**1. Introduction**

Eutrophication, defined as the nutrient enrichment process (mainly nitrogen and phosphorus) of any water body which results in an excessive growth of phytoplankton and macrophytes [1–3], has become a major cause of concern in developing as well as developed countries [1]. Also, it was recognized as a pollution problem in the European and North American lakes and reservoirs in the mid-twentieth century. Since then, it has become more widespread in the whole world.

Eutrophication is due to several impacts resulting from the inefficient or nonexistent wastewater treatment; the agricultural expansion with inadequate soil uses and application of chemical fertilizers; the urbanization of watersheds; the increase of intensive husbandry of cattle, pigs, and chicken; the increase of aquaculture; the construction of reservoirs; and the destruction of natural

ecosystems [4]. The eutrophication event describes formation of a set of symptoms in a lake system exposed to excessive nutrient increase [2]. Common symptoms due to eutrophication include excessive algal blooms, tremendous organic and inorganic material accumulation, and lower biodiversity, high turbidity, excessive sedimentation, and high anoxia conditions, particularly in the deeper parts of lakes. The increase in anoxia condition can cause fish deaths in midsummer. One of the first and worst symptoms of eutrophication has been formation of planktonic algal blooms. In freshwaters, former of these algal blooms are mostly nitrogen (N)-fixing cyanobacteria [5].

Eutrophic water bodies are richly supplied with plant nutrients (N, P, as well other nutrients of less acute demand), and consequences include the increase of biological productivity and turbidity of water because of dense growths of phytoplankton [6, 7]. Thus, phytoplankton community structures and their relevant participants could be used as a biological indicator of negative environmental impacts formed in lakes and reservoirs, as was eutrophication event [8].

In the Americas, as was reported in previous studies, the increase in nutrient concentrations leads to greater biomass of phytoplankton in freshwater systems. In this new region of the world, there are numerous experiences relating the effect of eutrophication on the phytoplankton community.

In this book chapter, we aimed to provide a short overview based on the sparse and scattered literature sources and fixed practices in the American continent related to the proliferation of certain groups of phytoplankton in lakes and reservoirs in terms of eutrophication. We try to depict some generalizations that have arisen from this review, in relation to dominant phytoplankton in the eutrophic lakes and reservoirs in the Americas.

## **2. Eutrophication and phytoplankton**

Excessive nutrient accumulation in aquatic ecosystems by carrying of anthropogenic sources, mainly rich in phosphorus (P) and nitrogen (N), creates a series of changes in their structure and function in the direction of deterioration of water quality, known as eutrophication [9]. Among the structural changes caused by the eutrophication, there is the dominance of the "r" selective species in the community structure of phytoplankton known as tiny primary pelagic producers, particularly in the predominance of cyanobacteria in the freshwater ecosystems such as lakes and reservoirs.

As were reported by Bellinger and Sigee [10], the detection of excessive harmful blooms of some algae that are biological indicators of environmental pollution, particularly of nutrient pollution, reveals anthropogenic activities in freshwater systems and a rapid change in their trophic status. It is known that in the mid-twentieth century, some researchers such as Thunmark [11], Nygaard [12], and Stockner [13] developed trophic status indexes by using typical algal groups of oligotrophic (particularly desmids, a group of green algae) or typical algal groups of eutrophic conditions (chlorococcal, cyanobacterial, and euglenoid species). Although these indices provide useful information about trophic status of the lakes, generally they are not enough to indicate a lot of environmental problems since a lot of algal species have been living in both eutrophic and oligotrophic freshwater systems. In the other word, there are a lot of similarities in view of species homogeneity and seasonal succession of species for both systems. The rehabilitation of previous methods on sampling and taxonomic analysis, and development of new methods in this framework have provided the development in indices based on more specific indicator algal species from different taxonomic groups. Thus, Bellinger and Sigee

**29**

**Table 1.**

*and Sigee [10].*

*Eutrophication and Phytoplankton: Some Generalities from Lakes and Reservoirs of the Americas*

[10] revealed in their books what the indicator species of the trophic status would

In the Americas, there are some examples about how phytoplankton groups and species have been used for the determination of the trophic status and quality of surface waters. Some of these experiences will be presented in the following sections.

The dominant indicator species list for trophic status of various lake types in the western region of Canada is revealed in **Table 2**. This list bases on 25 years of

In the Experimental Lake Area (ELA), located in Ontario, Schindler [15] and Schindler et al. [5] showed that water fertilization (N and P) causes quantitative increase of all phytoplankton groups, especially the cyanobacteria species *Aphanizomenon schindleri* Kling, Findlay and Komárek 1994, and *Limnothrix redekei*

In 1978, the Environmental Protection Agency (EPA) published a study about eutrophication relating aquatic plant response to nutrient loading to lakes and reservoirs [16]. There was good correlation between phosphorus loading and the average chlorophyll *a* and water transparency. In general, the correlations between phosphorus-loading concentrations and eutrophication response data are better than those observed between nitrogen-loading concentrations and the same eutrophication parameters, supporting the phosphorus limitation of most of the United States water bodies. Summarizing, the characteristic algal species in relation to the phytoplankton in eutrophic lakes are represented by *Anabaena* spp., *Aphanizomenon* spp., *Microcystis* spp., and *Oscillatoria rubescens* De Candolle ex

Oligotrophic Diatoms: *Cyclotella comensis* Grunow in Van Heurck 1882, *Rhizosolenia* spp.

Chrysophytes: *Dinobryon divergens* O. E. Imhof 1887, *Mallomonas caudata* Iwanoff

Green algae: *Sphaerocystis schroeteri* Chodat 1897, *Dictyosphaerium elegans* Bachmann

Green algae: *Eudorina* spp., *Pandorina morum* (O. F. Müller) Bory 1897, *Volvox* spp. Cyanobacteria: *Anabaena* spp., *Aphanizomenon flos-aquae* Ralfs ex Bornet and

Dinoflagellates: *Ceratium hirundinella* (O. F. Müller) Dujardin 1841

Flahault 1886, *Microcystis aeruginosa* (Kützing) Kützing 1846

*Phytoplankton indicative species of trophic status in temperate lakes in mid-summer, modified from Bellinger* 

Green algae: *Scenedesmus* spp., *Ankistrodesmus* spp., *Pediastrum* spp. Cyanobacteria: *Aphanocapsa* spp., *Aphanothece* spp., *Synechococcus* spp.

Green algae: *Staurodesmus* spp. Mesotrophic Diatoms: *Tabellaria flocculosa* (Roth) Kützing 1844

1913, *Cosmarium* spp., *Staurastrum* spp.

Eutrophic Diatoms: *Aulacoseira* spp., *Stephanodiscus rotula* (Kützing) Hendey 1964

Cyanobacteria: *Gomphosphaeria* spp.

Hypereutrophic Diatoms: *Stephanodiscus hantzschii* Grunow 1880

(Ivanov) 1899

*DOI: http://dx.doi.org/10.5772/intechopen.89010*

**2.1 North America**

observations by Rawson [14].

*2.1.2 The United States of America*

**Lake types Algal indicators**

(Goor) Meffert 1988.

Gomont 1892.

*2.1.1 Canada*

be in mid-summer in temperate lakes (**Table 1**).

*Eutrophication and Phytoplankton: Some Generalities from Lakes and Reservoirs of the Americas DOI: http://dx.doi.org/10.5772/intechopen.89010*

[10] revealed in their books what the indicator species of the trophic status would be in mid-summer in temperate lakes (**Table 1**).

In the Americas, there are some examples about how phytoplankton groups and species have been used for the determination of the trophic status and quality of surface waters. Some of these experiences will be presented in the following sections.

#### **2.1 North America**

#### *2.1.1 Canada*

*Microalgae - From Physiology to Application*

(N)-fixing cyanobacteria [5].

eutrophication on the phytoplankton community.

lakes and reservoirs in the Americas.

**2. Eutrophication and phytoplankton**

ecosystems [4]. The eutrophication event describes formation of a set of symptoms in a lake system exposed to excessive nutrient increase [2]. Common symptoms due to eutrophication include excessive algal blooms, tremendous organic and inorganic material accumulation, and lower biodiversity, high turbidity, excessive sedimentation, and high anoxia conditions, particularly in the deeper parts of lakes. The increase in anoxia condition can cause fish deaths in midsummer. One of the first and worst symptoms of eutrophication has been formation of planktonic algal blooms. In freshwaters, former of these algal blooms are mostly nitrogen

Eutrophic water bodies are richly supplied with plant nutrients (N, P, as well other nutrients of less acute demand), and consequences include the increase of biological productivity and turbidity of water because of dense growths of phytoplankton [6, 7]. Thus, phytoplankton community structures and their relevant participants could be used as a biological indicator of negative environmental impacts formed in lakes and reservoirs, as was eutrophication event [8].

In the Americas, as was reported in previous studies, the increase in nutrient concentrations leads to greater biomass of phytoplankton in freshwater systems. In this new region of the world, there are numerous experiences relating the effect of

In this book chapter, we aimed to provide a short overview based on the sparse and scattered literature sources and fixed practices in the American continent related to the proliferation of certain groups of phytoplankton in lakes and reservoirs in terms of eutrophication. We try to depict some generalizations that have arisen from this review, in relation to dominant phytoplankton in the eutrophic

Excessive nutrient accumulation in aquatic ecosystems by carrying of anthropogenic sources, mainly rich in phosphorus (P) and nitrogen (N), creates a series of changes in their structure and function in the direction of deterioration of water quality, known as eutrophication [9]. Among the structural changes caused by the eutrophication, there is the dominance of the "r" selective species in the community structure of phytoplankton known as tiny primary pelagic producers, particularly in the predominance of cyanobacteria in the freshwater ecosystems such as lakes

As were reported by Bellinger and Sigee [10], the detection of excessive harmful blooms of some algae that are biological indicators of environmental pollution, particularly of nutrient pollution, reveals anthropogenic activities in freshwater systems and a rapid change in their trophic status. It is known that in the mid-twentieth century, some researchers such as Thunmark [11], Nygaard [12], and Stockner [13] developed trophic status indexes by using typical algal groups of oligotrophic (particularly desmids, a group of green algae) or typical algal groups of eutrophic conditions (chlorococcal, cyanobacterial, and euglenoid species). Although these indices provide useful information about trophic status of the lakes, generally they are not enough to indicate a lot of environmental problems since a lot of algal species have been living in both eutrophic and oligotrophic freshwater systems. In the other word, there are a lot of similarities in view of species homogeneity and seasonal succession of species for both systems. The rehabilitation of previous methods on sampling and taxonomic analysis, and development of new methods in this framework have provided the development in indices based on more specific indicator algal species from different taxonomic groups. Thus, Bellinger and Sigee

**28**

and reservoirs.

The dominant indicator species list for trophic status of various lake types in the western region of Canada is revealed in **Table 2**. This list bases on 25 years of observations by Rawson [14].

In the Experimental Lake Area (ELA), located in Ontario, Schindler [15] and Schindler et al. [5] showed that water fertilization (N and P) causes quantitative increase of all phytoplankton groups, especially the cyanobacteria species *Aphanizomenon schindleri* Kling, Findlay and Komárek 1994, and *Limnothrix redekei* (Goor) Meffert 1988.

#### *2.1.2 The United States of America*

In 1978, the Environmental Protection Agency (EPA) published a study about eutrophication relating aquatic plant response to nutrient loading to lakes and reservoirs [16]. There was good correlation between phosphorus loading and the average chlorophyll *a* and water transparency. In general, the correlations between phosphorus-loading concentrations and eutrophication response data are better than those observed between nitrogen-loading concentrations and the same eutrophication parameters, supporting the phosphorus limitation of most of the United States water bodies. Summarizing, the characteristic algal species in relation to the phytoplankton in eutrophic lakes are represented by *Anabaena* spp., *Aphanizomenon* spp., *Microcystis* spp., and *Oscillatoria rubescens* De Candolle ex Gomont 1892.


#### **Table 1.**

*Phytoplankton indicative species of trophic status in temperate lakes in mid-summer, modified from Bellinger and Sigee [10].*


#### **Table 2.**

*The list of dominant algal indicator species for trophic status of various lake types in the western region of Canada, modified from Rawson [14].*

#### *2.1.3 Mexico*

In several lakes suffering the eutrophication process, green algae and diatoms have been replaced by cyanobacteria, particularly *Anabaena* spp., *Microcystis aeruginosa* (Kützing) Kützing 1846, *Oscillatoria* spp., and *Lyngbya* spp. ([17–22], among others).

Cyanobacteria dominance in the eutrophic Lake Chapala is described by de Anda and Shear [23]. The high TN and TP concentrations contained in the large quantities of domestic, agricultural, and industrial sewage that enter to the lake through its main tributary, the Lerma river, increased the phytoplankton biomass and resulted in the dominance of *Anabaena flos-aquae* Brébisson ex Bornet and Flauhault 1886.

Tomasini-Ortiz et al. [24] reported the dominance of *Aphanizomenon gracile* Lemmermann 1907, followed by *M. aeruginosa*, *Microcystis pulverea* (HC Wood) Forti 1907, and *Anabaena affinis* Lemmermann 1898 in the eutrophic Lake Pátzcuaro, Michoacán State. The authors pointed out that many cyanobacterial blooms have been reported in eutrophic lakes along the Mexican states of Jalisco, Michoacán, Veracruz, San Luis Potosí, Querétaro, Guanajuato, Puebla, Oaxaca, and Hidalgo and in Mexico City.

Valle de Bravo reservoir (State of Mexico) provides drinking water to about 2,500,000 inhabitants in Mexico City [25]. This water body also shows frequent cyanobacterial blooms as consequence of the high nutrient load in its waters, posing health risks for human population. The common genera found during blooms are *Microcystis* sp., *Oscillatoria* sp., *Anabaena* sp., *Cylindrospermopsis raciborskii* (Woloszynska) Seenayya and Subba Raju 1972, and *Nostoc* sp.

#### **2.2 Central America**

#### *2.2.1 Guatemala*

Unregulated land use and lack of wastewater treatment have led to eutrophication in many lakes of Guatemala [26]. Some examples of this situation are the following studies.

Basterrechea [27] found the prevalence of cyanobacteria in the Lake Amatitlán due to eutrophic conditions. Similarly, Rejmánková et al. [28] recorded blooms of the *Lyngbya* species complex (cyanobacteria) as a consequence of the change in land use

**31**

*Eutrophication and Phytoplankton: Some Generalities from Lakes and Reservoirs of the Americas*

in the Lake Atitlán basin. Brocard et al. [26] pointed out that eutrophication has had a dramatic impact on the lake Chichój environment; among other effects, fertilization of lake waters produced severe hypoxia, massive development of the water hyacinth *Eichhornia crassipes* (Mart.) Solms 1883, and "blue-green" algae dominance.

The Lake Yojoa is the largest natural lake in the country and represents an important natural resource for Hondurans [29]. The lake is used extensively for commercial production of tilapia fish; fishes are raised to full maturity in floating cages in the lake, and subsequently, high nutrient load is directly supplied to the water body. Other sources of nutrients are: (a) significant amount of wastewater from the ineffective product of water treatment plant, (b) wastewater from restaurants around the lake, and (c) agricultural practices in the neighboring lands, where fertilizers are commonly used, thus contributing with nutrients to the system,

Because of the high input of nutrients, cyanobacteria are the dominant phytoplankton group that accounted for 59.0% of total phytoplankton in the lake [30]. Dominant species in the lake are *M. aeruginosa*, *Aphanocapsa delicatissima* West and GS West 1912, and *Oscillatoria limosa* C. Agardh ex Gomont 1892, all of them common in eutrophic tropical and temperate lakes. Other species that present high densities in lake are the green algae *Staurastrum leptocladum* Nordstedt 1870 and *Sphaerocystis schroeteri* Chodat 1897 and the diatom *Aulacoseira granulata*

Wastewater effluents and similar runoffs with high nutrient concentrations derived from agricultural fertilizers, which are increased by the susceptibility to erosion, deforestation, and sediment trawling, have induced the eutrophication process and, consequently, produced the proliferation of *M. aeruginosa* (cyanobac-

The Cerrón Grande reservoir also suffered the eutrophication process, and its waters are classified as hypereutrophic. The dominant cyanobacteria species is

In the eutrophic Lake Xolotlán (Lake Managua), Hooker and Hernández [33] and Erikson [34] found high phosphorus concentrations (≈150 μg/L), turbid waters (0.40 m of transparency), and high algal biomass of mainly "blue-greens" (cyanobacteria). Phytoplankton community was dominated by cyanobacteria throughout the entire year [35], and *Lyngbya contorta* Lemmermann 1898 accounted for more than 35.0% of total phytoplankton in the lake, followed by the diatom *Cyclotella* 

Vammen et al. [36] pointed out that increased eutrophication in Lake Cocibolca

Hernández González et al. [37] also found that the most representative phytoplankton genera detected during most of the period sampled in the eutrophic lakes Cocibolca, Tiscapa, and Masaya, were cyanobacteria, among which are distin-

(Lake Nicaragua) had resulted in the increase of phytoplankton density and a marked dominance of two cyanobacterial species (*M. aeruginosa* and *C. raciborskii*).

Cyanobacteria accounted for almost 99% of total phytoplankton in the lake.

guished *Anabaenopsis*, *Merismopedia*, *Chroococcus*, and *Lyngbya*.

*DOI: http://dx.doi.org/10.5772/intechopen.89010*

having an impact on water quality [29].

teria) in the volcanic Lake Coatepeque [31].

(Ehrenberg) Simonsen 1979.

*2.2.3 El Salvador*

*Microcystis* spp. [32].

*meneghiniana* Kützing 1844.

*2.2.4 Nicaragua*

*2.2.2 Honduras*

in the Lake Atitlán basin. Brocard et al. [26] pointed out that eutrophication has had a dramatic impact on the lake Chichój environment; among other effects, fertilization of lake waters produced severe hypoxia, massive development of the water hyacinth *Eichhornia crassipes* (Mart.) Solms 1883, and "blue-green" algae dominance.
