High Nutrient Concentrations Research Articles

Nutrient sources, phytoplankton blooms, and hypoxia along the Chinese coast in the East China Sea: Insight from summer 2014

Phytoplankton blooms are common along the Chinese coast in the East China Sea, driven by various nutrient sources including river discharge, bottom water regeneration, and Kuroshio subsurface water intrusion. A notable 2014 summer bloom off the Zhejiang coast, exhibiting a Chl a concentration of 20.1 μg L−1, was significantly influenced by Changjiang River discharge, and high nutrient concentrations are often observed in the region's surface water. During blooms, primary production peaks at 1686.3 mg C m−3 d−1, indicating substantial CO2 absorption, with surface water fCO2 declining to 299.5 μatm, closely linked to plankton activities. Hypoxia often coincides with these frequent bloom occurrences, implicating marine-derived organic matter decomposition as a pivotal factor. Elevated particulate organic carbon concentrations further support this assumption, alongside increased nutrient levels, fCO2, and low pH in hypoxic waters. These findings underscore the intricate interplay between phytoplankton, nutrient cycling, and hypoxia formation, essential for effective coastal ecosystem management.

Valorization of Fecal Sludge Stabilization via Vermicomposting in Microcosm-Enriched Substrates Using Organic Plant-Derived Materials and Agricultural Soil for Compost Production

The enormous generation of fecal sludge without proper treatment is a major sanitation problem. Vermicomposting of fecal sludge is an innovative way of producing value added compost called vermicompost. A vermicomposting technique that involves augmenting vermibed substrates with organic rich materials to provide additional nutrients and underlying layers needed for microcosm development to produce desirable vermicompost is mostly referred to as substrate enrichment. This study investigated the substrate enrichment of using plant-derived materials, which include coconut coir, palm coir and saw dust, combined with agricultural soil for the production of vermicompost from fecal sludge. Enriched substrates were prepared with 80 g of agricultural soil as amending material, 120 g of fecal matter (65-70% dry matter) and 160 g of the plant-derived materials. The treatments were labeled T1-T3, thus, T1 contained coconut coir, T2 contained palm coir and T3 contained saw dust, followed by a control treatment (T4) that had no plant-derived material. Treatments were triplicated and about 3-week-old 20 clitellated, E. fetida (live weight ∼255–275 mg) were used in the vermicomposting for 12 wk. Physicochemical parameters such as pH, Organic Carbon (Corg), Total Nitrogen (Ntot), Available Phosphorus (Pavail), Exchangeable Calcium (Caexch), Iron (Fe), Lead (Pb) and Aluminum (Al) test were performed. Vermicompost at T1 had the most Corg mineralization, most enhancement in Ntot, Pavail, Caexch, and least concentration of Fe, Pb and Al. Less than 20% earthworm mortality was recorded in all treatments except T4 (28.38 ± 8.71%). The enriched substrates were suitable for vermiculture with a worm weight ranged from 593.77 to 569.39 ± 2.30 mg and the vermicompost recorded high nutrient contents. The nutritious nature and the reduced metal concentration of the produced vermicompost might be safe and productive for agricultural use. However, further studies on the effectiveness of the vermicompost on plants growth and yield needs to be investigated.

Investigation of optimum conditions for the recovery of magnesium ammonium phosphate from human urine using the Box–Behnken design

ABSTRACT Urine from domestic wastewater greatly increases the nutritional value of wastewater. Urine has a high concentration of nutrients and minerals that can be utilized as plant growth agents, according to a chemical analysis. Due to its high phosphate, nitrogen, and potassium content, human urine can serve as a sustainable substitute for chemical fertilizers. Struvite, also referred to as MAP, can be considered as a sustainable fertilizer and it is a magnesium ammonium phosphate crystal with the chemical formula of MgNH4PO4·6H2O. Struvite may be formed from many types of wastewater, one inexpensive and reliable source for struvite formation being human urine. However, struvite formation requires an external magnesium supply due to the extremely low concentration of magnesium in human urine. In this work, magnesium ammonium phosphate was precipitated from human urine by examining the effects of Mg2+ dose, temperature, and pH on struvite crystals. Several experiments for struvite precipitation were created using the Box–Behnken design. Struvite crystals formed upon the addition of a magnesium source at 20 °C, pH 10, and a mole ratio of 1:1. The results show that the large-scale application and nutrient recovery of struvite crystals from human urine are promising.

Irrigation-Initiated Changes in Physicochemical Properties of the Calcisols of the Northern Part of Fergana Valley

Agriculture in Central Asia and in the Fergana Valley in general strongly depends on irrigation and drainage of agricultural lands. The Fergana Valley includes about 45% of the irrigated area in the Syr Darya River basin. Active use of irrigation in agriculture can lead to changes in the soil’s natural composition, as well as pollution and changes in the soil’s physical and chemical properties. Soil degradation in the process of irrigation can lead to a decrease in crop yields and, as a consequence, to a decrease in food security in the region. In this study, a comparative analysis of three main types of Calcisols (Dark, Light, and Typical) before (uncultivated soil) and after agricultural use (surface-irrigated agricultural soil) was carried out. Irrigation leads to increment of SOC stocks in Typical (from 113.8 to 126.3 t/ha) and Light (from 62.8 to 100.1 t/ha) Calcisols and to decreasing of SOC stocks in Dark Calcisols (from 160.1 to 175.3 t/ha). In general, the content of biophilic elements (SOC and TN) is lower in irrigated soils, and their distribution in the soil profile is close to the functional relationship (r2 0.98 to 0.99). In uncultivated Calcisols, the profile distribution of SOC and TN is more heterogeneous (r2 0.67 to 0.97). Changes in the humification processes of soil organic matter are also identified; in soils after irrigation the carbon ratio of humic/fulvic acids (CHA/CFA) is lower (<1) compared to their uncultivated counterparts (~1). The alteration of the soil water regime also resulted in transformation of the individual compositions of amino acids. All studied types of Calcisols are characterized by changes in particle-size distribution of soils especially in the number of the silt fraction (0.01–0.05 mm) and the difference between uncultivated and irrigated soils, 10–20%, which is associated with the processes of colmatage by accumulation of a fine fraction and replacement of sub-fractions in the fraction of sand. The highest concentrations of nutrients are characteristic of the upper soil horizons (P up to 231, K up to 2350 mg/kg), which indicate their pedogenic and agrogenic origins rather than inheritance from the parent material. Soil P and K availability is rather high, with non-labile forms prevailing, although of near reserve. The surface irrigation results in apparent accumulation of water-soluble Mg2+ (1.6–2.1 meq/100 g) and K+ (0.6–0.9 meq/100 g), but the cation of Ca2+ predominates in the base cations’ composition, which is the most favorable in terms of soil agrogenic property formation. Data obtained will be useful for development of strategies for effective land use in arid, subtropical, overpopulated regions of Central Asia that have deficient water sources and intensive soil degradation.

Salt stress amelioration and nutrient strengthening in spinach (Spinacia oleracea L.) via biochar amendment and zinc fortification: seed priming versus foliar application

Soil salinity is a major nutritional challenge with poor agriculture production characterized by high sodium (Na+) ions in the soil. Zinc oxide nanoparticles (ZnO NPs) and biochar have received attention as a sustainable strategy to reduce biotic and abiotic stress. However, there is a lack of information regarding the incorporation of ZnO NPs with biochar to ameliorate the salinity stress (0, 50,100 mM). Therefore, the current study aimed to investigate the potentials of ZnO NPs application (priming and foliar) alone and with a combination of biochar on the growth and nutrient availability of spinach plants under salinity stress. Results demonstrated that salinity stress at a higher rate (100 mM) showed maximum growth retardation by inducing oxidative stress, resulted in reduced photosynthetic rate and nutrient availability. ZnO NPs (priming and foliar) alone enhanced growth, chlorophyll contents and gas exchange parameters by improving the antioxidant enzymes activity of spinach under salinity stress. While, a significant and more pronounced effect was observed at combined treatments of ZnO NPs with biochar amendment. More importantly, ZnO NPs foliar application with biochar significantly reduced the Na+ contents in root 57.69%, and leaves 61.27% of spinach as compared to the respective control. Furthermore, higher nutrient contents were also found at the combined treatment of ZnO NPs foliar application with biochar. Overall, ZnO NPs combined application with biochar proved to be an efficient and sustainable strategy to alleviate salinity stress and improve crop nutritional quality under salinity stress. We inferred that ZnO NPs foliar application with a combination of biochar is more effectual in improving crop nutritional status and salinity mitigation than priming treatments with a combination of biochar.

Response of the phytoplankton size fractions along environmental gradients from an oxygen minimum zone in the central Mexican Pacific

The marine phytoplankton community responds to latitudinal, longitudinal (coast to ocean), and vertical environmental gradients, an important subject in Oxygen minimum zones (OMZ). The phytoplankton structure and the effect of environmental gradients along the central Mexican Pacific, an area within an OMZ, were studied, especially the importance of size fractions and taxonomic groups. A combination of various methods and protocols, such as microscopic analysis, flow cytometer, and pigment analysis, were followed in this study. Oceanographic conditions included thermal gradients along the study area and unreported evidence of a weak upwelling in the southern zone (Acapulco). Vertical distribution of chlorophyll a showed subsurface maxima (SCM, 15-45 m depth) in all stations, and deeper chlorophyll-a maxima (DCM, 85-95 m depth) in more oceanic stations. Chain-forming diatoms dominated in the northern zone stations. Prochlorococcus, Synechococcus, and picoeukaryotes abundances ranged between 0.01 to 21.7 cells×104 mL-1, although most samples showed the highest contribution to biomass (47.95 μg C L-1) by picoeukaryotes. Expected tendencies of Prochlorococcus distribution were observed: highest densities coincided with the DCM and divinyl chlorophyll-a distribution at oceanic stations. Fucoxanthin had the highest concentrations, whereas fucoxanthin and zeaxanthin concentrations were higher at SCM depths. We documented the co-dominance of the pico- and microplankton: picoplankton was important at the DCM, related to oligotrophic and more stratified water column, whereas microplankton prevailed in coastal stations, with mixed water column, high nutrient concentrations, and diatoms as the dominant group. Picoeukaryotes abundances were related to the concentration of prasinoxanthin, which suggests an important mamiellophyte component not previously revealed.

Optimal N/P Ratio of the Shrimp Culture Waste Fertilizer For Growth Rate of Spirulina platensis

The cultivation of vaname shrimp produces waste with a high nutrient content. This waste can be used as fertilizer in microalgae culture like Sprulina platensis. However, the N / P ratio in shrimp culture waste is low, namely 5.5: 1, while the need for growth of blue-green algae ranges from 10:1 - 16:1. Therefore, it is necessary to regulate the N: P ratio in shrimp culture waste to match the needs of S. platensis. The purpose of this study was to determine the effect of different N / P ratios on shrimp culture waste fertilizer on the growth of S. plantesis. This study used a Completely Randomized Design (CRD) which was divided into 6 treatments with 3 replications, as P0: Walne fertilizer (N / P ratio 17: 1), P1: shrimp culture waste fertilizer enriched with urea (N / P ratio 5,5: 1), P2 with N/P ratio of 10.5: 1, P3 with N/P ratio of 15.5: 1, P4 with N/P ratio of 20.5: 1 and P5 with N/P ratio 25.5: 1. The parameters observed were density and growth rate of S. platensis and water quality namely: temperature, salinity, and pH. The data obtained were processed using Analysis of Variance (ANOVA) and continued with Duncan's multiple range test. The results of this study indicate that the application of shrimp culture waste fertilizer with different N/P ratios affect the population and growth rate of S. platensis. Shrimp culture waste fertilizer with a N: P ratio of 15.5: 1 (P3) is the best treatment for the growth of S. platensis because it produces the highest population and growth rate compared to the other treatments.

Amazonian Fruits for Treatment of Non-Communicable Diseases.

The Amazon region has a high biodiversity of flora, with an elevated variety of fruits, such as Camu-Camu (Myrciaria dúbia), Açaí (Euterpe oleracea Mart.), Tucumã (Astrocaryum aculeatum and Astrocaryum vulgare), Fruta-do-conde (Annona squamosa L.), Cupuaçu (Theobroma grandiflorum), Graviola (Annona muricata L.), Guarana (Paullinia cupana Kunth var. sorbilis), and Pitanga (Eugenia uniflora), among many others, that are rich in phytochemicals, minerals and vitamins with prominent antioxidant and anti-inflammatory potential. Studies evaluating the chemical composition of these fruits have observed a high content of nutrients and bioactive compounds. Such components are associated with significant biological effects in treating various non-communicable diseases (NCDs)and related complications. Regular intake of these fruits from Amazonas emerges as a potential therapeutic approach to preventing and treating NCDs as a nutritional strategy to reduce the incidence or mitigate common complications in these patients, which are the leading global causes of death. As studies remain largely unexplored, this narrative review discusses the possible health-beneficial effects for patients with NCDs.

The Impact of Chlorella vulgaris Fortification on the Nutritional Composition and Quality Characteristics of Beef Burgers.

Chlorella vulgaris (C.V) is known for its high protein and nutrient contents and has been touted as a potential functional ingredient in food products. For this study, beef burgers were formulated with varying levels of Chlorella vulgaris fortification (0%, 0.5%, 1%, and 1.5% by weight). The nutritional composition, including proximate analysis and mineral content, was determined for each treatment group. The quality characteristics evaluated included thiobarbituric acid (TBA), total volatile base nitrogen (TVBN), pH, and total acidity. The study included extracting the active substances from Chlorella vulgaris using three solvents, 50% ethanol, 95% ethanol, and water, to evaluate the effect on the antimicrobial and antioxidant activity. The results showed that the water extract had the highest total phenolic content (183.5 mg gallic acid equivalent per gram) and the highest flavonoid content (54 mg quercetin per gram). The aqueous extract had the highest content of total antioxidants, followed by the 95% ethanol and 50% ethanol extracts. Meanwhile, the 50% ethanol extract showed the best antimicrobial activity, while the aqueous extract had less of an effect on Gram-positive bacteria and no effect on E. coli. For the burger treatments, at the end of the storage period, it was observed that the microbial load of the treatments decreased compared to the control, and there was a high stability in the total volatile base nitrogen (TVBN) values for the treatments compared to the control, reaching a value of 22.4 at month 5, which is well above the acceptable limit, indicating spoilage. The pH values were higher for all of the treatments, with a lower total acidity for all of the treatments compared to the control. In conclusion, utilizing Chlorella vulgaris algae as a natural preservative to extend the freshness of burgers is a sustainable and innovative approach to food preservation. By harnessing the power of this green superfood, we not only enhance the shelf life of our food products but also contribute to a healthier and more environmentally friendly food industry.

Evaluation of Various Concentrations of Rumen Waste in making Liquid Organic Fertilizer

Slaughterhouses are known as places to produce meat for human consumption. On the other hand, slaughterhouses produce livestock waste, one of which is rumen. The rumen's high nutrient and microbial content provide an excellent opportunity for its use as liquid organic fertilizer for plant growth and development. However, evaluation of rumen addition concentration during the manufacture of liquid organic fertilizer is still scarce and needs to be carried out. Therefore, this research aims to obtain a suitable rumen addition formulation for making liquid organic fertilizer. Rumen waste was varied in 4 concentrations, namely 20%, 40%, 60% and 80%. Supporting ingredients, such as laos, ginger, turmeric, galangal, and rice washing water, are mixed with the rumen, which is then incubated for 15 days to obtain liquid organic fertilizer. Analysis of total nitrogen content, C/N ratio, total phosphate, total potassium, total microbes, and physical characteristics was carried out to evaluate the quality of liquid organic fertilizer. The results showed that the addition of 80% rumen was able to play a role in producing liquid organic fertilizer with high total nitrogen (2.35%), low C/N ratio (6.05), high total phosphate (1.19%), and high total potassium (1.75%). Furthermore, liquid organic fertilizer made with the addition of 80% rumen contains high total microbes (5.5 x 1010 CFU/mL), is bright brown, yellowish in color, and has an earthy aroma. This research indicates that adding 80% rumen can produce good quality liquid organic fertilizer. This information can be the basis for further research regarding the rumen potency as an ingredient of organic fertilizer.

Distribution of nutrients and dissolved organic matter in a eutrophic equatorial estuary: the Johor River and the East Johor Strait

Abstract. Estuaries have strong physicochemical gradients that lead to complex variability and often high rates of biogeochemical processes, and they are also often impacted by humans. Yet, our understanding of estuarine biogeochemistry remains skewed towards temperate latitudes. We examined seasonal and spatial variability in dissolved organic matter (DOM) and nutrients along a partly eutrophic, agricultural–urban estuary system in Southeast Asia: the Johor River and the East Johor Strait. Dissolved organic carbon (DOC) and coloured DOM (CDOM) showed non-conservative mixing, indicating significant DOM inputs along the estuary. The CDOM spectral slopes and CDOM : DOC ratios suggest that terrigenous, soil-derived DOM dominates along the Johor River, while phytoplankton production and microbial recycling are important DOM sources in the Johor Strait. CDOM properties were not unambiguous source indicators in the eutrophic Johor Strait, which is likely due to heterotrophic CDOM production. Nitrate concentrations showed conservative mixing, while nitrite concentrations peaked at intermediate salinities of 10–25. Ammonium concentrations decreased with salinity in the Johor River but increased up to 50 µmol L−1 in the Johor Strait, often dominating the dissolved inorganic nitrogen (DIN) pool. Phosphate concentrations were low (<0.5 µmol L−1) throughout the Johor River but increased in the Johor Strait, where DIN : phosphate ratios were typically ≥ 16 : 1. This suggests that the Johor Strait may experience phosphorus limitation and that internal recycling is likely important for maintaining high nutrient concentrations in the Johor Strait. Overall, our results indicate that the Johor River and Johor Strait are clearly not part of the same estuarine mixing continuum and that nutrient recycling processes must be quantified to understand nutrient dynamics in the Johor Strait. Moreover, our results highlight the need for better techniques for DOM source tracing in eutrophic estuaries.

Bacterial Communities, Network Complexity, and Multifunctionality Affected by Soil Types in Northeastern China

The Northeast China Plain (NCP) is the country’s most important grain-producing area. Unraveling how bacterial communities in this region assemble and distribute according to soil type is essential for sustainable agricultural development and optimizing the precise management of soil resources. In this study, 106 soil samples were collected from three typical zonal soil types (black calcium soil (BCS), black soil (BS), and dark brown soil (DBS)) spanning from west to east in the NCP. By combining soil field surveys and high-throughput microbial sequencing analysis, we found that bacterial diversity and community structure differed significantly by soil type. Proteobacteria, Gemmatimonadetes, and Acidobacteria were enriched in BCS, BS, and DBS, respectively. Compared to BSC and DBS, BS had the highest nutrient concentration and most neutral pH values, which may recruit more diverse bacterial communities and construct a more connected ecological network. Network analysis further identified Burkholderiales, Sphingomonadales, and SC_I_84 as key hubs in BS, BCS, and BCS, respectively. The majority of classified hubs consistent with the results of the linear discriminant analysis effect size belonged to the predominant biomarkers. Redundancy and Mantel test analyses revealed that the bacterial composition in various soil types showed distinctive responses to heterogeneity in soil physicochemical properties. Soil pH and TP were the primary factors shaping the soil bacterial community structure in these three soil types on the NCP. Moreover, bacterial composition and diversity were strongly related to changes in soil multifunctionality in BCS, and the relative abundances of three classes (TM1, Opitutae, and Deinococci) were the most important biotic variables for predicting BCS ecosystem multifunctionality. In summary, our results suggest that soil type variation has a strong influence in terms of shaping bacterial community structure and affecting soil multifunctionality. Correspondingly, diverse co-occurrence patterns were observed in different soil types.

Geochemical and palynological characteristics of the Maykop sections in the north-west of the Shamakha-Gobustan region (Azerbaijan)

The article provides a comparative analysis of the results of complex palynological and geochemical studies of rocks from natural outcrops of Lagich, Angekharan and Agsu in the north-west of the Shamakhi-Gobustan region. A comparison of the distribution features of palynomorph species with the lithofacies variability of sediments made it possible to reveal the conditions of sedimentation during the formation of the described sections. In addition, the age of the units identified in the Maikop deposits in Lagich and Angekharan was clarified by analogy with the formations and horizons of similar ages in the Western and Central Ciscaucasia. The boundary of Eocene and Oligocene deposits in the Lagich section is assumed to be in the interval of 80–115 m. Late Eocene deposits occurring at the base of the section are apparently an analogue of the boundary deposits of the Beloglinskaya and Pshekhskaya formations of the Ciscaucasia. The presence of cold-water dinocysts of the species I.recurvus and calcareous nannofossils Coccolithus pelagicus in the boundary interval corresponds to the existing ideas about climate cooling at the end of the Eocene - beginning of the Oligocene. The formation of sediments in the upper intervals of the section probably occurred in more open marine conditions, relatively warm water, but with low levels of nutrients (nitrates). This interval of sediments with a characteristic phytoplankton complex can be correlated with the middle part of the Khadum horizon, an analogue of the Nizhny Morozkinsky subformation and, possibly, with the upper clayey part of the Polbinsky formation of Western and Central Ciscaucasia. The accumulation of the lower units of the studied part in the Angekharan, dated to the Early Oligocene, most likely occurred in a marine, shallower environment with possible short-term transgressive impulses. Overall, it is possible to suggest a proximal environment of high nutrient content in well-mixed waters within the inner neritic zone. An analogue of the deposits of this interval can be the Lower Morozkinsky Formation and the lower parts of the Upper Morozkinsky Formation of the Ciscaucasia. The significant increase in deflandroids in the upper part of the Angekharan section is similar to the changes noted during the transition to the zone of Deflandrea spinulosa f. Majkopica in the upper part of the Batalpashinskaya Formation of the late Oligocene in Ciscaucasia. The accumulation of sediments probably occurred in a marine basin with signs of stagnation in brackish, eutrophic environment, with a short-term supply of material from the photic zone. The conclusions about the peculiarities of changes in the depositional conditions in the study area are also confirmed by the results of geochemical studies. The deposits of the studied sections are represented by both terrestrial and aquatic types of organic matter (OM). Terrigenous OM was more typical in rocks from the Lagich and Agsu outcrops. The OM of rocks from the Lagich section varies from marginally mature to mature. In the Angekharan section the OM is thermally immature, as evidenced by the low Tmax values. Despite the small thickness of the Agsu outcrop, rock samples from this section contain kerogen of various stages of transformation from immature to mature. The carbon isotope composition (CIC) of Corg in sediments within the studied sections is in the δ13C range, characteristic of Oligocene sediments in the Paratethys. There is a higher enrichment of the 13C isotope in OM in sediments from the Agsu section.

Advanced Technology for Energy, Plant Nutrients and Water Recovery at Wastewater Treatment Plants

In present times, with increasing emphasis on circular economies, municipal wastewater treatment plants (WWTPs) are considered resource recovery facilities. The targeted resources are water, biogas, and sludge, organic residuals containing nutrients and elements needed by plants (nitrogen and phosphorus). Sludge is a byproduct that constitutes the largest volume of all other byproducts obtained in wastewater treatment plants. Its processing and disposal are challenging for environmental engineers because of its complexity. Thus, quick development and implementation in industrial practice of sludge valorization and utilization technologies is required, where high nutrient content must be taken into account. Also, the occurrence of a variety of pathogens in sewage sludge is a matter of concern, even in the case of developed countries. The use of untreated sludge or wastewater in agricultural activities poses a serious risk of bacterial and parasitic infection in human beings. To overcome such issues, the application of ionizing radiation processing, especially electron beam (EB), can be considered a promising method. Its effectiveness in pathogen removal has been proven by researchers. Water radiolysis products created during irradiation of water are highly reactive and cause some effects such as DNA damage, OH • radical production, etc. Additionally, ionizing radiation technologies in sewage sludge treatment enhance the efficiency of the methane fermentation process. Depending on specific needs, different types of ionizing radiation sources can be discussed. Based on the review information and our research results, the basic engineering parameters of hybrid installation have been presented as the conclusion of the report. In this technical solution, a notably effective additional step would be the use of EB irradiation, combined with conventional wastewater treatment, to achieve efficient removal of pollutants.

Spatial, Temporal, and Interspecific Differences in Composition of Stable Isotopes in Fishes in Maryland Coastal Bays

Carbon (δ13C) and nitrogen (δ15N) isotopes were used to evaluate spatial, temporal, and interspecific differences in trophic relationships of four fish species (Paralichthys dentatus, Anchoa mitchilli, Leiostomus xanthurus, and Bairdiella chrysoura) in Maryland’s coastal bays. The δ13C values for all species were more enriched in 2017 than in 2018, a year of higher-than-average rainfall that likely caused higher amounts of terrestrial carbon to enter the estuary. There were significant differences among species in the δ13C values, with L. xanthurus being the least depleted (−17.2‰ in 2017; −18.8‰ in 2018). Spatially, the δ13C values of the species, particularly P. dentatus and B. chrysoura, were more depleted in the northern bays, which have a higher nutrient content and receive more freshwater inflow directly from tributaries, than the southern bays. The observed δ13C values (−19.5 ± 0.2‰ to –17.2 ± 0.3‰), however, indicate that marine phytoplankton was the primary carbon source of the fishes. Overall, A. mitchilli was the most enriched in δ15N (13.0‰), and L. xanthurus was the most depleted (10.2‰). δ15N was more enriched in fish from the more human-impacted northern bays than in fish from the southern bays, though this might also have stemmed from the differences in the diet composition of the species in the northern and southern bays. A. mitchilli had the highest trophic level, while L. xanthurus and P. dentatus had the lowest trophic levels. Niche breadth was widest in L. xanthurus compared to the other fish species, suggesting a higher variability in diets among L. xanthurus individuals, leading to specialized diets. There was a high niche overlap between B. chrysoura, A. mitchilli, and L. xanthurus, which indicates they fed on similar prey resources.

Study on the quality and consumer acceptance of sorghum (Sorghum bicolor L. Moench) flour-based dried noodle

Abstract Sorghum is growing to become an alternative substitute of food ingredients for various food products. Supported by its productivity and high nutrient content, sorghum can be converted into flour, substituting wheat flour in food products, such as dried noodles. This study aimed to evaluate the chemical, physical, and sensory quality of sorghum-based dried noodles. The research was conducted by Complete Randomized Design of Experiment (CRD) with Two Factors: the variety of sorghum and the level of sorghum substitution. The combinations of variety and substitution levels used in this study were Numbu-30%, 45%, 60% and Super 2-30%, 45%, 60%. The increased proportion of sorghum flour in noodles formulation resulted in higher ash, fat, and carbohydrate content but lower water and protein content. In addition, substituting wheat flour with sorghum flour increased the swelling index of the dried noodles but resulted in a higher cooking loss. In terms of sensory acceptance evaluation, the higher level of sorghum substitution increased the colour’s acceptance score, while on the other hand, reduced the acceptance score for aroma, flavour, and texture attributes of dried noodles.

Metabolome and transcriptome reveal high abundance of bioactive substances in albino jujube fruit as potential function food

Little is known about the fruit quality of albino mutants, due to generally exhibited lethal phenotypes caused by restrained photosynthesis and energy metabolism. In this study, a non-lethal bud mutant of jujube that could bear fruit with higher nutrient content after leaf albinism was described. Compared to normal mature fruit, the albino fruit contained lower soluble sugar and titratable acid, as well as higher ascorbic acid, phenols and flavonoids contents. Through metabolome and transcriptome analyses, 109, 117, and 126 differentially accumulated metabolites (DAMs) and 1169, 797, and 3059 differentially expressed genes (DEGs) were identified in the young, white-ripened, and mature stages of albino and normal fruits, respectively. KEGG annotation indicated that DEGs and DAMs were mainly enriched in phenylpropanoid and flavonoid biosynthesis, glutathione metabolism, and α-linolenic acid metabolism. Moreover, ADH, GST17, and POD16 were identified as hub genes that play major roles in high abundance of chalcone, (−)-epigallocatechin, GSH, and total ascorbate. The alteration of bioactive substance content in albino fruits was an adaptive molecular mechanism that responded to adverse mutations, and reflected a higher antioxidant capacity. These findings provide new insights into bioactive compounds accumulation in albino mutants, and provide experimental evidence for albino fruit as a potential nutraceutical or functional food.

Plankton Community Metabolism Variations in Two Temperate Coastal Waters of Contrasting Nutrient Richness

AbstractEstuarine ecosystems play a crucial role in global carbon cycling. Understanding the factors controlling plankton metabolism in these regions is critical. This study investigates how contrasting nutrient conditions influence plankton metabolism and carbon flow in two Danish estuaries, Roskilde Fjord (RF) (eutrophic) and the Great Belt (GB) (less eutrophic). Despite higher nutrient concentrations in RF, chlorophyll a and biomass only showed a moderate increase compared to the GB. Interestingly, metabolic rates (photosynthesis and respiration) in RF displayed greater temperature sensitivity, suggesting potential nutrient limitation effects in the GB. While both stations exhibited similar annual net primary production, RF's higher net community production highlights the importance of nutrient availability for carbon accumulation within the system. Additionally, the study observed significant seasonal variations in plankton metabolism and its impact on the carbon cycle. Notably, the more dynamic hydrography in the GB weakened correlations between biological and environmental factors.

Gully regulates snowmelt runoff, sediment and nutrient loss processes in Mollisols region of Northeast China

Gully is a prominent indicator of land degradation in agroecosystems, functioning as a crucial pathway connecting upslopes to downstream channels. However, little is known about how gully regulates runoff, sediment, and nutrient loss processes in the catchment during snowmelt. In this study, we monitored these processes in situ at both the gully head (the upslope accumulated catchment of the gully head, CGH) and outlet of two representative and typical gully-dominated catchments (F1 and F2) during snowmelt in Mollisols region of Northeast China. Our results showed that runoff discharge of CGH and outlet exhibited a multi-peak trend during snowmelt, driven by the transition from snow melting to soil thawing. This transition resulted in distinct runoff patterns in both CGH and outlet, with significant differences in their response to air temperature. The total runoff yield of CGH accounted for 57.8 % in F1 and 40.6 % in F2 of the total runoff yield of the outlet. Notably, the peak sediment concentration displayed a marked lag compared to the peak runoff discharge, primarily dominated by the increased sensitivity of gully erosion after the thawing of gully slopes. Gully erosion was the main source of sediment yield in the catchment, contributing 98.2 % in F1 and 96.6 % in F2. Furthermore, nutrient concentrations exhibited a decreasing trend during snowmelt. The comparison of high nutrient concentrations in CGH and relatively low nutrient concentrations in outlet highlighted the gully's role in intercepting and diluting runoff nutrients. Hysteresis analysis confirmed the differential contribution of CGH and gully to nutrient sources. CGH accounting for 50.9 % and 93.3 % of runoff TN and runoff TP loss, while contributing only 8.3 % and 5.8 % to sediment TN and sediment TP loss, respectively. These findings offer valuable insights for effective erosion control and nonpoint source pollution management in gully-dominated agroecosystems during snowmelt.

Warming induced shade tolerance to become a key trait in invasion success of free-floating plant Pistia stratiotes over the native Hydrocharis morsus-ranae

Changes in nutrient concentration, temperature and light intensity due to climate change can alter the species composition of aquatic ecosystems, since global climate change can intensify the process of eutrophication. Eutrophication can enhance the biological invasion and the distribution of alien aquatic plants. Here we investigated the competition ability of alien Pistia stratiotes and native Hydrocharis morsus-ranae and the effect of different light intensities, temperatures and nutrient concentrations on the functional traits of the two species. In short term (8 days) monoculture experiment, we applied low (0.5 mg L-1 N; 0.05 mg L-1 P) and high nutrient concentrations (2 mg L-1 N; 0.2 mg L-1 P), four different light intensities (25–295 μmol m−2 s−1) as well as cold and warm (21.5; 27.5 ± 0.5°C) water treatments in full factorial design. In mixed cultures we cultivated the plants for 28 days with various biomass ratio, in shaded and well illuminated conditions, at a high nutrient concentration (4 mg L-1 N 1 mg L-1 P). In monocultures, the relative growth rate of P. stratiotes in warm water was significantly higher than that of H. morsus-ranae, however, this difference was not significant in colder water. In the co-culture experiment, P. stratiotes had significantly higher growth rate compared to H. morsus-ranae regardless of initial plant biomass ratio. Under shaded (65 ± 5 μmol m−2 s−1) conditions, P. stratiotes outcompeted H. morsus-ranae, resulting in its decay. Experimental results imply that with elevated temperature, the spread of alien P. stratiotes can be expected. Furthermore, under shaded conditions, P. stratiotes has a higher chance of occupying the water surface over the native plant H. morsus-ranae.