Effects of irradiance and spectral composition on the establishment of macroalgae in streams in southern Brazil

Autor(es)

Tonetto, Aurelio Fajar ^[1] ; Branco, Ciro Cesar Zanini ^[1] ; Peres, Cleto Kaveski ^[2]

Afiliação do(s) autor(es)

^[1] Sao Paulo State Univ, UNESP, Dept Biol Sci, Lab Aquat Biol, BR-19806900 Assis, SP - Brazil

^[2] Fed Univ Latin Amer Integrat, UNILA, BR-85867970 Foz Do Iguacu, PR - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ANNALES DE LIMNOLOGIE-INTERNATIONAL JOURNAL OF LIMNOLOGY; v. 48, n. 4, p. 363-370, 2012.
• Citações Web of Science: 6

Resumo

The relative effects of irradiance and spectral composition on the colonization and development of macroalgal communities were examined in four streams exposed to full sunlight in southern Brazil. A set of solar filters surrounded the artificial substrata to provide various quantitative and qualitative light conditions. In addition to the control, the conditions were full sunlight attenuated by 50, 70 and 90%, blue light (filter transmitting 430-500 nm), green light (500-600 nm) and red light (> 600 nm). Macroalgal percent cover was determined three times during the colonization period (15, 39 and 70 days). Significant differences occurred in the mean values for macroalgal community percent cover between treatments at 15 and 39 days, suggesting that early and intermediate stages of the colonization were directly influenced by irradiance. There was an almost complete absence of macroalgae with 90% attentuation, but progressive increases with 70 and 50% attenuation. However, the mean values for macroalgal community percent cover did not differ significantly between color treatments, suggesting that the effects of irradiance on macroalgal colonization were stronger than those of spectral composition at similar intensity. The quantitative responses differed among the taxa. (AU)

• Processo FAPESP: 07/52608-1 - Macroalgas de riachos da regiao sul do brasil.
• Beneficiário: Ciro Cesar Zanini Branco
• Modalidade de apoio: Auxílio à Pesquisa - Regular