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ALGAE

A threat to the quality of water

Biologists find 20 species of algae which contaminate reservoirs

When during the summer of 1996, more than 40 patients from a clinic of hemodialysis died in Caruaru, in the state of Pernambucano, it took some time to discover the cause of the problem. The water which supplied the clinic contained toxins produced by cyanophiceas a fact  known only after many tests. These organisms are also known as cyanobacteria or blue algae, a group of living species, very old, which have been on the earth for more or less 2.5 billion years and are considered a link in the chain between the true bacteria and algae and possess characteristics of both.

Under normal conditions the cyanobacteria and the other aquatic organisms live in an equilibrium state in lakes and reservoirs. There is no dominance of one determined species to the detriment of the other. However, when there is some type of interference, which enriches the water with nitrogen and phosphate, the so called eutrophication, some species begin to be dominant: multiply excessively and give origin to the phenomenon  called bloom. This bloom form a dense mass on the surface of the water which alters the ecological balance and creates problems.

Some species of cyanobacteria produce toxins and on their blooming can cause the fish and of other animals death or even human beings as occurred in Caruaru. The cyanobacteria occur in the most diverse types of water environments. In lakes and reservoirs the planktonic species, that is those which live loose in the body of the water, are the ones that frequently cause flowering.

Eutrophication is a phenomenon that has been occurring more and more often. It can be a consequence of industrial or domestic sewage, the fertilizing of fields,  fish farming and of the rearing of animals such as cattle of pigs near to water. One very important step in the understanding of this problem was given through the project Cyanophyceae/ Planktonic Cyanobacteria of the state of São Paulo, which took place between 1997 and 1999, which was financing by FAPESP with R$32,900 and a further US$47,900. Coordinated by the biologist Célia Leite Sant’Anna, researcher at the
Botany Institute of the Environment Department f the State of São Paulo, the project identified twenty potentially toxic species of cyanobacteria found in Brazil, thirteen of them being in the State of São Paulo. The project discovered as well three new species for science, one of them placed in a new genre.

The team from the Botanical Institute gave it the name Sphaerocavum, which signifies “hollow sphere”, to the new genre which they discovered. The name suggested for the species is Sphaerocavum brasiliensis, found in eutrophic urban lakes in the city of São Paulo and in Montevideo in Uruguay. In the state of São Paulo it appears as well in the Billings reservoir. It occurs together with genre species Microcystis, forming bloomings. The tests to determine whether the algae is toxic or not are still ongoing.

nother new species is Coelosphaerium evidenter-marginatum, found in an eutrophic lake in the State Park of Fontes do Ipiranga, in the south of the city of São Paulo. A study on that species, which is not toxic, has already been published in the German magazine Algological Studies. A third species newly described is Microcystis panniformis, found in various reservoirs n the State such as Billings, Guarapiranga, Barra Bonita and Americana. The tests dealing with its toxicity are still ongoing.

Identification
The project has two fundamental objectives. One of them was to get to know the biodiversity of planktonic cyanobacteria  (those that float on water) in the state of São Paulo. The other was to detail the development, the morphological variability and the geographical distribution of the potentially toxic species in Brazil. “These results could assist, in a more practical and safe form the programs of the monitoring of the blooming of cyanobacteria”, says Célia.

According to her, the taxonomy of cyanobacteria is very complex and requires the observation of the different phases of the development of the species. In Brazil, there are few specialists in this specific area. Normally, say the researchers, the laboratories which carry out the toxicity tests don’t have specialists to identify the cyanobacteria. From here springs the interest of developing  joint studies so that in the future, there will be a bank of data with precise information about the Brazilian species.

Genetic make-up
The biologist Maria Teresa de Paiva Azevedo, who worked with Célia on the project, is the person responsible for the Culture Bank of Cyanobacteria, created in the Laboratory of Algae Culture of the Botanical Institute. In this bank, isolated cultures of material taken from nature are kept. “We could guarantee that in every test tube deposited in the Culture Bank there exists only one species with the same genetic make-up, ” she says.

The state of São Paulo area was the main focus of this project, but the biologists also examined samples of potentially toxic cyanobacteria from other states. Normally these samples are sent by technicians of sewage treatment companies. It is a common  interchange, especially when there is doubt in relation to the identification of the algae.

The interchange most frequent of the researchers of the Botanical Institute, however, is with technicians of Cetesb (Environment Sanitation Technology Company – the state of São Paulo environmental authority) and of Sabesp ( The Basic Sanitation Company of the State of São Paulo), the organs of the São Paulo government linked to the preservation of the environment and to public water supply, respectively. “Our exchange program has been going for more than ten years,” says  the biologist Marta Condé Lamparelli, manager  of the division of water analysis biology of Cetesb.

Illustrated manual
The researchers intend to prepare an illustrated manual describing the species of potentially toxic species of cyanobacteria. This manual could be used by technicians of Sabesp and Cetesb and by sewage companies of other states. Furthermore,   the results of the study, above all the 80 species of cyanobacteria plankton, will be passed on Biota-FAPESP, the program which is mapping the fauna and flora of the State of São Paulo.

The next step for the researchers is to define the toxic lineage in the Cyaonobacteria Culture Bank. To this end, they have begun to set up a laboratory at the Botanical Institute. In the isolation and identification of the toxins, they will be able to count on the collaboration of another researcher of the Institute, Luciana Retz de Carvalho, a Doctor in Phytochemistry through the Institute of Chemistry of the University of São Paulo (USP).

Spread throughout Brazil

The case of Caruaru is the most serious seen so far regarding the effects of toxic algae. However, it is not the only one. In 1990 a blooming f the cyanobacteria Anabaena solitaria, in the Guarapiranga reservoir, which supplies one third of the population of the city of São Paulo, provoked a strong smell of insecticide in the water which reached homes. Immediately, an increase in the cases of dermatitis, diarrhoea and vomiting were registered, especially in children.

In the reservoir Barra Lagoon, in Rio de Janeiro, a blooming of Synechocystis aquatilis f. salina caused the deaths of fish. Proliferation of Microcystis aeruginosa in a lake in the city of Araras in São Paulo killed pigeons and, in a lake of the Zoo of  São Paulo, they were responsible for the deaths of various ducks.

Technicians from Cetesb informed that the control of the water destined for consumption is treated by adding algaecides, such as copper sulfate or hydrogen peroxide, in the reservoirs. It doesn’t always solve the problem as the death of algae ends up releasing toxins into the water. “The ideal solution is to avoid that the body of water be  eutrophied” say the biologists Marta Condé Lamparelli and Maria do Carmo Carvalho, about this reservoir. Prevent the water from being contaminated by sewage or other sources of pollution.

Presently, international groups of researchers have prioritized the study of a species which is extremely aggressive and competitive, the Cylindrospermopsis raciborkii, which has spread quickly in Brazilian lakes and reservoirs. One of the toxic species most common in Brazil is Anabaena spiroides. Generally, it forms flowerings in eutrophic bodies of water. Other species of the same genre, solitaria and A. planctonica, are also among the best known algae for producing toxin. Nevertheless, they are not the best distributed  in Brazil.

That honor goes to Microcystis aeruginosa, a very competitive specie and easily found in our reservoirs and whose toxin causes the deaths of fish and domesticated animals such as cattle and ducks. The explanation for the ever increasing presence of toxic algae is in eutrophication. “We have observed that the distribution of the potentially toxic species is increasing rapidly in proportion to the number of reservoirs eutrophised in the State”, says Célia.

Profile:
Célia Leite Sant’Anna
graduated in Biological sciences from the Bioscience Institute of the University of São Paulo (USP), where she also her masters and doctorate degree. A researcher for the Botanical Institute since 1976, she assumed this year the direction of the division of the Institute of Phytotaxonomy.
Maria Teresa de Paiva Azevedo graduated in Biology through the Brás Cubas Colleges in Mogi das Cruzes, and took her doctorate at the São Paulo State University (Unesp) of Rio Claro. Since 1986 she has been a researcher for the Botanic Institute.

Project
Cyanophyceae/planktonic Cyanobacteria of the State of  São Paulo (nº 97/05488-7); Modality Regular; Coordinator Célia Leite Sant’Anna; Investment: R$ 32.911,00, and a further  US$ 47.907

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