As the primary component of harmful algal blooms, cyanobacteria exhibit unique adaptation strategies under environmental stress. The impact of erythromycin (ETM), a common macrolide antibiotic in aquatic environments, on colonial cyanobacteria remains unclear. This study examined the chronic toxic effects of different ETM concentrations (0.01, 0.1, 1, 10, 20 and 100 μg/L) on colonial Microcystis aeruginosa (M. aeruginosa) under varying nutrient conditions. Results showed that at 0.01–1 μg/L, ETM could promote the growth of M. aeruginosa, while high concentrations of ETM (≥10 μg/L) significantly inhibited growth (p < 0.05). Low-level ETM exposure accelerates M. aeruginosa growth by boosting PSII efficiency, extracellular polymeric substance (EPS) production, and the activities of superoxide dismutase (SOD) and catalase (CAT). Metatranscriptomic and metabolomic analyses further reveal that this stimulation is underpinned by enhanced trace-element uptake, reinforced carbon cycling, and increased biosynthesis of proteins, polysaccharides, and chlorophyll precursors. High-level ETM exposure inhibited the growth of M. aeruginosa, as evidenced by decreased photosynthesis, damaged membranes and suppressed metabolic activity. Metatranscriptomic and metabolomic analyses showed the upregulation of photosynthesis andpathways, metabolic pathways, and the accumulation of potent allelochemicals in P-limited cells exposed to 10 µg/L ETM relative to 10 µg/L ETM in nutrient-replete BG11 medium. Furthermore, phosphorus deficiency may enhance the potential of net methane formation. These findings underscore the complex interactions between antibiotic exposure and nutrient stress in cyanobacteria, with significant implications for environmental management of antibiotic contamination.

Lake eutrophication is increasingly shaped by climate extremes, but how short-lived events yield persistent blooms remains unclear. Using global satellite records and laboratory and field experiments, here we show that heatwaves and extreme precipitation drive bloom dynamics beyond gradual warming. In harmful bloom-forming algae (HBFA), heatwaves trigger oxidative stress that rapidly induces intracellular polyphosphate and stabilisomes, dense polyphosphate-rich organelles. As intracellular ballast, stabilisomes drive downward migration, enabling access to sediment-derived phosphorus while avoiding thermal stress; CO2 depletion elevates pH and reinforces a thermo-alkaline cascade amplification effect. Extreme precipitation delivers pulsed phosphorus inputs that are stored as intracellular polyphosphate, creating long-lived phosphorus reserves that prime later heatwaves. When precipitation pulses precede heatwaves, stabilisome formation, vertical migration, and bloom expansion are amplified, even in oligotrophic lakes. Compound climate extremes thus convert episodic disturbances into sustained ecological advantages, challenging nutrient-centric models and redefining bloom-risk prediction and management.

Under anthropogenic climate change, intensifying extreme climatic events are increasingly reshaping lake cyanobacterial blooms. However, their contributions remain poorly quantified and the causal pathways are unclear, limiting their integration into attribution and early warning systems and posing risks to drinking water safety. Here, we fuse 22 years of multisource daily records, build a distributed lag nonlinear model (DLNM) with counterfactual decomposition to separate the marginal effects of extremes from the concurrent normal climate load, and develop a transferable machine learning nowcast centered on extreme exposure features. From 2003 to 2024, extreme climatic events contributed more cumulatively than the normal climate load and served as proximate triggers through predominantly lagged responses. Extreme heat events (EHEs) and extreme drought events (EDEs) generally amplified blooms, whereas extreme rainfall events (EREs) tended to suppress them, primarily by altering water temperature and internal and external nutrient loading. Centering on daily extreme exposure features, we built a nowcasting and threshold alert model that requires no contemporaneous water quality inputs. Bias corrected projections indicate monotonic increases in the frequency, persistence, and cumulative exposure of heat and compound extremes toward 2100, driving a shift from frequent to near normalized blooms; under a high emission pathway (SSP5-8.5), annual bloom duration in Lake Hongze exceeds 200 days. Even when current nitrogen and phosphorus targets are met, blooms still intensify under increasingly severe extremes. Importantly, even with aggressive phosphorus abatement, strong extreme climate forcing alone can sustain frequent blooms. We thus propose an interpretable, transferable, extreme event centric framework that supports operational early warning and climate-resilient nutrient target setting in shallow eutrophic lakes.

Accelerating anthropogenic activity in watersheds is reshaping reservoir ecosystems and threatening their ecological integrity and services, yet the scarcity of long-term records limits our understanding of how ecosystems respond to cumulative watershed disturbance. Here we used microeukaryotic sedimentary DNA (sedDNA) to reconstruct four decades (1981-2019) of watershed disturbance and ecological change in Duihekou Reservoir. Consistent with a concurrent shift in watershed disturbance, microeukaryotic communities underwent a clear state shift around 2000, from a moderately disturbed, low-nutrient state to a human-impacted, nutrient-enriched mesotrophic regime. This shift favoured mixotrophic and phagotrophic taxa as "winners", potentially threatening water quality and higher trophic levels. At the same time, co-occurrence networks reorganized from a fungus-centered web into a denser, multi-core architecture with higher robustness metrics, motivating the hypothesis that recovery may face a higher barrier once the mesotrophic state is established. Community assembly also became increasingly deterministic, with watershed human activities emerging as the strongest correlates of succession and the regime shift. Using random forest algorithms, we developed microeukaryotic sedDNA indicator models to reconstruct watershed disturbance and clarified their applicability and limitations for hindcasting past watershed conditions. Together, these findings demonstrate that microeukaryotic sedDNA archives can serve as sensitive, integrative sentinels of cumulative watershed disturbance and reservoir regime shifts, providing a basis for applying sedDNA-based indicator models in long-term monitoring and adaptive management.

Despite the pivotal role of fungi in regulating algal blooms and ecosystem health, community-level fungal dynamics in natural cyanobacterial bloom events, and their correlation with changes in algal communities, remain poorly understood. Through a year-long survey in eutrophic Lake Chaohu, China, we analyzed the planktonic fungal and phytoplankton community changes. The results showed that Chytridiomycota dominated the fungal community throughout the year, whereas Ascomycota and Basidiomycota increased markedly during late-bloom and post-bloom periods, suggesting a functional shift from potential parasitism to saprotrophy. Algal and fungal communities showed significant concordance at the community level, as indicated by the positive relationship between their Bray-Curtis distances (P < 0.001). Separate fitting of dominant algal taxa onto the fungal ordination space showed that Microcystis was primarily associated with the bloom-period fungal assemblage, whereas Chlorella and others were more closely associated with non-bloom fungal community variation. The strength of algal-fungal associations also increased significantly with the relative dominance of algal taxa (P < 0.05), supporting a dominance-dependent interaction pattern. Together, these results indicate that planktonic fungal communities were closely associated with algal community dynamics through both host-abundance- and host-dominance-related patterns, and highlight the importance of considering fungal processes in ecological frameworks for understanding phytoplankton succession and cyanobacterial bloom dynamics.

Submerged macrophytes influence sediment microbial communities in shallow lakes; however, the ecological roles of their community-level characteristics remain underexplored. In this study, we examined the relationships between macrophyte community coverage and diversity and the composition of sediment bacterial communities in Dongshan Bay, Lake Taihu. We combined high-throughput sequencing, functional prediction, and multivariate statistical modelling to analyse sediment bacterial composition, potential metabolic functions, community assembly proceses, and their associations with macrophyte communities and environmental factors. Macrophyte community structure explained more variation in sediment bacterial community structure than seasonal dynamics. Higher coverage and diversity were related to improved water clarity, elevated sediment nutrient concentrations, and enhanced bacterial metabolic potential. In macrophyte-dominated zones, bacterial communities were primarily structured by homogeneous selection, and microbial co-occurrence networks became less complex. Our results indicate that species richness, diversity, and coverage most effectively capture the ecological functions of submerged macrophyte communities, and collectively influence sediment bacterial communities through multiple pathways, including habitat modification and altered selection pressures. This study underscores the ecological role of macrophyte diversity and coverage in shaping sediment microbiota, offering insights for lake restoration strategies.

A systematic classification of lakes is essential for effective management, conservation, and scientific research. However, existing approaches often overlook the continuous variability of certain indicators among lakes and are constrained by data availability. In this study, we developed a classification system for 439 lakes larger than 10 km2 in China using geomorphological, hydrological, climatic, and landscape features, employing an archetypal analysis approach. Based on the model fitting results, we identified six distinct lake archetypes, which differ from the traditional five classifications based on geographical regions in China. The water quality of lakes across different archetypes responded to a range of geographic, hydrological, meteorological, soil, and anthropogenic factors. Lakes with the highest nutrient levels were predominantly found in Archetypes 5 and 6, located in northeastern China and the Yunnan-Guizhou Plateau, respectively, followed by Archetype 3. In these regions, nutrient levels were strongly associated with human activities. In contrast, indicators such as conductivity and permanganate index in different archetypes were primarily influenced by non-human activities, with the impact of human activities being relatively weak. Phytoplankton, represented by chlorophyll-a, showed a significant response to total phosphorus only in Archetypes 3 and 6, while the response to nitrogen and phosphorus was not significant in the other archetypes. This variation in phytoplankton responses may have been influenced by the climatic conditions in these regions, such as temperature. These findings underscore the importance of developing targeted management and conservation strategies for different lake types, considering their distinct responses to nutrient and temperature changes. Smaller lakes, with relatively simple ecological characteristics, can be managed through targeted strategies tailored to specific types. In contrast, larger lakes require more specialized conservation and management efforts to tackle their complex ecosystem challenges.

In natural aquatic ecosystems, algal-derived organic carbon (AOC) often coexists with exogenous organic carbon (EOC). Microbial utilization of these distinct carbon sources affects carbon flux and transformation in water column and algal growth. Microcystis blooms significantly increase AOC levels in water, but the microbial transformation process of Microcystis-derived AOC in the presence of EOC remain poorly understood. We conducted a simulated experiment by introducing 13C-sodium bicarbonate and 13C-glucose as substrates for indoor simulation of non-axenic Microcystis aeruginosa (M. aeruginosa) populations in a sealed system. The microbial transformation processes of AOC and EOC and their effects on M. aeruginosa growth were investigated. Results demonstrated that the addition of glucose accelerated M. aeruginosa growth and significantly increased their biomass. During the experiment, as the particulate organic carbon and nitrogen content increased, the concentrations of CO2 and N2O were gradually decreased, while the concentration of CH4 were gradually increased. Significant differences were observed in the microbial processes involved in the uptake of AOC and EOC. Bacteria involved in AOC transformation throughout the growth period were dominated by Proteobacteria, Gemmatimonadota, Actinobacteriota, Bacteroidota, Acidobacteriota, and Firmicutes. The bacteria involved in EOC transformation were dominated by Proteobacteria, Actinobacteriota, Firmicutes, Cyanobacteria, Armatimonadota, and Bacteroidota. Linear discriminant analysis Effect Size (LEfSe) analysis revealed Massilia and Akkermansia as biomarkers involved in AOC transformation, while Ligilactobacillus was associated with EOC transformation. These findings provide valuable insights into the effects of EOC on algae-bacteria interaction, and on the dynamics of carbon and nitrogen cycling among M. aeruginosa and its associated bacteria.

Periphyton plays a critical role in the progress of the regime shift between macrophytes and phytoplankton in shallow lakes, since its overgrowth could trigger metaphytic blooms and lead to the collapse of submerged macrophytes. Understanding the mechanisms of metaphytic blooms and the subsequent prediction are important for lake managers to prevent ecological disaster. In this study, a one-year field survey on periphyton was conducted in Lake Ulansuhai to explore the driving factors of metaphytic blooms. The result revealed that the filamentous chlorophyta Mougeotia was identified as the key genus involved in metaphytic blooms. Structural Equation Modeling showed that Mougeotia biomass was positively correlated with total nitrogen, temperature, and submerged vegetation density. While phytoplankton biomass was primarily positively correlated with total phosphorus and temperature. A logistic regression model indicated that when the biomass of Mougeotia reached 1.78 g m−2 (95

Dissolved carbon is a crucial component of freshwater ecosystems and plays an important role in the Earth’s carbon cycle. This paper delivers a groundbreaking exploration of dissolved carbon (DOC and DIC) variations spanning 12 years in a eutrophic lake where nutrient levels are gradually declining to reveal their spatial and temporal distribution patterns and the key drivers behind this variation. Our findings indicate that both DIC and DOC concentrations in Lake Chaohu exhibit a westward spatial gradient, with an overall upward trend in DIC levels from 2012 to 2023, contrasting with a downward trend in DOC. A similar variation trend in the inflowing rivers suggests that exogenous inputs predominantly dictate long-term carbon concentration changes in the lake. Additionally, a reduction of eutrophication levels in the lake may have also contributed to a decrease in endogenous DOC generated by algal metabolism. Seasonally, DIC and DOC concentrations display inverse trends throughout the year, with DOC levels closely tracking the seasonal patterns of the cyanobacterium Microcystis. Correlation and regression analyses reveal a significant positive relationship between Microcystis and DOC and a negative association with DIC, while Dolichospermum shows no correlation with either. This suggests that the impact of phytoplankton on DOC and DIC variations is species-specific. In Lake Chaohu, the annual succession of Microcystis may be a major driving factor for the intra-annual variations in DOC and DIC. Our findings deepen the comprehension of how phytoplankton modulates the intra-annual dynamics of DOC and DIC.

Understanding size-dependent grazing dynamics is critical for elucidating trophic interactions in eutrophic lakes. This study employed a dual-zone (littoral vs. pelagic) framework in Lake Chaohu to quantify zooplankton grazing on size-classified phytoplankton from April 2023 to March 2024 via dilution experiments. Our results reveal inedible cyanobacteria colonies (>200 μm) dominated phytoplankton biomass (86% -96%) during peak-blooms, accumulating in littoral zones. Edible phytoplankton (<200 μm), predominantly in the 40-200 μm (56%) and 3-20 μm (28%) size fractions, sustained zooplankton feeding in pre- and post-bloom periods. Zooplankton consumed 19.4% of phytoplankton biomass during non-bloom periods compared to only 8.3% during blooms. Meso-zooplankton filter feeders (dominant in littoral zones) exerted strong grazing pressure on S-sized phytoplankton (3-20 μm), contributing to clear-water phases (May-Jun). Cyanobacterial proliferation suppressed meso‑zooplankton grazing and shifted the primary grazing pressure to micro-zooplankton filter feeders, which exhibited significant consumption of L-sized cyanobacteria (40-200 μm) during peak-bloom. However, this micro-zooplankton grazing on bloom-forming cyanobacteria was constrained by predation from meso‑zooplankton carnivores in pelagic zones. These results underscore the interplay of phytoplankton size structure, zooplankton functional traits, and trophic cascades in mediating bloom dynamics and energy flow pathways in eutrophic lakes.

Fractal analysis was used to characterize the organic matter nanopore structure in tectonically deformed shales, providing insights into the heterogeneity and complexity of the pore network. Shale samples from different tectonic deformation styles (undeformed, brittle deformed, and ductile deformed) in the Lower Cambrian Niutitang Formation in western Hunan, South China, were collected. By comprehensively applying techniques such as low-temperature gaseous (CO2 and N2) adsorption (LTGA), scanning electron microscopy (SEM), and ImageJ analysis, we accurately obtained key parameters of the pore structure. The results show ductile deformation reduces fractal dimension (DM) by ~0.2 compared to brittle deformed shale, reflecting the homogenization of organic nanopore structures. Brittle deformation leads to a more complex pore network, while ductile deformation reduces the complexity of the organic nanopore structure. The fractal dimensions are affected by various factors, with micropore development being crucial for undeformed shale, clay and pore length–width ratio dominating in brittle deformed shale, and all-scale pores being key for ductile deformed shale. This study provides the first comparative analysis of fractal dimensions across undeformed, brittle deformed, and ductile deformed shales, revealing distinct pore structure modifications linked to deformation styles. These findings not only enhance our understanding of the influence mechanism of tectonic deformation on shale pore structure and fractal characteristics but also provide a theoretical basis for optimizing shale gas exploration and production strategies. These findings offer a framework for predicting gas storage and flow dynamics in tectonically complex shale reservoirs. For instance, in areas with different tectonic deformation styles, we can better evaluate the gas storage capacity and production potential of shale reservoirs according to the obtained fractal characteristics, which is of great significance for efficient shale gas development.

The seasonal fluctuation of phosphorus in shallow water lakes is a crucial process in the response of lake ecosystems to environmental changes. Unravelling the seasonal fluctuation pattern of phosphorus and its influencing factors in lakes is key to scientific and effective lake management. This study utilized 12 years of continuous monthly monitoring data from Lake Chaohu to analyze the seasonal variation pattern of phosphorus and its driving factors. The results indicated that phosphorus in Lake Chaohu exhibited a distinct intra-annual fluctuation pattern. The period from February to April represented the low values of phosphorus, which gradually increased thereafter, with the peak phosphorus concentration occurring from August to October, reaching the annual high. During the high phosphorus period, the total phosphorus concentration was 0.058 mg/L higher on average than the low phosphorus period, representing an average increase of 84%. Moreover, this fluctuation amplitude increased gradually from east to west. The intra-annual variation patterns of phytoplankton biomass and chlorophyll- a did not precisely align with the phosphorus fluctuation pattern. The peak values of phytoplankton biomass occurred earlier in the year than the peak phosphorus values, and there was a period of substantial phytoplankton distribution even in winter when phosphorus concentrations were relatively low. The explanatory power of algal intra-annual fluctuation amplitude on phosphorus fluctuation amplitude was less than 10%, indicating a limited influence of phytoplankton's intra-annual changes on the seasonal phosphorus fluctuation in Lake Chaohu. The intra-annual fluctuation pattern of phosphorus in Lake Chaohu was likely primarily driven by the natural release of internal phosphorus, with limited evidence of the regulatory effects of algal pump suction and external pollution entering the lake. This study enhanced our understanding of the seasonal variation of phosphorus in shallow lakes and held significant scientific implications for formulating strategies to control internal pollution in lakes.

Understanding the response of the phytoplankton community to climate change is essential for reservoir management. We analyzed a long-term data series (2009–2020) on the phytoplankton community in a large mesotrophic reservoir in the wet season to investigate the impacts of temperature and precipitation increases caused by climate change on the functioning and trait composition of the phytoplankton community. Over the last twelve years, the 3-month accumulative precipitation increased from 291.03 mm to 590.91 mm, and the surface water temperature increased from 25.06 °C to 26.49 °C in wet season, respectively. These changes caused a higher water level, stronger thermal stratification and lower nitrogen concentration in Daxi Reservoir. The dynamic equilibrium model indicated that the increased precipitation and water temperature-related environmental changes would result in a more diverse and productive phytoplankton community. The effects of increasing water temperature and precipitation on the niche complementarity and selection effects within the phytoplankton community were analyzed using structural equation model by means of the functional divergence index and functional evenness index, respectively, elucidating the reasons for the increase in cyanobacteria in the absence of a significant increase in nutrient levels. Based on these results, it is advisable that more stringent phosphorus control standards might be conducted to reduce the risks of cyanobacteria proliferation in the context of global warming.

In recent years, initiatives aimed at mitigating eutrophication have successfully reduced nitrogen and phosphorus concentrations in numerous lakes across China. Notably, the management of total nitrogen levels has prompted a shift in the dominant genera responsible for harmful algal blooms. Among these, Dolichospermum, a typical diazotrophic cyanobacterium, exhibits the ability to differentiate heterocysts for atmospheric N2 fixation under nitrogen-limited conditions. However, the underlying mechanisms driving heterocyst differentiation in response to the absence of specific nitrogen compounds remain poorly understood. This study analyzed the driving factors influencing heterocyst frequency using field data from Lake Chaohu collected between January and June 2022. Furthermore, an experiment was conducted utilizing NH4Cl, NaNO3 and urea as nitrogen sources, with specific nitrogen deficiencies created to investigate the response mechanisms of Dolichospermum under these conditions. The results indicated significant monthly variations in heterocyst frequency in Lake Chaohu, which were associated with the interaction of multiple driving factors. Nutrient changes emerged as the most intuitive driving factor, with heterocyst frequency showing a significant negative correlation with total nitrogen and dissolved total nitrogen levels. Experimental results demonstrated that the absence of NO3N promoted both the biomass and heterocyst frequency of Dolichospermum. When NH4N was limited, the proliferation of Dolichospermum was inhibited, leading to an extended period of heterocyst development. Although a lack of urea eventually increased heterocyst frequency in Dolichospermum, there was no significant increase in biomass. The concentrations of the three nitrogen sources exhibited a negative correlation with heterocyst differentiation, with the effects of NO3N and urea deficiency on heterocyst differentiation being significantly stronger than those of NH4N. Moreover, heterocyst differentiation frequency was positively correlated with photosynthetic efficiency, which indicated that the acquisition and distribution of photosynthetic energy between heterocysts and vegetative cells also influence the differentiation process of heterocysts to some extent. The findings highlight the differing responses of heterocyst differentiation to various forms of nitrogen, emphasizing the importance of prioritizing NH4N removal in nutrient control. However, further research is needed to determine the key threshold concentrations of different nitrogen sources that trigger heterocyst differentiation.

Cyanobacteria cells migrate into sediment due to a decrease in buoyancy,leading to increased sediment pollution.Some of cyanobacteria cells can overwinter as vegetative cells at low temperature and dark condition,and serve as a"seed bank"that can revive into the water column to form pelagic blooms as temperature rise and wind-wave disturbance.To study the spatial-temporal variations of benthic cyanobacteria and their environmental factors,an eight-year field investigation of the cyanobacteria in sediment was carried out in Lake Chaohu.The results showed that chlorophyll-a(Chl.a)content of sediment increased firstly and then de-creased from 2016-2023 with the peak in 2019-2020.Chi.a content of water and sediment both decreased from west to east in space.The high Chl.a content of sediment occurred in March and November was related to the sink and dormancy of Microcystis and Dolichospermum,while the low Chl.a content occurred in July and August due to the cyanobacteria cells recruitment.Stepwise re-gression analysis showed that the total nitrogen in sediments,wind speed,total phosphorus in sediment,and water temperature were important influencing factors of Chl.a content of sediment.These results revealed the spatial and temporal distribution of cya-nobacteria in the bottom of Lake Chaohu,which have important scientific significance for the control of lake internal pollution and cyanobacteria blooms.

Large cyanobacterial colonies as visible particles floating on the water surface provide different microbial niches from small particles suspended in the water column in eutrophic freshwaters. However, functional potential differences among microbes colonizing on these contrasting particles are not well understood. Here, the metatranscriptome of microbes inhabiting these two kinds of particles during cyanobacterial bloom (dominated by Microcystis spp.) was analyzed and compared. Community compositions of active bacteria associated with small suspended particles (SA, aggregates dominated by small cyanobacteria colonies, other algae and detritus, etc.) were much more diverse than those associated with large buoyant cyanobacterial colonies (LA), but functional diversity was not significantly different between them. Transcripts related to phosphorus and nitrogen metabolism from Proteobacteria, and respiration from Bacteroidetes were enriched in LA, whereas many more pathways such as photosynthesis from Cyanobacteria, cofactors, and protein metabolism from all dominant phyla were enriched in SA. Nevertheless, many transcripts were significantly correlated within and between LA and SA. These results indicated interconnection of bacteria between LA and SA. Moreover, many transcripts in SA were significantly correlated with transcripts from cyanobacterial phycobilisome in LA, indicating that bacterial metabolism in SA may influence cyanobacterial biomass in LA. Thus, the prediction of cyanobacterial blooms by bacterial activity in SA may be possible when there is no visible bloom on the water surface.

模拟了叶绿素a浓度为1001.63μg/L的高浓度蓝藻水华,选用聚合氯化铝(PAC),氯化铁(FeCl3),阳离子淀粉-壳聚糖(CSC)3种絮凝剂实施应急控藻,探究其对水质和沉水植被恢复的影响.研究发现,FeCl3和CSC处理后水体DO分别降至1.35,0.61mg/L,氨氮则高达24.93,45.74mg/L,引发水体持续的重度黑臭;相比之下,PAC处理后ORP、DO、氨氮明显改善,分别为-76.00mV、3.64mg/L、9.25mg/L,且优于空白处理的-140.43mV、2.34mg/L、13.10mg/L,水体重度黑臭持续时长从15d减少至4d,沉水植被恢复潜力提升,其中伊乐藻(Elodea canadensis)的生物量显著增加,优于无藻华对照(P＜0.05);FeCl3和CSC处理未能缓解苦草(Vallisneria natans),伊乐藻受到的生长胁迫,甚至加剧了对伊乐藻的生长胁迫,且CSC处理显著抑制了伊乐藻的叶数,株高,生物量的增长(P＜0.05).结果表明,絮凝沉降可以快速控制湖滨带高浓度蓝藻水华,但可能会产生黑臭,应考虑增加曝气增氧等措施以缓解水质恶化,并选取合适的沉水植被进行生态修复,以期实现长效控藻目标.

Understanding the biotic mechanisms of community stability in variable environments has been a focal point of fundamental ecological research. A multitude of mechanisms, encompassing compensatory dynamics arising from negative species covariance, portfolio effect linked to species richness and evenness, and dominant species stability, have been found to collectively enhance community stability. However, it is not clear how their stabilizing effects change and contribute to the maintenance of community stability along environmental gradients. We performed a ten-year investigation in a large shallow lake with a eutrophic gradient across space. With the dataset, we quantified the role of the three stability mechanisms, and their changes in effect size along the eutrophic gradient to determine their relative importance in biomass stability. Our results showed that the biomass stability shifted from one stable state at eutrophic sites to another stable state at hypertrophic sites, and biomass stability was positively correlated with composition stability. In the relatively stable state, biomass stability exhibited a closely synchronized variation along with compositional stability in response to environmental changes. Conversely, in the unstable state, biomass stability displayed weaker sensitivity to environmental changes compared to compositional stability. The effect sizes of different biotic mechanisms of biomass stability varied across the eutrophic gradient. Compensatory dynamics emerged as the primary force governing biomass stability in eutrophic waters, overshadowing the relatively weak impact of the portfolio effect, which might help resist the shift from turbid state to clear state with decreasing nutrient concentrations. However, as nutrient levels increased, the primary force shifted from compensatory dynamics toward the dominant species stability. This study improves our understanding for the biotic mechanisms of phytoplankton community responding to nutrients mitigation in eutrophic waters, which might be one of the most important ecological components for managing communities to maintain ecosystem functioning.