**6. Zooplanktons used to mitigate HABs**

Several natural grazing environments are having selective herbivores like *Cyclopoid, Copepods*, and *Calanoid*, affecting Cyanobacterial growth by lowering Cyanobacterial densities [41]. Zooplankton show eco-friendly, contamination-free, and low-cost exclusion, but not beneficial at low oxygen conditions. Furthermore it was found that *Daphnia longispina* can ingest many Cyanobacteria [42]. For example grazing is one of the fore most mitigation options for zooplankton, *Daphnia ambigua, Eudiaptomus gracilis* shows graze on *M. aeruginosa* [41]. Besides *Cyclopoid copepods* graze on *Anabaena, Microcystis,* and *Planktothrix* species [41].

## **7. Fungi used to mitigate HABs**

Studies, show that fungi have algicidal activity, and some findings also showed that fungi could produce antibiotics to lyse HABs [43]. Some fungal species, attack directly for lysis of Cyanobacteria or algal species [43]. *Trichaptum abietinum, Lophariaspadicea, Irpexlacteus, Trametes hirsute, Trametes versicolor* and *Bjerkandera adusta* was used to remove *Microcystis* and *Oocystisborgei* [43]. Uses of bio-flocculation method were algae, itself used as a control agent (**Figure 2**) [44]. Flocculating micro

**41**

**Figure 2.**

*Considering Harmful Algal Blooms*

*DOI: http://dx.doi.org/10.5772/intechopen.94771*

alga could be used to concentrate non-flocculating alga of attention. The main advantage of this method is that it does not require any flocculating agent [44]. *Ankistrodesmus falcatus, Scenedesmus obliquus* flocculate *Chlorella vulgaris,* and *Tetraselmis suecica* flocculates *Neochloris oleoabundans* [44]. A species of golden alga (*Poterioochromonas* Sp. strain ZX1), is identified as a feeding agent for toxic *M. aerugi-*

When working with HAB it becomes equally important to consider effects of climate change, as change in climatic conditions supports unwanted growth of algae. At many instance record shows that HABs intensify as water have warmed closer to temperatures that yield maximal growth [18, 45, 46]. It becomes essential to notice that in marine systems, warming has been concerned with intensifying multiple HABs in a number of mid and higher latitude regions [45–47]. On the other hand, these regions with increasing frequencies and intensities of HABs due to progressive warming may be balanced by region that warms beyond of the optimal range for other HABs [47]. Considering together, all such circumstances hypothesis avowed by several case studies explains that HABs may be migrating pole-ward with progressive warming [46–48]. Such migration of HABs to new ecosystems, conversely may create significant risk to aquatic ecosystems, humans and other animals living near them. Because of which indigenous species, experiences selective pressures and thus suffer the

There is no conclusive report available for the causes of HABs, unfortunately, the causes of HABs are uncertain to date. Though, some of the factor which are thought

*nosa* and also does not affected by cyanotoxin.

*Interface events of environment and microorganism with HABs.*

most population declines [49, 50].

**8. Intention for formation HABs**

*Considering Harmful Algal Blooms DOI: http://dx.doi.org/10.5772/intechopen.94771*

**Figure 2.**

*Environmental Issues and Sustainable Development*

level experiment confirmation [37].

**5. Fish species used to mitigate HABs**

**6. Zooplanktons used to mitigate HABs**

**7. Fungi used to mitigate HABs**

antagonistic towards Cyanobacteria and are predatory bacteria, some other acts as toxin-degrading. Were Predatory helps to make an environmentally pleasant solution to available HABs. Also number of prey–predator and the mechanism of Cyanobacterial lysis, were some effectual biological control approach [23]. Few of Cyanobacteria mitigated using the secretion of *Cyanobacteriolytic* substances by some *Bacillus* Sp. typically *Bacillus cereus* and [24], *S. neyagawaensis* [25], *Streptomyces* [26], *Pseudomonas fluorescens* species [27]. *Pedobacter* Sp*.* secretes some mucus-like secretion as self-defense against *M. aeruginosa*. *Raoultella* Sp. removes *M. aeruginosa* by dissolving microbial metabolites and humic acid [28]. *Agrobacterium vitis* use Quorum sensing to lyse *M. aerugenosa* [29]. *Sandaracinobactor sibiricus, Methylobacterium zatmanii* and *Rhizobium* Sp. use lytic mechanism to remove *M. aeruginosa* [30]. Some *Bacillus* Sp. use cell-to-cell contact mechanism and production of an extracellular product to remove *Aphanizomenon flos-aquae* [31] and *M. aeruginosa* [32, 33]. Several reports suggested that algal viruses often existed at stable numbers, even when their hosts were absent [34]. With claim of that summer and spring season showing the eminent decay of cultivated viruses succeeding to four-seasons of analysis [35]. The regular seasonal study also noticed that the stumpy decay of algal virus during the wintry weather that permitted for the survival of about 126 continues days under the ice-cover in the freezing freshwater pond [36]. These agents show high specificity and high efficiency, but it gain limited attention due to high cost, as also requires upscaled

Fish species for all time used an option for bloom removal as number of fishes can ingest and digest the toxin itself. Therefore Bio-manipulation is a promising tool to control HABs for the lake-ecosystem [38]. High toxin production during bloom conditions [39] the massive fish kill was also reported, as its challenging for fishes to survive in oxygen-poor conditions, which suggest result another option to remove HABs [40].

Several natural grazing environments are having selective herbivores like *Cyclopoid, Copepods*, and *Calanoid*, affecting Cyanobacterial growth by lowering Cyanobacterial densities [41]. Zooplankton show eco-friendly, contamination-free, and low-cost exclusion, but not beneficial at low oxygen conditions. Furthermore it was found that *Daphnia longispina* can ingest many Cyanobacteria [42]. For example grazing is one of the fore most mitigation options for zooplankton, *Daphnia ambigua, Eudiaptomus gracilis* shows graze on *M. aeruginosa* [41]. Besides *Cyclopoid* 

Studies, show that fungi have algicidal activity, and some findings also showed that fungi could produce antibiotics to lyse HABs [43]. Some fungal species, attack directly for lysis of Cyanobacteria or algal species [43]. *Trichaptum abietinum, Lophariaspadicea, Irpexlacteus, Trametes hirsute, Trametes versicolor* and *Bjerkandera adusta* was used to remove *Microcystis* and *Oocystisborgei* [43]. Uses of bio-flocculation method were algae, itself used as a control agent (**Figure 2**) [44]. Flocculating micro

*copepods* graze on *Anabaena, Microcystis,* and *Planktothrix* species [41].

**40**

*Interface events of environment and microorganism with HABs.*

alga could be used to concentrate non-flocculating alga of attention. The main advantage of this method is that it does not require any flocculating agent [44]. *Ankistrodesmus falcatus, Scenedesmus obliquus* flocculate *Chlorella vulgaris,* and *Tetraselmis suecica* flocculates *Neochloris oleoabundans* [44]. A species of golden alga (*Poterioochromonas* Sp. strain ZX1), is identified as a feeding agent for toxic *M. aeruginosa* and also does not affected by cyanotoxin.

When working with HAB it becomes equally important to consider effects of climate change, as change in climatic conditions supports unwanted growth of algae. At many instance record shows that HABs intensify as water have warmed closer to temperatures that yield maximal growth [18, 45, 46]. It becomes essential to notice that in marine systems, warming has been concerned with intensifying multiple HABs in a number of mid and higher latitude regions [45–47]. On the other hand, these regions with increasing frequencies and intensities of HABs due to progressive warming may be balanced by region that warms beyond of the optimal range for other HABs [47]. Considering together, all such circumstances hypothesis avowed by several case studies explains that HABs may be migrating pole-ward with progressive warming [46–48]. Such migration of HABs to new ecosystems, conversely may create significant risk to aquatic ecosystems, humans and other animals living near them. Because of which indigenous species, experiences selective pressures and thus suffer the most population declines [49, 50].
