TITLE:
Dynamics of Primary Productivity and Oceanographic Parameters under Influence of the Amazon River Plume
AUTHORS:
Amanda Otsuka, Fernando Feitosa, Moacyr Araújo, Dóris Veleda, Maria da Gloria Silva Cunha, Nathalie Lefévre, Felipe Gaspar, Manuel Flores Montes, Gislayne Borges, Carlos Noriega
KEYWORDS:
Amazon River Plume, Continental Shelf, Oceanic Region, Environmental Variables, Phytoplankton Biomass, Primary Productivity
JOURNAL NAME:
Open Journal of Ecology,
Vol.8 No.11,
November
28,
2018
ABSTRACT: The watershed of the Amazon River discharges about
120,000 m3·s-1of freshwater into the adjacent platform and oceanic region. The aim of
this work was to analyze the distribution of oceanographic parameters,
chlorophyll a and primary productivity under the influence of the Amazon River
plume, during the period of greatest extension of the Amazon plume. Collections
were carried out in September 14 in 16 stations including continental platform
and oceanic region. It was possible to observe superficial currents along the
coast in the northwest direction, but with less intensity and currents with
greater speeds towards the east due to the North Brazil Current retroflexion at
this time of the year, transporting the plume to the central Atlantic Ocean.
The spatial influence of the plume was observed in the salinity, which ranged
from 28 to 36.75, although the high precipitation in the region may also have
contributed as a source of freshwater. However, the sampled region showed
strong negative linear correlation of silicate, chlorophyll a and primary
productivity with salinity. The primary productivity values ranged from 0.04 to
18.81 mg C m-3day-1, whereas chlorophyll a
concentrations ranged from 0.15 mg·m-3to 1.83 mg·m-3,
decreasing their values as they move away from the coast. The Amazon River
plume can reach and influence the oceanographic and biological parameters in a
large area of this oligotrophic region. However, the results also suggest that
the export of material from the adjacent coastal region is another determinant
of the region’s productivity.