*2.3.2 Ecuador*

*Microalgae - From Physiology to Application*

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.).

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].

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,

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.

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

and *Oscillatoria chalybea* Mertens ex Gomont 1892.

*2.2.5 Costa Rica*

*2.2.6 Panama*

*2.2.7 Cuba*

*2.2.8 Puerto Rico*

**2.3 South America**

*2.3.1 Colombia*

**32**

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 tourism industry around the lake.
