Addressing the growing threat of harmful algal blooms driven by eutrophication and climate change, biomanipulation via fish has emerged as a promising strategy to enhance water quality in lake ecosystems. While biomanipulation is often evaluated by its impact on algal control, the influence of food web structure and function on water quality requires further mechanistic understanding. This study pioneers a 22-year ecosystem-scale analysis using Ecopath with Ecosim (EwE) model to quantify how a dual biomanipulation strategy involving filter-feeding fish and piscivorous fish reshapes energy flow pathways and nitrogen cycling dynamics in a subtropical eutrophic lake. The findings indicate that the introduction of filter-feeding fish (silver carp, Hypophthalmichthys molitrix, and bighead carp, Aristichthys nobilis) suppress cyanobacterial blooms by redirecting 52.7% of nitrogen to fisheries, while piscivorous fish (bass, Lateolabrax japonicus, and eel, Anguilla japonica) amplify trophic cascades, enhancing zooplankton-mediated microalgal regulation. Food web connectivity increased (connectance: 0.12 to 0.21), minimizing nitrogen flux to detritus and improving water quality by 38%, driven by cyanobacterial biomass suppression, enhanced energy transfer efficiency, and fish-mediated nitrogen removal. These results demonstrate that integrated biomanipulation balances fishery yields with eutrophication control, offering a climate-resilient framework for restoring subtropical lakes globally. This work advances mechanistic insights into nutrient-energy synergies and provides actionable strategies for sustainable aquatic management in warming ecosystems.

Coastal wetlands face dual pressures from high salinity and heavy metal pollution, presenting significant ecological challenges. Halophytes like Sesuvium portulacastrum possess unique physiological mechanisms to mitigate metal toxicity. This study investigates how silicon (Si) availability influences the accumulation of copper (Cu) and cadmium (Cd) in S. portulacastrum. Our results show that Si supplementation at environmentally relevant levels significantly increases Cu and Cd concentrations in the roots, while simultaneously reducing the root-to-shoot translocation of these metals. In situ non-invasive micro-testing revealed decreased metal efflux from the xylem, indicating an enhanced retention of metals in the roots. Furthermore, analyses using X-ray photoelectron spectroscopy and atomic force microscopy demonstrated a higher density of oxygen-containing functional groups and SiO- on the extracellular matrix of Si-enriched roots. This structural transformation resulted in a significant reduction in root surface potential, facilitating greater metal ion attraction and uptake. The findings from this study provide critical insights into the mechanisms by which Si availability regulates metal accumulation in halophytes, suggesting potential strategies for mitigating metal pollution in coastal wetland ecosystems.

Microplastics (MPs) are prevalent in marine environments and can adsorb contaminants from surrounding seawater, potentially transferring harmful chemicals through the food chain and raising ecological concerns. While the adsorption of aquatic pollutants by MPs has been intensively studied, research on phthalate esters (PAEs, common plasticizers frequently found in seawater) remains limited, primarily focusing on pristine MPs in artificial media. This study characterized the surface physicochemical properties of polyethylene (PE) and polystyrene (PS) MPs before and after natural aging for one week to three months off the coast, and investigated the adsorption isotherms of dibutyl phthalate (DBP, one of the most abundant PAEs in seawater) on these MPs in both natural seawater and ultrapure water. Surface characterization revealed significant alterations in MP surface characteristics due to natural aging, with morphologies and nanomechanical features varied by MP type and oxidation occurring after one-month aging. The best-performing Langmuir-Freundlich model suggested that DBP adsorption onto MPs involved multilayer processes on heterogeneous surfaces with varying adsorption energies. Further analysis indicated that PS had a higher DBP adsorption capacity than PE, attributed to its porous glassy structure and π-π interactions with DBP. The trivial impact of natural aging could relate to competing effects of increased roughness and the formation of polar oxygen-containing groups on aged MPs. The "salting-out" effect in natural seawater was likely impeded by free ion competition and MP aggregation under higher ionic strength. This study provides valuable insights into the interactions between MPs and their coexisting contaminants in marine environments.

This study investigated the level of dissolved heavy metals in the water of Longhu Lake and focused on the speciation, mobility, and risks of heavy metals (Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb) in sediment. The levels of heavy metals in the water were found to be below the thresholds set by the Chinese safe drinking water standard. The highest average percentages of Cr, Ni, Zn, and As were bound with residual fractions, while Pb and Cu were bound with reducible fractions. Additionally, the highest percentage of Cd and Mn was bound to the acid-soluble fraction in the sediment. These findings suggest that Cd, Mn, Pb, and Cu likely originated from anthropogenic sources in the lake. There was a strong correlation between total organic carbon (TOC) and metal fractions in the sediment, indicating that TOC may play a role in transporting heavy metal fractions. Risk assessment code values for Cd and Mn indicated higher risks and mobility, while Ni, Cu, and Zn showed medium risks and mobility for aquatic biota. To mitigate heavy metal contamination, it is recommended to improve monitoring and regulation of urban runoff and inlet areas.

Lead (Pb) pollution in sediments remains a major concern for ecosystem quality due to the robust interaction at the sediment/water interface, particularly in shallow lakes. However, understanding the mechanism behind seasonal fluctuations in Pb mobility in these sediments is lacking. Here, the seasonal variability of Pb concentration and isotopic ratio were investigated in the uppermost sediments of a shallow eutrophic drinking lake located in southeast China. Results reveal a sharp increase in labile Pb concentration during autumn-winter period, reaching ~ 3-fold higher levels than during the spring-summer seasons. Despite these fluctuations, there was a notable overlap in the Pb isotopic signatures within the labile fraction across four seasons, suggesting that anthropogenic sources are not responsible for the elevated labile Pb concentration in autumn-winter seasons. Instead, the abnormally elevated labile Pb concentration during autumn-winter was probably related to reduction dissolution of Fe/Mn oxides, while declined labile Pb concentration during spring-summer may be attributed to adsorption/precipitation of Fe/Mn oxides. These large seasonal changes imply the importance of considering seasonal effects when conducting sediment sampling. We further propose a solution that using Pb isotopic signatures within the labile fraction instead of the bulk sediment can better reflect the information of anthropogenic Pb sources.

A large quantity of metal compounds in plastics are released into the marine environment every year. However, our understanding of the extent and mechanism by which polymer-bound metals leach into seawater is still limited. In this study, a comprehensive survey was conducted to measure the metal concentrations in commonly used plastics and evaluate the effects of environmental factors (temperature, radiation, and salinity) and the physiochemical properties (surface roughness, specific surface area, hydrophobicity, and crystallinity) of the plastics on their metal leaching into seawater. In particular, we observed the metal loss from six plastics sub-merged in coastal seawater for eight months and studied the role of biofilm in controlling the leaching of Sb, Sn, Pb, Ba, and Cr. Our results indicate that increased temperature enhanced the release of these metals, while exposure to ultraviolet radiation significantly increased the leaching of Sn from polylactide (PLA). High salinity facilitated the leaching of Sn from PLA and Pb from polyvinylchloride ball, however inhibited the leaching of Ba from PE wrap. The leaching rate was primarily determined by the inherent property of crystallinity. Metal loss from the plastics in the field was apparent during the first three weeks, but then was hindered by the devel-opment of biofilm. Our study provides the mechanisms underlying metal leaching from physical, chemical, and biological perspectives, which is useful for understanding the environmental risk of the plastic-containing metals.

Microorganisms display nonequilibrium predator-prey behaviors, such as chasing-escaping and schooling via chemotactic interactions. Even though artificial systems have revealed such biomimetic behaviors, switching between them by control over chemotactic interactions is rare. Here, a spindle-like iron-based metal-organic framework (MOF) colloidal motor which self-propels in glucose and H2 O2 , triggered by UV light is reported. These motors display intrinsic UV light-triggered fuel-dependent chemotactic interactions, which are used to tailor the collective dynamics of active-passive colloidal mixtures. In particular, the mixtures of active MOF motors with passive colloids exhibit distinctive "chasing-escaping" or "schooling" behaviors, depending on glucose or hydrogen peroxide being used as the fuel. The transition in the collective behaviors is attributed to an alteration in the sign of ionic diffusiophoretic interactions, resulting from a change in the ionic clouds produced. This study offers a new strategy on tuning the communication between active and passive colloids, which holds substantial potentials for fundamental research in active matter and practical applications in cargo delivery, chemical sensing, and particle segregation.

Mangrove sediments act as both sinks and secondary sources for lead (Pb), yet the sources, migration, and transformations of Pb in mangrove environments are poorly understood. In this study, Pb concentration in three mangrove sediments adjacent to different land-use types was evaluated. The Pb sources were quantitatively identified using Pb isotopes. Our data indicated minor Pb contamination in the mangrove sediments, possibly due to the relative lack of developed industry in this region. The Pb isotopic ratios suggested, on average, natural sources, coal combustion, agricultural activities, and traffic-related emissions respectively contributed approximately 61.4 %, 18.8 %, 14.0 %, and 5.8 % of the Pb accumulation in the mangrove sediments, suggesting that coal combustion and agriculture were important anthropogenic Pb sources. Significant relationships were observed between the 206Pb/207Pb ratios and total organic content (TOC) in mangrove sediments, which implied contrasting Pb cycling in two mangrove environments. We further suggested that organic matter and sulfur content significantly reduced Pb mobility and bioavailability in mangrove sediments. Our study provides isotopic method to investigate the Pb sources and migration in the mangrove environment.

Mangrove ecosystems serve as an important carbon sink but also could be a hotspot that produces neurotoxic methylmercury (MeHg). Although many studies have focused on mercury (Hg) contamination in this carbon-rich ecosystem, our understanding of the effects and mechanisms of the organic matter (OM) regulation of MeHg production in mangrove sediments is still limited. Here, we examined the effects of Hg contamination and OM enrichment on MeHg production in anoxic mangrove sediments and identified the major microbial guilds attending this process. The mangrove sediments possessed a high potential for producing MeHg, but this was counterbalanced by its rapid degradation. Sulfate-reducing bacteria (SRB) such as Desulfobacterales, Desulfovibrionales, and Syntrophobacterales were the major methylators. OM diagenesis significantly changed the biogeochemical conditions, accelerating MeHg degradation in the sediments. The enhanced MeHg degradation could be attributed to the abundant sulfide produced during OM decomposition, which could potentially inhibit the Hg methylation by immobilization of inorganic Hg, abiotically degrade MeHg, and favor the non-mer-mediated degradation of MeHg by SRB. Our study provides both geochemical and microbial clues that can partly explain the low MeHg levels widely observed in mangrove sediments.

Industrialization and urbanization of coastal wetlands have caused metal pollution worldwide. Phytoremediation has been widely used for treating soil and water pollution, and halophytes are considered a promising remediation method to address metal pollution. However, application of halophytes in phytoremediation is still in its infancy. To increase awareness of halophytes, the metal accumulation, tolerance, and mechanisms of metal detoxification in halophytes are reviewed here. Several halophytes are considered as potential candidates for phytoremediation because they have strong accumulation capacity of metals.

In this study, distribution and accumulation of trace elements (Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb) in water, tissues of aquatic organisms (e.g. fishes: Oreochromis niloticus, Platycephalus indicus, Clupanodon punctatus; crabs: Charybdis japonica, Portunus sanguinolentus, and Charybdis varuegata; prawns: Litopenaeus vannamei, Metapenaeus joyneri, Penaeus japonicas, Penaeus penicillatus; mollusks: Mytilus spp., Perna spp.), and trophic transfer in food web were investigated in Yundang Lagoon at Xiamen in China. Most of the studied metals such as Cr, Mn, Ni, Cu, Cd, and Pb were biodiluted in the food web except As which was biomagnified in the food web. Moreover, the target hazard quotient and total target hazard quotient risk values were higher than threshold limit values indicating that non-carcinogenic health risk to the inhabitants due to consumption of aquatic organisms.

The polyculture of shellfish and seaweed together is an effective way to solve the current bottleneck in developing the shellfish culture industry, and determining the optimal ratio is an important prerequisite for its application. Large-scale oyster monocultures in the Beibu Gulf (South China) have led to environmental degradation and exceeded the aquaculture carrying capacity. In order to cope with the problem, this study designed a microcosm of polyculture with shellfish and seaweed, trying to explore the optimal ratio with both environmental protection and economic benefits. Different densities of Gracilaria tenuistipitata (0.33-4.17 kg/m(3)) combined with a fixed density (83.3 ind/m(3)) of Crassostrea hongkongensis were investigated to measure the growth rate and nutrient removal effects. The oyster growth rates in the polyculture groups were 6-14-fold that of the oysters in the monoculture group. The highest oyster and seaweed growth rates were in the medium-density seaweed group (0.83 kg/m(3)). Compared with the low-density seaweed groups, a high density of seaweed effectively removed the nutrients released by the oysters. A response surface analysis showed that a seaweed density of 1.567 kg/m(3) was the optimal proportion with 83.3 ind/m(3) (10 individuals) of C. hongkongensis, with a predicted growth rate of 0.110%/day for the oyster and 0.564%/day for the seaweed. This research indicates that combining G. tenuistipitata in a polyculture system could increase oyster production and provide the exciting prospect of improving seawater quality in the Beibu Gulf.

ABSTRACT Low biological productivity causes ecosystem energy deficiency. Sansha Bay is an important spawning and nursery ground for migratory fish in the East China Sea (ECS). There is significant mariculture in this area, but stock enhancement programs and seasonal fishery closures have failed to recover populations of the commercially important species, Larimichthys crocea . We want to figure out the potential reason of unsuccessful L. crocea resource in recent 30 years. In this study, the trophic status of L. crocea , the food source proportions of L. crocea and zooplankton, and the food web structure and functioning of Sansha Bay was analyzed. A high nutrient low chlorophyll phenomenon was observed: this prevented harmful algal blooms, and phytoplankton growth was restrained by intensive macroalgal culture, resulting in a low abundance of zooplankton in Sansha Bay. Phytoplankton was the most important food source of zooplankton, and zooplankton was the greatest food source of juvenile L. crocea . Analyzed L. crocea suffered from starvation. Crucially, most of the phytoplankton was not used efficiently in the Sansha Bay ecosystem. This study suggests that trophic bottleneck, caused by food limitation, is a potential reason for unsuccessful fishery recovery in enclosed bay with macroalgal culture.

Light-powered fuel-free colloidal motors possess significant potential for practical applications ranging from nanomedicine to environmental remediation. However, current light-powered colloidal motors often require the incorporation of expensive metals or high concentrations of toxic chemical fuels, which is a severe limitation for their practical applications. Integrating highly ordered and porous materials with a large surface area into colloidal motors is a promising strategy for upsurging their self-propelled speed and adsorption, which will benefit many applications. Here, highly efficient, fuel-free, and light-activated metal organic framework (MOF)-3-trimethoxysilyl propyl methacrylate Janus colloidal motors with a hierarchical morphology are reported. These colloidal motors can be driven by UV or visible light, with a self-propelled speed tuned by the light intensity. The speed can be further enhanced by morphology optimization or by the addition of H2O2 as a fuel. The colloidal motors display a superior efficiency in removing heavy metal ions of Hg, which is up to ∼90% within 40 min from the contaminated water, attributed to their high surface area, hierarchical morphology, large number of active sites, and high mobility. This work not only offers a facile approach to incorporate a versatile MOF family into the design of fuel-free and light-powered Janus colloidal motors, but also demonstrates their potential for real-life applications such as environmental remediation.

Biomanipulation is one of the most promising measures in ecological restoration and used to mitigate eutrophication in water bodies. Current biomanipulation methods, such as traditional biomanipulation (based on large-size zooplankton) and non-traditional biomanipulation (based on filter-feeding fish), are often carried out independently and focus on algae control. Integrated biomanipulation, including traditional and non-traditional biomanipulation, was implemented in Longhu Lake, a drinking water source, to successfully control cyanobacterial blooms and improve water quality for 20 years. In order to study the mechanism of algae control and the ecosystem stability, we analysed the effects of integrated biomanipulation and single-biomanipulation on the phytoplankton community and the ecosystem via model simulation. The results revealed that compared with the other single-biomanipulation scenarios of 'filter-feeding fish biomanipulation', 'omnivorous fish biomanipulation', 'piscivore biomanipulation', and 'without biomanipulation', integrated biomanipulation combined the advantages of traditional and non-traditional biomanipulation. In this case, cyanobacteria biomass (4.5 ton/km2) was kept at a low level, although the biomass of small phytoplankton was high. The slope of trophic-levels spectrum was low (18.54%), and the biomass distribution of the community was balanced (less 'up-and-down'). The energy flow transfer efficiency of food web was as high as 14.1% and the ratio of grazing food chain and detrital food chain was close to 1:1. The ascendency was better than other scenarios. These data indicated that the ecosystem after integrated manipulation was more stable and mature than that other single-biomanipulation. Moreover, integrated biomanipulation could substantially increase fishery income. Integrated biomanipulation can therefore be used to meet the requirements of sustainable development, especially in tropical and subtropical eutrophic lakes used as drinking water source.

This study investigates the pollution status, spatial distribution of heavy metals including Cr, Mn, Ni, Cu, Zn, As, Cd and Pb, in sediments from the Longhu Lake, and evaluates possible ecological risk of these metals. Average concentrations of Cu, Zn, Cd and Pb were 2.1, 3.5, 8.0 and 2.5 times higher than Grade I Chinese soil quality standard respectively. The geo-accumulation index indicates that the lake sediments are moderate to heavily contaminated by Zn, Cd and Pb, which may have higher toxic effects than other metals. The potential ecological risk factor (E (i) (R)) suggests low risk to aquatic organisms except for Cd which has a considerable risk to aquatic biota. Spearman correlation and principal component analysis suggest that Mn, Zn, Cd and Pb possibly having similar anthropogenic sources and behaviors in the lake. Overall, this study suggests that anthropogenic inputs are from local point and non-point sources, runoff and atmospheric deposition.

To characterize the plankton size structure and evaluate plankton community stability in Longhu Lake, a shallow eutrophic lake in southeast China that has been biomanipulated for similar to 20 years, the biomass-size spectra of the plankton were seasonally studied from August 2017 to November 2018. The plankton-size spectra revealed a typical bimodal structure in all seasons. The higher peak consisted of small-sized phytoplankton ranging from 10 to 30 mu m, while the lower peak consisted mainly of rotifers and ciliates ranging from 66 to 83 mu m. Compared with other eutrophic lakes, the size classes of the bimodal structure in Longhu Lake were relatively smaller, indicating individual miniaturization in the lake's plankton community. There was also a trough in the 90 to 370 mu m region of the size spectra, indicating a low biomass for crustacean zooplankton in the lake. The slope (b = -1.27 +/- 0.04) of the normalized size spectra was lower than that of the theoretical equilibrium state (b = -1), suggesting high energy transfer from the large phytoplankton (>30 mu m) and zooplankton (>90 mu m) to the planktivorous silver and bighead carps via filter feeding. Although the seasonal size spectra fluctuated with the water temperature (positively) and nutrients (negatively) in Longhu Lake, their patterns and coefficients of determination did not significantly vary with the seasons (R-2 = 0.98 +/- 0.01, p < 0.05), indicating the plankton community is stable in this long-term biomanipulated eutrophic lake.

This study aims to assess the pollution status and spatial distribution of heavy metals, including Chromium (Cr), Manganese (Mn), Nickel (Ni), Copper (Cu), Zinc (Zn), Arsenic (As), Cadmium (Cd), and Lead (Pb), in sediments from the Yundang Lagoon catchment, and to determine the risk from such metals and associated possible sources. Results show considerable spatial variations in total concentrations of heavy metals within sediment samples. The Geo-accumulation index indicates that sediment is not contaminated with Cr, Mn, Ni, and As, but moderate to high levels of Cu, Zn, Cd, and Pb are present. The potential ecological risk is low for Cr, Mn, Ni, Cu, Zn, As, and Pb, but Cd in lagoon sediments poses a considerable ecological risk to biota. A high positive correlation was found between Zn, Cu, and Cd (r > 0.8), while Zn, Cd, and Cu (r > 0.7) were positively correlated with total organic carbon. Principal component analysis indicated that Cr, Ni, Mn, and As was mainly from the lithogenic origin and Zn, Cu, Cd, and Pb were influenced by anthropogenic contamination. We identified evidence of point source and runoff are the main contributors to enhanced heavy metals levels.

The genes encoding HSP70 and HSP90 proteins were isolated from kaluga by homologous cloning and rapid amplification of complementary DNA (cDNA) ends (RACE). HSP70 (GenBank accession no. KP050541) and HSP90 (GenBank accession no. KP050542) cDNAs were composed of 2275 and 2718 bp and encoded polypeptides of 650 and 725 amino acids, respectively. Basic Local Alignment Search Tool (BLAST) analysis showed that HSP70 and HSP90 of kaluga shared high identities with those of Acipenser ruthenus, Acipenser schrenckii, and Acipenser baerii (98–99 %). Fluorescent real-time RT-PCR under unstressed conditions revealed that HSP70 and HSP90 were expressed in 11 different tissues of kaluga. Messenger RNA (mRNA) expressions of both HSP70 and HSP90 were highest in the intestine and lowest in the muscle. In addition, the patterns of mRNA expression of HSP70 and HSP90 were similar, although the level of expression was more in HSP90 than in HSP70 (P < 0.05).We also analyzed patterns of HSP70 and HSP90 expression in the muscle, gill, and liver of kaluga under different combinations of temperature and salinity stress, including temperatures of 4,10, 25, and 28 °C at 0 ppt salinity, and salinities of 10, 20, 30, and 40 ppt at 16 °C, where 16 °C at 0 ppt (parts per thousand) served as the control. We found that levels of mRNA expression of both HSP70 and HSP90 were highest at 4 °C in the muscle, gill, and liver and changed little with salinity stress. These results increase understanding of the mechanisms of stress response of cold freshwater fish.

为研究直额裸腹溞Moina rectirostris线粒体细胞色素氧化酶Ⅰ亚基（COⅠ）基因的特点,使用WizardTM基因组DNA纯化试剂盒提取直额裸腹溞DNA,以其DNA为模板,用线粒体COⅠ基因通用引物进行PCR扩增、测序。结果表明:直额裸腹溞线粒体DNA COⅠ基因部分cDNA序列长度为709 bp,其中碱基A、G、T、C含量分别为26.23%、19.89%、38.50%、15.37%,A+T含量（64.74%）明显高于G+C含量（35.26%）;将该基因的cDNA序列与裸腹溞科5个种的同源序列进行比对,并用邻接法（NJ）构建系统进化树,结果显示,直额裸腹溞与短型裸腹溞的遗传距离最小,同属于一个分支,亲缘关系最近。研究表明,应用COⅠ基因序列可以有效地区别裸腹溞科各个种类,与传统形态学分类学的结果基本一致。