Auto- and heterotrophic nanoplankton and filamentous bacteria of Guanabara Bay (RJ, Brazil): estimates of cell/filament numbers versus carbon content

Authors

  • Viviane Severiano Santos Habtec Engenharia Ambiental Ltda
  • Maria Célia Villac Universidade de Taubaté; Departamento de Biologia
  • Denise Rivera Tenenbaum Universidade Federal do Rio de Janeiro; Instituto de Biologia; Departamento Biologia Marinha
  • Rodolfo Paranhos Universidade Federal do Rio de Janeiro; Instituto de Biologia; Departamento Biologia Marinha

DOI:

https://doi.org/10.1590/S1679-87592007000200006

Keywords:

Estuary, Guanabara Bay, Nanoplankton, Filamentous bacteria, Autotrophs, Heterotrophs, Biomass, Cell density

Abstract

Variations of nanoplankton (2-20 µm) and filamentous bacteria (diameter: 0.5-2.0 µm) of Guanabara Bay (RJ, Brazil) are presented, considering cell density and carbon content of auto- and heterotrophs. Our goal is to contribute to future modeling of local trophic dynamics. Subsurface water samples were taken weekly during the year 2000 at two sites: Urca (close to the entrance, more saline, eutrophic) and Ramos (inner area, less saline, hypertrophic). Microscopic analysis was done by epifluorescence and cell density was converted to biomass through cell biovolume. Total nanoplankton was about 10(8) cells.l-1 in most samples (>;57%), and total filamentous bacteria densities varied from 10(5) to 10(8) fil.l-1. Autotroph density was one order of magnitude higher at Ramos, both for nanoplankton (Md: 10(8)cells.l-1 at Ramos and 10(7)cells.l-1 at Urca) and for filamentous bacteria (Md: 10(6) fil.l-1 at Ramos and 10(5) fil.l-1 at Urca). The same was observed for autotrophic biomass (Md: 10³µgC.l-1 at Ramos and 10¹µgC.l-1 at Urca for nanoplankton; Md: 28µgC.l-1 at Ramos and 1.4µgC.l-1 at Urca for filamentous bacteria). The relative contribution of autotrophs increased after conversion to biomass. Seasonal variation was conspicuous for filamentous bacteria at both sites and for nanoplankton only at Ramos, with maximum autotrophic abundances during the rainy period (spring-summer).

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Published

2007-06-01

Issue

Section

Research Articles

How to Cite

Auto- and heterotrophic nanoplankton and filamentous bacteria of Guanabara Bay (RJ, Brazil): estimates of cell/filament numbers versus carbon content. (2007). Brazilian Journal of Oceanography, 55(2), 133-143. https://doi.org/10.1590/S1679-87592007000200006