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  • 1
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    Presentation_1.pdf
    Frontiers Media SA ; 2022
    In:  Frontiers in Marine Science Vol. 9 ( 2022-6-9)
    Details
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 9 ( 2022-6-9)
    Abstract: The abyssal seafloor in the Clarion-Clipperton Zone (CCZ) in the NE Pacific hosts the largest abundance of polymetallic nodules in the deep sea and is being targeted as an area for potential deep-sea mining. During nodule mining, seafloor sediment will be brought into suspension by mining equipment, resulting in the formation of sediment plumes, which will affect benthic and pelagic life not naturally adapted to any major sediment transport and deposition events. To improve our understanding of sediment plume dispersion and to support the development of plume dispersion models in this specific deep-sea area, we conducted a small-scale, 12-hour disturbance experiment in the German exploration contract area in the CCZ using a chain dredge. Sediment plume dispersion and deposition was monitored using an array of optical and acoustic turbidity sensors and current meters placed on platforms on the seafloor, and by visual inspection of the seafloor before and after dredge deployment. We found that seafloor imagery could be used to qualitatively visualise the redeposited sediment up to a distance of 100 m from the source, and that sensors recording optical and acoustic backscatter are sensitive and adequate tools to monitor the horizontal and vertical dispersion of the generated sediment plume. Optical backscatter signals could be converted into absolute mass concentration of suspended sediment to provide quantitative data on sediment dispersion. Vertical profiles of acoustic backscatter recorded by current profilers provided qualitative insight into the vertical extent of the sediment plume. Our monitoring setup proved to be very useful for the monitoring of this small-scale experiment and can be seen as an exemplary strategy for monitoring studies of future, upscaled mining trials. We recommend that such larger trials include the use of AUVs for repeated seafloor imaging and water column plume mapping (optical and acoustical), as well as the use of in-situ particle size sensors and/or particle cameras to better constrain the effect of suspended particle aggregation on optical and acoustic backscatter signals.
    Type of Medium: Online Resource
    ISSN: 2296-7745
    URL: Article
    URL: Article
    DOI: 10.3389/fmars.2022.882155
    DOI: 10.3389/fmars.2022.882155.s001
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2757748-X
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  • 2
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    Physical and hydrodynamic properties of deep sea mining-generated, abyssal sediment plumes in the Clarion Clipperton Fracture Zone (eastern-central Pacific)
    University of California Press ; 2019
    In:  Elementa: Science of the Anthropocene Vol. 7 ( 2019-01-01)
    Details
    In: Elementa: Science of the Anthropocene, University of California Press, Vol. 7 ( 2019-01-01)
    Abstract: The anthropogenic impact of polymetallic nodule harvesting in the Clarion-Clipperton Fracture Zone is expected to strongly affect the benthic ecosystem. To predict the long-term, industrial-scale impact of nodule mining on the deep-sea environment and to improve the reliability of the sediment plume model, information about the specific characteristics of deep-sea particles is needed. Discharge simulations of mining-related fine-grained (median diameter ≈ 20 μm) sediment plumes at concentrations of 35–500 mg L–1 (dry weight) showed a propensity for rapid flocculation within 10 to 135 min, resulting in the formation of large aggregates up to 1100 μm in diameter. The results indicated that the discharge of elevated plume concentrations (500 mg L–1) under an increased shear rate (G ≥ 2.4 s–1) would result in improved efficiency of sediment flocculation. Furthermore, particle transport model results suggested that even under typical deep-sea flow conditions (G ≈ 0.1 s–1), rapid deposition of particles could be expected, which would restrict heavy sediment blanketing (several centimeters) to a smaller fall-out area near the source, unless subsequent flow events resuspended the sediments. Planning for in situ tests of these model projections is underway.
    Type of Medium: Online Resource
    ISSN: 2325-1026
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    URL: Article
    DOI: 10.1525/elementa.343
    DOI: 10.1525/elementa.343.f1
    DOI: 10.1525/elementa.343.f2
    DOI: 10.1525/elementa.343.f3
    DOI: 10.1525/elementa.343.f4
    DOI: 10.1525/elementa.343.f5
    DOI: 10.1525/elementa.343.f6
    DOI: 10.1525/elementa.343.t1
    DOI: 10.1525/elementa.343.s1
    DOI: 10.1525/elementa.343.s2
    DOI: 10.1525/elementa.343.s3
    Language: English
    Publisher: University of California Press
    Publication Date: 2019
    detail.hit.zdb_id: 2745461-7
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  • 3
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    Tidally Driven Dispersion of a Deep-Sea Sediment Plume Originating from Seafloor Disturbance in the DISCOL Area (SE-Pacific Ocean)
    MDPI AG ; 2021
    In:  Geosciences Vol. 12, No. 1 ( 2021-12-24), p. 8-
    Details
    In: Geosciences, MDPI AG, Vol. 12, No. 1 ( 2021-12-24), p. 8-
    Abstract: The purpose of the study was to measure in situ the background suspended particulate matter concentration (SPMC) in the DISCOL area (SE Pacific) and its increase due to mechanical mobilization of the seabed. The disturbance experiment imitated future manganese nodule exploitations and was designed to measure the sediment plume generated by such activities. In the direct vicinity of the disturbance, landers equipped with acoustic and optical sensors measured the current velocities and the SPMC. The SPMC at the disturbance was easily up to 10 mg/L and thus about 200 times higher than the background concentration. The downstream sediment plume, measured by the lander, had a SPMC of about 1 mg/L. After tide reversal, the sediment plume was recorded a second time. A sediment transport model reproduced the plume dispersion. After rapid settling of the coarser fraction, a plume of hardly settling fine particles remained in suspension (and no deposition–resuspension cycles). The transport was controlled by the tides and by the vertical velocity component that resulted from bathymetrical differences. The plume may continue to disperse up to 100+ days (up to hundreds of km) depending on the particle size and until background concentration is reached.
    Type of Medium: Online Resource
    ISSN: 2076-3263
    URL: Article
    DOI: 10.3390/geosciences12010008
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2655946-8
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  • 4
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    Evidence of eddy-related deep-ocean current variability in the northeast tropical Pacific Ocean induced by remote gap winds
    Copernicus GmbH ; 2020
    In:  Biogeosciences Vol. 17, No. 24 ( 2020-12-23), p. 6527-6544
    Details
    In: Biogeosciences, Copernicus GmbH, Vol. 17, No. 24 ( 2020-12-23), p. 6527-6544
    Abstract: Abstract. There has been a steady increase in interest in mining of deep-sea minerals in the Clarion–Clipperton Zone (CCZ) in the eastern Pacific Ocean during the last decade. This region is known to be one of the most eddy-rich regions in the world ocean. Typically, mesoscale eddies are generated by intense wind bursts channeled through gaps in the Sierra Madre mountains in Central America. Here, we use a combination of satellite and in situ observations to evaluate the relationship between deep-sea current variability in the region of potential future mining and eddy kinetic energy (EKE) in the vicinity of gap winds. A geometry-based eddy detection algorithm has been applied to altimetry sea surface height data for a period of 24 years, from 1993 to 2016, in order to analyze the main characteristic parameters and the spatiotemporal variability of mesoscale eddies in the northeast tropical Pacific Ocean (NETP). Significant differences between the characteristics of eddies with different polarity (cyclonic vs. anticyclonic) were found. For eddies with lifetimes longer than 1 d, cyclonic polarity is more common than anticyclonic rotation. However, anticyclonic eddies are larger in size, show stronger vorticity, and survive longer in the ocean than cyclonic eddies (often 90 d or more). Besides the polarity of eddies, the location of eddy formation should be taken into consideration when investigating the impacted deep-ocean region as we found eddies originating from the Tehuantepec (TT) gap winds lasting longer in the ocean and traveling farther distances in a different direction compared to eddies produced by the Papagayo (PP) gap winds. Long-lived anticyclonic eddies generated by the TT gap winds are observed to travel distances up to 4500 km offshore, i.e., as far as west of 110∘ W. EKE anomalies observed in the surface of the central ocean at distances of ca. 2500 km from the coast correlate with the seasonal variability of EKE in the region of the TT gap winds with a time lag of 5–6 months. A significant seasonal variability of deep-ocean current velocities at water depths of 4100 m was observed in multiple-year time series data, likely reflecting the energy transfer of the surface EKE generated by the gap winds to the deep ocean. Furthermore, the influence of mesoscale eddies on deep-ocean currents is examined by analyzing the deep-ocean current measurements when an anticyclonic eddy crosses the study region. Our findings suggest that despite the significant modulation of dominant current directions driven by the bottom-reaching eddy, the current magnitude intensification was not strong enough to trigger local sediment resuspension in this region. A better insight into the annual variability of ocean surface mesoscale activity in the CCZ and its effects on deep-ocean current variability can be of great help to mitigate the impact of future potential deep-sea mining activities on the benthic ecosystem. On an interannual scale, a significant relationship between cyclonic eddy characteristics and El Niño–Southern Oscillation (ENSO) was found, whereas a weaker correlation was detected for anticyclonic eddies.
    Type of Medium: Online Resource
    ISSN: 1726-4189
    URL: Article
    DOI: 10.5194/bg-17-6527-2020
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2020
    detail.hit.zdb_id: 2158181-2
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  • 5
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    The Wadden Sea in transition - consequences of sea level rise
    Springer Science and Business Media LLC ; 2018
    In:  Ocean Dynamics Vol. 68, No. 1 ( 2018-1), p. 131-151
    Details
    In: Ocean Dynamics, Springer Science and Business Media LLC, Vol. 68, No. 1 ( 2018-1), p. 131-151
    Type of Medium: Online Resource
    ISSN: 1616-7341 , 1616-7228
    URL: Article
    DOI: 10.1007/s10236-017-1117-5
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2018
    detail.hit.zdb_id: 2063267-8
    detail.hit.zdb_id: 201122-0
    SSG: 14
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  • 6
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    Wind‐induced variability of estuarine circulation in a tidally energetic inlet with curvature
    American Geophysical Union (AGU) ; 2016
    In:  Journal of Geophysical Research: Oceans Vol. 121, No. 5 ( 2016-05), p. 3261-3277
    Details
    In: Journal of Geophysical Research: Oceans, American Geophysical Union (AGU), Vol. 121, No. 5 ( 2016-05), p. 3261-3277
    Abstract: Estuarine circulation is strongly modified by channel curvature Estuarine circulation is strongly correlated with wind straining Buoyancy gradients determine dynamics only during calm weather conditions
    Type of Medium: Online Resource
    ISSN: 2169-9275 , 2169-9291
    URL: Issue
    URL: Article
    DOI: 10.1002/jgrc.v121.5
    DOI: 10.1002/2015JC010945
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 2016
    detail.hit.zdb_id: 2016804-4
    detail.hit.zdb_id: 161667-5
    detail.hit.zdb_id: 3094219-6
    SSG: 16,13
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  • 7
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    Impact of a long-lived anticyclonic mesoscale eddy on seawater anomalies in the northeastern tropical Pacific Ocean: a composite analysis from hydrographic measurements, sea level altimetry data, and reanalysis model products
    Copernicus GmbH ; 2022
    In:  Ocean Science Vol. 18, No. 4 ( 2022-08-08), p. 1163-1181
    Details
    In: Ocean Science, Copernicus GmbH, Vol. 18, No. 4 ( 2022-08-08), p. 1163-1181
    Abstract: Abstract. Using observational data, satellite altimeters, and reanalysis model products, we have investigated eddy-induced seawater anomalies and heat and salt transport in the northeastern tropical Pacific Ocean. An eddy detection algorithm (EDA) was used to identify eddy formation at the Mexican Tehuantepec Gulf (TT) in July 2018 during an unusually strong summer wind event. The eddy separated from the coast with a mean translation velocity of 11 cm s−1 and a mean radius of 115 km and traveled 2050–2400 km westwards off the Central American coast, where it was followed at approx 114∘ W and 11∘ N for oceanographic observation between April and May 2019. The in situ observations show that the major eddy impacts are restricted to the upper 300 m of the water column and are traceable down to 1500 m water depth. In the eddy core at 92 m water depth an extreme positive temperature anomaly of 8.2 ∘C, a negative salinity anomaly of −0.78 psu, a positive fluorescence anomaly of +0.8 mg m−3, and a positive dissolved oxygen concentration anomaly of 137 µmol kg−1 are observed. Compared with annual climatological averages in 2018, the water trapped within the eddy is estimated to transport an average positive westward zonal heat anomaly of 85×1012 W and an average westward negative salt anomaly of -2.1×106 kg s−1. The heat transport is the equivalent of 1 % of the total annual zonal eddy-induced heat transport at this latitude in the Pacific Ocean. Understanding the dynamics of long-lived mesoscale eddies that may reach the seafloor in this region of the Pacific Ocean is especially important in light of potential deep-sea mining activities that are being targeted on this area.
    Type of Medium: Online Resource
    ISSN: 1812-0792
    URL: Article
    URL: Article
    DOI: 10.5194/os-18-1163-2022
    DOI: 10.5194/os-18-1163-2022-supplement
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2022
    detail.hit.zdb_id: 2183769-7
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  • 8
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    Numerical Simulation of Deep-Sea Sediment Transport Induced by a Dredge Experiment in the Northeastern Pacific Ocean
    Frontiers Media SA ; 2021
    In:  Frontiers in Marine Science Vol. 8 ( 2021-8-31)
    Details
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 8 ( 2021-8-31)
    Abstract: Predictability of the dispersion of sediment plumes induced by potential deep-sea mining activities is still very limited due to operational limitations on in-situ observations required for a thorough validation and calibration of numerical models. Here we report on a plume dispersion experiment carried out in the German license area for the exploration of polymetallic nodules in the northeastern tropical Pacific Ocean in 4,200 m water depth. The dispersion of a sediment plume induced by a small-scale dredge experiment in April 2019 was investigated numerically by employing a sediment transport module coupled to a high-resolution hydrodynamic regional ocean model. Various aspects including sediment characteristics and ocean hydrodynamics were examined to obtain the best statistical agreement between sensor-based observations and model results. Results show that the model is capable of reproducing suspended sediment concentration and redeposition patterns observed during the dredge experiment. Due to a strong southward current during the dredging, the model predicts no sediment deposition and plume dispersion north of the dredging tracks. The sediment redeposition thickness reaches up to 9 mm directly next to the dredging tracks and 0.07 mm in about 320 m away from the dredging center. The model results suggest that seabed topography and variable sediment release heights above the seafloor cause significant changes especially for the low sedimentation pattern in the far-field area. Near-bottom mixing is expected to strongly influence vertical transport of suspended sediment.
    Type of Medium: Online Resource
    ISSN: 2296-7745
    URL: Article
    DOI: 10.3389/fmars.2021.719463
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2757748-X
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  • 9
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    Digging deep: lessons learned from meiofaunal responses to a disturbance experiment in the Clarion-Clipperton Zone
    Springer Science and Business Media LLC ; 2023
    In:  Marine Biodiversity Vol. 53, No. 4 ( 2023-08)
    Details
    In: Marine Biodiversity, Springer Science and Business Media LLC, Vol. 53, No. 4 ( 2023-08)
    Abstract: The deep-sea mining industry is currently at a point where large-sale, commercial polymetallic nodule exploitation is becoming a more realistic scenario. At the same time, certain aspects such as the spatiotemporal scale of impacts, sediment plume dispersion and the disturbance-related biological responses remain highly uncertain. In this paper, findings from a small-scale seabed disturbance experiment in the German contract area (Clarion-Clipperton Zone, CCZ) are described, with a focus on the soft-sediment ecosystem component. Despite the limited spatial scale of the induced disturbance on the seafloor, this experiment allowed us to evaluate how short-term ( 〈  1 month) soft-sediment changes can be assessed based on sediment characteristics (grain size, nutrients and pigments) and metazoan meiofaunal communities (morphological and metabarcoding analyses). Furthermore, we show how benthic measurements can be combined with numerical modelling of sediment transport to enhance our understanding of meiofaunal responses to increased sedimentation levels. The lessons learned within this study highlight the major issues of current deep-sea mining-related ecological research such as deficient baseline knowledge, unrepresentative impact intensity of mining simulations and challenges associated with sampling trade-offs (e.g., replication).
    Type of Medium: Online Resource
    ISSN: 1867-1616 , 1867-1624
    URL: Article
    DOI: 10.1007/s12526-023-01353-0
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2478073-X
    detail.hit.zdb_id: 2493558-X
    SSG: 12
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  • 10
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    Numerical analysis of stratification and destratification processes in a tidally energetic inlet with an ebb tidal delta
    American Geophysical Union (AGU) ; 2015
    In:  Journal of Geophysical Research: Oceans Vol. 120, No. 1 ( 2015-01), p. 225-243
    Details
    In: Journal of Geophysical Research: Oceans, American Geophysical Union (AGU), Vol. 120, No. 1 ( 2015-01), p. 225-243
    Abstract: Within a tidal inlet, dynamics at two nearby stations is different A baroclinic numerical 3‐D model is able to reproduce these differences Weak lateral stratification is enhanced due to narrowing of the channel
    Type of Medium: Online Resource
    ISSN: 2169-9275 , 2169-9291
    URL: Issue
    URL: Article
    DOI: 10.1002/jgrc.v120.1
    DOI: 10.1002/2014JC010325
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 2015
    detail.hit.zdb_id: 2016804-4
    detail.hit.zdb_id: 161667-5
    detail.hit.zdb_id: 3094219-6
    SSG: 16,13
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