%0 Journal Article
%T Small time scale plankton structure variations at the entrance of a tropical eutrophic bay (Guanabara Bay, Brazil)
%A Mariana Guenther
%A Isabel Lima
%A Glenda Mugrabe
%A Denise Rivera Tenenbaum
%J Brazilian Journal of Oceanography
%D 2012
%I Universidade de S?o Paulo
%X The dynamics of the plankton compartments at the entrance of Guanabara Bay (SE Brazil) were assessed during a short-term temporal survey to estimate their trophic correlations. Size-fractioned phytoplankton (picoplankton: < 2米m, nanoplankton: 2-20米m and microplankton: > 20米m) biomass and photosynthetic efficiency, composition and abundance of the auto-and heterotrophic nano-and microplankton, and mesozooplankton were evaluated at a fixed station for 3 consecutive days at 3-h intervals, in the surface and bottom (20m) layers. The variability of almost all plankton compartments in the surface layer was directly dependent on temperature, indicating the great influence of the circulation at the entrance of the bay on plankton structure. In the surface layer, the mesozooplankton seems to be sustained by both autotrophic nano-and picoplankton, this last being channeled through the microzooplankton. Near the bottom, both auto-and heterotrophic microplankton are probably supporting the mesozooplankton biomass. Our findings thus suggest that the entrance of Guanabara bay presents a multivorous food web, i.e., a combination of both grazing and microbial trophic pathways. A dinamica dos v芍rios compartimentos do plancton foi avaliada durante uma s谷rie de curta dura  o na entrada da ba赤a de Guanabara (SE do Brasil), com o objetivo de estimar suas correla  es tr車ficas. A biomassa e efici那ncia fotoss赤nt谷tica das tr那s fra  es do fitoplancton (picoplancton: < 2米m, nanoplancton: 2-20米m e microplancton: > 20米m), juntamente com a composi  o e abundancia do nano-e microplancton auto-e heter車trofos e do mesozooplancton, foram determinadas em uma esta  o fixa durante 3 dias consecutivos, a intervalos de 3h, nas camadas de superf赤cie e de fundo (20m). A variabilidade de quase todos os compartimentos do plancton na superf赤cie foi diretamente relacionada 角 temperatura, indicando forte influ那ncia da circula  o da entrada da ba赤a na estrutura planct nica. Na camada superficial, o mesozooplancton parece ser alimentado pelo nano-e picoplancton aut車trofos, esse 迆ltimo sendo sustentado pelo microzooplancton. Pr車ximo ao fundo, o microplancton auto-e heter車trofo est o possivelmente sustentando a biomassa mesozooplanct nica. Nossos resultados sugerem, portanto, que na entrada da ba赤a de Guanabara esteja estabelecida uma rede tr車fica mult赤vora, i.e., uma combina  o entre as cadeias microbiana e de pastagem.
%K Fitoplancton
%K Microzooplancton
%K Mesozooplancton
%K Rede tr車fica de pastagem
%K Rede tr車fica microbiana
%K Fluxos de carbono
%K Phytoplankton
%K Microzooplankton
%K Mesozooplankton
%K Grazing food web
%K Microbial food web
%K Carbon fluxes
%U http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-87592012000400001