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Previous issue date: 2016-12-28 / A eutrofiza??o artificial tem sido considerada um problema de grande preocupa??o nos
ecossistemas aqu?ticos em todo o mundo. Desde 1960, os avan?os cient?ficos t?m sido feitos a
fim de desenvolver t?cnicas que atenuem os efeitos da eutrofiza??o. V?rios procedimentos
f?sicos, qu?micos e biol?gicos podem ser usados e combinados para recuperar lagos de flora??es
de cianobact?rias, como a aplica??o de um floculante combinado com argila natural ou
modificada. No entanto, a efic?cia dos solos de regi?es ?ridas na mitiga??o de flora??es ?
desconhecida para lagos artificiais brasileiros. Neste artigo, apresentamos uma an?lise
bibliom?trica da evolu??o de publica??es sobre flora??es de cianobact?rias e identificamos
registros que diretamente objetivam superar a ocorr?ncia dessas flora??es. Al?m disso,
avaliamos, por meio de experimentos laboratoriais, o efeito do uso combinado do floculante
policloreto de alum?nio (PAC) e um solo local do entorno do lago (LS), como lastro, no controle
de flora??es de cianobact?rias em um lago raso da regi?o semi?rida do Brasil. A pesquisa
bibliom?trica foi conduzida com o banco de dados "Web of Science" atrav?s da fun??o de busca
?TS = ((cyanobacteri* or blue green algae or cyanoprokariote or cyanophyceae) and (mass
accumulation or bloom or domina*))?, de 1969 a junho de 2016. Realizamos uma an?lise de
freq??ncia de palavras-chave e quantificamos o n?mero de registros com uma abordagem de
restaura??o. Al?m disso, foram realizadas tr?s s?ries de experimentos em tr?s momentos com
flora??es diferentes em composi??o e biomassa no Reservat?rio Armando Ribeiro Gon?alves.
Nossa pesquisa revelou que os estudos sobre as flora??es de cianobact?rias aumentaram
exponencialmente e seu impacto quantitativo nas ci?ncias aqu?ticas aumentou significativamente
ao longo dos anos (F = 97,52; p <0,0001). Os EUA se destacam como a na??o mais produtiva,
seguida pela China e pa?ses europeus. A China aumentou impressionantemente sua contribui??o
para essa ?rea, superando os EUA nos ?ltimos cinco anos. Estudos sobre Microcystis e toxinas,
tais como microcistinas, s?o tend?ncias de investiga??o, devido a sua omnipresen?a e suas
consequ?ncias negativas hist?ricas. Tamb?m enfatizamos a necessidade de mais estudos com o
objetivo de desenvolver t?cnicas para resolver e/ou mitigar a quest?o das flora??es. Em vista
disso, nossos experimentos revelaram que o uso de PAC e LS teve um efeito not?vel na
biomassa de cianobact?rias da coluna de ?gua em todas as amostragens, reduzindo at? 90% a
concentra??o de clorofila-a. O uso de LS sozinho foi ineficiente para remover a biomassa de algas azuis. Em duas amostragens, a combina??o de floculante e lastro apresentou a mesma
efic?cia que o uso apenas de PAC. Mesmo assim, o uso de LS ? importante para garantir a
sedimenta??o. Combinado com PAC, o LS foi um lastro t?o eficiente em remover cianobact?rias
quanto uma argila modificada comercialmente dispon?vel (Phoslock?). Embora LS in natura
tenha liberado quantidades consider?veis de f?sforo e n?o apresentou capacidade de adsor??o de
P, tal argila conseguiu adsorver quantidades moderadas de f?sforo dissolvido ap?s a mat?ria
org?nica ter sido removida por muflagem. Este estudo mostra que LS ? uma alternativa
economicamente vi?vel e sustent?vel para ser utilizada como a??o de manejo em reservat?rios
apresentando flora??es na regi?o semi?rida do Brasil. / Artificial eutrophication has been considered a problem of major concern in aquatic ecosystems
around the world. Since 1960, scientific advances have been made in order to develop techniques
that mitigate the effects of eutrophication. Several physical, chemical and biological procedures
can be used and combined to recover lakes from cyanobacterial blooms, such as the application
of a flocculant combined with natural or modified clay. However, the efficacy of local dryland
soils in mitigating blooms is unknown for Brazilian manmade lakes. In this paper, we present a
bibliometric analysis of the evolution of publications about cyanobacterial blooms and identify
records that directly aim to overcome the occurrence of these blooms. Also, we evaluate, through
laboratory experiments, the effect of the combined use of flocculent polyaluminum chloride
(PAC) and a local soil from the lake catchment (LS), as ballast, in controlling cyanobacterial
bloom in a shallow lake of the semiarid region of Brazil. The bibliometric research was
conducted with the ?Web of Science? database through the search function ?TS =
((cyanobacteri* or blue green algae or cyanoprokariote or cyanophyceae) and (mass
accumulation or bloom or domina*))?, from 1969 to June 2016. We performed a keyword
frequency analysis and quantified the number of records with a restoration approach. Besides,
three sets of experiments were performed in three sampling occasions with different bloom
compositions and biomass in Armando Ribeiro Gon?alves Reservoir. Our study revealed that
studies about cyanobacterial blooms increased exponentially and their quantitative impact on the
aquatic sciences increased significantly along the years (F = 97.52; p < 0.0001). The USA stands
out as the most productive nation, followed by China and European countries. China has
impressively increased its contribution to this area, surpassing the USA in the last five years.
Studies about Microcystis and toxins, such as microcystins, are trends in research, due to their
ubiquitousness and historical negative consequences. We also emphasize the need for more
studies aiming at developing techniques to solve and/or mitigate the issue of blooms. In view of
this, our experiments revealed that the use of PAC and LS had a remarkable effect on
cyanobacterial biomass in the water column in all samplings, reducing up to 90% top
chlorophyll-a concentration. The use of LS alone was inefficient to settle blue-green-algal
biomass. In two samplings, the combination of flocculant and ballast exhibited the same efficacy
as the use of solely PAC. Even so, the use of LS is important to ensure sedimentation. Combined with PAC, LS was as efficient a ballast to remove cyanobacteria as a commercially available
modified clay (Phoslock?). Althugh LS in natura released considerable amounts of phosphorus
and did not present P adsorption capacity, it managed to adsorb some dissolved phosphorus after
organic matter was removed through muffling. This study shows that LS is a cheap, feasible and
environment-friendly alternative to be used as a management action in reservoirs undergoing
blooms in the semiarid region of Brazil.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/22293 |
| Date | 28 December 2016 |
| Creators | Medeiros, Leonardo Rafael |
| Contributors | 12243214806, http://lattes.cnpq.br/2543467420133635, Carneiro, Luciana Silva, 07015083701, http://lattes.cnpq.br/0236958347394500, Silva, Maria Cristina Bas?lio Crispim da, 39553310400, http://lattes.cnpq.br/1103302506132951, Panosso, Renata de F?tima |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM ECOLOGIA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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