Geochemical cycling of silver in marine sediments along an offshore transect

Abstract

Although there have been many surface water and water column silver (Ag) analyses in the ocean, the absence of high resolution pore water and solid phase Ag profiles has hampered our understanding of its oceanic geochemical cycling. This manuscript presents pore water and solid phase profiles of Ag along an offshore transect water profiles represent non-steady state conditions. Clearly, the early diagenesis of Ag is a highly dynamic process and more research is required to fully understand Ag cycling in sediments in continental margin locations.

Porewater dynamics of silver, lead and copper in coastal sediments and implications for benthic metal fluxes

“…The MB average porewater Ag concentration is lower than the HB Ag average (at the 95% level of certainty). Ag data from both sites fall within the range of values found by Rivera-Duarte and Flegal (1997a) in San Francisco Bay and Morford et al (2008) on the Washington Margin in water depths of 400-3800 m. The Cu concentrations range from 4-45 and 8-43, and the Pb concentrations range from 0.3-24 and 0.6-9 nM in HB (Fig. 6) and MB (Fig.…”

“…However, the results of Wen et al (1997) do not discount Fe-oxyhydroxides adsorbing Ag in these sediments as hematite is a crystalline phase and the amorphous phase is the most reactive fraction of the Fe-oxide pool in coastal sediments (Canfield, 1989). The higher Fe content in coastal sediments, likely leads to the observation of Ag and Cu adsorption by Fe-oxyhydroxides in this study compared with those of open ocean sites (Klinkhammer, 1980;Shaw et al, 1990;Morford et al, 2008).…”

“…In sediments from the Washington Margin, Ag was released to the porewaters close to the surface, and there was no relationship with either porewater Fe or Mn concentrations (Morford et al, 2008). Wen et al (1997) investigated a relationship between Ag and Fe in estuarine particulates by conducting a radiotracer experiment with Ag and hematite in seawater.…”

The accumulation of silver in marine sediments: A link to biogenic Ba and marine productivity

“…Previous studies in these regions have focused on understanding the geochemistry of redox‐sensitive metals such as Re, U, Cd, and Mo (Western Canadian Margin, McKay et al [2007]; Mexican Margin, Nameroff et al [2002]; Peruvian Margin, Morford [1999], Böning et al [2004], and McManus et al [2006]; Chilean Margin, Morford [1999], Böning et al [2005], and McManus et al [2006]). With the exception of three recent papers [ Böning et al , 2004, 2005; Morford et al , 2008] there is little information in the literature about the geochemistry of Ag in continental margin sediments. The primary objective of this study is to improve our understanding of the biogeochemical controls on Ag accumulation in marine sediments.…”

Origin and accumulation of trace elements in sediments of the northwestern Mediterranean margin

“…Studies addressing Ag biogeochemistry in coastal and marine sediments are scarse, but the Ag interaction with planktonic material and its highly dynamic diagenetic behaviour have been already reported (Crusius and Thomson, 2003;Morford et al, 2008).…”