Optical and geochemical study of organic matter in present oxic sediments (Equatorial North Pacific Ocean Nixo area)

Optical (palynofacies) and geochemical (C, N, amino acids) study of surface sediments from the Equatorial North Pacific Ocean, which are deposited in an oxic environment and characterized by ferromanganese nodule occurrence, revealed figured remains of pelagic, benthic and terrestrial organic matter. These organic remains consist of a residual organic fraction, related to alteration phenomena. The scarcity of amorphous organic matter contrasts markedly with anoxic sediments. Amino acid comparison between hand-picked figured organic elements and bulk sediments indicates that coarse components have distinct compositions, some being biologically active sites; the preserved amino acid content of bulk sediments being mostly related to fine fractions as clays.