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Crop Protection in Open Ponds
Published in Stephen P. Slocombe, John R. Benemann, Microalgal Production, 2017
Robert C. McBride, Val H. Smith, Laura T. Carney, Todd W. Lane
Additions of hypochlorite also have been used to control contaminants in open ponds, especially in Nannochloropsis cultures to control protozoa (Richmond 2013). Quinine has been shown to effectively kill ciliates while not killing Dunaliella strains (Moreno-Garrido and Canavate 2001). Glyphosate has been added to Nannochloropsis cultures resistant to glyphosate to maintain selectivity (Vick 2010). Disinfectant and ozone shock have been used in Nannochloropsis culture to clear contaminants (Weissman et al. 2010; Weissman and Radaelli 2010). Metronidazole has been successfully used in disinfecting Scenedesmus sp. cultures invaded by the zooflagellate Amphelidium sp. (Heussler et al. 1978). Pesticides such as trichlorphon, decamethrin, tralocythrin, and buprofezin have also been used to eradicate zoo-plankton in microalgal suspensions (Wang et al. 2013). Fungicides such as Triton-N and Funginex have been used as control measures for some fungal contaminants of Scenedesmus, such as P. scenedesmi (Benderliev et al. 1993; Ravikumar 2014), and chytrid-like organisms have also been successfully controlled in the field using the pesticide Headline (McBride et al. 2014). The fungicide benomyl has been used to treat pathogenic fungi in cultures of Euglena gracilis (Mokrosnop and Zolotareva 2013). DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) has been proposed as an effective herbicide to manage contaminant algae growth in cultures of Nannochloropsis (Gonen-Zurgil et al. 1996). Formaldehyde has been used to control some ciliates in algae cultures (Moreno-Garrido and Canavate 2001).
Nutrient and algal responses to a managed drawdown in an agricultural riverine lake
Published in Chemistry and Ecology, 2023
R. E. Lizotte, J. N. Murdock, J. M. Taylor, M. A. Locke
Algae and associated cyanobacteria harmful algal blooms are a key product of eutrophication. Chlorophyll concentrations have frequently been used as an indirect measure of water column algal biomass composed of phytoplankton and detached epiphytic and benthic algae in shallow freshwater systems [21,22]. More recently, the phycobilin photosynthetic pigment, phycocyanin, has been used to monitor freshwater cyanobacteria [23–26]. Six types of surface phytoplankton measurements were collected. Algal biomass was determined using solvent-extracted chlorophyll a (Chl a; trichomatic method [20]) from a single sample at each site for each sampling day.Triplicate samples from each site on each sampling day were collected and real-time measurement of algal biomass and cyanobacteria (blue-green algae) biovolume [27] were determined via in-vivo chlorophyll (IV Chl) and in-vivo phycocyanin (IV PC) using a fixed spectral region fluorometer (Aquafluor, Turner Designs, San Jose, CA USA) [28–30].Concentrations of IV Chl were calculated from a standard curve using measured Chla from the same samples as described above (R2 = 0.793).Concentrations of IV PC were calculated from a standard curve using C-phycocyanin from Spirulina sp. (Lot #074M4104 V Sigma Aldrich, St. Louis, MO USA) (R2 = 0.999) according to Marion et al. [31].Phycocyanin:chlorophyll (PC:Chl) ratios were calculated to assess blue-green algal blooms in relation to nutrient limitation [32,33].Photosynthetic activity as algal maximum photosystem II (PSII) efficiency (Chl Fv/Fm) and blue-green algal PSII efficiency (PC Fv/Fm) were assessed using the 3′-(3,4-dichlorophenyl)−1′, 1′-dimethyl urea (DCMU) method (20 min dark-adapted) for determining photosynthetic condition, cell viability, and physiological status (health) [34–37].