Assessment of mercury levels in modern sediments of the East Siberian Sea

Arctic mercury cycling

“…New observations on the Siberian shelf suggest Hg burial rates of up to 75 Mg y -1 and that earlier estimates are biased low because of underestimated sediment density 217 . Using all available data 191,216,217 gives a revised shelf Hg burial flux of 42±31 Mg y -1 (n=114). Net benthic Hg diffusion flux from the AO sediments to the overlying water column is estimated at 5 Mg y -1 for both shelf and deep basins based on limited data 6 , calling for further measurements especially in the deep basin.…”

“…Recent observations on the Siberian shelf suggest that Hg burial rates of up to 75 Mg y -1 are possible 217 , and that earlier estimates are biased low because of underestimated sediment density. Large observed shelf Hg settling of 122±55 Mg y -1 from surface waters 191 also indicates that the revised shelf burial flux (42±31 Mg y -1 ) using all available data (n=114) 191,216,217 might be underestimated by up to 80±63.1 Mg y -1 , which is in the range of excess AO Hg input (52.2±43.5 Mg y -1 ) found here. Riverine and erosional Hg exports to the AO are highly seasonal, primarily occurring during spring freshet and summer months 7,165 .…”

“…Higher Hg burial rates are estimated in shelf sediments (30 Mg y -1 and 20±14 Mg y -1 ) 6,191 . However, the shelf Hg burial flux is likely underestimated due to a lack of measurements in the inner shelf, where burial is expected to be higher 217 . New observations on the Siberian shelf suggest Hg burial rates of up to 75 Mg y -1 and that earlier estimates are biased low because of underestimated sediment density 217 .…”

“…However, the shelf Hg burial flux is likely underestimated due to a lack of measurements in the inner shelf, where burial is expected to be higher 217 . New observations on the Siberian shelf suggest Hg burial rates of up to 75 Mg y -1 and that earlier estimates are biased low because of underestimated sediment density 217 . Using all available data 191,216,217 gives a revised shelf Hg burial flux of 42±31 Mg y -1 (n=114).…”

“…In contrast, the revised AO Hg inputs (204.5±27.3 Mg y -1 ) exceed outputs (152.3±33.9 Mg y -1 ) by 52.2±43.5 Mg y -1 (Table S9), and indicate that Hg removal from the AO ocean waters is currently underestimated. Shelf Hg burial flux is likely underestimated due to a lack of measurements in the inner shelf, where burial is expected to be higher 217 (arrow q, Fig. 4).…”