scholarly journals Technical note: Sampling and processing of mesocosm sediment trap material for quantitative biogeochemical analysis

2016 ◽  
Vol 13 (9) ◽  
pp. 2849-2858 ◽  
Author(s):  
Tim Boxhammer ◽  
Lennart T. Bach ◽  
Jan Czerny ◽  
Ulf Riebesell
Keyword(s):  
Sediment Trap ◽  
Euphotic Zone ◽  
Sediment Traps ◽  
Particle Formation ◽  
Technical Note ◽  
Surface Ocean ◽  
Freeze Dried ◽  
Marine Realm ◽  
Silicon Tube ◽  
Sample Recovery

Abstract. Sediment traps are the most common tool to investigate vertical particle flux in the marine realm. However, the spatial and temporal decoupling between particle formation in the surface ocean and particle collection in sediment traps at depth often handicaps reconciliation of production and sedimentation even within the euphotic zone. Pelagic mesocosms are restricted to the surface ocean, but have the advantage of being closed systems and are therefore ideally suited to studying how processes in natural plankton communities influence particle formation and settling in the ocean's surface. We therefore developed a protocol for efficient sample recovery and processing of quantitatively collected pelagic mesocosm sediment trap samples for biogeochemical analysis. Sedimented material was recovered by pumping it under gentle vacuum through a silicon tube to the sea surface. The particulate matter of these samples was subsequently separated from bulk seawater by passive settling, centrifugation or flocculation with ferric chloride, and we discuss the advantages and efficiencies of each approach. After concentration, samples were freeze-dried and ground with an easy to adapt procedure using standard lab equipment. Grain size of the finely ground samples ranged from fine to coarse silt (2–63 µm), which guarantees homogeneity for representative subsampling, a widespread problem in sediment trap research. Subsamples of the ground material were perfectly suitable for a variety of biogeochemical measurements, and even at very low particle fluxes we were able to get a detailed insight into various parameters characterizing the sinking particles. The methods and recommendations described here are a key improvement for sediment trap applications in mesocosms, as they facilitate the processing of large amounts of samples and allow for high-quality biogeochemical flux data.

scholarly journals Technical Note: Sampling and processing of mesocosm sediment trap material for quantitative biogeochemical analysis

2015 ◽  
Vol 12 (22) ◽  
pp. 18693-18722 ◽  
Author(s):  
T. Boxhammer ◽  
L. T. Bach ◽  
J. Czerny ◽  
U. Riebesell
Keyword(s):  
Sediment Trap ◽  
Euphotic Zone ◽  
Sediment Traps ◽  
Particle Formation ◽  
Technical Note ◽  
Freeze Dried ◽  
Marine Realm ◽  
Silicon Tube ◽  
Sample Recovery ◽  
Closed Systems

Abstract. Sediment traps are the most common tool to investigate vertical particle flux in the marine realm. However, the spatial decoupling between particle formation and collection often handicaps reconciliation of these two processes even within the euphotic zone. Pelagic mesocosms have the advantage of being closed systems and are therefore ideally suited to study how processes in natural plankton communities influence particle formation and settling in the ocean's surface. We therefore developed a protocol for efficient sample recovery and processing of quantitatively collected pelagic mesocosm sediment trap samples. Sedimented material was recovered by pumping it under gentle vacuum through a silicon tube to the sea surface. The particulate matter of these samples was subsequently concentrated by passive settling, centrifugation or flocculation with ferric chloride and we discuss the advantages of each approach. After concentration, samples were freeze-dried and ground with an easy to adapt procedure using standard lab equipment. Grain size of the finely ground samples ranges from fine to coarse silt (2–63 μm), which guarantees homogeneity for representative subsampling, a widespread problem in sediment trap research. Subsamples of the ground material were perfectly suitable for a variety of biogeochemical measurements and even at very low particle fluxes we were able to get a detailed insight on various parameters characterizing the sinking particles. The methods and recommendations described here are a key improvement for sediment trap applications in mesocosms, as they facilitate processing of large amounts of samples and allow for high-quality biogeochemical flux data.

scholarly journals Biogenic sinking particle fluxes and sediment trap collection efficiency at Ocean Station Papa

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Margaret Estapa ◽  
Ken Buesseler ◽  
Colleen A. Durkin ◽  
Melissa Omand ◽  
Claudia R. Benitez-Nelson ◽  
...  
Keyword(s):  
Water Column ◽  
Sediment Trap ◽  
Collection Efficiency ◽  
Net Primary Production ◽  
Late Summer ◽  
Euphotic Zone ◽  
Sediment Traps ◽  
Tight Coupling ◽  
Large Particles ◽  
Ocean Station Papa

Comprehensive field observations characterizing the biological carbon pump (BCP) provide the foundation needed to constrain mechanistic models of downward particulate organic carbon (POC) flux in the ocean. Sediment traps were deployed three times during the EXport Processes in the Ocean from RemoTe Sensing campaign at Ocean Station Papa in August–September 2018. We propose a new method to correct sediment trap sample contamination by zooplankton “swimmers.” We consider the advantages of polyacrylamide gel collectors to constrain swimmer influence and estimate the magnitude of possible trap biases. Measured sediment trap fluxes of thorium-234 are compared to water column measurements to assess trap performance and estimate the possible magnitude of fluxes by vertically migrating zooplankton that bypassed traps. We found generally low fluxes of sinking POC (1.38 ± 0.77 mmol C m–2 d–1 at 100 m, n = 9) that included high and variable contributions by rare, large particles. Sinking particle sizes generally decreased between 100 and 335 m. Measured 234Th fluxes were smaller than water column 234Th fluxes by a factor of approximately 3. Much of this difference was consistent with trap undersampling of both small (<32 μm) and rare, large particles (>1 mm) and with zooplankton active migrant fluxes. The fraction of net primary production exported below the euphotic zone (0.1% light level; Ez-ratio = 0.10 ± 0.06; ratio uncertainties are propagated from measurements with n = 7–9) was consistent with prior, late summer studies at Station P, as was the fraction of material exported to 100 m below the base of the euphotic zone (T100, 0.55 ± 0.35). While both the Ez-ratio and T100 parameters varied weekly, their product, which we interpret as overall BCP efficiency, was remarkably stable (0.055 ± 0.010), suggesting a tight coupling between production and recycling at Station P.

scholarly journals Metabolite composition of sinking particles reflects a changing microbial community and differential metabolite degradation

2018 ◽  
Author(s):  
Winifred M. Johnson ◽  
Krista Longnecker ◽  
Melissa C. Kido Soule ◽  
William A. Arnold ◽  
Maya P. Bhatia ◽  
...  
Keyword(s):  
Microbial Community ◽  
Deep Sea ◽  
Euphotic Zone ◽  
Suspended Particles ◽  
Equatorial Atlantic ◽  
Surface Ocean ◽  
Sinking Particles ◽  
Compositional Changes ◽  
Amazon River Plume ◽  
Small Biomolecules

AbstractMarine sinking particles transport carbon from the surface and bury it in deep sea sediments where it can be sequestered on geologic time scales. The combination of the surface ocean food web that produces these particles and the particle-associated microbial community that degrades these particles, creates a complex set of variables that control organic matter cycling. We use targeted metabolomics to characterize a suite of small biomolecules, or metabolites, in sinking particles and compare their metabolite composition to that of the suspended particles in the euphotic zone from which they are likely derived. These samples were collected in the South Atlantic subtropical gyre, as well as in the equatorial Atlantic region and the Amazon River plume. The composition of targeted metabolites in the sinking particles was relatively similar throughout the transect, despite the distinct oceanic regions in which they were generated. Metabolites possibly derived from the degradation of nucleic acids and lipids, such as xanthine and glycine betaine, were an increased mole fraction of the targeted metabolites in the sinking particles relative to surface suspended particles, while algal-derived metabolites like the osmolyte dimethylsulfoniopropionate were a smaller fraction of the observed metabolites on the sinking particles. These compositional changes are shaped both by the removal of metabolites associated with detritus delivered from the surface ocean and by production of metabolites by the sinking particle-associated microbial communities. Further, they provide a basis for examining the types and quantities of metabolites that may be delivered to the deep sea by sinking particles.

Supplementary material to "Technical note: A time-integrated sediment trap to sample diatoms for hydrological tracing"

2020 ◽  
Author(s):  
Jasper Foets ◽  
Carlos E. Wetzel ◽  
Núria Martinez-Carreras ◽  
Adriaan J. Teuling ◽  
Jean-François Iffly ◽  
...  
Keyword(s):  
Sediment Trap ◽  
Technical Note ◽  
Supplementary Material

Numerical modelling of bed load sediment traps in sewer systems by density currents

1999 ◽  
Vol 39 (9) ◽  
pp. 153-160 ◽  
Author(s):  
F. Schmitt ◽  
V. Milisic ◽  
J.-L. Bertrand-Krajewski ◽  
D. Laplace ◽  
G. Chebbo
Keyword(s):  
Sediment Trap ◽  
Sediment Traps ◽  
Bed Load ◽  
Density Currents ◽  
Solid Concentration ◽  
Two Phase ◽  
Trap Design ◽  
Continuous Layer ◽  
Sewer Systems ◽  
Load Sediment

A model with density currents has been developed and tested to simulate bed load sediment traps. In this model, the bed load layer over the pipe invert is considered as a continuous layer characterised by a density and a viscosity which depends on the solid concentration. A set of equations has been established that describes the trapping of the bed load material as the dynamics of two non-miscible fluids over and in the bed load sediment trap. The Fluent package has been used and adapted to solve the equations of the model. The VOF method (Volume Of Fluid) has been chosen to solve the two phase approach according to a Euler-Euler scheme. Several series of simulations have been carried out in order to assess the influence of the slot position and trap design on efficiency. The results obtained agree with previous empirical findings, and allow confirmation (in a more reliable manner than before) that the best sediment trap design involves a centrally-placed slot with the two plates covering the trap reservoir placed at the same height as one another.

scholarly journals Inorganic Radiocarbon in Time-Series Sediment Trap Samples: Implication of Seasonal Variation of 14C in the Upper Ocean

Radiocarbon ◽  
1996 ◽  
Vol 38 (3) ◽  
pp. 583-595 ◽  
Author(s):  
Makio C. Honda
Keyword(s):  
Time Series ◽  
Bering Sea ◽  
Sediment Trap ◽  
Seasonal Variability ◽  
Sea Of Okhotsk ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Sediment Traps ◽  
Upper Ocean ◽  
The Bering Sea

In order to verify sediment trap samples as indicators of upper ocean 14C concentrations, particulate inorganic radiocarbon (PICΔ14C) collected by time-series sediment traps in the Sea of Okhotsk and the Bering Sea was measured by accelerator mass spectrometry (AMS). All of the PICΔ14C measurements were < 0‰, in contrast to GEOSECS 14C data in the upper ocean from the northwestern North Pacific. This difference is attributed to the upwelling of deepwater that contains low Δ14C of dissolved inorganic carbon (DICΔ14C) and to the decrease over time of surface DICΔ14C owing to the decrease of atmospheric Δ14C values. In addition, PICΔ14C values showed significant seasonal variability: PICΔ14C collected in the fall was the greatest (-22‰ on average), whereas PICΔ14C collected in winter showed an average minimum of −48‰. It is likely that this difference was caused by changes in mixed layer thickness. Although some uncertainties remain, further study on PICΔ14C will enable us to estimate seasonal variability in DICΔ14C and air-sea CO2 exchange rate.

scholarly journals Design optimization of permeable sediment traps for fluvial bed load transport

2018 ◽  
Vol 40 ◽  
pp. 03009 ◽  
Author(s):  
Anita Roth ◽  
Mona Jafarnejad ◽  
Sebastian Schwindt ◽  
Anton Schleiss
Keyword(s):  
Sediment Trap ◽  
Sediment Traps ◽  
Sediment Supply ◽  
Bed Load ◽  
Hydraulic Control ◽  
Check Dam ◽  
Sediment Retention ◽  
Existing Structures ◽  
Load Transport ◽  
Set Up

Sediment traps are crucial elements for flood protection in mountain rivers with high sediment transport capacity. Existing structures often interrupt the channel connectivity. Ideally, a sediment trap should be permeable for bed load during non-hazardous floods and ensure sediment retention during hazardous discharges. A new sediment trap concept, fulfilling these requirements was recently developed and tested in a laboratory flume. A guiding channel trough the deposition area is combined with a slot check dam having an upstream bar screen with bottom clearance. This study aims to validate the proposed concept with a finer sediment mixture on an experimental set-up. Furthermore, we provide improved recommendations for bar screen design regarding minimal bar spacing and the range of applicable clearance heights. Optimal bar spacing and clearance heights of the bar screen are determined through individual tests of the bar screen with steady discharges and varying sediment supply intensity. The best performing bar screen configuration is subsequently tested in combination with a slot check dam using a flood hydrograph to simulate the influence of quasi-unsteady discharge. The proposed concept corresponds to a combined mechanical-hydraulic control and works well for a large range of grain sizes, if the bar screen is correctly adapted.

scholarly journals A Time Series of Water Column Distributions and Sinking Particle Flux of Pseudo-Nitzschia and Domoic Acid in the Santa Barbara Basin, California

Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 480 ◽  
Author(s):  
Blaire Umhau ◽  
Claudia Benitez-Nelson ◽  
Clarissa Anderson ◽  
Kelly McCabe ◽  
Christopher Burrell
Keyword(s):  
Time Series ◽  
Water Column ◽  
Sediment Trap ◽  
Domoic Acid ◽  
Particle Flux ◽  
Sediment Traps ◽  
Benthic Organisms ◽  
Santa Barbara ◽  
Santa Barbara Basin ◽  
Potential Source

Water column bulk Pseudo-nitzschia abundance and the dissolved and particulate domoic acid (DA) concentrations were measured in the Santa Barbara Basin (SBB), California from 2009–2013 and compared to bulk Pseudo-nitzschia cell abundance and DA concentrations and fluxes in sediment traps moored at 147 m and 509 m. Pseudo-nitzschia abundance throughout the study period was spatially and temporally heterogeneous (<200 cells L−1 to 3.8 × 106 cells L−1, avg. 2 × 105 ± 5 × 105 cells L−1) and did not correspond with upwelling conditions or the total DA (tDA) concentration, which was also spatially and temporally diverse (<1.3 ng L−1 to 2.2 × 105 ng L−1, avg. 7.8 × 103 ± 2.2 × 104 ng L−1). We hypothesize that the toxicity is likely driven in part by specific Pseudo-nitzschia species as well as bloom stage. Dissolved (dDA) and particulate (pDA) DA were significantly and positively correlated (p < 0.01) and both comprised major components of the total DA pool (pDA = 57 ± 35%, and dDA = 42 ± 35%) with substantial water column concentrations (>1000 cells L−1 and tDA = 200 ng L−1) measured as deep as 150 m. Our results highlight that dDA should not be ignored when examining bloom toxicity. Although water column abundance and pDA concentrations were poorly correlated with sediment trap Pseudo-nitzschia abundance and fluxes, DA toxicity is likely associated with senescent blooms that rapidly sink to the seafloor, adding another potential source of DA to benthic organisms.

scholarly journals Compositional changes of present-day transatlantic Saharan dust deposition

2016 ◽  
Author(s):  
Laura F. Korte ◽  
Geert-Jan Brummer ◽  
Michèlle van der Does ◽  
Catarina V. Guerreiro ◽  
Rick Hennekam ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Sediment Trap ◽  
Deep Ocean ◽  
Sediment Traps ◽  
Saharan Dust ◽  
The West ◽  
Dust Transport ◽  
Mass Fluxes ◽  
The Caribbean ◽  
Particle Fluxes

Abstract. Massive amounts of Saharan dust are blown from the African coast across the Atlantic Ocean towards the Americas each year. This dust has, depending on its chemistry, direct and indirect effects on global climate including reflection and absorption of solar radiation as well as transport and deposition of nutrients and metals fertilizing both ocean and land. To determine the temporal and spatial variability of Saharan dust transport and deposition and their marine environmental effects across the equatorial North Atlantic Ocean, we have set up a monitoring experiment using deep-ocean sediment traps as well as land-based dust collectors. The sediment traps were deployed at five ocean sites along a transatlantic transect between northwest Africa and the Caribbean along 12⁰ N, in a down-wind extension of the land-based dust collectors placed at 19⁰ N on the Mauritanian coast in Iwik. In this paper, we lay out the setup of the monitoring experiment and present the particle fluxes from sediment trap sampling over 24 continuous and synchronised intervals from October 2012 through to November 2013. We establish the temporal distribution of the particle fluxes deposited in the Atlantic and compare chemical compositions with the land-based dust collectors propagating to the down-wind sediment trap sites, and with satellite observations of Saharan dust outbreaks. First-year results show that the total mass fluxes in the ocean are highest at the sampling sites in the east and west, closest to the African continent and the Caribbean, respectively. Element ratios reveal that the lithogenic particles deposited nearest to Africa are most similar in composition to the Saharan dust collected in Iwik. Down-wind increasing Al, Fe and K contents suggest a downwind change in the mineralogical composition of Saharan dust and indicate an increasing contribution of clay minerals towards the west. In the westernmost Atlantic, admixture of re-suspended clay-sized sediments advected towards the deep sediment trap cannot be excluded. Seasonality is most prominent near both continents but generally weak, with mass fluxes dominated by calcium carbonate and clear seasonal maxima of biogenic silica towards the west. The monitoring experiment is now extended with autonomous dust sampling buoys for better quantification Saharan dust transport and deposition from source to sink and its impact on fertilization and carbon export to the deep ocean.

Sediment trapping as a method for monitoring microplastic flux rates and deposition at aquatic environments

2020 ◽  
Author(s):  
Saija Saarni ◽  
Samuel Hartikainen ◽  
Emilia Uurasjärvi ◽  
Senja Meronen ◽  
Jari Hänninen ◽  
...  
Keyword(s):  
Bottom Sediment ◽  
Surface Area ◽  
Sediment Trap ◽  
Sediment Traps ◽  
Environmental Conservation ◽  
Aquatic Environments ◽  
Influx Rate ◽  
Wide Range ◽  
Control Evaluation ◽  
Sedimentation Processes

&lt;p&gt;Microplastics are reported from wide range of aquatic environments with concentrations up to thousands of particles per kilogram of sediment. Due to a lack of temporal control, evaluation of the influx rate of microplastic pollution is not enabled. However, understanding the annual flux rate of microplastics to the aquatic environments is a crucial aspect for environmental monitoring and for risk assessment. A sediment trap method is widely applied in aquatic sedimentary studies in order to measure sedimentation rates and understand sedimentation processes. We have tested near-bottom sediment trap method in lacustrine and estuary environments, at central and coastal Finland, for measuring and quantifying the microplastic influx rate during one year. Near-bottom sediment traps with two collector tubes and known surface area, fixed one meter from the bottom, collect all particles that are about to accumulate on the basin floor of the water body. Controlled temporal interval of trap maintenance enables calculation and determination of local microplastic influx rate i.e. number of accumulating particles per time per surface area. The test results are very promising. &amp;#160;Near-bottom sediment traps can be used for long term monitoring in order to gain a deeper understanding of the microplastic transport and sedimentation processes, confirm and compare the feasibility and efficiency of different environmental conservation methods, setting threshold values for microplastic influx, and supervising that the defined target conditions are met.&lt;/p&gt;

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