**2. Algal blooms**

HABs consist of organisms which are able to deplete oxygen levels in water systems; it also kills life in same water system and lasts for several days to months [2]. They are considered harmful as producing massive biomass and toxins. Huge amount of cell biomass produced by them hinders the light penetration resulting into decreased density of submerged aquatic vegetation [3]. Decaying, these algal blooms increases oxygen consumption leading to mortality of aquatic life in that area [4]. The effects of the blooms have been identified in numerous ways, even in the marine ecosystem were aquatic life gets exposed to toxins by ingestion. Therefore biological control of HABs is seen to be an economically and environment-friendly resolution [5]. In addition some biotic organisms were isolated and used to eradicate HABs, for example secretion of *Cyanobacteriolytic* substances by bacteria [6]. Characteristic species-specific interaction by some virus [7], the bursting of host cells, and the virus lytic cycle [8]. Viral degradation has the benefit of the species-specific attack. Golden algae have also been found as a mitigator of microcystis cells as well as toxin degraders. (**Figure 1**) shows spreading of algal blooms in different climatic conditions [9].

**39**

**4. Toxins**

*Considering Harmful Algal Blooms*

HABs [13, 14].

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

protect marine resources community health.

**3. Control agents related to HABs**

Some environmental factors found to supports growth of algal blooms. The temperature always is important when bearing in mind about water-ecosystem [10]. Increase in heat could significantly expand Chlorophyll-*a* concentration, signifying that warmer conditions could develop a dominant population of Cyanobacteria [11]. Reports suggest that variation in temperature also affects the interaction of physical, chemical, and biological parameters in shallow lakes. Were for Cyanobacteria, these factors emulate fluctuating physiological changes such as nutrient uptake capacity, N-fixation, as well as optimum temperature. Effect of temperature was also noticed with *Microcystis aeruginosa* biomass production [12]. It is important to note that freshwater HABs caused by Cyanobacterial blooms appear to be the most noticeable examples of warming induced intensification indicating that the temperatures yielding maximal growth rates for many Cyanobacterial

Evident shows that there is an increase and spreading of phytoplankton bloom globally in the sea and also nutrient loading is dependent on biomass composition. As such autotrophic growth can result only from the increased photosynthesis and primary production must be an outcome of improved nutrient levels. All through addition of nutrients, variation in the amount of nutrient be practical, encouraging struggle for resources among various community and species. As near to coast food fortification is caused due to riverine input in connection with dissimilar discharges, resultant of new nutrient input eliciting some new algal blooms. Breathing space and geographical location generally influences nutrient availability, acting as significant aspect in defining their eutrophication values. As known geographical factors including latitude, elevation, and longitude possibly affects the openness of nutrients to algal growth. Were elevation is amazingly associated with strength of light and also human interference. Availability of nutrition also found to be elevated in some of the lakes at high elevation [15]. Accordingly the all-inclusive occurring of marine phytoplankton blooms can be linked to improved primary production rates. It is important to note that global wave of phytoplankton was firstly reported on Dino-flagellate *Gyrodinium aureolum* in some European waters, which was beforehand present in some other north-east coast of the U.S. Similarly, many species spread globally and was responsible for shellfish poisoning global wave of HABs [16]. Lake Taihu was also reported for annual Cyanobacteria occurrence [17]. Considering research from last some decades, capabilities for management of HABs have grown with scientific advances working independently. New technological developments have altered the way to monitored and managed HABs [18–20]. Problems related to HAB are serious and worse in many parts of the world, however thinking, working capabilities and existing knowledge can help to curtail impacts to

Studies have been carried out to find a better way of controlling HABs. Different biotic factors have been identified to mitigate the option of HABs. Where use of different bacteria was done to tone down HABs in coastal and freshwater community [21].

The most toxic algal strain is *M. aeruginosa,* which constantly produces microcystins, acts harmful to aquatic organisms as well as to humans. Were microcystins have been reported as tumor-promoting [22]. Some bacteria mainly acts

**Figure 1.**

*Pervasiveness of different conditions enhancing HABs.*

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

*Environmental Issues and Sustainable Development*

**2. Algal blooms**

also water column stratification. These blooms are significant part for energy and material transport through the food web, as well plays an important role in the vertical flux of material out of the surface waters therefore these blooms are known to be prominent considering with those acknowledged as "harmful." These algae can form harmful algal blooms, when they assemble and grow in massive amounts damaging the ecosystem, or if the algal community shifts to species that makes some toxin compounds disrupting the normal food web and also harmful to human beings [1]. Problem of harmful algal bloom is wide and persistent, affecting numerous estuaries, coasts, and freshwaters system throughout the world, along with disturbing ecosystems, human health, social life style as well as dilemma for economy systems.

HABs consist of organisms which are able to deplete oxygen levels in water systems; it also kills life in same water system and lasts for several days to months [2]. They are considered harmful as producing massive biomass and toxins. Huge amount of cell biomass produced by them hinders the light penetration resulting into decreased density of submerged aquatic vegetation [3]. Decaying, these algal blooms increases oxygen consumption leading to mortality of aquatic life in that area [4]. The effects of the blooms have been identified in numerous ways, even in the marine ecosystem were aquatic life gets exposed to toxins by ingestion. Therefore biological control of HABs is seen to be an economically and environment-friendly resolution [5]. In addition some biotic organisms were isolated and used to eradicate HABs, for example secretion of *Cyanobacteriolytic* substances by bacteria [6]. Characteristic species-specific interaction by some virus [7], the bursting of host cells, and the virus lytic cycle [8]. Viral degradation has the benefit of the species-specific attack. Golden algae have also been found as a mitigator of microcystis cells as well as toxin degraders. (**Figure 1**) shows spreading of algal blooms in different climatic conditions [9].

**38**

**Figure 1.**

*Pervasiveness of different conditions enhancing HABs.*

Some environmental factors found to supports growth of algal blooms. The temperature always is important when bearing in mind about water-ecosystem [10]. Increase in heat could significantly expand Chlorophyll-*a* concentration, signifying that warmer conditions could develop a dominant population of Cyanobacteria [11]. Reports suggest that variation in temperature also affects the interaction of physical, chemical, and biological parameters in shallow lakes. Were for Cyanobacteria, these factors emulate fluctuating physiological changes such as nutrient uptake capacity, N-fixation, as well as optimum temperature. Effect of temperature was also noticed with *Microcystis aeruginosa* biomass production [12]. It is important to note that freshwater HABs caused by Cyanobacterial blooms appear to be the most noticeable examples of warming induced intensification indicating that the temperatures yielding maximal growth rates for many Cyanobacterial HABs [13, 14].

Evident shows that there is an increase and spreading of phytoplankton bloom globally in the sea and also nutrient loading is dependent on biomass composition. As such autotrophic growth can result only from the increased photosynthesis and primary production must be an outcome of improved nutrient levels. All through addition of nutrients, variation in the amount of nutrient be practical, encouraging struggle for resources among various community and species. As near to coast food fortification is caused due to riverine input in connection with dissimilar discharges, resultant of new nutrient input eliciting some new algal blooms. Breathing space and geographical location generally influences nutrient availability, acting as significant aspect in defining their eutrophication values. As known geographical factors including latitude, elevation, and longitude possibly affects the openness of nutrients to algal growth. Were elevation is amazingly associated with strength of light and also human interference. Availability of nutrition also found to be elevated in some of the lakes at high elevation [15]. Accordingly the all-inclusive occurring of marine phytoplankton blooms can be linked to improved primary production rates. It is important to note that global wave of phytoplankton was firstly reported on Dino-flagellate *Gyrodinium aureolum* in some European waters, which was beforehand present in some other north-east coast of the U.S. Similarly, many species spread globally and was responsible for shellfish poisoning global wave of HABs [16]. Lake Taihu was also reported for annual Cyanobacteria occurrence [17]. Considering research from last some decades, capabilities for management of HABs have grown with scientific advances working independently. New technological developments have altered the way to monitored and managed HABs [18–20]. Problems related to HAB are serious and worse in many parts of the world, however thinking, working capabilities and existing knowledge can help to curtail impacts to protect marine resources community health.
