The Hartbeespoort Dam, located 40 km west of Tshwane on the Crocodile River, is an extremely eutrophic water body. Situated in one most economically active areas South Africa, it receives a high nutrient input from wastewater treatment works (WWTW), leaking sewers, as well urban and agricultural runoff. Metsi Me programme, which ran 2006 to 2016, aimed mitigate in-lake stocks using biomanipulat...

Target point manipulation inside a deformable object by a robotic system is necessary in many medical and industrial applications such as breast biopsy, drug injection, suturing, precise machining of deformable objects etc. However, this is a challenging problem because of the difficulty of imposing the motion of the internal target point by a finite number of actuation points located at the bo...

Piscivorous fish play an important role in regulating lake food web structure. However, most ultimately piscivorous fish pass through a period of planktivory before becoming piscivorous. In 1993 and 1994, two large cohorts of young-of-the-year largemouth bass (Micropterus salmoides) were recorded in Paul Lake, Michigan. The 1993 and 1994 cohorts were the largest recorded in data extending back ...

Based on monthly mass balances on 7–8 yr of data from 16 shallow (mean depth: 1–10 m), eutrophic, unstratified, or only temporarily stratified Danish lakes, we developed a simple empirical model relating the seasonal variation in lake total phosphorus (TP) concentrations to external loading, accumulated phosphorus in the sediment, hydraulic retention time, and water temperature. The aim was to ...

Many phytoplankton species form resting stages when environmental conditions are harsh and these can survive for a long time in the sediment (Livingstone and Jaworski, 1980; Lampert, 1995). When environmental conditions are favourable again, they recruit to the water phase and continue growing (Hansson et al., 1994; Hansson, 1996a). Many species of cyanobacteria, for example Microcystis, Anabae...

The sensitivity analysis of atomic force microscope (AFM) based manipulation of gold spherical nanoparticles in air medium has been carried out in previous research works. In the AFM-based manipulations conducted in various biological liquid mediums, the new environmental parameters associated with these biological fluids also affect the dynamics of the manipulation process. Therefore in this r...

—Fishes can provide an important link between benthic and pelagic habitats by removing nutrients from sediments and excreting them into the water column. The relative importance of nutrients excreted by fishes to ecosystem productivity may vary among species and with abiotic conditions. I measured excretion rates of three benthic feeding fishes, gizzard shad Dorosoma cepedianum, smallmouth buff...

浮游动物牧食、水温及营养可利用性均可影响优势浮游植物功能群的转变,但这些驱动因素的交互作用尚不清楚。为了解云南高原湖泊--洱海浮游植物优势功能群的分布特征及其主要驱动因素,于2018年1月-2020年12月进行月度采样,结合聚类分析、方差分析和冗余分析等,分析驱动浮游植物优势功能群转变的主要因素。结果表明,共鉴定浮游植物7门96属,划分为27个浮游植物功能群,其中优势功能群有15个。聚类分析结果表明,根据浮游植物功能群密度数据可将优势功能群转变过程分为3个由不同类型藻类主导的时期(S期、M期和P期),其中S期(为期18个月)以功能群S1和H1(代表藻为假鱼腥藻、浮丝藻和长孢藻等丝状蓝藻)为主,M期(为期10个月)以功能群M(微囊藻群体)为主,P期(为期8个月)以功能群P和M(脆杆藻和单个微囊藻等)为主。RDA分析及变差分解分析结果表明,卡尔森营养状态指数(TSI)(主要是总磷)是影响...

The assumption that macrophytes can provide zooplankton a daytime refuge against fish predation is central to the diel horizontal migration hypothesis. However, previous observations and experiments have shown that largebodied zooplankton avoid macrophytes. To directly test these contrasting roles of macrophytes, we measured the reaction of Daphnia pulex to macrophytes (Elodea canadensis or pla...