Profile sediment cores geochemical characteristics Callao, October 2008

Abstract

We determined the trend and vertical variability of the geochemical characteristics of sediments and interstitial water in the first 10 cm of two sediment cores from Callao, collected in two stations of the Callao profile, during the Research Cruise BIC Olaya MINIOX 0810: (1) E -2, at 8 nm from the coast and 98 m in depth, where organic matter showed a wide range of variability (4.75% to 56.34%) and a tendency to increase along with the depth of the vertical profile, as there were geochemical conditions to favor the preservation of organic matter and slowing down the process of remineralization; and (2) E-5, 30 nm off the coast and 178 m in depth, where organic matter showed a more homogeneous distribution in the vertical profile (30.72% to 36.17%). The high correlations (r> 0.7) of total organic matter with total organic carbon, as well as with phosphates and silicates in surface sediments, indicate that organic matter partially dominates concentrations of carbon and phosphorus. The variability in the distribution pattern of Redox-sensitive metal concentrations in recent sediments is associated to anoxic conditions and the intense sulfate-reduction activity typical in the area of study