Aquaculture wastewater contains elevated levels of nutrients and organic pollutants that can accelerate eutrophication and impair aquatic ecosystems if discharged untreated. In the study, a fungal-based remediation approach was investigated for the removal of pollutants from aquaculture wastewater collected from Baltim Station ponds (31.55244° N, 31.092855° E) near Lake Burullus, Egypt. Two native fungal isolates, Aspergillus niger and Aspergillus flavus, were employed for primary mycoremediation experiments, while Ganoderma mbrekobenum was included only in the Plackett–Burman experimental design to evaluate the influence of environmental and nutritional factors on total phosphorus (TP) removal under optimized conditions. The fungal treatment significantly improved water quality, showing substantial reductions in total protein, phosphorus, nitrogen, organic matter, and chemical oxygen demand (COD) indicating a vital role of Aspergillus species in the bioremediation of nutrient-rich aquatic environments. The Plackett–Burman design (PBD) showed that fungal treatment significantly reduced pollutant concentrations with higher metabolic activity and enzymatic production as dehydrogenase and total protein from 9 to 12 days. Moreover, PBD identified KH2PO4 and MgSO₄ as the most influential variables for enhancing TP removal in the presence of G. mbrekobenum, while peptone and yeast extract exhibited the greatest effect in the non-fungal control system. The regression models demonstrated strong predictive accuracy (R2 > 0.99), confirming the validity of the optimization approach. The results highlight the effectiveness of fungal biomass as a cost-effective and eco-friendly bioremediation strategy for mitigating nutrient pollution in aquaculture effluents and protecting sensitive aquatic environments such as Lake Burullus.

Reseeding native species indirectly enhances degraded desert steppe stability by increasing functional diversity in arid areas.

Soil aggregates, which form the basic framework of soil structure, exert significant control over soil quality and crop yield. However, the influence of organic amendments on the relationships between aggregate formation and crop yield are still unclear. To investigate this issue, a long-term field experiment was established including four fertilizer treatments: control without fertilization (CK), chemical fertilizer (NPK), NPK combined with straw (NPKS), and NPK combined with organic manure (NPKM). Soil aggregates were fractionated into >2 mm (LMA), 2–0.25 mm (MMA), 0.25–0.053 mm (SMA), and <0.053 mm (MIC) fractions. NPKS and NPKM treatments increased the proportion of large macroaggregates (LMAs) by 8–12% and significantly elevated soil organic carbon (SOC) and nutrient levels relative to CK. NPKS and NPKM significantly increased the soil quality index (SQI) of LMA and MIC by 45.5–116.7% and 21.1–32.1%, compared with CK and NPK. Random forest (RF) analysis revealed that among the nutrient variables across the four aggregate fractions, the SOC content in LMA and the total phosphorus (TP) content in MIC contributed the highest to soybean yield. Partial least squares modeling further confirmed that the SQI of LMA was the dominant factor influencing soybean yield. Therefore, long-term organic amendments improve soybean yield mainly by enhancing soil quality at the aggregate scale, providing a practical pathway for sustaining soil quality and crop productivity.

Agricultural non-point source pollution (ANPSP) is one of the important factors leading to water environmental pollution. Identifying the spatial distribution of ANPSP and implementing regional control measures are, therefore, important for ensuring effective pollution prevention and control. However, analyzing regional ANPSP using a single approach is challenging due to the impacts of geographical, economic, and policy differences. In this context, the present study aims to assess the long-term spatiotemporal characteristics of pollutants and their sources in Henan Province over the 2001–2023 period using inventory analysis, equal standard pollution load method, and cluster analysis. In addition, we investigated the decoupling relationship between ANPSP and agricultural output value using the Tapio decoupling model. The results showed that: (1) distinct variation stages of total pollution, including total emission reduction, structural transition, and emerging conflicts. Specifically, there was a increase in total pollution over the 2001–2006 period, followed by a fluctuation, continuous decrease, and stabilization in the 2007–2013, 2014–2019, and 2020–2023 periods, respectively. The pollution loads of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) were reduced by 26.2, 23.5, and 18.2%, respectively. In addition, increases in the contribution rates of livestock and farmland straw. On the other hand, rural households and livestock were the main sources of COD and TP emissions, respectively. The main source of TN emissions has shifted from livestock to farmland straw; (2) the total pollutant load exhibited a distinct spatial distribution pattern. Specifically, the southern part of the study area had the highest pollutant loads, followed, respectively, by the eastern, northern, and western parts; (3) the decoupling relationship between ANPSP emissions and agricultural output values showed fluctuating changes, dominated by weak and strong decoupling status, with gradual improvement. (4) Henan Province was divided into three primary non-point source pollution control zones using cluster analysis, namely high, moderate, and low-risk zones. The high, moderate, and low risk areas had average equivalent pollution indices of 61.89, 40.44, and 15.37, respectively. In this study, we proposed targeted prevention and control measures for ANPSP in Henan Province. These findings provide a reference for the governance and planning of ANPSP in Henan Province, as well as a novel perspective for investigating the relationship between rural development and the environment.

Environmental DNA-based tracking and mapping reveal process-driven seasonal dynamics in fish diversity and community assemblages.

This study investigated the impact of Epichloë gansuensis, a fungal endophyte that forms a long-term symbiosis with the grass Achnatherum inebrians, on fungal and bacterial communities, nutrient concentrations, and microorganismal-nutrient relationships associated with host roots. Both fungal and bacterial communities associated with the host root endosphere were characterized for plants infected with E. gansuensis (symbiotic) and for those that lacked a symbiosis with E. gansuensis (non-symbiotic) using high-throughput sequencing. Concentrations of multiple nutrients were measured in the plant roots, i.e., total carbon, total nitrogen, total phosphorus, total potassium, and organic carbon. In the roots of symbiotic and non-symbiotic plants, fungal communities were dominated by members within Ascomycota, Basidiomycota, and Mortierellomycota, while bacterial communities were predominantly composed by members within Pseudomonadota, Acidobacteriota, and Actinomycetota. The presence of E. gansuensis in plants increased the root concentrations of total carbon, total nitrogen, and organic carbon, but decreased the concentration of total potassium. There were 11 positive (3 fungi and 3 bacteria) and 2 negative (0 fungi and 2 bacteria) significant correlations between microorganismal taxa abundance and nutrient concentrations. The abundance of the fungal phyla Aphelidiomycota, Glomeromycota, and Olpidiomycota were positively correlated with the concentrations of total carbon and organic carbon. The abundance of the bacterial phylum Methylomirabilota was positively correlated with the concentrations of total carbon, total nitrogen, and organic carbon, while negatively correlated with total potassium concentration. Furthermore, the abundance of bacterial phyla Actinomycetota and Nitrospirota were positively correlated with the concentrations of total potassium and organic carbon, respectively, while Pseudomonadota abundance was negatively correlated with the concentration of total potassium. Our findings emphasize the effect of a fungal endophyte, E. gansuensis, that is exclusively found in the aboveground organs of its host plants and absent from belowground plant organs on the concentrations of nutrients within plant roots and the existence of putative functional relationships between root-associated fungal/bacterial communities and root nutrients.

Introduction Sugarcane is a critical global crop, primarily used for sugar production, with applications spanning the food, industrial, and pharmaceutical sectors. Improving nutrient efficiency in sugarcane varieties is essential to enhance yield, ensure sugar security, and improve nutritional value. Methods This study analyzed 109 sugarcane stem segment samples to assess major (magnesium, calcium, phosphorus) and trace (manganese, iron, copper) nutrient content, along with SNP genotyping data. Two multi-model Genome-Wide Association Study (GWAS) approaches—MLM_Q+Kinship and MLM_PCA+Kinship—were employed to identify SNPs associated with nutritional traits. Results Under a P-value threshold of <10⁻⁴, the MLM_Q+Kinship approach identified SNPs linked to several traits, including total sugar (4), nitrogen (7), phosphorus (179), potassium (4), sulfur (41), magnesium (26), calcium (20), and silicon (66). Similar results were obtained with MLM_PCA+Kinship. A stricter threshold (P < 1.53×10⁻⁶) yielded 59 reliable "Peak" SNP loci, which explained over 15% of phenotypic variance. Notably, SNPs 3B_33126337 and 5C_64683842 were strongly associated with magnesium, calcium, and iron utilization. Genotypic analysis revealed superior nutrient accumulation in genotypes TT (3B_33126337) and AA/AG (2D_29369331, 3B_14919731). Bioinformatics analysis identified 12 candidate genes involved in magnesium, calcium, and manganese metabolism, linked to pyruvate metabolism, purine metabolism, and glycolysis/gluconeogenesis pathways. RT-qPCR analysis confirmed significant expression differences in three genes (Sspon.003B0015150, Sspon.002D0013560, and Sspon.003B0007030) between genotypes, suggesting their potential as key targets. Conclusion These findings provide valuable genetic markers and candidate genes for the development of nutrient-efficient, high-yield sugarcane varieties, contributing to advancements in both agriculture and nutrition.

Increasing concern on the role of phosphorus in crop production across fields of agricultural research call for concern. This study assesses the effect of land use types on various forms of soil phosphorus in Gashua. Soil samples were collected across three different locations namely forested land (FL), bare land (BL), and cultivated land (CL) from 0–15 cm and 15-30cm depth. ANOVA was used to show the significant difference between the variables. The results from the study area showed Available phosphorus (A-P) with values ranging from 8.33 mg kg-1 to 8.57 mg kg-1. Bulk density remained stable 1.20-1.42 gcm-³, and pH values 6.60 - 7.40 indicated slightly alkaline conditions. Electrical conductivity (EC) varies between 0.09 - 0.19, suggesting low salinity. Organic carbon content of the study area ranged from 0.70% to 1.18%. Phosphorus fractions from the study revealed that calcium-phosphorus (Ca-P) was highest in forested regions with 20.63 mg kg-1 while iron-bond phosphorus (Fe-P) was higher in bare land with value of 14.84 mg kg-1. Aluminum-bound phosphorus (Al-P) recorded a maximum value of 143 mg kg-1 in cultivated land, and organic phosphorus (Or-P) recorded a maximum of 65.55 mg kg-1 in bared land. Total phosphorus (T-P) was higher in both cultivated land and bare-land with 143.85 mg kg-1 and 140.06 mg kg-1 and forested areas showed an appreciably decreased values of 98.27 mg kg-1. The study Concluded that there were no variations in A-P, Ca-P, and Fe-P throughout the land use types, while the Al-P and Or-P show higher variations.

ABSTRACT Objective The purpose of this study was to evaluate the efficacy of the aquatically formulated humic acid product AC Aqua in reducing total phosphorus concentrations and controlling the proliferation of two harmful algal species, golden algae Prymnesium parvum and Microcystis aeruginosa. Methods Three treatments of AC Aqua (prophylactic, low dose, and high dose) and a control were tested in 13.3-L mesocosms with and without sediment (n = 6 per treatment) to simulate lined and earthen pond conditions. Prophylactic treatment (5 mL/m3) was applied 10 d before P. parvum (91 cells/mL) and M. aeruginosa (246 cells/mL) inoculation. Low (5 mL/m3) and high (7.67 mL/m3) doses were applied 6 h after inoculation. Phosphorus concentrations were measured before and after application to assess binding, while algal cell counts were monitored weekly for 7 weeks for each trial. Results Within 6 h, all AC Aqua treatments reduced total phosphorus, with the high-dose and sediment treatments having a significant reduction in phosphorus, compared with control groups, in both trials. Significant reductions in P. parvum cell counts were observed in the prophylactic treatments beginning in week 3 (P = 0.017). By week 7, all treatments had substantially lower cell counts compared with controls, with several treatment groups, particularly those with sediment, falling below 10,000 cells/mL, while control groups remained above 90,000 cells/mL. Significant reductions in M. aeruginosa cell counts were observed in the prophylactic treatments beginning in week 2 (P = 0.014). By week 6, all treatments were below 10,000 cells/mL, while control groups remained above 65,000 cells/mL. Conclusions AC Aqua effectively reduced P. parvum and M. aeruginosa cell densities in eutrophic systems when applied prophylactically. Its lag effect indicates a nutrient management mechanism, supporting its use as a sustainable, preventative strategy.

Spatiotemporal variation and impact factors of steady-state TN and TP in lake sediments in China since 1850.

Regulatory mechanisms of total phosphorus on N2O concentrations: A case study of Dongting lake.

Contrasting seasonal variations in riverine nitrogen and phosphorus concentrations in China: implications for N/P imbalances.

Enhanced wastewater treatment using microalgae-bacteria-fungi consortia with brassinolide.

Linking spatial patterns of chlorophyll a and phosphorus concentrations: River length and upstream lakes control realized eutrophication in German rivers.

Controlling and optimizing the volatile organic compound and organic contaminant removal by improved water management in plastic recycling plants.

Mechanisms and management of rainfall-triggered phytoplankton bloom in a deep stratified reservoir: key drivers and reactivation thresholds.

Stricter reductions of nutrient pollution support riverine community recovery in degraded catchments.

Efficient removal of nitrogen, phosphorus and antibiotics in freshwater aquaculture wastewater using a novel hybrid aeration biological filter.

BackgroundEnhanced nitrogen (N) load was considered a critical factor influencing phosphorus (P) availability and P-cycling in marsh soils. However, information on the links between soil P availability and microbial genes involved in P-cycling processes under N enrichment conditions remains scarce.MethodsA field N load experiment with four treatments (N0, Nlow, Nmedium, and Nhigh) was conducted in Cyperus malaccensis marsh of the Min River estuary, and soil P availability, the relative abundances of P-cycling functional genes and their regulatory roles on P availability were investigated.ResultsThe total phosphorus (TP) contents in soils were significantly positively correlated with N load levels (p < 0.05). Compared with the N0 treatment, the TP in the Nlow, Nmedium and Nhigh treatments increased by 8.97%, 17.34% and 15.21%, respectively. With increasing N load levels, the proportions of easily- and moderately-available P in TP contents noticeably increased, suggesting that N additions enhanced soil P availability. Metagenomic sequence analyses showed that N enrichment markedly altered the relative abundances of P-cycling functional genes. Briefly, the abundances of inorganic P solubilization genes (particularly ppa and ppx) increased substantially with increasing N load levels. The total abundances of organic P mineralization genes in the Nlow and Nmedium treatments decreased markedly, while those in the Nhigh treatment increased greatly. The abundances of genes coding for phytase (phy and appA) markedly increased with increasing N load levels, implying that phytase was more sensitive to N enrichment. Furthermore, enhanced N load noticeably reduced the abundances of genes participated in P transportation (particularly ugpABEC) and those involved in P-assimilating process (e.g., phoR, phoB, pstABCS and pit). As affected by enhanced N load, the contents of easily-available P showed strong correlations with the abundances of genes involved in inorganic P solubilization while those of moderately-available P (particularly Sonic-Pi, Sonic-Po and NaOH-Pi) were positively correlated with the abundances of genes involved in P regulation and transportation, indicating strong linkages between P-cycling functional genes and soil P availability.ConclusionsThis paper found that, under N enrichment conditions, the increased inorganic P solubilization potential and the weakened microbial P immobilization capacity were beneficial to increasing soil P availability.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40793-025-00813-3.

Effect of catchment characteristics and water physicochemical parameters on nitrogen and phosphorus concentrations in streams and small reservoirs.