Trace metals in burrow walls and sediments, Georgia Bight, USA
Titel:
Trace metals in burrow walls and sediments, Georgia Bight, USA
Auteur:
Over, D. Jeffrey
Verschenen in:
Ichnos
Paginering:
Jaargang 1 (1990) nr. 1 pagina's 31-41
Jaar:
1990-07
Inhoud:
Cu, Fe, Mn, Ni, and Zn in the burrow walls of Callianassa major (Decapoda), collected from littoral sands from the Georgia coast, are concentrated by factors of 2 to 4 relative to the surrounding sediments. Clay minerals (mixed-layer, montmorillonite, kaolinite) are concentrated in the burrow walls. However, trace metals in burrow walls are enriched independently of the abundance of fine-grained materials. Cu, Mn, and Ni associate strongly with organic material. Iron forms oxyhydroxides or associates with organic material; Mn and Zn are positively correlated with Fe. Trace-metal concentrations in polychaete dwelling tubes and burrows from the nearshore shelf are somewhat species-dependent and metal-specific. Tube walls, constructed primarily of organic material, are relatively poor in trace metals. Tube-wall and sediment-metal concentrations decrease away from shore as a result of reduced availability of metals in offshore waters. Weakly bound metals become mobile soon after burrow abandonment. Analogous Pleistocene burrow structures (Ophiomorpha nodosa) from environmentally equivalent sediments are enriched in trace metals, as are recent burrows, but at concentrations 20 to 500% less than Callianassa major burrows.
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