Author
Anas Ghadouani
Other affiliations: Cooperative Research Centre, Université de Montréal, University of Waterloo ...read more
Bio: Anas Ghadouani is an academic researcher from University of Western Australia. The author has contributed to research in topics: Biomass (ecology) & Phytoplankton. The author has an hindex of 26, co-authored 73 publications receiving 2221 citations. Previous affiliations of Anas Ghadouani include Cooperative Research Centre & Université de Montréal.
Topics: Biomass (ecology), Phytoplankton, Wastewater, Zooplankton, Microcystin
Papers published on a yearly basis
Papers
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TL;DR: More effort is needed to understand the relationship between rainfall patterns and cyanobacterial bloom dynamics, and in particular toxin production, to be able to assess and mediate the significant threat cyanobacteria blooms pose to the authors' water resources.
299 citations
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TL;DR: It is demonstrated that zooplankton communities can be negatively affected by cyanobacterial blooms and therefore the potential to use herbivory to reduce algal blooms in such eutrophic lakes appears limited.
Abstract: SUMMARY 1. Large in situ enclosures were used to study the effects of experimentally induced cyanobacterial blooms on zooplankton communities. A combination of N and P was added to shallow (2 m) and deep enclosures (5 m) with the goal of reducing the TN : TP ratio to a low level (� 5 : 1) to promote cyanobacterial growth. After nutrient additions, high biomass of cyanobacteria developed rapidly in shallow enclosures reaching levels only observed during bloom events in eutrophic lakes. 2. In the shallow enclosures, particulate phosphorus (PP) was on average 35% higher in comparison with deep enclosures, suggesting that depth plays a key role in P uptake by algae. Phytoplankton communities in both deep and shallow enclosures were dominated by three cyanobacteria species – Aphanizomenon flos-aquae, Anabaena flos-aquae and Microcystis aeruginosa – which accounted for up to 70% of total phytoplankton biomass. However, the absolute biomass of the three species was much higher in shallow enclosures, especially Aphanizomenon flos-aquae. The three cyanobacteria species responded in contrasting ways to nutrient manipulation because of their different physiology. 3. Standardised concentrations of the hepatotoxic microcystin-LR increased as a result of nutrient manipulations by a factor of four in the treated enclosures. Increased biomass of inedible and toxin producing cyanobacteria was associated with a decline in Daphnia pulicaria biomass caused by a reduction in the number of individuals with a body length of >1 mm. Zooplankton biomass did not decline at moderate cyanobacteria biomass, but when cyanobacteria reached high biomass large cladocerans were reduced. 4. Our results demonstrate that zooplankton communities can be negatively affected by cyanobacterial blooms and therefore the potential to use herbivory to reduce algal blooms in such eutrophic lakes appears limited.
234 citations
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TL;DR: An organizational typology, the Resilience Architecture Framework (RAF), is introduced, which forms a platform for the integration of divergent research streams – organizational rigidity, dynamic capabilities and organizational ambidexterity – into the study of organizational resilience.
192 citations
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TL;DR: This work proposed the application of hydrogen peroxide (H2O2) to induce cyanobacterial cell death to induce phytoplankton blooms containing elevated levels of cyanobacteria in wastewater treatment plants to establish the effect of H2O1 addition on phy toplankon in wastewater samples.
Abstract: Phytoplankton blooms containing elevated levels of cyanobacteria are common in wastewatertreatment plants. Microcystis aeruginosa, the most common freshwater cyanobacterial species, produces the hepatotoxin microcystin, which is a threat to human and environmental health. Blooms also affect the viability of treating and reusing water and cause problems when detritus accumulates in pipe and pumping delivery infrastructure. We proposed the application of hydrogen peroxide (H2O2) to induce cyanobacterial cell death. Spectral fingerprinting of phytoplankton into four groups (cyanobacteria, chlorophyta, diatoms, and cryptophyta) allowed for determination of equivalent chlorophyll-a (chl-a) concentrations contributed by photosynthetic pigments, an indicative measure of the photosynthetic activity of each phytoplankton group. This was used to establish the effect of H2O2 addition on phytoplankton in wastewater samples. The lowest H2O2 dose that caused statistically significant exponential decay of phytoplankton groups was approximately 3.0 x 10(-3) g H2O2/microg phytoplankton chl-a. At this dose, cyanobacteria and total phytoplankton exhibited a half-life of 2.3 and 4.5 h, respectively. Cyanobacteria decayed at a rate approximately twice that of chlorophyta and diatoms, and the combined chl-a of all phytoplankton groups decreased to negligible levels within 48 h of H202 application.
146 citations
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TL;DR: WSP operators are offered the possibility to assess the benefit of using H 2 O 2 to rapidly suppress cyanobacterial and microcystin concentrations and hence prevent them from entering the environment.
110 citations
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TL;DR: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols used xiii 1.
Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201
14,171 citations
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TL;DR: A review of the relationship between eutrophication, climate change and cyanobacterial blooms in freshwater, estuarine, and marine ecosystems can be found in this paper.
1,675 citations
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TL;DR: This paper presents a review of recent research articles related to defining and quantifying resilience in various disciplines, with a focus on engineering systems and provides a classification scheme to the approaches, focusing on qualitative and quantitative approaches and their subcategories.
1,072 citations
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TL;DR: In this paper, a coupled biological-physical model was developed to investigate how competition for light between buoyant cyanobacteria, diatoms and green algae in eutrophic lakes is affected by the meteorological conditions of this extreme summer heatwave.
Abstract: Dense surface blooms of toxic cyanobacteria in eutrophic lakes may lead to mass mortalities of fish and birds, and provide a serious health threat for cattle, pets, and humans. It has been argued that global warming may increase the incidence of harmful algal blooms. Here, we report on a lake experiment where intermittent artificial mixing failed to control blooms of the harmful cyanobacterium Microcystis during the summer of 2003, one of the hottest summers ever recorded in Europe. To understand this failure, we develop a coupled biological-physical model investigating how competition for light between buoyant cyanobacteria, diatoms and green algae in eutrophic lakes is affected by the meteorological conditions of this extreme summer heatwave. The model consists of a phytoplankton competition model coupled to a one-dimensional hydrodynamic model, driven by meteorological data. The model predicts that high temperatures favour cyanobacteria directly, through increased growth rates. Moreover, high temperatures also increase the stability of the water column, thereby reducing vertical turbulent mixing, which shifts the competitive balance in favour of buoyant cyanobacteria. Through these direct and indirect temperature effects, in combination with reduced wind speed and reduced cloudiness, summer heatwaves boost the development of harmful cyanobacterial blooms. These findings warn that climate change is likely to yield an increased threat of harmful cyanobacteria in eutrophic freshwater ecosystems.
867 citations