Evaluation of impact of land use and landscape metrics on surface water quality in the northeastern part along Lake Tanganyika, Africa.

As the second deepest lake in Africa, Lake Tanganyika plays an important role in supplying fish protein for the catchment's residents and is irreplaceable in global biodiversity. However, the lake's water environment is threatened by socioeconomic development and rapid population growth along the lake. This study analyzed the spatial scale effects and seasonal dependence of land use types and landscape metrics on water quality in 16 sub-basins along northeastern Lake Tanganyika at different levels of urbanization.

Burial or mineralization: Origins and fates of organic matter in the water-suspended particulate matter-sediment of macrophyte- and algae-dominated areas in Lake Taihu.

Increased algal blooms and loss of aquatic vegetation are critical environmental issues associated with shallow lakes worldwide. The increase in organic matter (OM) in both macrophyte-dominated areas (MDAs) and algae-dominated areas (ADAs) has exacerbated these problems. Most OM in water is concentrated as suspended particulate matter (SPM), which eventually migrates to the sediment.

Evaluation of the distribution and mobility of labile phosphorus in sediment profiles of Lake Nansi, the largest eutrophic freshwater lake in northern China.

Understanding various biogeochemical processes, especially in eutrophic sediments, necessitates fine-scale phosphorus (P) measurements in pore waters. To the best of our knowledge, the fine-scale distributions of P across the sediment profiles of Lake Nansi have rarely been investigated. Herein we evaluated the dynamic distributions of labile P and Fe across the sediment-water interface (SWI) of Lake Nansi at two-dimensional (2D) and sub-millimeter resolution, using well-established colorimetric diffusive gradients in thin films (DGT) methodology.

New insights into the growth response of the macrophyte Vallisneria natans exposed to phosphite.

Renewed interest in phosphite, an analog of phosphate, has increased due to its widespread distribution and increasing abundance in many waterbodies. However, up until recently very little is known about their ecological effects on aquatic organisms. Herein we studied the effects of phosphite via root and foliar exposure on the growth responses of the dominant pioneer macrophyte V.

Ignored effects of phosphite (P) on the growth responses of three typical algae species.

Nowadays, the ubiquitous distribution and increasing abundance of P in waterbodies have caused serious concerns regarding its bioavailability and potential toxicity. However, our knowledge on these issues is relatively limited. We addressed previously unknown effects of P on three dominate algae species i.

[Screening of Priority Pollutants and Risk Assessment for Surface Water from Shengjin Lake].

Shengjin Lake, which serves as an important National Nature Reserve, is suffering from chemical pollution due to rapid industrial and agricultural development in the circumjacent basin. Therefore, 168 anthropogenic toxic chemicals were determined to examine their spatial distribution and identify priority pollutants using a ranking system based on occurrence(O), persistence(P), bioaccumulation(B), ecological risk(E), and human health risk(H). Ecosystem and human health risks were also assessed.

Environmental implications from the priority pollutants screening in impoundment reservoir along the eastern route of China's South-to-North Water Diversion Project.

Screening priority pollutants from vast anthropogenic contaminants discharged into aquatic environment is urgent for protecting water quality definitely. The multi-criteria scoring method involved in the occurrence (O), persistence (P), bioaccumulation (B), ecological risk (Eco-T), and human health risk (Hum-T), was established for pollutants prioritization in waters and applied in Dongping Lake, the final impoundment reservoir along the eastern route of China's South-to-North Water Diversion Project (SNWDP). A total of 170 chemicals including heavy metals (HMs), volatile organic chemicals (VOCs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), phthalate esters (PAEs), and antibiotics (ANTs) were investigated as the candidates.

Spatial variations in diffusive methane fluxes and the role of eutrophication in a subtropical shallow lake.

Shallow lakes account for most of the diffusive CH emissions from global lakes, and they also suffer from eutrophication worldwide. Determining the effect of eutrophication on diffusive CH fluxes is fundamental to understanding CH emissions in shallow lakes. This study aimed to investigate the spatial variations in diffusive CH fluxes and explore the role of eutrophication in Lake Chaohu, a large and shallow eutrophic lake in the lower reaches of the Yangtze River.

Characterization of phosphorus availability in response to radial oxygen losses in the rhizosphere of Vallisneria spiralis.

The viewpoint that radial oxygen loss (ROL) of submerged macrophytes induces changes in redox conditions and the associated phosphorus (P) availability has been indirectly confirmed at larger spatial scales using conventional, destructive techniques. However, critical information about microniches has largely been overlooked due to the lack of satisfactory in situ mapping technologies. In this study, we deployed a recently developed hybrid sensor in the rhizosphere of Vallisneria spiralis (V.

In situ sampling and speciation method for measuring dissolved phosphite at ultratrace concentrations in the natural environment.

Phosphite (P) is of emerging chemical interest due to its importance within the global phosphorus cycle. Yet, to date, precise/accurate measurements of P are still lacking due to the inherent analytical challenges linked to its instability/ease of oxidation and ultra-trace concentration. Here, we present the first in-situ sampling and speciation analysis method, for dissolved P, using the diffusive-gradients-in-thin-films (DGT) technique, combined with capillary-column-configured-dual-ion-chromatography (CC-DIC).

Wet deposition of atmospheric nitrogen contributes to nitrogen loading in the surface waters of Lake Tanganyika, East Africa: a case study of the Kigoma region.

Lake Tanganyika, an African Great Lake, is a complex tropical ecosystem that has been subjected to extreme climate-related changes in the last century, including seasonal changes in temperature and rainfall, decreased overall annual rainfall, and greater frequency of rainstorms. Atmospheric nitrogen (N) is an important component of the lake's N loading, but how long-term and seasonal changes in precipitation affect this loading still needs clarification. This study aimed to improve our understanding of the seasonal features of N deposition in the lake, by monitoring atmospheric N deposition concentrations and fluxes from March 2013 to February 2014.

Nitrogen exchange across the sediment-water interface after dredging: The influence of contaminated riverine suspended particulate matter.

Dredging has been widely implemented in shallow lakes to reduce internal nitrogen (N) loading. The suspended particulate matter (SPM) coming from polluted rivers usually contains high levels of N and ultimately deposits on the dredged sediment surfaces near the river mouth. To study the influence of the riverine SPM on N exchange across the sediment-water interface (SWI) after dredging, a 360-day experiment was carried out comparing un-dredged and dredged sediments from Lake Chaohu, China.

A novel hybrid sensor for combined imaging of dissolved oxygen and labile phosphorus flux in sediment and water.

A novel sensor assembled by a hybrid film was developed for 2D combined measurements of DO dynamic and labile P flux in sediment and water at sub-millimeter resolution based on PO and DGT techniques. The hybrid film is comprised of a transparent polyester membrane supporting two ultrathin sensing layers, i.e.

Response of N₂O emissions to elevated water depth regulation: comparison of rhizosphere versus non-rhizosphere of Phragmites australis in a field-scale study.

Emissions of nitrous oxide (N2O) from wetland ecosystems are globally significant and have recently received increased attention. However, relatively few direct studies of these emissions in response to water depth-related changes in sediment ecosystems have been conducted, despite the likely role they play as hotspots of N2O production. We investigated depth-related differential responses of the dissolved inorganic nitrogen distribution in Phragmites australis (Cav.

Phosphorus partitioning between sediment and water in the riparian wetland in response to the hydrological regimes.

Water quality in watersheds is severely impacted by nutrient enrichment as a result of agricultural activities. Understanding hydrological effects on P dynamics can optimize the ecological function of riparian wetlands to reduce nonpoint source pollution. The XiaZhuHu wetlands were selected for field P investigation, and two typical hydrological batch studies of 35 d each (a static column observation simulating the dry season, and a steady-flow flume observation simulating the rainy season) were conducted to understand sediment P dynamics and evaluate capacity of P immobilization.

Improving water management practices to reduce nutrient export from rice paddy fields.

Nitrogen (N) and phosphorus (P) loss from rice paddy fields represents a significant threat to water quality in China. In this project, three irrigation-drainage regimes were compared, including one conventional irrigation-drainage regime, i.e.

Impact of different benthic animals on phosphorus dynamics across the sediment-water interface.

As a diagenetic progress, bioturbation influences solute exchange across the sediment-water interface (SWI). Different benthic animals have various mechanical activities in sediment, thereby they may have different effects on solute exchange across the SWI. This laboratory study examined the impacts of different benthic animals on phosphorus dynamics across the SWI.

[Phosphorus characteristics and the impact to water quality across interface of overlying water and sediment of Xiazhuhu wetland in Northern Zhejiang Province, China].

Healthy wetland system is regarded as an effective way for biological remediation of non-point source pollutants. A case field investigation on phosphorus (P) status of overlying water and sediment was carried out for Xiazhuhu wetland located in Northern Zhejiang Province, China. A static wetland microcosm experiment was conducted to understand the characteristics and mechanisms related to P exchanging, P forms changing, and water quality impact across the interface of water and sediment.

A reformed SBR technology integrated with two-step feeding and low-intensity aeration for swine wastewater treatment.

Wastewater from animal farms in China is threatening the quality and security of the local water environment. A traditional sequencing batch reactor (SBR) and a reformed SBR integrated with two-step feeding and low-intensity aeration at laboratory scale were investigated in this study for biological removal of nutrients and organic matter from swine wastewater. A low efficiency and poor stability were found under the traditional SBR, and the reduction of total nitrogen (TN), total phosphorus (TP) and biochemical oxygen demand (BOD5) reached 89.

[Denitrifying phosphorus-accumulating SBR combined with low-intensity aeration technology for piggery wastewater treatment].

The wastewater from animal farms in China is threatening the quality and security of local water environment. In the laboratory scale, a traditional SBR (A/O) and a denitrifying phosphorus-accumulating organisms (DNPAO) sequencing batch reactor (SBR) in biologically removing nutrients and organic matters from swine manure were investigated in this study. When piggery wastewater was directly treated with a traditional SBR, the efficiency was low with unstable working state, the reduction of TN, TP and BOD5 reached 89.

Phosphorus interception in floodwater of paddy field during the rice-growing season in TaiHu Lake Basin.

A field experiment located in TaiHu Lake Basin in China was conducted, by application of superphosphate or a mixture of superphosphate with manure, to elucidate the interception of P export during a typical rice growing season through 'zero-drainage water management' combined with sound irrigation, rainfall forecasting and field drying. P concentrations in floodwater rapidly declined before the first event of field drying, and subsequently tended to return to the background levels. Before the first field drying TPP was the predominant P form in floodwater on fields with no P input, DRP on plots that received superphosphate only, and DOP on plots treated with the mixture of superphosphate and manure.