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Ken O Buesseler - One of the best experts on this subject based on the ideXlab platform.
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Carbon Flux from Bio-optical Profiling Floats: Calibrating Transmissometers for Use as Optical Sediment Traps
Deep Sea Research Part I: Oceanographic Research Papers, 2017Co-Authors: Meg Estapa, Ken O Buesseler, Colleen A. Durkin, Rod Johnson, Melanie FeenAbstract:Abstract Our mechanistic understanding of the processes controlling the ocean's biological pump is limited, in part, by our lack of observational data at appropriate timescales. The “optical Sediment trap” (OST) technique utilizes a transmissometer on a quasi-Lagrangian platform to collect Sedimenting particles. This method could help fill the observational gap by providing autonomous measurements of particulate carbon (PC) flux in the upper mesopelagic ocean at high spatiotemporal resolution. Here, we used a combination of field measurements and laboratory experiments to test hydrodynamic and zooplankton-swimmer effects on the OST method, and we quantitatively calibrated this method against PC flux measured directly in same-platform, neutrally buoyant Sediment Traps (NBSTs) during 5 monthly cruises at the Bermuda Atlantic Time-series Study (BATS) site. We found a well-correlated, positive relationship (R2=0.66, n=15) between the OST proxy, and the PC flux measured directly using NBSTs. Laboratory tests showed that scattering of light from multiple particles between the source and detector was unlikely to affect OST proxy results. We found that the carbon-specific attenuance of sinking particles was larger than literature values for smaller, suspended particles in the ocean, and consistent with variable carbon: size relationships reported in the literature for sinking particles. We also found evidence for variability in PC flux at high spatiotemporal resolution. Our results are consistent with the literature on particle carbon content and optical properties in the ocean, and support more widespread use of the OST proxy, with proper site-specific and platform-specific calibration, to better understand variability in the ocean biological pump.
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a bottom up view of the biological pump modeling source funnels above ocean Sediment Traps
Deep Sea Research Part I: Oceanographic Research Papers, 2008Co-Authors: David A. Siegel, E Fields, Ken O BuesselerAbstract:Abstract The sinking of particles that make up the biological pump is not vertical but nearly horizontal. This means that the locations where the particles are formed may be distant from their collection in a Sediment trap. This has led to the development of the concept of the statistical funnel to describe the spatial–temporal sampling characteristics of a Sediment trap. Statistical funnels can be used to quantify the source region in the upper ocean where collected particles were created (source funnels) or the location of the collected particles during that deployment (collection funnels). Here, we characterize statistical funnels for neutrally buoyant, surface-tethered and deep-ocean moored trap deployments conducted just north of Hawaii in the Pacific Ocean. Three-dimensional realizations of the synoptic velocity field, created using satellite altimeter and shipboard acoustic Doppler current profiler data, are used to advect sinking particles back to their source for sinking velocities of 50–200 m per day. Estimated source- and collection-funnel characteristics for the 5-day collections made by neutrally buoyant and surface-tethered Traps are similar with typical scales of several km to several 10s of km. Deep-moored Traps have daily source-funnel locations that can be many 100s of km distant from the trap and have long-term containment radii that range from 140 to 340 km depending upon sinking rate. We assess the importance of particle source regions using satellite estimates of chlorophyll concentration as a surrogate for the spatial distribution of particle export. Our analysis points to the need to diagnose water-parcel trajectories and particle sinking rates in the interpretation of sinking-particle fluxes from moored or freely drifting Sediment Traps, especially for regions where there are significant horizontal gradients in the export flux. But whence come the little siliceous and calcareous shells…[brought up] from the depth of over miles? Did they live in the surface waters immediately above? Or is their habitat in some remote part of the sea, whence, at their death, the currents were set forth as pallbearers, with the command to deposit the dead corpses where the plummet found them? (Maury, 1858).
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an assessment of the use of Sediment Traps for estimating upper ocean particle fluxes
Journal of Marine Research, 2007Co-Authors: Ken O Buesseler, Anthony F. Michaels, Wilford D Gardner, Avan N Antia, Orjan Gustafsson, Min Chen, Scott W Fowler, Koh Harada, Michiel Rutgers M Van Der Loeff, M M SarinAbstract:This review provides an assessment of Sediment trap accuracy issues by gathering data to address trap hydrodynamics, the problem of zooplankton “swimmers,” and the solubilization of material after collection. For each topic, the problem is identified, its magnitude and causes reviewed using selected examples, and an update on methods to correct for the potential bias or minimize the problem using new technologies is presented. To minimize hydrodynamic biases due to flow over the trap mouth, the use of neutrally buoyant Sediment Traps is encouraged. The influence of swimmers is best minimized using Traps that limit zooplankton access to the sample collection chamber. New data on the impact of different swimmer removal protocols at the US time-series sites HOT and BATS are compared and shown to be important. Recent data on solubilization are compiled and assessed suggesting selective losses from sinking particles to the trap supernatant after collection, which may alter both fluxes and ratios of elements in long term and typically deeper trap deployments. Different methods are needed to assess shallow and short- term trap solubilization effects, but thus far new incubation experiments suggest these impacts to be small for most elements. A discussion of trap calibration methods reviews independent assessments of flux, including elemental budgets, particle abundance and flux modeling, and emphasizes the utility of U-Th radionuclide calibration methods.
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a comparison of major and minor elemental fluxes collected in neutrally buoyant and surface tethered Sediment Traps
Deep Sea Research Part I: Oceanographic Research Papers, 2004Co-Authors: Rachel H R Stanley, Steven J. Manganini, Ken O Buesseler, Deborah K Steinberg, James R ValdesAbstract:We compare material collected in Neutrally Buoyant Sediment Traps (NBSTs) to material collected in standard Particle Interceptor Traps (PITs) deployed during June and September 2001 at the Bermuda Atlantic Time-series Study site in order to compare Sediment Traps with various hydrodynamic properties. Current meters located on the PITs array indicated that both experiments were conducted during conditions of relatively low horizontal flow, which are optimal conditions for the unbiased collection of sinking particles by PITs. The NBSTs and PITs both recorded a range of overall flux conditions, as supported by the fluxes of mass, particulate organic carbon, and other elements (S, Mg, Sr, Fe, Mn, Ni, Ti, P, V), which do not significantly differ between the two types of Traps. However, the fluxes of Si, Ca, Al, and Ba collected by the PITs are significantly larger than the NBST fluxes of those same elements. Additionally, the fluxes of particulate organic nitrogen (PON) collected by the PITs are significantly smaller than the NBST PON fluxes. How these results compare under conditions of higher flow or differing particle characteristics cannot be assessed from this study.
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do upper ocean Sediment Traps provide an accurate record of particle flux
Nature, 1991Co-Authors: Ken O BuesselerAbstract:Sediment Traps are widely used to measure the vertical flux of particulate matter in the oceans. In the upper ocean, Sediment Traps have been used to determine the extent to which CO2 Axed by primary producers is exported as particulate organic carbon1–3. In addition, the observed decrease of particle flux with depth has been used to predict regeneration rates of organic matter and associated elements3. Over seasonal or annual timescales, the import of limiting nutrients into the upper ocean (new production) should be balanced by particle export4,5. Given the importance of accurately determining the sinking particle flux, it has been suggested that 234Th might be used to 'calibrate' shallow-trap fluxes6. Here I present a re-evaluation of existing 234Th data which indicates that trap-derived and model-derived 234Th particle fluxes can differ by a factor of ±3–10, suggesting that shallow Traps may not provide an accurate measure of particle fluxes.
Michel Michaelovitch De Mahiques - One of the best experts on this subject based on the ideXlab platform.
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Deep pockmarks as natural Sediment Traps: a case study from southern Santos Basin (SW Atlantic upper slope)
Geo-Marine Letters, 2019Co-Authors: Raíssa Basti Ramos, Rosangela Felicio Dos Santos, Uri Schattner, Rubens Cesar Lopes Figueira, Marcia Caruso Bícego, Francisco José Lobo, Michel Michaelovitch De MahiquesAbstract:This study examines the role of deep pockmarks in acting as natural Sediment Traps. Multibeam bathymetry, single-channel seismic and Sediment samples data were used for describing the morphology of pockmarks as well as the nature of Sediments inside and outside these depressed features, in an area of Santos Basin (SW Atlantic upper slope), dominated by the strong flow of Brazil Current. Results show that the grain size and chemical composition of Sediments inside pockmarks are distinct from the outside. Also, radiocarbon dating shows that Holocene ages are found only in samples located inside the pockmarks. Combination of Sedimentological, geochemical and geochronological data allowed to recognise that deep pockmarks might present distinct Sediment deposition processes when compared with those of shallow pockmarks, in which turbulence impedes Sediment deposition, as reported in the literature.
Orjan Gustafsson - One of the best experts on this subject based on the ideXlab platform.
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an assessment of upper ocean carbon and nitrogen export fluxes on the boreal continental shelf a 3 year study in the open baltic sea comparing Sediment Traps 234th proxy nutrient and oxygen budgets
Limnology and Oceanography-methods, 2013Co-Authors: Orjan Gustafsson, Johan Gelting, Per Andersson, Ulf Larsson, Per RoosAbstract:An assessment of upper ocean carbon and nitrogen export fluxes on the boreal continental shelf: A 3-year study in the open Baltic Sea comparing Sediment Traps, 234Th proxy, nutrient, and oxygen budgets
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an assessment of the use of Sediment Traps for estimating upper ocean particle fluxes
Journal of Marine Research, 2007Co-Authors: Ken O Buesseler, Anthony F. Michaels, Wilford D Gardner, Avan N Antia, Orjan Gustafsson, Min Chen, Scott W Fowler, Koh Harada, Michiel Rutgers M Van Der Loeff, M M SarinAbstract:This review provides an assessment of Sediment trap accuracy issues by gathering data to address trap hydrodynamics, the problem of zooplankton “swimmers,” and the solubilization of material after collection. For each topic, the problem is identified, its magnitude and causes reviewed using selected examples, and an update on methods to correct for the potential bias or minimize the problem using new technologies is presented. To minimize hydrodynamic biases due to flow over the trap mouth, the use of neutrally buoyant Sediment Traps is encouraged. The influence of swimmers is best minimized using Traps that limit zooplankton access to the sample collection chamber. New data on the impact of different swimmer removal protocols at the US time-series sites HOT and BATS are compared and shown to be important. Recent data on solubilization are compiled and assessed suggesting selective losses from sinking particles to the trap supernatant after collection, which may alter both fluxes and ratios of elements in long term and typically deeper trap deployments. Different methods are needed to assess shallow and short- term trap solubilization effects, but thus far new incubation experiments suggest these impacts to be small for most elements. A discussion of trap calibration methods reviews independent assessments of flux, including elemental budgets, particle abundance and flux modeling, and emphasizes the utility of U-Th radionuclide calibration methods.
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evaluation of the collection efficiency of upper ocean sub photic layer Sediment Traps a 24 month in situ calibration in the open baltic sea using 234th
Limnology and Oceanography-methods, 2004Co-Authors: Orjan Gustafsson, Per Andersson, Ulf Larsson, Per Roos, Zofia Kukulska, Dag Broman, Susanna Hajdu, Johan IngriAbstract:The collection efficiency of cylindrical Sediment Traps of common design was assessed in situ for more than 2 y in an offshore shelf regime using the 234 Th proxy and simultaneously collected hydrological and biogeochemical parameters. The Traps were found to systematically record an undertrapping bias of 234 Th by, on average, a factor of three (range 0.8 to 10). Seasonal variations in trapping efficiency were related to the seasonally varying ballasting properties of the settling particle pool. Sediment trap 234 Th fluxes agreed within a factor of two of the estimated 234 Th export from the overlying surface waters in the winter-spring periods in both 1999 and 2000 and appeared related to a particle pool that included, presumably rapidly sinking, mineral particles and diatom tests acting as ballast. In contrast, discrimination against slowly settling organic-rich aggregates of apparent exudate origin resulted in undertrapping of 234 Th by factors of three to ten throughout the summerfall seasons. These data are consistent with hydrodynamic predictions that the collection efficiency of sinking particles is inversely related to their intrinsic settling velocities. Recognition of changing particle composition along a settling velocity spectrum combine with carbon mass balance restrictions to suggest that these 234 Th
Josep Maria Gili - One of the best experts on this subject based on the ideXlab platform.
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canyon effect and seasonal variability of deep sea organisms in the nw mediterranean synchronous year long captures of swimmers from near bottom Sediment Traps in a submarine canyon and its adjacent open slope
Deep Sea Research Part I: Oceanographic Research Papers, 2017Co-Authors: Maria Del Mar Flexas, Sara Roman, Nixon Bahamon, Josep Maria Gili, Anna Sanchezvidal, Chiara Romano, Marta Segura, Daniel MartinAbstract:Numerous organisms, including both passive sinkers and active migrators, are captured in Sediment Traps together with Sediments. By capturing these “swimmers”, the Traps become an extraordinarily tool to obtain relevant information on the biodiversity and dynamics of deep-sea organisms. Here we analyze near-bottom swimmers larger than 500 μm and their fluxes collected from eight near-bottom Sediment Traps installed on instrumented moorings deployed nearby Blanes Canyon (BC). Our data, obtained from November 2008 to October 2009 with a sampling rate of 15 days, constitutes the first year-long, continuous time series of the whole swimmers’ community collected at different Traps and bottom depths (from 300 m to 1800 m) inside a submarine canyon and on its adjacent open slope (OS). The Traps captured 2155 specimens belonging to 70 taxa, with Crustacea (mainly Copepoda) and Annelida Polychaeta accounting for more than 90% of the total abundance. Almost half of the identified taxa (33) were only present in BC Traps, where mean annual swimmer fluxes per trap were almost one order of magnitude higher than in the OS ones. Temporal variability in swimmer fluxes was more evident in BC than in OS. Fluxes dropped in winter (in coincidence with the stormy period in the region) and remained low until the following spring. In spring, there was a switch in taxa composition, including an increase of planktonic organisms. Additionally, we report drastic effects of extreme events, such as major storms, on deep-sea fauna. The impact of such extreme events along submarine canyon systems calls to rethink the influence of climate-driven phenomena on deep-sea ecosystems and, consequently, on their living resources.
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polychaete species captured in Sediment Traps moored in northwestern mediterranean submarine canyons
Zoological Journal of the Linnean Society, 2009Co-Authors: Rafael Sarda, Joao Gil, Sergi Taboada, Josep Maria GiliAbstract:Sediment Traps were placed in the water column both inside and in the vicinity of three northwestern Mediterranean submarine canyons. The Sediment Traps with 12 rotary collectors were deployed on mooring lines 30 and 500 m above the sea floor, and were sampled fortnightly. Polychaete worms (Anelida) and hydromedusae (Cnidaria) were the most abundant zoological taxa captured. Whereas hydromedusae and three of the polychaete species were clearly planktonic organisms, 16 polychaete species were adult benthic forms without special adaptations for swimming, and sometimes also had a large biomass. Four of the 19 polychaete species are described as new species: Aricidea (Allia) longisetosa sp. nov., Paradoneis hirsuta sp. nov., Ophelina margaleffi sp. nov., and Exogone (Parexogone) canyonincolae sp. nov. The rich collection of polychaetes obtained leads us to postulate that these animals are supported by a continuous flux of organic matter, and that they are adapted to the rigorous physical conditions that may occur between the seafloor and the bottom water. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155, 1–21.
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high occurrence of the elasipodid holothurian penilpidia ludwigi von marenzeller 1893 in bathyal Sediment Traps moored in a western mediterranean submarine canyon
Deep Sea Research Part I: Oceanographic Research Papers, 2007Co-Authors: Francesc Pages, Jacobo Martin, Albert Palanques, Pere Puig, Josep Maria GiliAbstract:Abstract One hundred and fifty specimens of the elasipod holothurian Penilpidia ludwigi (von Marenzeller, 1893) were collected in Sediment Traps moored near the seabed in the La Fonera Canyon (Catalan Sea, north-western Mediterranean) and on the adjacent continental slope. These provide the third record of this apparently endemic Mediterranean species and the first record from the western Mediterranean. This was the only holothurian species trapped and the most abundant macroscopic organism found in the Traps between 1200 and 1700 m depth over the whole sampling period (March–November 2001). It was particularly abundant in spring during the main flux of organic particles in the canyon. This coupling suggests that Penilpidia may aggregate at the seafloor during these events, making food availability a plausible explanation of the seasonal occurrence. Lateral transport of material re-suspended locally or up-canyon by near bottom currents appear to be the mechanism behind this uncommon occurrence, although in situ observations have recently been made on the swimming capability of this holothurian. The occurrence of benthic organisms in Sediment Traps set close to the seabed can provide information on bathyal benthic and benthopelagic populations.
Raíssa Basti Ramos - One of the best experts on this subject based on the ideXlab platform.
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Deep pockmarks as natural Sediment Traps: a case study from southern Santos Basin (SW Atlantic upper slope)
Geo-Marine Letters, 2019Co-Authors: Raíssa Basti Ramos, Rosangela Felicio Dos Santos, Uri Schattner, Rubens Cesar Lopes Figueira, Marcia Caruso Bícego, Francisco José Lobo, Michel Michaelovitch De MahiquesAbstract:This study examines the role of deep pockmarks in acting as natural Sediment Traps. Multibeam bathymetry, single-channel seismic and Sediment samples data were used for describing the morphology of pockmarks as well as the nature of Sediments inside and outside these depressed features, in an area of Santos Basin (SW Atlantic upper slope), dominated by the strong flow of Brazil Current. Results show that the grain size and chemical composition of Sediments inside pockmarks are distinct from the outside. Also, radiocarbon dating shows that Holocene ages are found only in samples located inside the pockmarks. Combination of Sedimentological, geochemical and geochronological data allowed to recognise that deep pockmarks might present distinct Sediment deposition processes when compared with those of shallow pockmarks, in which turbulence impedes Sediment deposition, as reported in the literature.