Nutrient regeneration susceptibility under contrasting sedimentary conditions from the Rio de Janeiro coast, Brazil

Research areas:
Year:
2016
Keywords:
Pore water
Authors:
  • Christiene R. L. Matos
  • Ursula Mendoza
  • Rut Diaz
  • Manuel Moreira
  • Andre L. Belem
  • Édouard Metzger
  • Ana Luiza S. Albuquerque
  • Wilson Machado
Journal:
Marine Pollution Bulletin
Volume:
108
Number:
1–2
Pages:
297 - 302
ISSN:
0025-326X
Abstract:
Abstract Dissolved silicate (DSi), NH4+, NO3− and \{PO43\} − susceptibility to be exchanged between sediment pore waters and overlying waters was evaluated in Jurujuba Sound (JS station) and Coroa Grande Sound (CGS station), southeastern Brazil. Sedimentary elemental (C, N and P) and isotopic (δ13C and δ15N) compositions evidenced stronger anthropogenic fertilization in \{JS\} station. Net NO3− influxes from overlying waters occurred, which was two orders of magnitude higher under the more fertilized condition. This condition resulted in 6–13-times higher net effluxes of NH4+, \{DSi\} and \{PO43\} − to overlying waters. Vertical alternation between production and consumption processes in pore waters contributed for a more limited regeneration in \{CGS\} station. This was associated with diagenetic responses to sedimentary grain size variability in deeper layers and biological disturbance in upper layers. Nearly continuous production of NH4+, \{DSi\} and \{PO43\} − in pore waters implied in intensified susceptibility to remobilization under the eutrophic condition of \{JS\} station.