Iron nanoparticles surface decorated MXene via molten salts etching as selenium host for ultrafast sodium ion storage.

Sodium-selenium (Na-Se) batteries have gained attention due to their high energy density and power density, resulting from the liquid-liquid reaction at the interface in the dimethoxyethane electrolyte. Nevertheless, the pronounced shuttle effect of polyselenides causes low coulomb efficiency and inadequate cycling stability for Na-Se batteries. Herein, the iron nanoparticles surface modified accordion-like Ti3C2Tx MXene (MXene/Fe) synthesized via the molten salt etching is utilized as the host of Se species for high-performance Na-Se battery cathode. Benefiting from the layered structure and chemical adsorption of accordion-like MXene, the shuttle effect of the cathode is effectively inhibited. Simultaneously, electrochemical kinetics is boosted due to the catalytic effect of Fe nanoparticles, which facilitate the transformation of polyselenide from long-chain to short-chain, contributing to pseudocapacitive capacity. Consequently, the Se-based cathode delivers a steady capacity of 575.0 mA h g-1 at 0.2 A/g, and even a high capacity of 500 mAh/g at 50 A/g based on the mass of Se@MXene/Fe electrode, indicating the ultrafast Na+ ion storage. Most notably, this structure demonstrated remarkable long-term cycling stability for 5000 cycles with a high capacity retention of 97.4 %. The electrochemical energy storage mechanism is further revealed by in situ Raman. Herein, the confinement-catalysis structure shines light on inhibiting shuttling and facilitating ultrafast ion storage.

MoP quantum dots based multifunctional efficient electrocatalyst for stable and long-life flexible lithium-sulfur batteries.

The commercialization of lithium-sulfur (Li-S) batteries is challenging, owing to factors like the poor conductivity of S, the 'shuttle effect', and the slow reaction kinetics. To address these challenges, MoP quantum dots were decorated on hollow carbon spheres (MoPQDs/C) in this study and used as an efficient lithium polysulfides (LiPSs) adsorbents and catalysts. In this approach polysulfides are effectively trapped through strong chemisorption and physical adsorption while simultaneously facilitating LiPSs conversion by enhancing the reaction kinetics. MXene serves as a flexible physical barrier (MoPQDs/C@MXene), further enhancing the confinement of LiPSs. Moreover, both materials are conductive, significantly facilitating electron and charge transfer. Additionally, the flexible MoPQDs/C@MXene-S electrode offers a large specific surface area for sulfur loading and withstand volume expansion during electrochemical processes. As a result, the MoPQDs/C@MXene-S electrode exhibits excellent long-term cyclability and maintains a robust specific capacity of 992 mA h g-1 even after 800cycles at a rate of 1.0C (1C = 1675 mA g-1), with a minimal capacity decay rate of 0.034 % per cycle. This work proposes an efficient strategy to fabricate highly efficient electrocatalysts for advanced Li-S batteries.

Application of Inorganic Quantum Dots in Advanced Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries have emerged as one of the most attractive alternatives for post-lithium-ion battery energy storage systems, owing to their ultrahigh theoretical energy density. However, the large-scale application of Li-S batteries remains enormously problematic because of the poor cycling life and safety problems, induced by the low conductivity , severe shuttling effect, poor reaction kinetics, and lithium dendrite formation. In recent studies, catalytic techniques are reported to promote the commercial application of Li-S batteries. Compared with the conventional catalytic sites on host materials, quantum dots (QDs) with ultrafine particle size (<10 nm) can provide large accessible surface area and strong polarity to restrict the shuttling effect, excellent catalytic effect to enhance the kinetics of redox reactions, as well as abundant lithiophilic nucleation sites to regulate Li deposition. In this review, the intrinsic hurdles of S conversion and Li stripping/plating reactions are first summarized. More importantly, a comprehensive overview is provided of inorganic QDs, in improving the efficiency and stability of Li-S batteries, with the strategies including composition optimization, defect and morphological engineering, design of heterostructures, and so forth. Finally, the prospects and challenges of QDs in Li-S batteries are discussed.

In-Situ Synthesis of Carbon-Encapsulated Atomic Cobalt as Highly Efficient Polysulfide Electrocatalysts for Highly Stable Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries have been considered as one of the most promising electrochemical energy storage systems because of their high energy density. However, a series of issues severely limit the practical performances of Li-S batteries such as low conductivity, significant volume change, and shuttle effect. The hollow carbon spheres with huge voids and high electrical conductivity are promising as sulfur hosts. Unfortunately, the nonpolar nature of carbon materials cannot prevent the shuttle effect effectively. In this case, the atomic cobalt is introduced to a nitrogen-doped hollow carbon sphere (ACo@HCS) through polymerization and controlled pyrolysis. The atomic cobalt dopants not only act as active sites to restrict the shuttle effect, but also can promote the kinetics of the sulfur redox reactions. ACo@HCS acting as sulfur host exhibits a high discharge capacity (1003 mAh g-1 ) at a 1.0 C rate after 500 cycles, and the corresponding decay rate is as low as 0.002% per cycle. This exciting work paves a new way to design high-performance Li-S batteries.

Artificial light at night: an underappreciated effect on phenology of deciduous woody plants.

Artificial light at night (ALAN), an increasing anthropogenic driver, is widespread and shows rapid expansion with potential adverse impact on the terrestrial ecosystem. However, whether and to what extent does ALAN affect plant phenology, a critical factor influencing the timing of terrestrial ecosystem processes, remains unexplored due to limited ALAN observation. Here, we used the Black Marble ALAN product and phenology observations from USA National Phenology Network to investigate the impact of ALAN on deciduous woody plants phenology in the conterminous United States. We found that (1) ALAN significantly advanced the date of breaking leaf buds by 8.9 ± 6.9 days (mean ± SD) and delayed the coloring of leaves by 6.0 ± 11.9 days on average; (2) the magnitude of phenological changes was significantly correlated with the intensity of ALAN (P < 0.001); and (3) there was an interaction between ALAN and temperature on the coloring of leaves, but not on breaking leaf buds. We further showed that under future climate warming scenarios, ALAN will accelerate the advance in breaking leaf buds but exert a more complex effect on the coloring of leaves. This study suggests intensified ALAN may have far-reaching but underappreciated consequences in disrupting key ecosystem functions and services, which requires an interdisciplinary approach to investigate. Developing lighting strategies that minimize the impact of ALAN on ecosystems, especially those embedded and surrounding major cities, is challenging but must be pursued.

Multifunctional Metal Phosphides as Superior Host Materials for Advanced Lithium-Sulfur Batteries.

For the past few years, a new generation of energy storage systems with large theoretical specific capacity has been urgently needed because of the rapid development of society. Lithium-sulfur (Li-S) batteries are regarded as one of the most promising candidates for novel battery systems, since their resurgence at the end of the 20th century Li-S batteries have attracted ever more attention, attributed to their notably high theoretical energy density of 2600 W h kg-1 , which is almost five times larger than that of commercial lithium-ion batteries (LIBs). One of the determining factors in Li-S batteries is how to design/prepare the sulfur cathode. For the sulfur host, the major technical challenge is avoiding the shuttling effect that is caused by soluble polysulfides during the reaction. In past decades, though the sulfur cathode has developed greatly, there are still some enormous challenges to be conquered, such as low utilization of S, rapid decay of capacity, and poor cycle life. This article spotlights the recent progress and foremost findings in improving the performance of Li-S batteries by employing multifunctional metal phosphides as host materials. The current state of development of the sulfur electrode of Li-S batteries is summarized by emphasizing the relationship between the essential properties of metal phosphide-based hybrid nanomaterials, the chemical reaction with lithium polysulfides and the latter's influence on electrochemical performance. Finally, trends in the development and practical application of Li-S batteries are also pointed out.

Photoperiod decelerates the advance of spring phenology of six deciduous tree species under climate warming.

Vegetation phenology in spring has substantially advanced under climate warming, consequently shifting the seasonality of ecosystem process and altering biosphere-atmosphere feedbacks. However, whether and to what extent photoperiod (i.e., daylength) affects the phenological advancement is unclear, leading to large uncertainties in projecting future phenological changes. Here we examined the photoperiod effect on spring phenology at a regional scale using in situ observation of six deciduous tree species from the Pan European Phenological Network during 1980-2016. We disentangled the photoperiod effect from the temperature effect (i.e., forcing and chilling) by utilizing the unique topography of the northern Alps of Europe (i.e., varying daylength but uniform temperature distribution across latitudes) and examining phenological changes across latitudes. We found prominent photoperiod-induced shifts in spring leaf-out across latitudes (up to 1.7 days per latitudinal degree). Photoperiod regulates spring phenology by delaying early leaf-out and advancing late leaf-out caused by temperature variations. Based on these findings, we proposed two phenological models that consider the photoperiod effect through different mechanisms and compared them with a chilling model. We found that photoperiod regulation would slow down the advance in spring leaf-out under projected climate warming and thus mitigate the increasing frost risk in spring that deciduous forests will face in the future. Our findings identify photoperiod as a critical but understudied factor influencing spring phenology, suggesting that the responses of terrestrial ecosystem processes to climate warming are likely to be overestimated without adequately considering the photoperiod effect.

Ultrafine ZnS Nanoparticles in the Nitrogen-Doped Carbon Matrix for Long-Life and High-Stable Potassium-Ion Batteries.

Potassium-ion batteries (KIBs) have attracted researchers' widespread attention because of the luxuriant reserves of potassium salts and their low cost. Nevertheless, the absence of suitable electrode materials with a stable electrochemical property is a crucial issue, which seriously hampers the practical applications of KIBs. Herein, a scalable anode material consisting of ultrafine ZnS nanoparticles encapsulated in three-dimensional (3D) carbon nanosheets is explored for KIBs. This hierarchical anode is obtained via a simple and universal sol-gel method combined with a typical solid-phase sulfidation route. The special structure of this anode facilitates good contact with electrolytes and has enough voids to buffer the large volumetric stress changing during K+ insertion/extraction. Thus, the 3D ZnS@C electrode exhibitsour stable cycling performance (230 mAh g-1 over 2300 cycles at 1.0 A g-1) and superior rate capability. The kinetic analysis indicates that a ZnS@C anode with considerable pesoudecapactive contribution benefits a fast potassium/depotassium process. Detailed ex-situ and in-situ measurements reveal that this ZnS@C anode combines reversible conversion and alloying-type reactions. This rationally designed ZnS@C material is highly applicable for KIBs, and the current route opens an avenue for the development of highly stable K+ storage materials.

Cathodes for Aqueous Zn-Ion Batteries: Materials, Mechanisms, and Kinetics.

As concerns about the safety of lithium-ions batteries (LIBs) increases, aqueous zinc-ion batteries (ZIBs) with a lower cost, higher safety, and higher co-efficiency have attracted more and more interest. However, finding suitable cathode materials is still an urgent problem in ZIBs. In recent years, a lot of significant works have been reported, including manganese-based cathodes, vanadium-based cathodes, Prussian blue analog-based materials, and sustainable quinone cathodes. In this review, some typical cathode materials are introduced. The detailed storage mechanisms and methods for improving the reaction kinetics of the zinc ions are summarized. Finally, the issues, challenges, and the research directions are provided.

Scalable One-Pot Synthesis of Hierarchical Bi@C Bulk with Superior Lithium-Ion Storage Performances.

Lithium-ion batteries (LIBs), the most successful commercial energy storage devices, are now widespread in our daily life. However, the lack of appropriate electrode materials with long lifespan and superior rate capability is the urgent bottleneck for the development of high-performance LIBs. Herein, a hierarchical Bi@C bulk is developed via a scalable pyrolysis method. Due to the ultrafine size of Bi nanoparticles and in situ generated porous carbon framework, this Bi@C anode evidently facilitates the diffusion of Li+/electron, availably inhibits the agglomeration of active nano-Bi, and effectively mitigates the volume fluctuation. This hierarchical Bi@C bulk exhibits stable cycling performance for both LIBs (256 mAh g-1 at 1.0 A g-1 over 1400 cycles) and potassium-ion batteries (271 mAh g-1 at 0.1 A g-1 for 200 cycles). More importantly, when coupled with a commercial LiCoO2 cathode, the assembled LiCoO2//Bi@C cells provide an output voltage of 2.9 V and retain a capacity of 202 mAh g-1 at 0.15 A g-1. Moreover, kinetic analysis and in situ X-ray diffraction characterization reveal that the Bi@C anode displays a dominated pseudocapacitance behavior and a typical alloying storage mechanism during the cycling process.

Fe3 O4 @C Nanotubes Grown on Carbon Fabric as a Free-Standing Anode for High-Performance Li-Ion Batteries.

Recently, Li-ion batteries (LIBs) have attracted extensive attention owing to their wide applications in portable and flexible electronic devices. Such a huge market for LIBs has caused an ever-increasing demand for excellent mechanical flexibility, outstanding cycling life, and electrodes with superior rate capability. Herein, an anode of self-supported Fe3 O4 @C nanotubes grown on carbon fabric cloth (CFC) is designed rationally and fabricated through an in situ etching and deposition route combined with an annealing process. These carbon-coated nanotube structured Fe3 O4 arrays with large surface area and enough void space can not only moderate the volume variation during repeated Li+ insertion/extraction, but also facilitate Li+ /electrons transportation and electrolyte penetration. This novel structure endows the Fe3 O4 @C nanotube arrays stable cycle performance (a large reversible capacity of 900 mA h g-1 up to 100 cycles at 0.5 A g-1 ) and outstanding rate capability (reversible capacities of 1030, 985, 908, and 755 mA h g-1 at 0.15, 0.3, 0.75, and 1.5 A g-1 , respectively). Fe3 O4 @C nanotube arrays still achieve a capacity of 665 mA h g-1 after 50 cycles at 0.1 A g-1 in Fe3 O4 @C//LiCoO2 full cells.

Solvent-Free Method Prepared a Sandwich-like Nanofibrous Membrane-Reinforced Polymer Electrolyte for High-Performance All-Solid-State Lithium Batteries.

Solid polymer electrolytes (SPEs) with the advantages of high safety, low volatility, and the ability to suppress Li dendrites are highly desirable to be used in next generation high-safety and high-energy lithium-ion batteries. The exploration of SPEs with superior comprehensive properties has received extensive attention for high-performance all-solid-state batteries (ASSBs). Herein, a sandwich-like nanofibrous membrane-reinforced poly-caprolaclone diol and trimethyl phosphate (TMP) composite polymer electrolyte (CPE) has been designed by a facile "solvent-free" solution-casting method. Specifically, the flame-retardant TMP is employed as a plasticizer, which can improve the ionic conductivity effectively. The as-prepared solid electrolyte exhibits superior comprehensive performance in terms of high ionic conductivity, wide electrochemical window, good compatibility with lithium metal, and superior thermal stability. Furthermore, the assembled Li//LiFePO4 ASSBs with this solid CPE show outstanding cycling stability and high average discharge capacity at room temperature (30 °C). Undoubtedly, our study provides a new facile method and a qualified solid electrolyte material for next generation high-performance ASSBs.

Characterization of odorants in contrasting ecotypes of Lake Taihu: algae-dominated versus macrophyte-dominated zones.

Globally, odorant incidents are occurring at an increasing frequency, magnitude, and duration under the dual influences of eutrophication and climate change. However, the contribution of multiple ecotypes to odorant production in the complicated and dynamic lake ecosystems remains unclear. In this study, the odorants and environmental conditions in algae-dominated zones (ADZs) and macrophyte-dominated zones (MDZs) in Lake Taihu were identified and characterized. Results showed that the ADZs were characterized by an abundance of pigments and nutrients and low DO levels, while the MDZs were featured as high TOC/TN ratios and high DO levels. Most odorants in ADZs and several in MDZs exceeded the odorant threshold content. The dominant odorants were dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS), ß-ionone and ß-cyclocitral in ADZs, which were associated with the accumulation and decomposition of algal detritus. For MDZs, the dominant odorants were 2-methylisoborneol (2-MIB) and geosmin, which were at least partially attributed to the massive addition of bait in a traditional aquaculture area. In addition, the odorant concentration in the water of ADZs was approximately 3 to 21 times higher than that in MDZs, while in the benthic sediment, the odorant concentration in ADZs was approximately 2 to 3 orders of magnitude higher than in MDZs. This study highlights the production and accumulation of nuisance odorants in the benthic sediment of ADZs, indicating a risk of diffusion from the sediment to the water column. This was supported by the correlation of odorants in the water column with that in the sediment. The results of this study will be helpful for the management of different ecotypes suffering from nuisance odorants problems.

B,N Codoped Graphitic Nanotubes Loaded with Co Nanoparticles as Superior Sulfur Host for Advanced Li-S Batteries.

Lithium-sulfur batteries (LSBs) are considered as one of the best candidates for novel rechargeable batteries due to their high energy densities and abundant required materials. However, the poor conductivity and large volume expansion of sulfur and the "shuttle effect" of lithium polysulfides (LPSs) have significantly hindered the development and successful commercialization of LSBs. Bean-like B,N codoped carbon nanotubes loaded with Co nanoparticles (Co@BNTs), which can act as advanced sulfur hosts for the novel LSB cathode, are fabricated. Uniform graphitic nanotubes improve the conductivity of the electrode and load more electroactive sulfur and buffer volume expansion during the electrochemical reaction. In addition, loaded Co nanoparticles and codoped B,N sites can significantly suppress the "shuttle effect" of LPSs with strong chemical interaction. It is established that the Co nanoparticles and codoped B,N can provide more active sites to catalyze the redox reaction of sulfur cathode. This stable Co@BNTs-S cathode displays an exceptional electrochemical performance (1160 mA h g-1 after 200 cycles at 0.1 C) and outstanding stable cycle performance (1008 mA h g-1 after 400 cycles at 1.0 C with an extremely low attenuation rate of 0.038% per cycle).

Recent Progress in Organic-Inorganic Composite Solid Electrolytes for All-Solid-State Lithium Batteries.

Conventional lithium-ion batteries, with flammable organic liquid electrolytes, have serious safety problems, which greatly limit their application. All-solid-state batteries (ASSBs) have received extensive attention from large-scale energy-storage fields, such as electric vehicles (EVs) and intelligent power grids, due to their benefits in safety, energy density, and thermostability. As the key component of ASSBs, solid electrolytes determine the properties of ASSBs. In past decades, various kinds of solid electrolytes, such as polymers and inorganic electrolytes, have been explored. Among these candidates, organic-inorganic composite solid electrolytes (CSEs) that integrate the advantages of these two different electrolytes have been regarded as promising electrolytes for high-performance ASSBs, and extensive studies have been carried out. Herein, recent progress in organic-inorganic CSEs is summarized in terms of the inorganic component, electrochemical performance, effects of the inorganic ceramic nanostructure, and ionic conducting mechanism. Finally, the main challenges and perspectives of organic-inorganic CSEs are highlighted for future development.

Benthic cyanobacterial detritus mats in lacustrine sediment: Characterization and odorant producing potential.

Eutrophic freshwater lake ecosystems are receiving increasing public attention due to a global increase in large-scale harmful cyanobacterial blooms in surface waters. However, the contribution of phytodetritus accumulation in benthic sediments post-bloom remains unclear. In this study, field investigations were performed using microsensors to evaluate benthic phytodetritus mats by measuring TOC/TN ratios, pigments, biodegradable compounds and odorants as descriptive parameters. Results show that the massive amount of phytodetritus trapped by aquatic plants gradually evolved into benthic cyanobacterial detritus mats, which were characterized as anoxic, reductive and low pH. It was confirmed that the occurrence of odorants is more serious in the detritus mats due to decay and decomposition of the accumulated phytodetritus. The mean odorant content in the vegetated zones was 3-52 times higher than that in the unvegetated zones. The dominant odorants were dimethyl trisulfide (DMTS), ß-ionone and ß-cyclocitral, with mean contents of 52.38 ng·(g·dw)-1, 162.20 ng·(g·dw)-1 and 307.51 ng·(g·dw)-1, respectively, in the sediment. In addition, odorant production appears to be associated with the distribution of biodegradable compounds in the sediment. This is supported by the marked correlation observed between biodegradable compounds and odorants. Multiple regression analysis showed that biodegradable compounds can be used as indicators to predict odorant content in the sediment. It is noteworthy that the odorant trend in the water column and sediment is symmetrical, indicating a risk of diffusion from the sediment to the water column. This study helps to clarifying the contributions of benthic cyanobacterial detritus mats to odorant production in shallow eutrophic lakes. The information provided herein may also be useful for future management of aquatic ecosystems.

Climate change decreases the cooling effect from postfire albedo in boreal North America.

Fire is a primary disturbance in boreal forests and generates both positive and negative climate forcings. The influence of fire on surface albedo is a predominantly negative forcing in boreal forests, and one of the strongest overall, due to increased snow exposure in the winter and spring months. Albedo forcings are spatially and temporally heterogeneous and depend on a variety of factors related to soils, topography, climate, land cover/vegetation type, successional dynamics, time since fire, season, and fire severity. However, how these variables interact to influence albedo is not well understood, and quantifying these relationships and predicting postfire albedo becomes increasingly important as the climate changes and management frameworks evolve to consider climate impacts. Here we developed a MODIS-derived 'blue sky' albedo product and a novel machine learning modeling framework to predict fire-driven changes in albedo under historical and future climate scenarios across boreal North America. Converted to radiative forcing (RF), we estimated that fires generate an annual mean cooling of -1.77 ± 1.35 W/m2 from albedo under historical climate conditions (1971-2000) integrated over 70 years postfire. Increasing postfire albedo along a south-north climatic gradient was offset by a nearly opposite gradient in solar insolation, such that large-scale spatial patterns in RF were minimal. Our models suggest that climate change will lead to decreases in mean annual postfire albedo, and hence a decreasing strength of the negative RF, a trend dominated by decreased snow cover in spring months. Considering the range of future climate scenarios and model uncertainties, we estimate that for fires burning in the current era (2016) the cooling effect from long-term postfire albedo will be reduced by 15%-28% due to climate change.

[Spatial Distribution and Pollution Evaluation of Carbon, Nitrogen, and Phosphorus in Sediments of Zhushan Bay at Taihu Lake].

To reveal the distribution characteristics of carbon, nitrogen and phosphorus in the sediments of Zhushan Bay at Taihu Lake, sedimentary columns were collected and sliced by 2 cm vertically from ten sampling points in three sections of Zhushan Bay. The content of total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) were determined for each slice to reveal their horizontal and vertical distribution. The results showed that:spatially, the content of TN, TP, and TOC increased in the surface sediments of Zhushan Bay from the open lake area to the bay, and inside the bay these indexes were significantly higher than in the open lake area (P<0.01). The content of TN, TP, and TOC in the surface sediments in the bay (section A) were 1.53 mg·g-1, 1.55 mg·g-1, and 11.31 mg·g-1, respectively, while in the surface sediments near the open lake (section C) they were only 0.75 mg·g-1, 0.57 mg·g-1, and 6.70 mg·g-1, respectively. Vertically, a feature of surficial enrichment was shown, and the contents of carbon, nitrogen and phosphorus in all three sections showed a decreasing trend with increase of depth. The contents of TN, TP and TOC in the surface sediments are 2-3 times, 2-5 times, and 2-3 times those in the bottom sediments, respectively. Generally, the average TP content in the sediment of Zhushan Bay is 0.93 mg·g-1, suggesting an apparent heavy pollution, while the average TN content is 1.11 mg·g-1 as slight pollution. According to the organic nitrogen index and comprehensive pollution index, the northern part of Zhushan Bay is suffering from heavy pollution, where the organic pollution is relatively strong. The TP pollution index is between 1.03 and 3.87, indicating heavy pollution in Zhushan Bay.

[Composition and Distribution of Biodegradable Compounds in the Macrophyte Dominated Zone of Lake Taihu].

In shallow eutrophic lakes, benthic bioclastic deposits accumulate abundant organic carbon derived from macrophyte detritus. Taking the typical macrophyte-dominated Xukou Bay as the study area, field investigations were performed using sediment cores to evaluate benthic phytodetritus accumulation. Specifically, nutrient contents, TOC/TN ratios, pigmentation, and biodegradable compounds were measured as descriptive parameters. The results show that the benthic bioclastic deposit had accumulated abundant pigments, nutrients, and biodegradable compounds derived from macrophytes detritus. These were mainly localized in the top 15 cm of sediments. Nitrogen loading in the sediments was significantly higher than phosphorous loading, with a distinct spatial difference; the total nitrogen content ranged from 127.2-2092.8 mg·kg-1 and total phosphorous content ranged from 222.1-528.4 mg·kg-1. Moreover, nitrogen loading (1033.6 mg·kg-1) in the vegetated zones were higher than in the unvegetated zones (325.2 mg·kg-1). In addition, carbohydrate (3.7 mg·g-1) was the dominant component of sedimentary bioclastic material, with lipids (2.8 mg·g-1) being the second most abundant of the biodegradable compounds. The major sources of nutrients and biodegradable compounds in the sediment were massive aggregates of macrophyte detritus. The pigment, nutrient, and biodegradable compound contents in the vegetated zones were significantly higher than in unvegetated zones (P<0.01). The benthic eutrophic state showed a trend from mesotrophic to eutrophic in Xukou Bay, which should be given more attention in the future management of freshwater lake ecosystems.