Trophic-Level Interactive Effects of Phosphorus Availability on the Toxicities of Cadmium, Arsenic, and Their Binary Mixture in Media-Exposed Scenedesmus acutus and Media and Dietary-Exposed Daphnia pulex

2020 ◽  
Vol 54 (9) ◽  
pp. 5651-5666
Author(s):  
Olushola M. Awoyemi ◽  
Seenivasan Subbiah ◽  
Kelsey N. Thompson ◽  
Anahi Velazquez ◽  
Angela Peace ◽  
...  
Keyword(s):  
Binary Mixture ◽  
Trophic Level ◽  
Daphnia Pulex ◽  
Phosphorus Availability ◽  
Interactive Effects ◽  
Scenedesmus Acutus

Nitrate-N-mediated toxicological responses of Scenedesmus acutus and Daphnia pulex to cadmium, arsenic and their binary mixture (Cd/Asmix) at environmentally relevant concentrations

2020 ◽  
Vol 400 ◽  
pp. 123189
Author(s):  
Olushola M. Awoyemi ◽  
Seenivasan Subbiah ◽  
Anahi Velazquez ◽  
Kelsey N. Thompson ◽  
Angela L. Peace ◽  
...  
Keyword(s):  
Binary Mixture ◽  
Daphnia Pulex ◽  
Scenedesmus Acutus ◽  
Nitrate N

Comparative Study of the Interactive Effects of Salinity and Phosphorus Availability in Wild (Hordeum maritimum) and Cultivated Barley (H. vulgare)

2014 ◽  
Vol 33 (4) ◽  
pp. 860-870 ◽  
Author(s):  
Ons Talbi Zribi ◽  
Hayet Houmani ◽  
Saber Kouas ◽  
Ines Slama ◽  
Riadh Ksouri ◽  
...  
Keyword(s):  
Comparative Study ◽  
Phosphorus Availability ◽  
Interactive Effects ◽  
Cultivated Barley

scholarly journals Interactive Effects of Disturbance, Productivity, and Consumer Diversity on the Structure of Prey Communities

ISRN Ecology ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
Christopher F. Steiner
Keyword(s):  
Trophic Level ◽  
Prey Abundance ◽  
Interactive Effects ◽  
Disturbance Regime ◽  
System Productivity ◽  
High Productivity ◽  
Compensatory Responses ◽  
Prey Diversity ◽  
Diversity Effects ◽  
Consumer Diversity

Experiments show that consumer diversity can have important effects on the control of prey diversity and abundance. However, theory also indicates that the strength of consumer effects on such properties will vary depending on system productivity and disturbance regime. Using a laboratory-based system composed of ciliate consumers and bacterial prey, I explored the interactive effects of productivity, disturbance, and consumer diversity on prey diversity and trophic-level abundance. Consumer diversity had productivity-dependent effects on bacterial prey that were consistent with theoretical expectations. At low productivity, increasing consumer diversity reduced prey abundance while at high productivity no effects were detected due to compensatory responses among bacteria. In contrast, consumer diversity had weak effects on prey diversity at low productivity but significantly depressed prey diversity at high productivity. Disturbance on consumers enhanced prey diversity but did not alter consumer diversity effects on prey. These results indicate that consumer diversity may play an important role in the regulation of prey communities, but the strength of this effect varies with system productivity.

scholarly journals Interactive effects of copper and calcium in Daphnia pulex

2016 ◽  
Author(s):  
Andrew Liorti ◽  
Teresa Crease ◽  
Andreas Heyland
Keyword(s):  
Water Chemistry ◽  
Calcium Uptake ◽  
Anthropogenic Activities ◽  
Daphnia Pulex ◽  
Copper Toxicity ◽  
Radioactive Tracer ◽  
Interactive Effects ◽  
Natural Environments ◽  
Toxicity Screening ◽  
High Calcium

<p>Many freshwater habitats around the world suffered dramatic water chemistry changes over the last century mostly due to anthropogenic activities, including an overall reduction in pH due to high sulfur emissions and unsustainable forestry practices. One consequence of this change in water chemistry is a drop in available calcium concentration, which creates problems for aquatic organisms that rely on dissolved calcium to build their exo- or endoskeletons and reinforce their carapace during regular molts. <em>Daphnia</em> populations in shield lakes in northern Ontario are also exposed to other stressors, including copper, which persists at high concentrations in many of these freshwater lakes and ponds due to mining and other human activities. Copper toxicity on animals is influenced by the availability of other competing ions, such as calcium. Using our newly developed high throughput toxicity screening system, we show that mortality of <em>Daphnia pulex</em> increases with exposure to low calcium (0.05 mg L<sup>-1</sup>) and high copper (300 µg L<sup>-1</sup>). When these two stressors were combined, we found that copper was less toxic at high calcium concentrations, indicating a protective effect of calcium against copper toxicity. We then established basic calcium uptake kinetics in <em>D. pulex</em> using radioactive tracer <sub>45</sub>Ca and provide evidence that copper, at environmentally relevant concentrations, competes with calcium uptake based on K<sub>m</sub> and V<sub>max</sub>. Our data show that both calcium decline and copper increase in aquatic ecosystems may negatively impact natural <em>Daphnia</em> populations, and that interactions between these two metals may occur in natural environments that result in fitness consequences for zooplankton. </p>

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