Sediment redistribution during simulated benthic disturbance and its implications on deep seabed mining

Sharma, Rahul; Nath, B. Nagender; Parthiban, G.; Sankar, Syam

doi:10.1016/s0967-0645(01)00046-7

Cited by 73 publications

(52 citation statements)

References 17 publications

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“…The environmental impact studies that have been conducted on nodule ecosystems in the CCZ, the Indian Ocean and the Peru basin (e.g., Amos et al, 1977;Ozturgut et al, 1980;Tilot, 1989;Foell et al, 1990;Thiel et al, 1991Thiel et al, , 2001Bluhm et al, 1995;Fukushima, 1995;Tkatchenko et al, 1996;Radziejewska, 1997;Schriever et al, 1997;Trueblood et al, 1997;Shirayama, 1999;Fukushima et al, 2000;Chung et al, 2001;Oebius et al, 2001;Sharma et al, 2001) mostly focused on alterations to the sediment-nodule interface and impacts to epibenthic faunal communities over very localized areas, compared to the size and the number of areas to be mined. Several reviews (e.g., Smith, 1999;Sharma, 2015;Jones et al, 2017) concluded that there is a lack of information on the potential impact of sediment burial at the scale of the CCZ and that there would be considerable long-term negative effects on the ecosystem.…”

Section: Sedimentation Rates and Mixing Sediment Plumesmentioning

confidence: 99%

The Benthic Megafaunal Assemblages of the CCZ (Eastern Pacific) and an Approach to their Management in the Face of Threatened Anthropogenic Impacts

et al. 2018

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We present here the results of a UNESCO/IOC baseline study of the megafaunal assemblages of the polymetallic nodule ecosystem of 5 areas within the Clarion Clipperton Zone (CCZ) of the eastern Pacific Ocean. The work was undertaken with a view to investigating the structure of the epifaunal populations associated with the benthic biotopes being targeted for nodule mining and developing an appropriate set of management tools and options. The general characteristics of nodule ecosystem and assemblages and their sensitivity to deep-sea mining are discussed in relation to water masses, surface to seabed water circulation, the nepheloid layer and processes taking place at the sediment interface. Management tools considered include species diversity and vulnerability indexes, GIS systems, zoning, and 3D rapid environmental assessment (REA). These strategies are proposed for trial during pilot mining operations within the CCZ.

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Section: Sedimentation Rates and Mixing Sediment Plumesmentioning

confidence: 99%

The Benthic Megafaunal Assemblages of the CCZ (Eastern Pacific) and an Approach to their Management in the Face of Threatened Anthropogenic Impacts

et al. 2018

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“…At the present time, the "impacts and effects of mining surrounding the directly mined area are poorly understood" (MIDAS 2016a). Although it is known that fine particles whirled up by SMTs and released from the MSV can be transported over large distances of several hundreds of kilometers, forming a thin sediment layer on the seafloor which may overlap and suppress the benthic ecosystem (SPC 2013;Sharma et al 2001), it is not yet possible to define absolute threshold values or to predict the severity of the impact (MIDAS 2016a). Sound criteria need yet to be defined.…”

Section: Environmental Considerationsmentioning

confidence: 99%

A comprehensive approach for a techno-economic assessment of nodule mining in the deep sea

2018

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Mine planning of land-based mineral deposits follows well-established methods. The deep sea is currently under exploration, but mine planning approaches are still lacking. A spatial planning tool to assess the techno-economic requirements and implications of manganese nodule mining on deep-sea deposits is proposed in this paper. The comprehensive approach has been validated using research findings of the Blue Mining project, which received funding from the European Commission. A part of the German exploration area E1, located in the Clarion-Clipperton Fracture Zone, Pacific Ocean, serves as a case study area. The approach contributes to a responsible utilization of mineral resources in the deep sea, considering geological, economic and financial as well as technical and operational aspects. The approach may also be applicable for an early-stage assessment of other projects related to spatially distributed mineral resources, e.g., marine phosphate nodules. Furthermore, it could also be helpful for the investigation of the environmental impacts of seafloor manganese nodule mining.

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“…The suspended sediment plume can clog filter organs of suspension feeders and the re-depositioning of suspended sediment will bury sessile organisms. These physical impacts could further be accompanied by bio-geochemical disequilibria in the water column and the sediment surface that 30 will impact the local environment on short and long time scales Shirayama and Fukushima (1997); Kotlinski et al (1998); Sharma et al (2001); Thiel and Tiefsee-Umweltschutz (2001). The release of toxic substances or metals might also be of importance.…”

Section: Nodule Abundance Estimation In Relation To Benthic Structuresmentioning

confidence: 99%

Understanding Mn-nodule distribution and related deep-sea mining impacts using AUV-based hydroacoustic sensing and optical observations

Peukert

Schoening

Alevizos

et al. 2017

Preprint

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Abstract. In this study ship-and AUV-based multibeam data from the German Mn-nodule license area in the ClarionClipperton Zone (CCZ; eastern Pacific) are linked to ground truth data from optical imaging. Photographs obtained by an AUV enable semi-quantitative assessments of nodule coverage at a spatial resolution in the range of meters. Together with high resolution AUV bathymetry this revealed a correlation of small-scale terrain variations (<5m horizontally, <1m vertically) with nodule abundance. In the presented data set, increased nodule coverage could be correlated with slopes >1.8• and concave 5 terrain. On a more regional scale, factors such as the geological setting (existence of horst and graben structures, sediment thickness, outcropping basement) and influence of bottom currents seem to play an essential role for the spatial variation of nodule abundance and the related hard substrate habitat. AUV imagery was also successfully employed to map the distribution of re-settled sediment following a disturbance and sediment cloud generation during a sampling deployment of an Epibenthic Sledge. Data from before and after the 'disturbance' allows a direct assessment of the impact. Automated image processing 10 analyzed the nodule coverage at the seafloor, revealing nodule blanketing by resettling of suspended sediment within 16 hours after the disturbance. The visually detectable impact was spatially limited to a maximum of 100m distance from the disturbance track, downstream of the bottom water current. A correlation with high resolution AUV bathymetry reveals that the blanketing pattern varies in extent by tens of meters, strictly following the bathymetry, even in areas of only slightly undulating seafloor (<1m vertical change). These results highlight the importance of detailed terrain knowledge when engaging in resource assess-15 ment studies for nodule abundance estimates and defining minable areas. At the same time, it shows the importance of high resolution mapping for detailed benthic habitat studies that show a heterogeneity at scales of 10m to 100m. Terrain knowledge is also needed to determine the scale of the impact by seafloor sediment blanketing during mining-operations.

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Sediment redistribution during simulated benthic disturbance and its implications on deep seabed mining

Cited by 73 publications

References 17 publications

The Benthic Megafaunal Assemblages of the CCZ (Eastern Pacific) and an Approach to their Management in the Face of Threatened Anthropogenic Impacts

The Benthic Megafaunal Assemblages of the CCZ (Eastern Pacific) and an Approach to their Management in the Face of Threatened Anthropogenic Impacts

A comprehensive approach for a techno-economic assessment of nodule mining in the deep sea

Understanding Mn-nodule distribution and related deep-sea mining impacts using AUV-based hydroacoustic sensing and optical observations

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