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Stabilization Ponds
Published in Subhash Verma, Varinder S. Kanwar, Siby John, Environmental Engineering, 2022
Subhash Verma, Varinder S. Kanwar, Siby John
Algal blooms refer to the rapid mass growth of algae. This usually happens seven to twelve days after wastes have been introduced into the lagoon. After another week, the bacterial decomposition of bottom solids will usually become established, limiting the food produced for the algae.
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Published in Igor Linkov, Emily Moberg, Benjamin D. Trump, Boris Yatsalo, Jeffrey M. Keisler, Multi-Criteria Decision Analysis, 2020
Igor Linkov, Emily Moberg, Benjamin D. Trump, Boris Yatsalo, Jeffrey M. Keisler
Algae are phytoplankton, or tiny aquatic plants which, as living organisms, have several habitat needs which must be fulfilled in order for thriving growth: nutrients, light, and space in particular. Within these broad categories, each species has its preferences to the ratio of nutrients which will best allow it compete with other phytoplankton, the optimal amount of light it should receive, the optimal water temperature, etc. The alignment of such factors is, in a conceptual sense, what allows algal blooms to occur, although the exact mechanisms of how and why blooms occur are still not fully understood and may differ for particular species. Algal blooms are often benign; they are given the distinction “harmful” when the proliferation of algae causes adverse effects either via the production of toxins; through competition with other species; or depletion of oxygen to the ecosystem, humans, or other organisms (Woods Hole Oceanographic Institute 2008). The distinction of algae as “harmful” versus “noxious” or “nuisance” is sometimes made with the former indicating those producing toxins and the latter two referring to non-toxic species (Erdner et al. 2008). Some of the non-toxic, ecological effects induced by algal blooms are listed in Table 17.1.
Coastal Environments
Published in Yeqiao Wang, Coastal and Marine Environments, 2020
The most important contaminants[20] in the coastal zone are organic matter, synthetic organic compounds (e.g., PCBs and pesticides such as DDT and residues), and microbial organisms, nutrients (mainly nitrogen and phosphorus), and so on. This is the main reason for the steadily increase of harmful algal bloom (HAB) in coastal waters in recent years. Algal blooms[21] may cause harm through the production of toxins or by their accumulated biomass, which can affect co-occurring organisms and alter food-web dynamics. Impacts include human illness and mortality following consumption of or indirect exposure to HAB toxins, substantial economic losses to coastal communities and commercial fisheries, and HAB-associated fish, bird, and mammal mortalities. For example, in recent years, the frequent toxic red tide in the Gulf of Mexico has increasingly becoming a threat to the sea turtle population.
Assessing the effects of migratory waterbird droppings on potential lake eutrophication using water quality models: A case study of Yangming Lake on Kinmen Island, Taiwan.
Published in Inland Waters, 2023
Chi-Feng Chen, Yang-Ming Chen, Jen-Yang Lin
Eutrophication is a major issue of concern in the management of lakes or reservoirs because such waterbodies have slow flow and deep water levels, and nutrients can easily accumulate, thus creating an environmental condition for algal blooms (Chislock et al., 2013). Algal blooms damage aquatic ecosystems and increase the health risk of water supply systems. An algal bloom is related to excess nutrients, including external inputs from the watershed and internal inputs from sediments. The external inputs, such as domestic and industrial effluents and runoff from agricultural lands, bring extra nutrients into receiving lakes or reservoirs and these nutrients accumulate. Therefore, good watershed management including land use management influences reservoir water quality. In Taiwan, the key mission for reservoir management is to provide a clean source of water. However, the reservoirs on Kinmen Island have suffered eutrophication because they are located downstream and unavoidably receive anthropogenic pollution from the watershed. Moreover, migratory birds represent a unique pollution source. Kinmen Island is famous for its migratory birds, and the dominant species is the cormorant. Great cormorants will stay on Kinmen Island from late October to March. Birdwatching is helpful for the tourist economy, and the birds are protected and welcomed. However, in recent years, citizens have noted that the large amount of excrement is harmful to the landscape, and more seriously, the excrement might flow into reservoirs that supply drinking water. Therefore, a debate between ecosystem protection and water quality protection occurs.
Microalgae: a cheap tool for wastewater abatement and biomass recovery
Published in Environmental Technology Reviews, 2022
Haruna Saidu, Jibrin Mohammed Ndejiko, Nafiatu Abdullahi, Aisha Bello Mahmoud, Shaza Eva Mohamad
Algae bloom is often caused by an alteration in the physico-chemical features of water mainly nutrients (nitrogen and phosphorus). High amount of nitrogen and phosphorus in water ensures excessive growth of microalgae scum leading to the release of an unpleasant odour that pollutes the environment. Some algal blooms affect humans by the production of harmful toxins such as microcystin and anatoxin-a [66]. This problem can be controlled via physical methods. The method involved using hand or skimmer net to remove growing filamentous algae in a pond. Biological method entails growing aquatic plants such as water lilies and other taller plant that could reduce the intensity of light penetrating into the water. These plants will compete for available nutrient in water. Consumption of excess nutrients will prevent the occurrence of algal bloom. Algaecides and herbicides as a chemical method can also be applied for the control of algae bloom [66]. Physical and algaecide methods are inefficient, costly and cannot be applied in a complex aquatic environment.
Smart Nutrient Retention Networks: a novel approach for nutrient conservation through water quality management
Published in Inland Waters, 2022
Dianneke van Wijk, Sven Teurlincx, Robert J. Brederveld, Jeroen J. M. de Klein, Annette B. G. Janssen, Lilith Kramer, Luuk P. A. van Gerven, Carolien Kroeze, Wolf M. Mooij
In SNRNs, nutrient retention is maximized to benefit the whole catchment. The catchment covers the largest spatial scale of networks of inland waters, including connected waterbodies and the land draining into these waters. At the waterbody level, nutrients are either retained or flow freely with the water in dissolved or particulate forms such as detrital matter or phytoplankton (Teurlincx et al. 2019). Nutrient retention processes include (1) natural internal retention (e.g., long-term storage by sedimentation, burial of biomass, and P bound to mineral particles; Uhlmajnn and Horn 1992, Smolders et al. 2006, Finlay et al. 2013, Kong et al. 2019), (2) natural losses from the waterbody (e.g., denitrification and consumption by migrating waterfowl; Saunders and Kalff 2001, Doughty et al. 2016, Kong et al. 2019), or (3) harvesting by humans (e.g., in the form of macrophytes, sediment, or fish). Water management can influence nutrient retention pathways directly (e.g., harvesting by humans), and indirectly through ecosystem state management (e.g., increased denitrification by bank reshaping). In general, increases in nutrient retention processes could decrease the risk of harmful algal blooms. Some nutrient retention processes counteract nutrient conservation (e.g., N2 degases by denitrification), which enhances water quality but constitutes a loss process.