Infaunal burrow densities and sediment monomethyl mercury distributions in Boston Harbor, Massachusetts

Benoit, Janina M.; Shull, David H.; Robinson, P.; Ucran, L.R.

doi:10.1016/j.marchem.2005.09.017

Cited by 43 publications

(32 citation statements)

References 34 publications

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“…with Leptocheris pinguis also important in 2008 (Tucker et al, 2014). There were 0.3-1 × 10 5 organisms/m 2 retained on a 1 mm sieve in the spring and summer of 2003 (Benoit et al, 2006). Measurements of burrow surface area show burrows present to a maximum depth of 6 cm (Benoit et al, 2006) and the depth of bioturbation is also unlikely to extend below 6-8 cm, the depth where dissolved sulfide is detected in the porewaters (Morford et al, 2009).…”

Section: Study Sitesmentioning

confidence: 99%

“…There were 0.3-1 × 10 5 organisms/m 2 retained on a 1 mm sieve in the spring and summer of 2003 (Benoit et al, 2006). Measurements of burrow surface area show burrows present to a maximum depth of 6 cm (Benoit et al, 2006) and the depth of bioturbation is also unlikely to extend below 6-8 cm, the depth where dissolved sulfide is detected in the porewaters (Morford et al, 2009). The sedimentation rate was 1.8 cm/yr in 1978 (Bothner et al, 1998) and has since declined considerably due to cessation of sewage discharge.…”

Section: Study Sitesmentioning

confidence: 99%

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

Kalnejais

Martin

Bothner

2015

Science of The Total Environment

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Section: Study Sitesmentioning

confidence: 99%

Section: Study Sitesmentioning

confidence: 99%

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

Kalnejais

Martin

Bothner

2015

Science of The Total Environment

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“…However, benthic recolonization may not necessarily result in higher potential for mercury bioconcentration in lake biota. Lake oxygenation has been shown to result in benthic recolonization of profundal sediments (Dinsmore & Prepas, 1997), and in combination with elevated DO levels at the sediment water interface, bioirrigation could enhance penetration of oxygen into sediments with the net result of pushing the site of mercury methylation deeper into sediments (Benoit et al, 2006). Additional advantages of oxygen over nitrate as a treatment of the anaerobic profundal zone include repression of ammonia release from sediments (Beutel, 2006) and expanded habitat for cold water biota (Moore et al, 1996;Prepas et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Nitrate uptake rate in anoxic profundal sediments from a eutrophic reservoir

2008

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There is renewed interest in the use of nitrate to treat the profundal zone of lakes to inhibit anaerobic biogeochemical processes that result in the degradation of bottom water quality (e.g., sediment phosphorus release, mercury methylation). In this study we used experimental sediment-water interface chambers to quantify the rate of sediment nitrate uptake (SNU) in profundal sediments from Lake Perris, a eutrophic raw water reservoir in Southern California. Deoxygenated chamber water was spiked with nitrate, and nitrate concentration was monitored over time under quiescent conditions, followed by mixed conditions with average water velocities of 1 cm/s. Key findings included: (1) SNU decreased with decreasing nitrate concentration, (2) SNU was higher under mixed versus quiescent conditions by nearly 50%, and (3) nitrate uptake as a function of nitrate concentration followed a conventional sediment oxygen demand model in which nitrate uptake was proportional to the square root of nitrate concentration. The probable mechanism for elevated SNU under mixed conditions was an increased diffusional concentration gradient combined with a decrease in the diffusional boundary layer at the sediment-water interface, both of which enhanced the flux of nitrate from overlaying water into sediment. Managers planning to implement lake nitrate addition should account for induced nitrate demand when determining dosing rates. For example, based on our modeling efforts from this data set, SNU in Lake Perris could range by an order of magnitude, from around 12 mg N/m 2 /d under quiescent, low nitrate conditions (0.1 mg N/l) to around 120 mg N/m 2 /d under mixed, high nitrate conditions (5 mg N/l).

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“…1d). Deeper peaks in MeHg with depth have been previously observed at sediments with a high degree of bioturbation in Boston Harbor (Benoit et al, 2006). Methylmercury production is sensitive not only to the redox environment but also to the availability of Hg i for methylation by microbes (Jonsson et al, 2012), which is controlled by its partitioning to the solid phase.…”

Section: Discussionmentioning

confidence: 70%

The effect of sediment mixing on mercury dynamics in two intertidal mudflats at Great Bay Estuary, New Hampshire, USA

et al. 2015

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Estuarine sediments store particulate contaminants including mercury (Hg). We studied Hg sediment dynamics in two intertidal mudflats at Great Bay estuary, NH, over multiple years. Sediments at both mudflats were physically mixed down to ~10 cm, as determined by 7Be measurements, albeit via different mechanisms. Portsmouth mudflat (PT) sediments were subject to bioturbation by infaunal organisms and Squamscott mudflat (SQ) sediments were subject to erosion and redeposition. The presence of higher concentrations of fresh Fe(III) hydroxide at PT suggested bioirrigation by the polychaetes (Nereis virens). At depths where infaunal bioirrigation was observed, pore-water inorganic Hg (Hgi) and methylmercury (MeHg) were lower potentially due to their interaction with Fe(III) hydroxide. Methylmercury concentrations increased immediately below this zone in some samples, suggesting that the observed increase in material flux in bioirrigated sediments may initiate from lower depths. Pore water in sediment at PT also had higher fractions of more protein-like and labile DOC than those at SQ that can lead to increased MeHg production in PT, especially at depths where Hgi is not removed from solution by Fe(III) hydroxide. Where sediment erosion and redeposition were observed at SQ, Hg species distribution was extended deeper into the sediment column. Moreover, methyl coenzyme M reductase (MCR) and mercury reductase (mer-A) genes were higher at SQ than PT suggesting differences in conditions for Hg cycling. Results showed that the near-surface region of high MeHg concentrations commonly observed in unmixed sediments does not exist in physically mixed sediments that are common in many estuarine environments.

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Infaunal burrow densities and sediment monomethyl mercury distributions in Boston Harbor, Massachusetts

Cited by 43 publications

References 34 publications

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

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

Nitrate uptake rate in anoxic profundal sediments from a eutrophic reservoir

The effect of sediment mixing on mercury dynamics in two intertidal mudflats at Great Bay Estuary, New Hampshire, USA

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