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Azizullah A.,Friedrich - Alexander - University, Erlangen - Nuremberg | Azizullah A.,Kohat University of Science and Technology | Jamil M.,Gomal University | Richter P.,Friedrich - Alexander - University, Erlangen - Nuremberg | Hader D.-P.,Neue Str. 9
Journal of Applied Phycology | Year: 2014

Wastewater is a big source of water pollution in the world. Selected wastewater samples from Dera Ismail Khan (D.I. Khan), a city in Pakistan, were analyzed for physicochemical and ecotoxicological properties. Samples from the Indus River before and after the municipal wastewater is discharged into it were tested to determine the effects of municipal wastewaters from D.I. Khan on the river Indus. Different parameters of the freshwater flagellate Euglena gracilis such as motility, swimming velocity, gravitactic orientation, cell shape, and photosynthetic efficiency were used as end points. Gravitactic orientation and cell shape were found to be significantly impaired by the wastewater samples. Swimming velocity and relative electron transport rate of cells were positively affected by all water samples. Quantum yield of photosystem II (F v/F m) was not affected, except by ghee (oil) industry effluent where it was significantly increased. Comparison of upstream and downstream samples from the Indus River showed that waste effluents from D.I. Khan affect the physicochemical and ecological properties of the river Indus. © 2013 Springer Science+Business Media Dordrecht.

Azizullah A.,Friedrich - Alexander - University, Erlangen - Nuremberg | Azizullah A.,Kohat University of Science and Technology | Richter P.,Friedrich - Alexander - University, Erlangen - Nuremberg | Jamil M.,Gomal University | Hader D.-P.,Neue Str. 9
Ecotoxicology | Year: 2012

Chronic toxicity of the common laundry detergent Ariel on the freshwater alga Euglena gracilis was investigated by growing the alga in a medium containing the detergent for 7 days. Cell density, motility, swimming velocity, gravitactic orientation, cell shape, photosynthesis and concentration of light-harvesting pigments were used as end point parameters for the assessment of toxicity. Cell density was significantly reduced at a concentration of 1 mg l-1 or above. Among the other tested parameters, with the exception of cell shape, gravitaxis and chlorophyll b, all were adversely affected by the detergent at concentrations exceeding 1 mg l-1. It is concluded that long-term (7-days) exposure to the detergent caused significant toxicity to E. gracilis. Furthermore, long-term tests with E. gracilis can be used as sensitive indicator for the toxicity assessment of laundry detergents in aquatic environments. © Springer Science+Business Media, LLC 2012.

Gao K.,Xiamen University | Helbling E.W.,CONICET | Hader D.-P.,Neue Str. 9 | Hutchins D.A.,University of Southern California
Marine Ecology Progress Series | Year: 2012

Anthropogenic CO2 is accumulating in the atmosphere and trapping reflected infrared radiation, resulting in warming of both terrestrial and ocean ecosystems. At the same time, the dissolution of CO2 into seawater is increasing surface ocean acidity, a process known as ocean acidification. Effects of ocean acidification on marine primary producers have been documented to be stimulative, inhibitive, or neutral. Elevated CO 2 and reduced pH levels can interact with solar radiation, which fluctuates over different time scales from limiting to saturating or even stressful levels, to bring about synergistic, antagonistic, or balanced effects on marine primary producers at different depths or under changing weather conditions. However, shoaling of the upper mixed layer (enhanced stratification) due to ocean warming and freshening (rain, ice melting) can lead to additional photosynthetically active radiation (PAR) and ultraviolet (UV) exposure, which can have both benefits and costs to photosynthetic organisms. Elevated CO 2 concentrations under low or moderate levels of PAR have been shown to enhance photosynthesis or growth of both phytoplankton and macroalgae; excessive levels of PAR, however, can lead to additional inhibition of photosynthesis or growth under elevated CO2, and addition of UV radiation (280 to 400 nm) can increase or down-regulate such inhibition, since solar UV-B (280 to 315 nm) radiation often harms algal cells, while UV-A (315 to 400 nm) at moderate levels stimulates photosynthetic carbon fixation in both phytoplankton and macroalgae. In view of warming effects, increased temperatures have been shown to enhance photorepair of UV-damaged molecules, though it simultaneously enhances respiratory carbon loss. The net effects of ocean acidification on marine primary producers are therefore largely dependent on the photobiological conditions (light limitation, light or UV stress), as well as interactions with rising temperature and other variables such as altered nutrient availability. Hence, feedbacks between changing carbonate chemistry and solar radiation across the entire spectrum present complications to interpret and understand ocean acidification effects based on single-factor experiments. © Inter-Research 2012.

Azizullah A.,Friedrich - Alexander - University, Erlangen - Nuremberg | Richter P.,Friedrich - Alexander - University, Erlangen - Nuremberg | Hader D.-P.,Neue Str. 9
Chemosphere | Year: 2011

Synthetic detergents are among the commonly used chemicals in everyday life. Detergents, reaching aquatic environments through domestic and municipal wastewater, can cause many different effects in aquatic organisms. The present study was aimed at the toxicity evaluation of a commonly used laundry detergent, Ariel, using the freshwater flagellate Euglena gracilis as a biotest organism. Different parameters of the flagellate like motility, swimming velocity, cell shape, gravitactic orientation, photosynthesis and concentration of light harvesting pigments were used as end points for the toxicity assessment. No Observed Effect Concentration (NOEC) and EC 50 values were calculated for the end point parameters at four different incubation times, i.e. 0, 6, 24 and 72h. After 72h incubation, swimming velocity of the cells was found to be the most sensitive parameter giving NOEC and EC 50 values of 10.8 and 34mgL -1, respectively. After 72h exposure to the detergent, chlorophyll a and total carotenoids were significantly decreased in cultures treated with Ariel at concentrations of 50mgL -1 and above while chlorophyll b significantly decreased at concentrations above 750mgL -1. The maximum inhibitory effect on the quantum yield of photosystem II was observed after 24h exposure and thereafter a recovery trend was observed. Motility, gravitaxis and cell shape were strongly impaired immediately upon exposure to the detergent, but with increasing exposure time these parameters showed acclimatization to the stress and thus the NOEC values obtained after 72h were higher than those immediately after exposure. © 2011 Elsevier Ltd.

Hader D.-P.,Neue Str. 9 | Villafane V.E.,Estacion de Fotobiologia Playa Union | Villafane V.E.,CONICET | Helbling E.W.,Estacion de Fotobiologia Playa Union | Helbling E.W.,CONICET
Photochemical and Photobiological Sciences | Year: 2014

The productivity of aquatic primary producers depends on a number of biotic and abiotic factors, such as pH, CO2 concentration, temperature, nutrient availability, solar UV and PAR irradiances, mixing frequency as well as herbivore pressure and the presence of viruses, among others. The effects of these factors, within a climate change context, may be additive, synergistic or antagonistic. Since some of them, e.g. solar radiation and temperature, vary along a latitudinal gradient, this perspective about the effects of global climate change on primary producers will consider ecosystems individually, separated into polar (Arctic and Antarctic), temperate and tropical waters. As coastal waters are characterized by lower light penetration and higher DOM and nutrient concentrations, they are considered in a separate section. Freshwater systems are also governed by different conditions and therefore also treated in their own section. Overall, we show that although there are general common trends of changes in variables associated with global change (e.g. the impact of UVR on photosynthesis tends to decrease with increasing temperature and nutrient input), the responses of aquatic primary producers have great variability in the different ecosystems across latitudes. This is mainly due to direct or indirect effects associated with physico-chemical changes that occur within water bodies. Therefore we stress the need for regional predictions on the responses of primary producers to climate change as it is not warranted to extrapolate from one system to another. This journal is © the Partner Organisations 2014.

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