Metais na comunidade plantônica em um sistema de ressurgência, Cabo Frio, Sudeste do Brasil

Abstract

Metals has an approach relationship with marine plankton, as key functions for biological pump can act as micronutrients and participate as “co-fatores” of enzimes for plankton metabolism. In upwelling regions as in Cabo Frio (CF), source of nutrients in “intermediate water” allows intensify the biological pump with high productivity. In this study, 7 vessels (March to December) were performed with net plankton: Phytoplankton (< 64 e < 20 μm) and zooplankton (<300 e < 150 μm) in CF continental shelf. A taxonomic study was realized and metals (Al, Fe, Mn, Ni, Cr, Cu, Ti, Zn, Cd e As) analyzed in ICP-MS. Factor analysis about metals show strong positive (Cr, Mn and Fe) and negative scores (Zn, As and Cd) for zooplankton as Penilla avirostris, Paracalanidae and Gender Paracalanus, also species called as Others in this work. Phytoplankton represented Strong positive scores positives (Mn e Ti) and negatives (Ni, Cu and Zn), this indicated strongs affiliation for diatoms. The ratio M:Al in parallel to crust ratio was used for indicate source of metal. Ratios upper crust was classified as Biogenic/Anthropogenic for metals like: Cr (range: 0,01 – 56,1 μg/g), Mn (0,12- 35,5 μg/g), Zn (0,02-412,0 μg/g), Ni (0,004 – 25,9 μg/g), As (2,38 – 67 μg/g) and Cd (0,08 – 7,5 μg/g), ratios M:Al under/close crust founded in Iron (0,02 – 392 μg/g) and Ti (4,23 – 130,1 μg/g) indicated litogenic source. Furthermore, some metals (Cr, Zn, Fe, Ni, As e Ti) introduced linearity (R2 > 0,96) with regard to P:Al vs Metal:Al, this signal can represented plankton uptake in cells. On other hand, geochemistry composition of igneous rocks and metamorphics rocks in Cabo Frio performed as an important source of metals as Ti. This results indicated elevated potential to transference of metals through biological pump to sediments in CF.