Most probable transition paths in eutrophicated lake ecosystem under Gaussian white noise and periodic force

The effects of stochastic perturbations and periodic excitations on the eutrophicated lake ecosystem are explored.Unlike the existing work in detecting early warning signals,this paper presents the most probable transition paths to characterize the regime shifts.The most probable transition paths are obtained by minimizing the Freidlin-Wentzell(FW)action functional and Onsager-Machlup(OM)action functional,respectively.The most probable path shows the movement trend of the lake eutrophication system under noise excitation,and describes the global transition behavior of the system.Under the excitation of Gaussian noise,the results show that the stability of the eutrophic state and the oligotrophic state has different results from two perspectives of potential well and the most probable transition paths.Under the excitation of Gaussian white noise and periodic force,we find that the transition occurs near the nearest distance between the stable periodic solution and the unstable periodic solution.

Eutrophication of Jiangsu Coastal Water and Its Role in the Formation of Green Tide

Since 2007,the large-scale green tide caused by Ulva prolifera(U.prolifera)have occurred as a recurrent phenomenon in the southern Yellow Sea of China.Field surveys and satellite remote sensing showed that the small scattered patches of green tide algae were first observed along the Porphyra agriculture area of the Subei Shoal in late April.In this study,we attempted to identify the role of eutrophication in the origin of the green tide in the Subei Shoal and its adjacent area.Subei Shoal and its adjacent area are characterized by rich nutrients,especially NO_(3)^(-)-N,NH_(4)^(+)-N,PO_(4)^(3-)-P,and other bioavailable components(such as urea-N and amino acids).In the spring of 2017,the average concentrations of NO_(3)^(-)-N were 19.01±11.01μmolL^(-1),accounting for 86.68%of the dis-solved inorganic nitrogen(DIN).In addition,the average concentration of NH4^(+)-N was 2.51±1.60μmolL^(-1).PO_(4)^(3-)-P had an average concentration of 0.14±0.13μmolL-1.The average concentrations of urea-N and total hydrolyzed amino acids(THAA)were 1.73±1.36μmolL^(-1)and 1.33±0.80μmolL^(-1),respectively.Rich nutritive substances play a key role in the rapid production of U.prolifera and make the Jiangsu coastal water an incubator for green tide.

Plant Nitrogen Metabolism: Balancing Resilience to Nutritional Stress andAbiotic Challenges

Plant growth and resilience to abiotic stresses,such as soil salinity and drought,depend intricately on nitrogen metabolism.This review explores nitrogen’s regulatory role in plant responses to these challenges,unveiling a dynamic interplay between nitrogen availability and abiotic stress.In the context of soil salinity,a nuanced rela-tionship emerges,featuring both antagonistic and synergistic interactions between salinity and nitrogen levels.Salinity-induced chlorophyll depletion in plants can be alleviated by optimal nitrogen supplementation;however,excessive nitrogen can exacerbate salinity stress.We delve into the complexities of this interaction and its agri-cultural implications.Nitrogen,a vital element within essential plant structures like chloroplasts,elicits diverse responses based on its availability.This review comprehensively examines manifestations of nitrogen deficiency and toxicity across various crop types,including cereals,vegetables,legumes,and fruits.Furthermore,we explore the broader consequences of nitrogen products,such as N_(2)O,NO_(2),and ammonia,on human health.Understand-ing the intricate relationship between nitrogen and salinity,especially chloride accumulation in nitrate-fed plants and sodium buildup in ammonium-fed plants,is pivotal for optimizing crop nitrogen management.However,prudent nitrogen use is essential,as overapplication can exacerbate nitrogen-related issues.Nitrogen Use Effi-ciency(NUE)is of paramount importance in addressing salinity challenges and enhancing sustainable crop productivity.Achieving this goal requires advancements in crop varieties with efficient nitrogen utilization,pre-cise timing and placement of nitrogen fertilizer application,and thoughtful nitrogen source selection to mitigate losses,particularly urea-based fertilizer volatilization.This review article delves into the multifaceted world of plant nitrogen metabolism and its pivotal role in enabling plant resilience to nutritional stress and abiotic challenges.It offers insights into future directions for sustainable agriculture.

A summary of Copepoda:synthesis,trends,and ecological impacts

Copepoda are one of the most significant animal groups present in aquatic ecosystems.Ecologists,evolutionary biologists,and biotechnologists continue to test new methods to study the application of Copepoda as model organisms in various fields of pure and applied science,from evolution and ecology to aquaculture as live feed,as biological control of mosquito larvae,as biological indicators of water and sediment quality,in environmental monitoring and as a source of protein in the food industry.This paper reviews the current progress and trends within copepod research from a number of different perspectives.We emphasize the importance of Copepoda and the necessity of strengthening research on various topics related to copepod biology,some of which are of great significance to local sustainable development.

Seasonal implications for taxonomic sufficiency to simplify M-AMBI methodology in the coastal area adjacent to a eutrophic estuary

Taxonomic sufficiency(TS)refers to identifying taxa to a taxonomic level sufficient to detect community changes in stressed environments and may provide a cost-effective approach in routine monitoring programs.However,there is still limited information regarding the seasonal impact of applying TS and its implications for the ecological quality evaluation in the estuarine ecosystem.This study investigated the relationship between the multivariate-AZTI’s Marine Biotic Index(M-AMBI)and environmental variables in three seasons(i.e.,spring,summer,and autumn)in the Liaohe River Estuary.We tested the reliability of TS for simplifying the M-AMBI methodology.The results showed that family and genus level data could reproduce the spatial-temporal patterns of community structure at the species level.The M-AMBI values showed a consistent spatial distribution pattern in all sampling seasons,with a decreasing trend with the increasing distance from the estuary mouth.Both genus and family level data performed nearly as well as species level in detecting the seasonal variations of pollutants(i.e.,nutrients and total organic content).The family level M-AMBI was feasible to discern stress in the Liaohe River Estuary because of the high aggregation ratios at different taxonomic levels in all sampling seasons.These findings suggest that applying taxonomic sufficiency based on the M-AMBI provides an efficient approach for evaluating ecological quality in the Liaohe River Estuary.

Spatial changes and driving factors of lake water quality in Inner Mongolia, China

Lakes play important roles in sustaining the ecosystem and economic development in Inner Mongolia Autonomous Region of China,but the spatial patterns and driving mechanisms of water quality in lakes so far remain unclear.This study aimed to identify the spatial changes in water quality and the driving factors of seven lakes(Juyanhai Lake,Ulansuhai Lake,Hongjiannao Lake,Daihai Lake,Chagannaoer Lake,Hulun Lake,and Wulannuoer Lake)across the longitudinal axis(from the west to the east)of Inner Mongolia.Large-scale research was conducted using the comprehensive trophic level index(TLI(Σ)),multivariate statistics,and spatial analysis methods.The results showed that most lakes in Inner Mongolia were weakly alkaline.Total dissolved solids and salinity of lake water showed obvious zonation characteristics.Nitrogen and phosphorus were identified as the main pollutants in lakes,with high average concentrations of total nitrogen and total phosphorus being of 4.05 and 0.21 mg/L,respectively.The values of TLI(Σ)ranged from 49.14 to 71.77,indicating varying degrees of lake eutrophication,and phosphorus was the main driver of lake eutrophication.The lakes of Inner Mongolia could be categorized into lakes to the west of Daihai Lake and lakes to the east of Daihai Lake in terms of salinity and TLI(Σ).The salinity levels of lakes to the west of Daihai Lake exceeded those of lakes to the east of Daihai Lake,whereas the opposite trend was observed for lake trophic level.The intensity and mode of anthropogenic activities were the driving factors of the spatial patterns of lake water quality.It is recommended to control the impact of anthropogenic activities on the water quality of lakes in Inner Mongolia to improve lake ecological environment.These findings provide a more thorough understanding of the driving mechanism of the spatial patterns of water quality in lakes of Inner Mongolia,which can be used to develop strategies for lake ecosystem protection and water resources management in this region.

Effect of Incorporating Cowpea (Vigna unguiculata) Meal into Broiler Diets on Environmental Pollution by Nitrogen from Poultry Excreta: A Review

Poultry feeds are formulated using soybean meal and animal by-products as sources of protein. Animal proteins like fish meal, blood meal, meat and bone meal are being shunned in formulating poultry feeds nowadays because they are associated with zoonotic diseases like salmonellosis and this has left soybean meal as the only source of dietary protein in broiler feeds. Soybean meal is in short supply in Zimbabwe and this country is relying on some soybean meal imports from South Africa and Zambia resulting in prices of poultry feed and broiler meat going upwards. Cheap and locally available alternative sources of protein to soybean meal must be found in order to reduce the cost of making poultry feed. The selected alternative source of protein must have protein which is highly digestible such that the bulk of this protein can be metabolized and utilized by broilers to synthesize meat leaving a little of it to be excreted through faeces and urine. Highly digestible protein is very important in broiler feed making because this reduces the amount of nitrogen lost through poultry excreta into the environment. Cowpea has been chosen to entirely or partially replace soybean meal in this review paper because it is locally grown, drought tolerant, cheap and its true protein digestibility (TPD) of 71% to 76% is generally comparable to 81% to 83% of soybean meal. Nowadays, people are concerned about protecting the environment from being polluted by wastes from industrial and agricultural activities. Poultry farming pollutes the environment with ammonia emitted from poultry excreta. The grain legumes used in formulating broiler feed such as soybean meal contain anti-nutritional factors which reduce protein digestibility and increase nitrogen excretion through poultry faeces. The nitrogen in faeces is volatilized into ammonia, emitted into the atmosphere and cause eutrophication of surface waters. Therefore, the effect of incorporating cowpea meal in broiler diets on environmental pollution by nitrogen excretion from broiler faeces needs to be explored.

Adsorption Properties of Phosphate by CaCl2-loaded Straw Microwave Charcoal

Phosphate is the main limiting factor of water eutrophication. In order to effectively control phosphorus pollution in water, straw microwave charcoal(CaCl2SBC) was prepared with straw after CaCl2activation and microwave biomass carbonization, and the adsorption effect of phosphate by CaCl2SBC was analyzed. The results showed that the prepared straw microwave charcoal contained hydroxyl and carbon-carbon double bonds, and CaCl2SBC had a very obvious adsorption effect on phosphate in eutrophic water. The optimum conditions for the adsorption of phosphate by CaCl2SBC are as follows: initial concentration of phosphate was 50 mg/L;adsorption time was 120 min;pH was 9;adsorption temperature was 25 ℃;CaCl2SBC dosage was 300 mg/L. Under the optimum conditions, the maximum removal rate can reach 99%. The prepared straw microwave charcoal can be used for phosphorus removal from eutrophic water.

Analysis of Water Quality and Eutrophication Status of Artificial Lakes on Campus:A Case Study in Tibet University

In this paper,the artificial lake on the campus of Tibet University was taken as the research object.By detecting the water quality of the lake,the standard index method and comprehensive pollution index method were used to understand the water quality characteristics,pollution status,and main pollutants of the Siyuan Lake.On this basis,the comprehensive nutritional status index method was used to evaluate the eutrophication status of the Siyuan Lake.The results showed that the overall water quality of the artificial lake was good,showing as still clean,with TN and TP being the main pollution factors of the artificial lake.The main nutritional indicators were TN,TP,and transparency,with a comprehensive nutritional level of middle eutropher.Based on the environmental characteristics of the artificial lake area on the campus of Tibet University,reasonable treatment measures have been proposed.It hoped to prevent and improve the water environment through these measures,and provide reference for the protection and restoration of campus landscape water body.

Navigating Eutrophication in Aquatic Environments: Understanding Impacts and Unveiling Solutions for Effective Wastewater Management

Eutrophication is the term used to describe the presence of natural and artificial nutrients like phosphorus and nitrogen in aquatic ecosystems.The water quality in various bodies of water such as ponds,lakes,rivers,etc.is deteriorating as a result of an abundance of plant nutrients in these water sources.Over-enrichment of aquatic ecosystems with nutrients is a major hazard to the well-being of aquatic ecosystems worldwide.In addition,the circulations have lowered the requirements for home and agricultural consumption of water.The main origins of these plant nutrients within aquatic ecosystems stem from the discharges of industries engaged in activities like livestock farming,agriculture,fertilizer production,manufacturing of textiles,and clothing production.Therefore,a variety of methods and approaches have already been developed as safety measures to avoid the negative consequences of water tainted with those undesired minerals.Eutrophication presents many obstacles,but with the right public awareness campaign and global scientific efforts,its negative impacts may be lessened.This research seeks to pinpoint the primary origins of plant nutrients within the aquatic ecosystem and explore potential triggers for eutrophication.Additionally,it proposes innovative regulatory methods and offers suggestions for sustainable wastewater management practices.

Monitoring of the Physico-Chemical Parameters of the Waters of Lake Sonfonia,Municipality of Ratoma(Republic of Guinea)2021

As part of the determination of the possible impact of human activities on surface waters, case of Lake Sonfonia, six sampling sites were selected according to their solicitation by the population and their exposure to probable sources of pollution. The objective of this work is to monitor the physico-chemical quality of the waters of Lake Sonfonia during the low water level (March) and during the flood period (August) of the year 2021. Two sampling campaigns of water were carried out in dry weather and two others in cold weather. Parameters such as temperature, pH, EC (Electrical Conductivity), dissolved oxygen, TDS (Total Dissolved Solids) were measured in situ. Suspended matter, phosphate, nitrate, nitrite, sulphates, total iron, COD (Chemical Oxygen Demand) were measured in the laboratory by the colorimetric method. Stata 15 software was applied for the statistical analysis of the data and the correlation test between the parameters gave highly significant correlations. It has been noted that the situation is not very good and that this pollution comes mainly from human activities.

贵州红枫湖水库富营养化和蓝藻水华分析(英文)

[Objective] The research aimed to know the ecological environment pollution characteristics of Hongfeng Lake water area and the evolution rule,which provided the theory basis for improving the water quality condition.[Method] Based on the investigation and research of indoor and outdoor,the water quality,aquatic ecosystem,pollution characteristic of sediment and occurrence law of algae blooms in Hongfeng Lake were comprehensively analyzed by combining with the relevant literatures.[Result] Hongfeng Lake was in moderate-heavy eutrophication situation,and the water quality was V-bad V class.The sediment accumulated a lot of nutrient salt,which was the important pollution source of eutrophication in Hongfeng Lake Reservoir.The aquatic ecosystem degraded,and it was easy to form the algae blooms.[Conclusion] The pollution treatment of Hongfeng Lake was extremely urgent.

郑州市公园景观河流富营养化现状评价及防治方案探讨(英文)

The evaluation of landscape water eutrophication in Zhengzhou City could provide a scientific basis for the prevention of eutrophication.By taking landscape lakes in People Park and Zijing Mountain Park as the research objects,and selecting seven sampling spots,GPS had been conducted every week from March to April of 2010.By making use of TLI and TSIM,the landscape water eutrophication of the two parks had been evaluated.The research results showed that the average value of TLI of sampling waters in the two parks was 66.80 and 64.74;those of TSIM was 58.61 and 59.94,respectively.It could be known that landscape water eutrophication of the two parks was moderate and should be controlled and treated in time.Finally,the paper had pointed out that it should purify waters,reduce endogenous nutritions,and control exogenous nutritions by cultivating plants.

国外水域富营养化防治途径研究简介

江河、湖泊、水库等水域在自然和人为因素影响下,矿物质和有机物质的含量不断增加,引起水域的富营养化。富营养化(eutrophication)可分为自然富营养化与人为富营养化。本文重点介绍的是国外对人为富营养化防治途径的研究。人类在各种生产活动中,将各种不同物质和能量带入水环境中,并连续不断地积聚,破坏了水生生态系统的平衡。

杭州岳阳庙景观水体生态修复工程研究(英文)

On account of the existent problems of the small landscape water of 400 m2,with the recovery technique of submerged plants as the core,assisted by the measures of AquaMats ecological base,ecological floating bed construction,biological manipulation,the landscape water was treated comprehensively and the water quality obviously improved after the implementation and treatment of twelve month,CODMn,BOD5,NH3-N,TP,TN and SS respectively decreasing from 4.24,7.62,2.24,0.49,9.31,11.00 mg/L to 2.04,4.76,0.69,0.27,3.72,6.00 mg/L.After the treatment,the organic pollution and eutrophication of the landscape water was controlled to a certain degree,the eruption of the algal bloom was mitigated,and the color of landscape water changed from dark green to yellowish green,and the transparency degree increased from 50 cm to nearly 65 cm.The successful implementation of the restoration project provided certain guiding paradigm for the treatment of small landscape water in cities.

Exploration of relationships between phytoplankton biomass and related environmental variables using multivariate statistic analysis in a eutrophic shallow lake:A 5-year study

Understanding the process of the changing phytoplankton patterns can be particularly useful in water quality improvement and management decisions. However, it is generally not easy to illustrate the interactions between phytoplankton biomass and related environmental variables given their high spatial and temporal heterogeneity. To elucidate relationships between them, in a eutrophic shallow lake, Taihu Lake, relative long-term data set of biotic and abiotic parameters of water quality in the lake were conducted using multivariate statistical analysis within seasonal periodicity. The results indicate that water temperature and total phosphorus （TP） played governing roles in phytoplankton dynamics in most seasons （i.e. temperature in winter, spring and summer; TP in spring, summer and autumn）; COD （chemical oxygen demand） and BOD （biological oxygen demand） presented significant positive relationships with phytoplankton biomass in spring, summer and autumn. However, a complex interplay was found between phytoplankton biomass and nitrogen considering significant positive relationships occurring between them in spring and autumn, and conversely negative ones in summer. As the predatory factor, zooplankton presented significant grazing-pressure on phytoplankton biomass during summer in view of negative relationship between them in the season. Significant feedback effects of phytoplankton development were identified in summer and autumn in view that significant relationships were obser,qed between phytoplankton biomass and pH, Trans （transparency of water） and DO. The results indicate that interactions between phyto：plankton biomass and related environmental variables are highly sensitive to seasonal periodicity, which improves understanding of different roles of biotic and abiotic variables upon phytoplankton variability, and hence, advances management methods for eutrophic lakes.

Assessment of water pollution control strategies: a case study for the Dianchi Lake

Lake eutrophication has increasingly become a major environmental issue in China. Although significant efforts have been made towards its resolution in the last decade, most of the implemented control strategies are fragmented, and the formation of policy lacks of sound scientific basis and long\|term objectives. Taking the well\|known Dianchi Lake as a case study, this paper presented a comprehensive assessment for the effectiveness of various eutrophication control strategies. It is expected that the concluding lessons would have a major implication to future eutrophication control.

Effects of bacteria on nitrogen and phosphorus release from river sediment

To better understand the mechanisms of eutrophication, we addressed the microbial processes that influence many key aspects of water-sediment systems. In this study, a large column experiment was conducted for 30 d. Along the column, solution samples were collected at different locations at different time. The samples were analyzed for physical, chemical, and biological properties of the sediment and overlying water. The results showed that the amount of nitrogen transforming bacteria was higher than that of phosphorous bacteria. The amount of nitrogen transforming bacteria was in the order： ammonifier 〉 denitrifying bacteria 〉 nitrobacteria and nitrosomonas. Principal component analysis indicated that the three main factors accounted for more than 90% overall contributions for bacterium growth, which represented nutrition, organics and oxygen, and pH and redox potential （Eh） of the environment. Corresponding to the bacteria, the concentrations of nitrogen in the system was in the order： ammonia （NH4＋-N） 〉 nitrate （NO3^--N） 〉 nitrite （NO2^--N）. The fluxes of N and P clearly showed a temporal release and adsorption processes in the water-sediment system. The large magnitude of N fluxes suggested that N might act as an important contamination source for the water quality. However, P exchange between the sediment and overlying water was less intensive during the experiment.

AAssessment of the spatial-temporal eutrophic character in the Lake Dianchi

Water-quality deterioration and eutrophication of the Lake Dianchi have acquired more and more attention in the last few decades. In this paper, the spatial and temporal eutrophication status of the Lake Dianchi was assessed. The comprehensive trophic state index was chosen to assess the trophic status of the Lake Dianchi in the past 13 years. The result reveals that the trophic condition of Caohai is more serious than that of Waihai. Most of time Caohai was in extremely hypereutrophic state from 1988 to 2000. The trophic condition of Waihai had a worsening tendency from 1988 to 2000. Waihai was in eutrophic state before 1995, but it got in a hypereutrophic state after 1995. It was pointed out that TN and TP were the two biggest contributors of CTSIM in both Caohai and Waihai.

Adsorption behavior of phosphate on Lanthanum(Ⅲ) doped mesoporous silicates material

A series of lanthanum doped meosoporous MCM-41 （LaxM41, x is Si/La molar ratio） was prepared by sol-gel method. The surface structure of the materials was investigated with X-ray diffraction and N2 adsorption/desorption technique. The content of La in the materials was determined by ICE It was found that the La content of La25M41, La50M41 and La100M41 was 7.53%, 3.89% and 2.32%, respectively. The phosphate adsorption capacities increased with increasing amount of La incorporation. With 0.40 g La25M41 99.7% phosphate could be removed. The effects of Si/La molar ratio, LaxM41 dose, pH, initial concentration of phosphate solution, co-ions on phosphate adsorption were also evaluated. The phosphate adsorption kinetics of LaxM41 could be well-described by the pseudo second-order model, and Langmuir isotherm fit equilibrium data much better than the Freundlich isotherm.