Cycling of biogenic silica within the upper water column of the Ross Sea

Nelson, David M.; Ahern, Julie A.; Herlihy, Linda J.

doi:10.1016/s0304-4203(09)90037-8

Cited by 198 publications

(22 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The average initial specific bSiO 2 dissolution rates measured for freely suspended cells (6.6 ± 2.6% d -1 corresponding to 24.2 ± 9.5 yr ) are in the same range as the estimated global world average of 16 yr -1 (Van Cappellen et al 2002) and as in situ measurements compiled by Nelson et al (1991), which ranged from 5 to 1000 yr -1 .…”

Section: Applicability Of Laboratory-determined Specific Bsio 2 Dissosupporting

confidence: 66%

Evidence for reduced biogenic silica dissolution rates in diatom aggregates

Moriceau¹,

Garvey²,

Ragueneau³

et al. 2007

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

International audienceBecause aggregated diatoms sink rapidly through the water column, leaving little time for dissolution, aggregation influences the balance between recycling of biogenic silica (bSiO2) and its sedimentation and preservation at the seafloor. Additionally, aggregation may directly impact dissolution rates of opal. Laboratory experiments were conducted to investigate the influence of aggregation on bSiO2 dissolution rates using 3 different batch cultures of the diatoms Chaetoceros decipiens, Skeletonema costatum, and Thalassiosira weissflogii. Specific dissolution rates of bSiO2 of aggregated and freely suspended diatoms were compared. Additionally, the influences of the dissolved silicon (dSi) concentration in the pore water of aggregates, the viability of diatoms, and the concentrations of transparent exopolymer particles (TEP) and of bacteria on bSiO2 dissolution rates were determined. Initial specific dissolution rates of diatom frustules were significantly lower for aggregated diatoms (2.9% d–1) than for freely suspended diatoms (6.6% d–1). Lower specific dissolution rates in aggregates were attributed to elevated dSi concentrations in aggregate pore water (maximum 230 vs. 20 µmol l–1) and to the fact that aggregated diatoms remained viable for longer than freely suspended diatoms. Specific bSiO2 dissolution was significantly correlated to viability of cells independent of treatment. Bacterial concentrations in both treatments appeared high enough, so that after cell death the coating protecting the silica frustule was degraded without measurable delay. The TEP content of aggregates appeared to affect dissolution rates, possibly by retaining solutes within aggregates

show abstract

Section: Applicability Of Laboratory-determined Specific Bsio 2 Dissosupporting

confidence: 66%

Evidence for reduced biogenic silica dissolution rates in diatom aggregates

Moriceau¹,

Garvey²,

Ragueneau³

et al. 2007

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…It is likely that contamination of this sort has occurred in all previous isotopic measurements of silica dissolution rates in the ocean (e.g. Brzezinski and Nelson 1989;Nelson et al 1991). However, the lower precision of the mass spectrometry employed in those studies would have prevented the resulting isotopic shifts from being detectable.…”

Section: Discussionmentioning

confidence: 99%

“…Ratios of silica dissolution to silica production exceeding 50% have been measured isotopically in surface waters off northwest Africa (Nelson and Goering 1977b), in the plume of the Amazon River (DeMaster et al 1991), in the Ross Sea (Nelson et al 1991), and in a Gulf Stream warm-core ring (Brzezinski and Nelson 1989). In all of those studies, surface-layer biogenic silica concentrations were at least 40 times higher than those typical of the BATS site during nonbloom periods, permitting silica dissolution rates to be measured directly by isotope-dilution methods.…”

Section: Discussionmentioning

confidence: 99%

“…Each sample was drawn into a clear 2.8liter polycarbonate incubation bottle, injected with 0.70 pmol of 30Si-enriched Na,,SiO, solution (95.28 atom% 3oSi) and mixed well, resulting in an enrichment of 0.25 FM above the ambient [Si(OH),] in the 2.8-liter sample. The stock solutions of 3oSi tracer had been passed through Chelex resin to remove possible trace-metal contamination (Nelson et al 1991). Samples were then hung on a freefloating array for 8-14 h at the depths from which they had been collected.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Diatom growth and productivity in an oligo-trophic midocean gyre: A 3-yr record from the Sargasso Sea near Bermuda

1997

Self Cite

View full text Add to dashboard Cite

We measured the rate of biogenic silica production in the upper 160 m at the Bermuda Atlantic Time-series Study (BATS) site in the western Sargasso Sea on 12 cruises between August 1991 and May 1994 using a 30Si tracer method. Previously initiated time series of particulate silica concentrations and the gravitational flux of siliceous particles were extended to produce an October 1988-December 1994 time series for biogenic silica concentrations and August 1991-December 1994 time series for lithogenic silica concentrations and fluxes of biogenic and lithogenie silica. Specific rates of biogenic silica production during nonbloom periods indicate active diatom growth, with a mean doubling time of 4.5 d for biogenic silica. The annual silica production rate is conservatively estimated to be 240 mmol Si m-2, which corresponds to a diatom productivity of -20-45 g C m-2 yr-I, -15-25% of the mean annual primary productivity. Comparison of silica production rates with sinking fluxes from the upper 150 m (26-53 mmol Si m-2 yr-I) indicates that -80% of the silica produced in the euphotic zone dissolves in the upper 150 m. Sinking of diatoms and their remains can account for -30% of the particulate organic carbon export at the BATS site on an annual basis and nearly 100% during the annual winter/spring diatom bloom. Atmospheric dust inputs each summer, indicated by July-August maxima in the concentration and vertical flux of lithogenic silica, do not stimulate either biogenic silica production or primary productivity, implying that iron availability limits neither diatom growth nor total primary production in the western' Sargasso Sea.Most of the primary production in the oceans occurs in midocean gyres and other oligotrophic systems-a seemingly contradictory situation that results from those systems' enormous spatial extent (e.g. Ryther 1969). The phytoplankton in the midocean gyres is comprised mostly of small, nonsiliceous forms, with

show abstract

“…Of the silica produced in the mixed layer of the upper ocean layers, at least 50 % is believed to dissolve in the upper 100 m of the water column (e.g. Nelson et al, 1991;DeMaster et al, 1992). For deep waters, the production rates of Nelson et al (1995) could result in a mean increase in SiO 4 of 0.08-0.14 µmol kg −1 yr −1 in the water column (∼ 3400 m, mean depth).…”

Section: Circulation and Biological Processes At Steady Statementioning

confidence: 99%

Carbon uptake and biogeochemical change in the Southern Ocean, south of Tasmania

et al. 2017

View full text Add to dashboard Cite

Abstract. Biogeochemical change in the water masses of the Southern Ocean, south of Tasmania, was assessed for the 16-year period between 1995 and 2011 using data from four summer repeats of the WOCE-JGOFS-CLIVAR-GO-SHIP (Key et al., 2015;Olsen et al., 2016) SR03 hydrographic section (at ∼ 140 • E). Changes in temperature, salinity, oxygen, and nutrients were used to disentangle the effect of solubility, biology, circulation and anthropogenic carbon (C ANT ) uptake on the variability of dissolved inorganic carbon (DIC) for eight water mass layers defined by neutral surfaces (γ n ). C ANT was estimated using an improved back-calculation method. Warming (∼ 0.0352 ± 0.0170 • C yr −1 ) of Subtropical Central Water (STCW) and Antarctic Surface Water (AASW) layers decreased their gas solubility, and accordingly DIC concentrations increased less rapidly than expected from equilibration with rising atmospheric CO 2 (∼ 0.86 ± 0.16 µmol kg −1 yr −1 versus ∼ 1 ± 0.12 µmol kg −1 yr −1 ). An increase in apparent oxygen utilisation (AOU) occurred in these layers due to either remineralisation of organic matter or intensification of upwelling. The range of estimates for the increases in C ANT were 0.71 ± 0.08 to 0.93 ± 0.08 µmol kg −1 yr −1 for STCW and 0.35 ± 0.14 to 0.65 ± 0.21 µmol kg −1 yr −1 for AASW, with the lower values in each water mass obtained by assigning all the AOU change to remineralisation. DIC increases in the Sub-Antarctic Mode Water (SAMW, 1.10 ± 0.14 µmol kg −1 yr −1 ) and Antarctic Intermediate Water (AAIW, 0.40 ± 0.15 µmol kg −1 yr −1 ) layers were similar to the calculated C ANT trends. For SAMW, the C ANT increase tracked rising atmospheric CO 2 . As a consequence of the general DIC increase, decreases in total pH (pH T ) and aragonite saturation ( Ar ) were found in most water masses, with the upper ocean and the SAMW layer presenting the largest trends for pH T decrease (∼ −0.0031 ± 0.0004 yr −1 ). DIC increases in deep and bottom layers (∼ 0.24 ± 0.04 µmol kg −1 yr −1 ) resulted from the advection of old deep waters to resupply increased upwelling, as corroborated by increasing silicate (∼ 0.21 ± 0.07 µmol kg −1 yr −1 ), which also reached the upper layers near the Antarctic Divergence (∼ 0.36 ± 0.06 µmol kg −1 yr −1 ) and was accompanied by an increase in salinity. The observed changes in DIC over the 16-year span caused a shoaling (∼ 340 m) of the aragonite saturation depth (ASD, Ar = 1) within Upper Circumpolar Deep Water that followed the upwelling path of this layer. From all our results, we conclude a scenario of increased transport of deep waters into the section and enhanced upwelling at high latitudes for the period between 1995 and 2011 linked to strong westerly winds. Although enhanced upwelling lowered the capacity of the AASW layer to uptake atmospheric CO 2 , it did not limit that of the newly forming SAMW and AAIW, which exhibited C ANT storage rates (∼ 0.41 ± 0.20 mol m −2 yr −1 ) twice that of the upper layers.

show abstract

Cycling of biogenic silica within the upper water column of the Ross Sea

Cited by 198 publications

References 25 publications

Evidence for reduced biogenic silica dissolution rates in diatom aggregates

Evidence for reduced biogenic silica dissolution rates in diatom aggregates

Diatom growth and productivity in an oligo-trophic midocean gyre: A 3-yr record from the Sargasso Sea near Bermuda

Carbon uptake and biogeochemical change in the Southern Ocean, south of Tasmania

Contact Info

Product

Resources

About