Impoundment-induced stoichiometric imbalance exacerbated phosphorus limitation in a deep subtropical reservoir: Implications for eutrophication management.

Impoundments play a vital role as nutrient sinks, capable of retaining and exporting nitrogen (N) and phosphorus (P) at different rates. The imbalance in N and P stoichiometry relative to phytoplankton demand often determines the limiting nutrient of phytoplankton biomass in these systems. This critical factor has a substantial impact on the management of eutrophication, encompassing the formulation of nutrient control strategies and the setting of regulatory thresholds.

Design terahertz polarizers and vector polarized vortex terahertz wave generators based on the effective dielectric constant of metal gratings.

Polarization and phase devices for terahertz waves have important applications in terahertz detection, imaging, communication, etc. Spatially variable metal gratings can be used for broad-spectrum, miniaturized, and low-cost terahertz polarization and phase modulation devices. Based on the effective dielectric constant and the theory of light propagation in multilayer media, we obtain the relationship between the transmittance and extinction ratio and the parameters such as the duty cycle of the metal grating, the frequency of the incident terahertz wave, the angle of incidence, the thickness of the metal grating, the refractive index of the substrate, and the thickness of the substrate.

Nonreciprocal toroidal dipole resonance and one-way quasi-bound state in the continuum.

Bound states in the continuum (BICs) provide an alternative way of trapping light at nanoscale. Although the last 10 years have witnessed tremendous progress on BICs from fundamentals to applications, nonreciprocal BICs and their potential applications have not been fully exploited yet. In this study, we demonstrated a one-way quasi-BIC by leveraging an all-dielectric magneto-optical (MO) metasurface.

Thermal stratification controls taste and odour compounds by regulating the phytoplankton community in a large subtropical water source reservoir (Xin'anjiang Reservoir).

2-Methylisoborneol (2-MIB) and geosmin are compounds released by algae that significantly degrade reservoir water quality, posing a threat to both the safety of drinking water and the quality of aquatic products sourced from these environments. However, few studies have explored how enhanced thermal stratification affects the occurrence and regulation of odorants in large drinking water reservoirs. Through systematic monitoring and investigation of Xin'anjiang Reservoir, we found that enhanced thermal stratification promotes filamentous cyanobacteria, particularly Leptolyngbya sp.

High-Performance and Stable SbS Thin-Film Photodetectors for Potential Application in Visible Light Communication.

Photodetectors (PDs) are critical parts of visible light communication (VLC) systems for achieving efficient photoelectronic conversion and high-fidelity transmission of signals. Antimony sulfide (SbS) as a nontoxic, high optical absorption coefficient, and low-cost semiconductor becomes a promising candidate for applications in VLC systems. Particularly, SbS PDs were verified to have significantly weak light detection ability in the visible region.

Real-time wavefront correction using diffractive optical networks.

Real-time wavefront correction is a challenging problem to present for conventional adaptive optics systems. Here, we present an all-optical system to realize real-time wavefront correction. Using deep learning, the system, which contains only multiple transmissive diffractive layers, is trained to realize high-quality imaging for unknown, random, distorted wavefronts.

Self-Powered SbS Thin-Film Photodetectors with High Detectivity for Weak Light Signal Detection.

Photodetectors (PDs) for weak light signal detection have wide applications for optical communication and imaging. Antimony sulfide (SbS) as a nontoxic and stable light-sensitive material becomes a promising candidate for weak light PDs, which are developing in the direction of high response, high speed, and low cost. Herein, a self-powered SbS PD with the structure of FTO/TiO/SbS/Au is developed to achieve weak light detection for 300-750 nm visible light.

[Spatial-temporal Distribution of Suspended Solids and Its Sedimentation Flux and Nutrients Effects in Xin'anjiang Reservoir, China].

To analyze the spatial-temporal distribution and sedimentation characteristics of suspended solids in reservoirs, high-frequency monitoring of a sediment trap and buoy, combined with three-dimensional water sampling, was conducted and analyzed in Xin'anjiang Reservoir for a year. The results showed that the turbidity data of the buoy has significant correlation with rainfall, inflow, and suspended solids (SS), particularly for SS (<0.01, =0.

[High-Frequency Dynamics of Water Quality and Phytoplankton Community in Inflowing River Mouth of Xin'anjiang Reservoir, China].

The tail of the reservoir is the unstable zone regarding water quality and phytoplankton community. Therefore, it is the crucial zone in aquatic ecosystem transitions. To understand the transition characteristics and driving mechanisms of water environment dynamics, high-frequency monitoring of the water environment and phytoplankton community in the tail of a deep and large reservoir, the Xin'anjiang Reservoir in southeast of China, was conducted using a water quality monitoring buoy and three-day interval water sampling during 18 months.

Warming affects crustacean grazing pressure on phytoplankton by altering the vertical distribution in a stratified lake.

Zooplankton could efficiently graze algae and thus improve water quality. However, as thermal stratification commonly occurs in deep lakes, the effect of warming on the trophic interactions of plankton in depth profiles is still not clear. To explore the pressure of crustacean grazing on phytoplanktonic responses to enhanced thermal stratification under warming, we evaluated the monthly changes in the Secchi depth (SD), thermocline depth (TD), and the mean residence depth of zooplankton (zp MRD) and chlorophyll a (Chla MRD) in Lake Qiandaohu from January 2015 to December 2018.

Thermal stratification dynamics in a large and deep subtropical reservoir revealed by high-frequency buoy data.

We measure the thermal stratification dynamics in Lake Qiandaohu, China, a deep subtropical reservoir, to better understand the mixing mechanism and its response to lake warming. A high-frequency monitoring buoy dataset from February 2016 to October 2017 is used to evaluate variations in the water temperature profile, Schmidt stability (SS) and thermocline parameters, such as the thermocline depth (TD), bottom depth (TB), thickness (TT), and strength (TS), and elucidate the potential effects of thermal stratification on the lake's ecosystem. High-frequency observation data demonstrate that the lake's thermal-stratification cycle can be divided into three stages: formation, stationary and weakening periods.

Curvature wavefront sensing based on a single defocused image and intensity compensation.

Curvature wavefront sensing usually requires the measurement of two defocused images at equal distances before and after the focus. In this paper, a new wavefront recovery algorithm based on only one defocused image is proposed. This algorithm contains the following four steps: response matrix calculation, establishment of intensity distribution equations, Zernike coefficients solution derived from the least squares method, and defocused image compensation with the solved Zernike coefficients.

Seasonal-Spatial Distribution and Long-Term Variation of Transparency in Xin'anjiang Reservoir: Implications for Reservoir Management.

Water transparency is a useful indicator of water quality or productivity and is widely used to detect long-term changes in the water quality and eutrophication of lake ecosystems. Based on short-term spatial observations in the spring, summer, and winter and on long-term site-specific observation from 1988 to 2013, the spatial, seasonal, long-term variations, and the factors affecting transparency are presented for Xin'anjiang Reservoir (China). Spatially, transparency was high in the open water but low in the bays and the inflowing river mouths, reflecting the effect of river runoff.

Dissolved oxygen stratification and response to thermal structure and long-term climate change in a large and deep subtropical reservoir (Lake Qiandaohu, China).

From January 2010 to March 2014, detailed depth profiles of water temperature, dissolved oxygen (DO), and chromophoric dissolved organic matter (CDOM) were collected at three sites in Lake Qiandaohu, a large, deep subtropical reservoir in China. Additionally, we assessed the changes in DO stratification over the past 61 years (1953-2013) based on our empirical models and long-term air temperature and transparency data. The DO concentration never fell below 2 mg/L, the critical value for anoxia, and the DO depth profiles were closely linked to the water temperature depth profiles.

[Dynamic distributions of dissolved oxygen env in Lake Qiandaohu and its environmental influence factors].

Based on monthly in situ data collected at six sampling sites in Qiandaohu Lake between 2011 and 2012, the dynamic distributions of dissolved oxygen (DO) were analyzed and the relationships between DO and the environmental factors were investigated. The results showed that there were obviously vertical and temporal variations in the distributions of DO. In winter, the average values of DO were generally higher than those in other seasons, but no significant vertical distribution variation was found except Dabaqian.

[Pollution characteristics and health risk assessment of organochlorine pesticides (OCPs) in the water of Lake Qiandao and its major input rivers].

Organochlorine pesticides (OCPs) were quantitatively determined by GC in several surface water samples collected in July 2011 and November 2011 from Lake Qiandao (Xin'an River Reservoir) and its major input rivers. Then the component characteristics and source apportionment of HCHs and DDTs were confirmed, and the health risk assessment was evaluated. The results showed that 8 OCPs were found to be in trace amount, and p,p'-DDT, a-HCH and p,p'-DDE were the highest frequently detected OCPs.

[Study on seasonal characteristics of thermal stratification in lacustrine zone of Lake Qiandao].

Lake Qiandao is a typical subtropical man-made reservoir in China. The investigation on the seasonal and vertical dynamics of water temperature, dissolved oxygen (DO), pH value, turbidity, photosynthetic available radiation (PAR) and chlorophyll a was conducted in 2011 in order to find out the physical characteristics of Lake Qiandao. The average surface water temperature ranged from 10.