Particulate export and lateral advection in the Antarctic Polar Front (Southern Pacific Ocean): One-year mooring deployment

Tesi, Tommaso; Langone, Leonardo; Ravaioli, M.; Giglio, Federico; Capotondi, Lucilla

doi:10.1016/j.jmarsys.2012.06.002

Cited by 11 publications

(3 citation statements)

References 60 publications

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“…S1). Such a "dilution effect" of OC and N within the TMF, early reported for the site S1 (Matteucci et al,1997) and observed also in other areas (e.g., in NE-Mediterranean by Stavrakakis et al, 2000; in southern Adriatic by Langone et al, 2016; in Antarctica by Tesi et al, 2012), could be related to the increase of the mineral fraction. This could be the result of OC-and N-depleted resuspended sediments captured by the traps, as well as/or of an advective transport of riverine particulate matter (Pettine et al, 1998).…”

Section: Downward Fluxes and Composition Of Settling Mattersupporting

confidence: 63%

Fluxes of particulate matter, carbonates, organic carbon and nitrogen in the northern Adriatic continental shelf: A synthesis overview

et al. 2018

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Time series of composition and fluxes of settling particles in the marine environment, obtained by sediment traps, contribute to define the main processes driving the dynamics of particulate matter and of the time/space variability of benthic-pelagic exchanges. With this aim, the composition and seasonal and annual fluxes of settling matter, obtained from different projects and from published papers, at 8 sites of the Northern Adriatic shelf were estimated. The mean yearly particulate fluxes varied from 2763 to 14,447 g m-2 y-1, from 66 to 236 gC m-2y-1 for organic carbon (OC) flux, from 861 to 7525 g m-2y-1 for carbonates and from 12 to 42 gN m-2y-1 for nitrogen (N). The fluxes were characterized by high seasonal variations with marked increase in autumn or in winter with respect to spring or summer. The sink of particles occurs in relatively short episodes as about 50% of annual particle flux settles in less than 1-2 months in the western coastal area. This seasonality can be related to the riverine discharges, primary production and wind regimes of the basin. Utilizing the N/OC ratio as an index for discriminating the different origin of organic matter (i.e., resuspended/riverine and autochthonous), the primary marine carbon flux was estimated to range from 10 to 28% of the OC fluxes and accounted for 8-40% of the primary production, depending on the site. Then, due to the shallow waters of the basin and to the relevant riverine inputs, the total fluxes near the sea bottom were highly dependent on resuspension and advective transport processes. The important contribution of these last processes as source of organic matter is suggested also by the comparison between fluxes determined by sediment traps with mass accumulation rates (MAR) in sediments, derived from radionuclide measurements. Indeed, the fraction of OC fluxes which is not buried in the sediment is sufficient to support the benthic respiration processes. Utilizing the N/OC ratio as an index for discriminating the different origin of organic matter (i.e., resuspended/riverine and autochthonous), the primary marine carbon flux was estimated to range from 10 to 28% of the OC fluxes and accounted for 8-40% of the primary production, depending on the site. Then, due to the shallow waters of the basin and to the relevant riverine inputs, the total fluxes near the sea bottom were highly dependent on resuspension and advective transport processes. The important contribution of these last processes as source of organic matter is suggested also by the comparison between fluxes determined by sediment traps with mass accumulation rates (MAR) in sediments, derived from radionuclide measurements. Indeed, the fraction of OC fluxes which is not buried in the sediment is sufficient to support the benthic respiration processes.

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Section: Downward Fluxes and Composition Of Settling Mattersupporting

confidence: 63%

Fluxes of particulate matter, carbonates, organic carbon and nitrogen in the northern Adriatic continental shelf: A synthesis overview

et al. 2018

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“…One useful identifying parameter was the relative concentration of organic versus total flux. Using a similar approach, Tesi et al (2012) reported that resuspension events from flat-topped summits of the Pacific Antarctic Ridge in the Antarctic Polar Front of the Southern Ocean accounted for 60 to 90% of the material captured in sediment traps deployed below. The presence of benthic foraminifera and significant higher 210 Pb activity indicated the presence of material originating from the seafloor.…”

Section: Discussionmentioning

confidence: 99%

Scales of seafloor sediment resuspension in the northern Gulf of Mexico

Diercks

Dike

Asper

et al. 2018

Elementa: Science of the Anthropocene

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Diercks, A-R, et al. 2018 Scales of seafloor sediment resuspension in the northern Gulf of Mexico. Elem Sci Anth, 6: 32. DOI: https://doi. org/10.1525/elementa.285 IntroductionThe sedimentation of large amounts of oil via marine snow and its accumulation on the deep seafloor (>1,200 m) during and after the Deepwater Horizon (DwH) oil spill (Passow et al., 2012;Valentine et al., 2014;Brooks et al., 2015;Chanton et al., 2015;Daly et al., 2016;Joye, 2016;Joye et al., 2016;Passow, 2016) raised questions regarding the distribution and re-distribution processes of freshly sedimented material (marine snow) on the seafloor. Once on the seafloor, marine snow contributes to unconsolidated fluffy sediment layers (Gardner, 1978;Gardner et al., 1984;1985;Walsh et al., 1988;Pilskaln et al., 1998;Newell et al., 2005) that are subject to resuspension and the production of benthic nepheloid layers (BNLs).Resuspension leads to the re-invigoration of degradation processes, which would impact the degradation rates of the oil associated with marine snow following the DwH accident (Ziervogel et al., 2016). Additionally, resuspension leads to lateral transport and redistribution of the material that sank to the seafloor. After the DwH accident such re-distribution processes make it especially difficult to estimate the total amount of Macondo oil that reached the seafloor (Passow and Hetland, 2016).BNLs, which are formed when the frictional stress of water motion strips sediment off the seafloor, therewith carrying particles into the overlying water layer, exist near the seafloor, but may reach tens to hundreds of meters upward into the water column (McCave et al., 1976). The thickness of the BNL extending above the seafloor scales with the strength of the bottom currents and the particle composition. Bottom currents >10 cm s -1 may cause resuspension events (Gardner et al., 2017), especially when low density phytodetritus or fine silt covers sediments, but large benthic storms reach 20 cm s -1 (Gardner et al., 1985). Besides locally resuspended material, particles in the BNL also include aggregates settling from the upper ocean as Time-series data of size-specific in-situ settling speeds of marine snow in the benthic nepheloid layer (moored flux cameras), particle size distributions (profiling camera), currents (various current meters) and stacked time-series flux data (sediment traps) were combined to recognize resuspension events ranging from small-scale local, to small-scale far-field to hurricane-scale. One smallscale local resuspension event caused by inertial currents was identified based on local high current speeds (>10 cm s -1) and trap data. Low POC content combined with high lithogenic silica flux at 30 m above bottom (mab) compared to the flux at 120 mab, suggested local resuspension reaching 30 mab, but not 120 mab. Another similar event was detected by the changes in particle size distribution and settling speeds of particles in the benthic nepheloid layer. Flux data indicated two other small-scale events, which occurre...

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“…Freeze-dried samples were powdered and homogenized in an agate mortar. Acidified sediments (1.5 M HCl) were analysed using a Thermo Fisher Elemental Analyser (FLASH 2000 CHNS/O) coupled with a Thermo Finnigan Delta plus isotope ratio mass spectrometer (IRMS) for organic carbon (OC, wt.%), total nitrogen (TN, wt.%) and stable carbon isotopes ( 13 C, ‰) (D' Angelo et al, 2018;Tesi et al, 2012). Opal content (wt.%) was measured according to the leaching method developed by Mortlock and Froelich (1989).…”

Section: Bulk Analysesmentioning

confidence: 99%

Resolving sea ice dynamics in the north-western Ross Sea during the last 2.6 ka: From seasonal to millennial timescales

Tesi

Belt

Gariboldi

et al. 2020

Quaternary Science Reviews

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Particulate export and lateral advection in the Antarctic Polar Front (Southern Pacific Ocean): One-year mooring deployment

Cited by 11 publications

References 60 publications

Fluxes of particulate matter, carbonates, organic carbon and nitrogen in the northern Adriatic continental shelf: A synthesis overview

Fluxes of particulate matter, carbonates, organic carbon and nitrogen in the northern Adriatic continental shelf: A synthesis overview

Scales of seafloor sediment resuspension in the northern Gulf of Mexico

Resolving sea ice dynamics in the north-western Ross Sea during the last 2.6 ka: From seasonal to millennial timescales

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