*2.2.4 Nicaragua*

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 meneghiniana* Kützing 1844.

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

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

#### *2.2.5 Costa Rica*

Umaña et al. [38] stated that there are few long-term works in lakes in Costa Rica, which have shown a wide annual variation of their characteristics. In the Talamanca region of the province of Limón, Jones et al. [39] found a gradient of trophic states, varying from high-altitude lakes with a tendency to be oligotrophic, to lower-altitude lakes with a tendency to be eutrophic, despite being located in woodland regions where it is away from any human disturbances. These researchers express that, because they do not have a high burden of anthropic phosphorus, their planktonic communities do not show the classic dominance of cyanobacteria against other planktonic groups, but rather a higher prevalence of green algae, a few dinoflagellates and a few cryptomonadales, all of which suggest a more balanced availability between nitrogen and phosphorus. On the other hand, the Arenal reservoir, the largest water body in Costa Rica, located between the provinces of Guanacaste and Alajuela, has been classified as mesotrophic by Jones et al. [39], representing varied phytoplanktonic community that is dominated by green algae, some diatoms, and cyanobacteria (*Microcystis* spp.).

### *2.2.6 Panama*

Reservoirs of the Panama channel show a mesotrophic status, with a predominance of diatom populations that are represented by 40.0% of total phytoplankton in Gatún reservoir, 55.1% in Alajuela reservoir, and 58.0% in Miraflores reservoir [40].

#### *2.2.7 Cuba*

Gómez Luna et al. [41] identified the phytoplankton communities in three reservoirs which are used for drinking water supply to 80.0% of the inhabitants in the City of Santiago de Cuba. High concentrations of nutrients were detected in Chalóns, Charco Mono, and Paradas reservoirs, where the phytoplankton communities were dominated by the cyanobacterial species *Microcystis* spp., *Aphanothece minutissima* (West) J. Komárková-Legnerová and G. Cronberg 1994, and *Oscillatoria chalybea* Mertens ex Gomont 1892.

#### *2.2.8 Puerto Rico*

Pantoja Agreda [42] conducted a limnological characterization of Guajataca reservoir, which was classified as mesotrophic. The dominant phytoplankton group were Euglenophyta (43.8% of total phytoplankton), followed by Pyrrhophyta (34.9%) and Chlorophyta (10.7%); cyanobacteria accounted for less than 5.00% of total algal density. This fact is common in water bodies with high content of organic matter.

#### **2.3 South America**

#### *2.3.1 Colombia*

According to Roldán [43] and Roldán and Ramírez [44], water bodies with more signs of eutrophication (Porce II, El Peñol, Prado, and Tominé) have a predominance of cyanobacteria, especially of the genera *Anabaena* spp. and *Oscillatoria* spp. The main source of eutrophication is domestic wastewater that reaches the rivers and streams without any treatment. The use of agrochemicals also contributes to eutrophication. The most outstanding case of eutrophication is that of the Porce II reservoir, which receives the waters of the Medellín river, carrying pollutants of a city of about 3,000,000 inhabitants. Currently, there are two wastewater treatment

**33**

*2.3.4 Brazil*

eutrophic condition has also been reported.

in highly eutrophic shallow lakes and small reservoirs.

Komárková-Legnerová and Cronberg 1992 is the dominant species.

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

Composition of phytoplankton in the Lake Yahuarcocha is dominated by the following species: *Cylindrospermopsis* sp., *Anabaena* sp., *Microcystis* sp. (cyanobacteria), *Monoraphidium* sp. (chlorophyta), and *Fragilaria* sp. (diatom) [45]. Eutrophication in this lake is due to the entrance of wastewater caused by the

In the Lake Titicaca, in the corresponding Bolivian basin, Fonturbel and Castaño-Villa [46] considered nutrient concentrations and phytoplankton groups as a whole to determine that the families Oscillatoriaceae and Nostocaceae (cyanobacteria) respond positively to the increase in pH (alkalinization) and negatively to the increasing nutrients, while the families Naviculaceae (diatoms), Closteriaceae, and partly Zygnemataceae (green algae) showed an inverse tendency with proliferating in acidic water enriched with nutrients. The diatoms seem to respond negatively, both to the acidification of the water and to the excessive nutrient enrichments. Studies revealed

plants, one of which has started process a short time ago. It is expected that this reservoir will begin to recover in the future. Unfortunately, more than 95.0% of the

towns and cities in Colombia do not have wastewater treatment plants.

that they are the most sensitive groups to the eutrophication of waters.

Between the 1970s and 1990s, both sections of the Lake Titicaca, deep Lago Mayor and large part of shallow Lago Menor, were oligotrophic with high water transparency and strong nitrogen limitation. Chlorophyta and cyanobacteria (particularly *Anabaena* spp.) dominated the phytoplankton with low biomass and primary production, except for diatoms during the dry season [47]. Currently, the deep pelagic areas of the Lake Lago Mayor remain oligotrophic. However, shallow littoral areas of the Lake Lago Mayor and the Lago Menor turn to eutrophic from mesotrophic. In the northern littoral area of the Lago Menor, there are a lot of villages which have domestic pollution sources, while El Alto is responsible for the heavy contamination of the Cohana bay. In 2015, the extended rainy season produced the first major phytoplankton bloom event in dominance of *Carteria* sp., which is a harmless unicellular green algae in the northern part of the Lago Menor in the period of March–April. Phytoplankton blooms in the region have been spotted since the 2000s. Cyanobacteria *Limnoraphis* (syn. *Lyngbya*) predominates in the Puno bay.

Numerous studies on eutrophication of freshwater ecosystems have been conducted along the Brazilian territory. Prevalence of cyanobacteria under this

spp. in the reservoirs of the State of São Paulo, where they are characterized by a severe eutrophication in their waters due to industrial and agricultural wastewater. Huszar et al. [49] and Dantas et al. [50] also found the dominance of *Microcystis*

Lake Vaca Brava, in the State of Goiás (Central Western Brazil), is an urban water body that suffers the eutrophication process as a consequence of the human settlement in its neighboring areas [51]. Increased cyanobacterial density accompanies the eutrophication process, where *Planktolyngbya limnetica* (Lemmermann)

Tundisi [48] reported blooms of the cyanobacteria *Microcystis* spp. and *Anabaena*

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

tourism industry around the lake.

*2.3.3 Peru and Bolivia*

*2.3.2 Ecuador*

plants, one of which has started process a short time ago. It is expected that this reservoir will begin to recover in the future. Unfortunately, more than 95.0% of the towns and cities in Colombia do not have wastewater treatment plants.
