scholarly journals Impact of small-scale disturbances on geochemical conditions, biogeochemical processes and element fluxes in surface sediments of the eastern Clarion-Clipperton Zone, Pacific Ocean

2019 ◽  
Author(s):  
Jessica B. Volz ◽  
Laura Haffert ◽  
Matthias Haeckel ◽  
Andrea Koschinsky ◽  
Sabine Kasten
Keyword(s):  
Environmental Impact ◽  
Deep Sea ◽  
Surface Sediments ◽  
Small Scale ◽  
Mining Activities ◽  
Biogeochemical Processes ◽  
Mining Equipment ◽  
Transport Reaction ◽  
Element Fluxes ◽  
Polymetallic Nodules

Abstract. The thriving interest in harvesting deep-sea mineral resources, such as polymetallic nodules, calls for environmental impact studies, and ultimately, for regulations for environmental protection. Industrial-scale deep-sea mining of polymetallic nodules most likely has severe consequences for the natural environment. However, the effects of mining activities on deep-sea ecosystems, sediment geochemistry and element fluxes are still poorly conceived. Predicting the environmental impact is challenging due to the scarcity of environmental baseline studies as well as the lack of mining trials with industrial mining equipment in the deep sea. Thus, currently we have to rely on small-scale disturbances simulating deep-sea mining activities as a first-order approximation to study the expected impacts on the abyssal environment. Here, we investigate surface sediments in disturbance tracks of seven small-scale benthic impact experiments, which have been performed in four European contract areas for the exploration of polymetallic nodules in the Clarion-Clipperton Zone (CCZ). These small-scale disturbance experiments were performed 1 day to 37 years prior to our sampling program in the German, Polish, Belgian and French contract areas using different disturbance devices. We show that the depth distribution of solid-phase Mn in the upper 20 cm of the sediments in the CCZ provides a reliable tool for the determination of the disturbance depth, which has been proposed in a previous study (Paul et al., 2018). We found that the upper 5–15 cm of the sediments were removed during various small-scale disturbance experiments in the different exploration contract areas. Transient transport-reaction modelling for the Polish and German contract areas reveals that the removal of the surface sediments is associated with the loss of reactive labile organic carbon. As a result, oxygen consumption rates decrease significantly after the removal of the surface sediments, and consequently, oxygen penetrates up to tenfold deeper into the sediments inhibiting denitrification and Mn(IV) reduction. Our model results show that the post-disturbance geochemical re-equilibration is controlled by diffusion until the reactive labile TOC fraction in the surface sediments is partly re-established and the biogeochemical processes commence. While the re-establishment of bioturbation is essential, the geochemical re-equilibration of the sediments is ultimately controlled by the burial rates of organic matter. Hence, under current depositional conditions, the new geochemical equilibrium in the sediments of the CCZ is reached only on a millennia scale even for these small-scale disturbances simulating deep-sea mining activities.

scholarly journals Impact of small-scale disturbances on geochemical conditions, biogeochemical processes and element fluxes in surface sediments of the eastern Clarion–Clipperton Zone, Pacific Ocean

2020 ◽  
Vol 17 (4) ◽  
pp. 1113-1131 ◽  
Author(s):  
Jessica B. Volz ◽  
Laura Haffert ◽  
Matthias Haeckel ◽  
Andrea Koschinsky ◽  
Sabine Kasten
Keyword(s):  
Steady State ◽  
Environmental Impact ◽  
Deep Sea ◽  
Surface Sediments ◽  
Small Scale ◽  
Mining Activities ◽  
Biogeochemical Processes ◽  
Geochemical Conditions ◽  
Element Fluxes ◽  
Polymetallic Nodules

Abstract. The thriving interest in harvesting deep-sea mineral resources, such as polymetallic nodules, calls for environmental impact studies and, ultimately, for regulations for environmental protection. Industrial-scale deep-sea mining of polymetallic nodules most likely has severe consequences for the natural environment. However, the effects of mining activities on deep-sea ecosystems, sediment geochemistry and element fluxes are still poorly understood. Predicting the environmental impact is challenging due to the scarcity of environmental baseline studies as well as the lack of mining trials with industrial mining equipment in the deep sea. Thus, currently we have to rely on small-scale disturbances simulating deep-sea mining activities as a first-order approximation to study the expected impacts on the abyssal environment. Here, we investigate surface sediments in disturbance tracks of seven small-scale benthic impact experiments, which have been performed in four European contract areas for the exploration of polymetallic nodules in the Clarion–Clipperton Zone (CCZ) in the NE Pacific. These small-scale disturbance experiments were performed 1 d to 37 years prior to our sampling program in the German, Polish, Belgian and French contract areas using different disturbance devices. We show that the depth distribution of solid-phase Mn in the upper 20 cm of the sediments in the CCZ provides a reliable tool for the determination of the disturbance depth, which has been proposed in a previous study from the SE Pacific (Paul et al., 2018). We found that the upper 5–15 cm of the sediments was removed during various small-scale disturbance experiments in the different exploration contract areas. Transient transport-reaction modeling for the Polish and German contract areas reveals that the removal of the surface sediments is associated with the loss of the reactive labile total organic carbon (TOC) fraction. As a result, oxygen consumption rates decrease significantly after the removal of the surface sediments, and, consequently, oxygen penetrates up to 10-fold deeper into the sediments, inhibiting denitrification and Mn(IV) reduction. Our model results show that the return to steady-state geochemical conditions after the disturbance is controlled by diffusion until the reactive labile TOC fraction in the surface sediments is partly re-established and the biogeochemical processes commence. While the re-establishment of bioturbation is essential, steady-state geochemical conditions are ultimately controlled by the delivery rate of organic matter to the seafloor. Hence, under current depositional conditions, new steady-state geochemical conditions in the sediments of the CCZ are reached only on a millennium scale even for these small-scale disturbances simulating deep-sea mining activities.

Impact of simulated deep-sea polymetallic nodule mining on sediment and pore-water geochemistry in prospective mining areas in the NE Pacific Ocean

2020 ◽  
Author(s):  
Jessica Volz ◽  
Laura Haffert ◽  
Matthias Haeckel ◽  
Andrea Koschinsky ◽  
Sabine Kasten
Keyword(s):  
Steady State ◽  
Pacific Ocean ◽  
Deep Sea ◽  
Surface Sediments ◽  
Small Scale ◽  
Mining Activities ◽  
Mining Equipment ◽  
Geochemical Conditions ◽  
Polymetallic Nodules ◽  
Ne Pacific

<p>Industrial-scale harvesting of deep-sea mineral resources, such as polymetallic nodules, is likely to have severe consequences for the natural environment. However, the effects of mining activities on deep‑sea ecosystems, sediment geochemistry and element fluxes are still poorly understood. Predicting the environmental impact is challenging due to the scarcity of environmental baseline studies and the lack of mining trials with industrial mining equipment in the deep sea. Thus, currently we have to rely on small-scale disturbances simulating deep-sea mining activities as a first-order approximation to study the expected impacts on the abyssal environment and ecosystem.</p><p>We have investigated surface sediments in disturbance tracks of seven small-scale benthic impact experiments, which have been performed in four European contract areas for the exploration of polymetallic nodules in the Clarion-Clipperton Zone (CCZ) in the NE Pacific Ocean. These small-scale disturbance experiments were performed 1 day to 37 years prior to our sampling program in the German, Polish, Belgian and French contract areas using different disturbance devices, such as dredges and epibenthic sledges. We show that the depth distribution of solid-phase Mn in the upper 20 cm of the sediments in the CCZ provides a reliable tool for the determination of the disturbance depth. We found that the upper 5–15 cm of the sediments were removed during various small‑scale disturbance experiments in the different contract areas. Transient transport‑reaction modelling for the Polish and German contract areas reveals that the removal of the surface sediments is associated with the loss of reactive labile organic carbon. As a result, oxygen consumption rates decrease significantly after the removal of the surface sediments, and consequently, oxygen penetrates up to tenfold deeper into the sediments inhibiting denitrification and Mn(IV) reduction. Our model results show that the return to steady state geochemical conditions after the disturbance is controlled by diffusion until the reactive labile TOC fraction in the surface sediments is partly re‑established and the biogeochemical processes commence. While the re-establishment of bioturbation is essential, steady state geochemical conditions are ultimately controlled by the burial rate of organic matter. Hence, under current depositional conditions, new steady state geochemical conditions in the sediments of the CCZ are reached only on a millennium-scale even for these small-scale disturbances simulating deep-sea mining activities.</p>

scholarly journals Preliminary Economic Feasibility Study of Ferromanganese Nodule Mining by Mechanical Lifting and Small-Scale Collectors

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1389
Author(s):  
Sup Hong ◽  
Hyung-Woo Kim ◽  
Tae-Kyung Yeu ◽  
Rei Arai ◽  
Tetsuo Yamazaki
Keyword(s):  
Environmental Impact ◽  
Deep Sea ◽  
Economic Feasibility ◽  
Small Scale ◽  
Ferromanganese Nodule ◽  
Deep Sea Sediment ◽  
Metal Source ◽  
Environmental Considerations ◽  
Bulk Scale ◽  
Nodule Mining

Ferromanganese nodules have been recognized as a potential future metal source for over 50 years. Many research and development efforts have been conducted by many organizations. Most of the efforts have been concentrated into the mining technologies especially for hydraulic lifting through riser pipes with bulk-scale nodule collector. However, no commercial mining venture exists. Uncertainty in the economy of nodule mining is considered to be the reason for this. In order to improve the economy, a mining subsystem based on mechanical lifting and small-scale collectors is proposed and the preliminary economic feasibility is examined in this study. The benefit was at a favorable level compared with that using hydraulic lifting with bulk-scale collector. From the viewpoint of environmental impact assessment, environmental considerations of deep-sea sediment plume are explained.

scholarly journals RV SONNE Fahrtbericht/Cruise Report SO268 - Assessing the Impacts of Nodule Mining on the Deep-sea Environment: NoduleMonitoring, Manzanillo (Mexico) – Vancouver (Canada), 17.02. – 27.05.2019

2021 ◽  
Author(s):  
Matthias Haeckel ◽  
Peter Linke
Keyword(s):  
Environmental Impacts ◽  
Deep Sea ◽  
Industrial Test ◽  
Small Scale ◽  
Second Phase ◽  
Technical Problems ◽  
Fully Integrated ◽  
Polymetallic Nodules ◽  
Clarion Clipperton Fracture Zone ◽  
Nodule Mining

Cruise SO268 is fully integrated into the second phase of the European collaborative JPI-Oceans project MiningImpact and is designed to assess the environmental impacts of deep-sea mining of polymetallic nodules in the Clarion-Clipperton Fracture Zone (CCZ). In particular, the cruise aimed at conducting an independent scientific monitoring of the first industrial test of a pre-protoype nodule collector by the Belgian company DEME-GSR. The work includes collecting the required baseline data in the designated trial and reference sites in the Belgian and German contract areas, a quantification of the spatial and temporal spread of the produced sediment plume during the trials as well as a first assessment of the generated environmental impacts. However, during SO268 Leg 1 DEME-GSR informed us that the collector trials would not take place as scheduled due to unresolvable technical problems. Thus, we adjusted our work plan accordingly by implementing our backup plan. This involved conducting a small-scale sediment plume experiment with a small chain dredge to quantify the spatial and temporal dispersal of the suspended sediment particles, their concentration in the plume as well as the spatial footprint and thickness of the deposited sediment blanket on the seabed.

Time series of near-bottom currents and particle fluxes from Ocean Bottom Moorings in the NE equatorial Pacific

2020 ◽  
Author(s):  
Martina Hollstein ◽  
Annemiek Vink ◽  
Katja Schmidt ◽  
Niko Lahajnar ◽  
Andreas Lückge ◽  
...  
Keyword(s):  
Time Series ◽  
Deep Sea ◽  
Equatorial Pacific ◽  
Series Data ◽  
Bottom Current ◽  
Ocean Bottom ◽  
Mining Activities ◽  
Current Regime ◽  
Polymetallic Nodules ◽  
Particle Fluxes

<p>The globally increasing demand for metals and rare earth elements has raised the interest for potential mining of deep-sea mineral resources such as polymetallic nodules. One important field of polymetallic nodules is located within the Clarion-Clipperton Fracture Zone (CCZ) in the northeastern equatorial Pacific. To date, the International Seabed Authority (ISA) has granted 25 licenses for the exploration of polymetallic nodules in the CCZ. However, the impact of potential future mining activities on the deep-sea environment is only insufficiently known. To assess the environmental impacts of potential future mining activities, a nodule pre-prototype collector test is scheduled to occur in the German license area within the CCZ in autumn 2020, and will be accompanied by an extensive environmental monitoring program (joint effort between BGR and the European research project JPI-Oceans “MiningImpact2”). However, to assess the environmental impact of mining activities, for example due to the development of an operational sediment plume on the seafloor, prior knowledge on the bottom current regime and variability of particle flux and composition within the CCZ under natural conditions is a prerequisite. In order to analyze the bottom current regime and background particle fluxes, BGR deployed Ocean Bottom Moorings (OBM) equipped with current and turbidity meters (4 years between 2013 and 2019), and a sediment trap (2018-2019). Here, we present preliminary results and analyses of these oceanographic and sedimentological time-series data, and compare the results with other available information deriving from the region.</p>

scholarly journals Faunal carbon flows in the abyssal plain food web of the Peru Basin have not recovered during 26 years from an experimental sediment disturbance

2018 ◽  
Author(s):  
Tanja Stratmann ◽  
Lidia Lins ◽  
Autun Purser ◽  
Yann Marcon ◽  
Clara F. Rodrigues ◽  
...  
Keyword(s):  
Food Web ◽  
Deep Sea ◽  
Abyssal Plain ◽  
System Throughput ◽  
Small Scale ◽  
Total System ◽  
Surface Deposit ◽  
Deposit Feeders ◽  
Polymetallic Nodules ◽  
Linear Inverse Model

Abstract. Future deep-sea mining for polymetallic nodules in abyssal plains will impact the benthic ecosystem, but it is largely unclear whether this ecosystem will be able to recover from mining disturbance and if so, at what time scale and to which extent. In 1989, during the "DISturbance and reCOLonization" (DISCOL) experiment, a total of 22 % of the surface within a 10.8 km2 large circular area of the nodule-rich seafloor in the Peru Basin (SE Pacific) was ploughed to bury nodules and mix the surface sediment. This area was revisited 0.1, 0.5, 3, 7, and 26 years after the disturbance to assess macrofauna, megafauna and fish density and diversity. We used this unique abyssal faunal time series to develop carbon-based food web models for disturbed (sediment inside the plough tracks) and undisturbed (sediment inside the experimental area, but outside the plough tracks) sites. We developed a linear inverse model (LIM) to resolve carbon flows between 7 different feeding types within macrofauna, megafauna and fish. The total faunal biomass was always higher at the undisturbed sites compared to the disturbed sites and 26 years post-disturbance the biomass at the disturbed sites was only 54 % of the biomass at undisturbed sites. Fish and sub-surface deposit feeders experienced a particularly large temporal variability in biomass and model-reconstructed respiration rates making it difficult to determine disturbance impacts. Deposit feeders were least affected by the disturbance, with respiration, external predation and excretion levels only reduced by 2.6 % in the sediments disturbed 26-years ago compared with undisturbed areas. In contrast, the respiration rate of filter and suspension feeders was still 79.5 % lower after 26 years when comparing the same sites. The "total system throughput" (T..), i.e. the total sum of carbon flows in the food web, was always higher at undisturbed sites compared to the corresponding disturbed sites and was lowest at disturbed sites directly after the disturbance (8.63 × 10−3 ± 1.58 × 10−5 mmol C m−2 d−1). Therefore, 26 years after the DISCOL disturbance, the throughput discrepancy between the undisturbed and the disturbed sediment was still 56 %. From these results we conclude that C cycling within the fauna compartments of an abyssal plain ecosystem remains reduced 26 years after physical disturbance, and that a longer period of time is required for the system to recover from such a simulated small scale deep-sea mining experimental disturbance.

scholarly journals Artisanal-small Scale Mining in Myanmar

2014 ◽  
pp. 19-23
Author(s):  
Aung Kyin
Keyword(s):  
Developing Countries ◽  
Large Scale ◽  
Mining Operation ◽  
Small Scale ◽  
Mining Activities ◽  
Mining Equipment ◽  
Access To Finance ◽  
Mineral Commodity ◽  
Women And Children ◽  
Artisanal Miners

In many parts of the world, artisanal or small-scale mining activities are at least as important as large-scale mining activities. The numbers of people employed are actually considerably greater than in large companies. In 2002, an estimated 13 million people a large percentage of those are women and children are artisanal and small scale miners operating mainly in developing countries. Although the numbers of small-scale miners and their dependents are estimated at up to 80-100 million people, governments are frequently reluctant to give legal recognition to artisanal miners [1].This paper discusses approaches to developthe Artisanal–Small Scale Mining (ASM) sector in developing countries. This includes choice of mineral commodity, available technologies and economic/geological criteria. Other considerations include access to finance, area selection, and personnel. The parameters of mineral economic analysis are also essential for asuccessful ASM mining operation. Finally, choice of mining equipment is critical to success.

Managing the impacts of mining on Ghana’s water resources from a legal perspective

2018 ◽  
Vol 1 (3) ◽  
pp. 156-165 ◽  
Author(s):  
Nasirudeen Abdul Fatawu
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Environmental Protection Agency ◽  
Large Scale ◽  
Small Scale ◽  
Mining Activities ◽  
Protection Agency ◽  
Environmental Laws ◽  
Mining Areas ◽  
Legal Perspective

Recent floods in Ghana are largely blamed on mining activities. Not only are lives lost through these floods, farms andproperties are destroyed as a result. Water resources are diverted, polluted and impounded upon by both large-scale minersand small-scale miners. Although these activities are largely blamed on behavioural attitudes that need to be changed, thereare legal dimensions that should be addressed as well. Coincidentally, a great proportion of the water resources of Ghana arewithin these mining areas thus the continual pollution of these surface water sources is a serious threat to the environmentand the development of the country as a whole. The environmental laws need to be oriented properly with adequate sanctionsto tackle the impacts mining has on water resources. The Environmental Impact Assessment (EIA) procedure needs to bestreamlined and undertaken by the Environmental Protection Agency (EPA) and not the company itself.

Analysis of Environmental Impact of Deep Sea Development of Mineral Deposits

2019 ◽  
Vol 145 (3/2019) ◽  
pp. 92-97
Author(s):  
Yu.V. Kirichenko ◽  
A.S. Kashirskiy ◽  
G.S. Ivaschenko
Keyword(s):  
Environmental Impact ◽  
Deep Sea ◽  
Mineral Deposits
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