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Lake Diefenbaker Irrigation Canals in Canada are crucial in providing water for irrigation, preventing droughts and floods, and supporting the Saskatchewan agriculture industry and economy. Unfortunately, filamentous algal blooms occur every summer in Lake Diefenbaker Irrigation Canals. These algae are not toxic but a nuisance. They block farmers' pumps and reduce irrigation water flow rates. Currently, the Water Security Agency periodically adds the algaecide Magnacide H. to control the algal blooms, which is costly (i.e., one million dollars per year for the Lake Diefenbaker M1 Irrigation Canal only) and requires effort to dewater the canal to protect fish. Therefore, algae removal before the canal water enters farmer's pumps might be a cost-effective alternative, especially the removal of microalgae during the initial stages of growth in June of each year. This paper has summarized and evaluated algae removal technologies, considering their advantages, disadvantages, and potential solutions for addressing the challenges and limitations associated with these technologies. Five algae removal technologies were identified as promising, which are suspended air flotation (SAF), dissolved air flotation (DAF), hydrodynamic cavitation, spiral blade centrifuge, and coagulation. Among them, SAF seems the most suitable option, while DAF and hydrodynamic cavitation offer eco-friendly advantages. Further research and pilot testing are needed to determine the costeffective and feasible algae removal technology for Lake Diefenbaker Irrigation Canals. [ABSTRACT FROM AUTHOR]

Biofuels have generated global interest among oil companies and governments. In particular, algal biofuels are slated to be more promising than traditional biofuel feedstocks, like corn and sugarcane, which are simultaneously cultivated as food products. However, the drawbacks of harvesting algae on a large industrial scale has led to intense criticism. Most critics focus on issues of sustainability, scalability of production, and the legal and ethical concerns of genetically modified crops. New research in cyanobacteria, however, illustrates algae's potential to produce clean electricity in addition to oil, ethanol, and gasoline. Moreover, using Algal Turf Scrubbers ("ATS") in natural waterways offers a unique method for the cultivation of algae that also aims to reduce the growth of toxic or harmful algal blooms (HABs). This paper proposes two changes to the field of algae energy research in the United States: first, research should shift away from a focus on biofuels and towards more studies in electricity production, and second, small scale ATS projects need to be utilized on a wider scale, not only to prevent water pollution but also to benefit local economies. [ABSTRACT FROM AUTHOR]

The algae blooms caused by the eutrophication of water bodies have become a major pollution problem worldwide. Inhibiting the growth and proliferation of algae through the allelopathy of plants is also a new way to control "Algal Blooms". In this paper, the allelopathy inhibitory effects of Spartina alterni-flora and Potamogeton crispus on Microcystis aeruginosa have been systematically studied. The research results show that the Spartina alterniflora extract has a "low-promoting high-inhibition" concentration effect on the growth of Microcystis aeruginosa. That is, when the concentration of Spartina alterniflora extract is lower than 0.04 g/ml, it can promote the growth of Microcystis aeruginosa, and when the concentration is higher than 0.08 g/ml, it can inhibit the growth of Microcystis aeruginosa. Moreover, the inhibitory effect of Spartina alterniflora extract on Microcystis aeruginosa gradually increased with the increase of the extract concentration. When the concentration of Potamogeton crispus is lower than 0.01 g/mL, its inhibitory effect on Microcystis aeruginosa is poor, while when the concentration of Potamogeton crispus is higher than 0.02 g/mL, it can effectively inhibit the growth of Microcystis aeruginosa. When the concentration of Potamogeton crispus was 0.08g/mL, the cumulative maximum inhibition rate of Microcystis aeruginosa reached 69.7%. In addition, changes in the concentration of Spartina alterniflora extract can significantly affect the concentration of Chl-a. The allelochemicals secreted by Potamogeton crispus can inhibit the synthesis of chlorophyll or promote its decomposition. From a long-term perspective, the characteristics of Chl-a content changes indicate that Potamogeton crispus has a much stronger inhibitory effect on Microcystis aeruginosa than Spartina alterniflora. [ABSTRACT FROM AUTHOR]

Harmful algal blooms is a global problem of water pollution causing great economic losses to countries. Microcystis aeruginosa , as a dominant algal species in cyanobacterial blooms, has attracted extensive attention. However, most of the current studies on the treatment of alga-containing waters focus on the removal of algal cells or microcystins, lacking the exploration of the degradation pathways and analyses of the toxicity of the products. In this paper, we constructed a photo-Fenton system using Fe(III)-EDDS (EDDS: Ethylenediamine-N,N'-disuccinic acid) complex as an iron source for the simultaneous removal of Microcystis aeruginosa as well as microcystin-LR (MC-LR). The results showed that adding 0.1 mM of Fe(III)-EDDS complex and 1.0 mM of H 2 O 2 achieved 83.3% algal cell removal in 240 min under neutral pH conditions and also degraded 72.5% of MC-LR. Moreover, the degradation products of MC-LR and EDDS were analyzed by LC-MS, which showed that the toxicity of the MC-LR molecule was greatly reduced by benzene ring removal and decarboxylation of partial amino acids, while its degradation resulted from the destruction of amino acids in the MC-LR molecule. The toxicity analyses provide a basis for the practical application of the system, hence consideration can be given to combining or improving it with the existing UV disinfection technologies in water supply plants for potential algal bloom outbreaks. This study was the first time to apply the Fe(III)-EDDS system to the field of microalgae removal and MC-LR detoxication, aiming to provide new development ideas for water purification and photochemical algae removal technology. [Display omitted] • Simultaneous removal: algal cells and MC-LR via Fe(III)-EDDS photo-Fenton system. • System oxidative activity: hydroxyl radicals attacks both algal cells and MC-LR. • Mechanistic reveal: changes in physiological indexes of algal cells are monitored. • Further analysis: degradation pathways of MC-LR and toxicity of products. [ABSTRACT FROM AUTHOR]

Climate change is an issue that is causing a wide range of impacts along Australian coastlines including sea level rise, density of development and infrastructure, exposure to extreme weather, algal blooms, oil spills, availability of affordable property insurance, governmental policies, and regulations. Solutions will require the navigation of complex inter-relationships to facilitate the building of effective policy. Development of effective communications is essential to deployment of effective adaptations. This paper reports the results of a narrative review on how to communicate climate change impacts to marine and coastal communities. Results show communications must be tailored to the right audience at the right time and delivered by trustworthy messengers. A best practice communications strategy is suggested. • Communicating climate change in coastal and marine contexts has specific challenges. • Two-way communications must be tailored to the right audience. • Climate communications need to deliver the right messages. • Climate change communications need delivery by trusted messengers. [ABSTRACT FROM AUTHOR]

This paper analyzed the long-term variations in nutrients in Liaodong Bay and their potential influencing factors based on historical data from 1978 to 2019. Under the influence of both human activities and natural changes, the concentration of DIN increased approximately 4-fold from the end of the 1990s to the mid-2010s, while DIP and DSi concentrations decreased from the beginning to the end of the 1980s and have since increased again. Asynchronous changes in nutrient levels have led to changes in the nutrient composition, which has caused a series of ecological effects. The total phytoplankton abundance decreased from the 1980s to the end of the 1990s and then increased again. Additionally, the phytoplankton composition shifted from a diatom-dominated to a dinoflagellate-dominated system, and the dominant species of zooplankton changed. Harmful algal blooms (HABs) rarely occurred before the 1980s but have frequently occurred since the end of the 1990s. • Long-term changes of nutrients in Liaodong Bay during the past 40 years • Transport fluxes of nutrients from different sources affected by human activities in Liaodong Bay • Ecological effects caused by nutrient changes in Liaodong Bay [ABSTRACT FROM AUTHOR]

The prediction of algal bloom is one of the important links in eutrophication prevention. Chlorophyll a concentration is the indicating variable of algal bloom, and its time series is non-stationary and non-linear, which brings challenges to its effective prediction. Although the current algae growth model (AGM) can directly describe the algal bloom dynamics, the fixed parameters limit the adaptability of the model. If the fixed parameters are dynamically adjusted, the trend of chlorophyll a concentration can be better captured. Therefore, the adaptive dynamic programming (ADP) approach is used to optimize the parameters of the AGM. The ADP contains an action network and a critic network by echo state network, where the action network is used to output the increment value of the fixed parameters, and the critic network is used to approximate the performance index function. In this paper, the input of the action network uses the time series features extracted by the relevant variables, so that the time-varying parameters of the AGM have better dynamic characteristics. We verify the effectiveness of the proposed model through the dataset of the North Canal and Taihu Lake, and the convergence analysis proves the theoretical reliability. In this way, the improved mechanism model with time-varying parameters not only maintains the better interpretability of the original AGM, but also further enhances the prediction accuracy and adaptability by extracting inherent interactive features from the relevant variables. • A time-varying algae growth model (TAGM) is proposed for algal bloom prediction. • CMA-ES is used to estimate the fixed parameters. • Adaptive dynamic programming with ESN is used to solve the incremental parameters. • Time series feature is employed to enhance the prediction accuracy. • TAGM is adopted to the actual lakes with better interpretability and precision. [ABSTRACT FROM AUTHOR]