web demonstrated greater responsiveness in capturing temporal differences in resource use, suggesting that more complex food webs are better equipped to reflect temporal variability. The integration of isotopic metrics complemented with multivariate and univariate analyses proved to be an important tool for the analysis of different aspects of the benthic food web complexity in a spatial–temporal context providing a promising approach to assess the functional integrity of the estuarine ecosystems, especially in the context of the descriptor 4 within MSFD.

Production of low-sulfur fuels from catalytic pyrolysis of waste tires using formulated red mud catalyst

Waste tires (WT) are produced in millions of tons per annum and their safe disposal is always a major environmental challenge because of fire hazards and the increasing cost of landfills. WT has high organic matter content that can be converted into fuels and chemicals if suitable technologies can be developed. Herein we report the in situ catalytic pyrolysis of WT using formulated red mud catalyst to produce low sulfur fuel that can be fractionated or can be used without fractionation. The in situ catalytic pyrolysis was conducted at 450–550 °C using formulated red mud catalyst. The yield of pyrolysis liquids ranged from 35 to 40 wt%. The liquid was very rich in limonene and long chain aliphatic hydrocarbons. The catalyst was effective in removing the sulfur compounds in the oil through reactive adsorption desulfurization mechanism. The sulfur species reacted with hematite, calcite, sodium hydroxide, and zinc oxide to form sulfides and were retained in the catalyst. The minimum sulfur content of the catalytic pyrolysis oil was 0.38 wt%. After catalyst regeneration in air through combustion, the catalyst activity was restored, and the catalyst was reused.

Assessing sediment quality at tropical mangrove areas for using as reference sites in ecotoxicological bioassays

The sediment of five mangrove in Pernambuco/Brazil was investigated to find a reference site for toxicity bioassays. Sediment characteristics, metal levels, and toxic effects on the nauplius of the copepod Tisbe biminiensis were studied. The sediment was composed by terrigenous muds and siliciclastic sands with medium to high organic matter contents. The FeAs association show most of the high concentrations and positive correlation among its constituents in the south. In the north, the Ca-Sr-La association is higher and exhibits positive correlation among its components that usually found in carbonate rocks. Very intense toxic effects were observed, mainly in the south, with >70 % reductions in development. As and Hg were positively correlated with mortality and decrease in development. The sediment quality at studied mangroves prevent their use as a reference site in bioassays. These could be linked to the direct/perennial contribution of geogenic sources associated with anthropogenic environmental impacts.

Medium-Scale Soil Moisture Retrievals Using an ELBARA L-Band Radiometer Using Time-Dependent Parameters for Wetland-Meadow-Cropland Site

The soil moisture at the medium spatial scale is strongly desired in the context of satellite remote sensing data validation. The use of a ground-installed passive L-band radiometer ELBARA at the Bubnów-Sęków test site in the east of Poland gave a possibility to provide reference soil moisture data from the area with a radius of 100 m. In addition, the test site comprised three different land cover types that could be investigated continuously with one day resolution. The studies were focused on the evaluation of the ω-τ model coefficients for three types of land cover, including meadow, wetland, and cropland, to allow for the assessment of the soil moisture retrievals at a medium scale. Consequently, a set of reference time-dependent coefficients of effective scattering albedo, optical depth, and constant-in-time roughness parameters were estimated. The mean annual values of the effective scattering albedo including two polarisations were 0.45, 0.26, 0.14, and 0.54 for the meadow with lower organic matter, the meadow with higher organic matter, the wetland, and the cropland, respectively. The values of optical depth were in the range from 0.30 to 0.80 for the cropland, from 0.40 to 0.52 for the meadows (including the two investigated meadows), and from 0.60 to 0.70 for the wetland. Time-constant values of roughness parameters at the level of 0.45 were obtained.