Banca de DEFESA: MAIARA MENEZES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : MAIARA MENEZES
DATA : 04/05/2018
HORA: 14:00
LOCAL: SALA DE REUNIÕES DO CB
TÍTULO:

DYNAMIC OF PICOPLANKTON IN THE WESTERN COAST OF EQUATORIAL ATLANTIC OCEAN

PALAVRAS-CHAVES:

Picoplankton, microbial metabolism, coastal waters, equatorial Atlantic.

PÁGINAS: 58
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:

Most of the ocean biomass is microbial, and picoplankton microorganisms, which consists of small cells (<3 µm), are central players of global nutrient cycle and C production. Heterotrophic bacteria, cyanobacteria (Synechococcus) and autotrophic picoeukaryotes comprise picoplankton and commonly dominate microbial abundance and biomass production in oligotrophic waters of low latitude oceans. Thus, evaluate temporal dynamics of these organisms is crucial for understand microbial stocks and fluxes in equatorial regions. Here, we performed monthly samplings between 2013-2016 at Equatorial Atlantic Microbial Observatory (EAMO) situated on the coast of RN state – Brazil, to evaluate variations in abundance, biomass and activity (bacterial production and respiration) of picoplankton assemblage; and to identify the environmental factors that may regulate it in a scenario of greater environmental stability, where rainfall marks seasonality. Our results revealed that seasonality expressed a weak influence on picoplankton assemblage considering abundance, biomass and metabolic activity, with exception of Synechococcus, which peaked during dry seasons. Heterotrophic bacteria dominated picoplankton during entire study period; and showed higher abundances in July months, as well as picoeukaryotes. Interannual influence related to El Niño (ENSO) event in 2015 was also evidenced for total picoplankton assemblage. Autotrophic picoplankton (Synechococcus + picoeukaryotes) contributed in average for 30% of total picoplankton biomass (in contrast with heterotrophic fraction), and for 58% of total chlorophyll a. Among environmental factors, salinity proved to be the variable that best explained the abundance of picoplankton, with greater abundances during periods of low salinity water. However, weak environmental relationships found may suggest a greater importance of biological interactions (as competition and/or grazing) leading to picoplankton fluctuations throughout the year.

MEMBROS DA BANCA:
Presidente - 1639731 - ANDRE MEGALI AMADO
Externo ao Programa - 2326316 - NG HAIG THEY
Externo à Instituição - RODOLFO PARANHOS - UFRJ