Staining evaluation for detection of marine phytoplankton viability

Author(s)

Izadora De La Volpe Mattiello

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto Oceanográfico (IO/DIDC)
• Defense date: 2014-05-22

Examining board members

Rubens Mendes Lopes; Jose Juan Barrera Alba; Flavia Marisa Prado Saldanha Correa

• Advisor: Rubens Mendes Lopes

Abstract

Phytoplankton cells are sensitive to environmental perturbations and, therefore, identifying their viability is important for aquatic monitoring. The term viability has been used in this context to determine whether an organism is alive or dead. The use of vital and mortal stains to detect phytoplankton viability is a promising approach. In this study we investigated the efficiency of several vital and mortal dyes in detecting marine phytoplankton viability. Best results were achieved with neutral red, Evans blue and the fluorescent stain in tests with different percentages of live and dead cells. The combination of neutral red and Evans blue (vital and a mortal stains, respectively) was not effective in simultaneous analysis. Alexandrium tamiyavanichii had low affinity for any given stain. Different observational methods were compared, suggesting that direct microscopic counts can be replaced by image acquisition methods using either a microscope-mounted camera or a FlowCAM. Such imaging methods are fast, allow image archiving, and image processing can be performed on a later stage, which is useful when several experiments need to be run in a short period of time. (AU)

• FAPESP's process: 12/14311-5 - The use of vital stains to determine the viability of marine phytoplankton
• Grantee: Izadora de La Volpe Mattiello
• Support Opportunities: Scholarships in Brazil - Master