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  • 2020-2024  (28)
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  • 1
    Online Resource
    Online Resource
    MiningImpact - environmental impacts and risks of deep-sea mining : Abschlussbericht : Vorhabenbezeichnung: Natürliche und abbaubedingte Partikelflüsse in der Wassersäule und am Meeresboden in der Clarion Clippertin Zone (CCZ), NE-Pazifik : Laufzeit des Vorhabens: 01.08.2018-28.02.2022 = MiningImpact - environmental impacts and risks of deep-sea mining : natural and mining-related particle fluxes in the water column and close to the seafloor in the Clarion-Clipperton Zone (CCZ), NE Pacific (2022)
    Hannover : Bundesanstalt für Geowissenschaften und Rohstoffe
    Details Availability
    Keywords: Forschungsbericht ; Meeresbergbau ; Umweltbelastung
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (31 Seiten, 1,35 MB) , Diagramme
    URL: https://edocs.tib.eu/files/e01fb23/1857967488.pdf
    URL: https://doi.org/10.2314/KXP:1857967488
    DOI: 10.2314/KXP:1857967488
    Language: German
    Note: Förderkennzeichen BMBF 03F0812H , Verbundnummer 01183428 , Literaturverzeichnis: Seite 22+23 , Unterschiede zwischen dem gedruckten Dokument und der elektronischen Ressource können nicht ausgeschlossen werden , Sprache der Zusammenfassung: Deutsch, Englisch
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  • 2
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    Risk Assessment for Deep-Seabed Mining (2022)
    Springer
    Details
    Publication Date: 2023-10-06
    Description: Uncertainties concerning deep-seabed mining relate to the expected impacts on the abyssal benthic and pelagic environment and its ecosystems but also include geopolitical, economic, societal and cultural uncertainty. The uncertain impacts from mining lead to anxiety and a low societal acceptance for the activity and are not the same for everybody at the same time. Hence, uncertainty is an important element of the risk involved in deep-seabed mining. This chapter describes the different risks involved, develops a methodology for risk assessment for the exploitation of marine mineral resources that takes into consideration the state of knowledge and evolving research on deep-sea ecosystems, and informs on possible environmental threshold values in relation to deep-seabed mining operations.
    Type: Book chapter , NonPeerReviewed
    Format: text
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    OceanRep: Book chapter
  • 3
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    Unexpected high abyssal ophiuroid diversity in polymetallic nodule fields of the Northeast Pacific Ocean, and implications for conservation (2020)
    Copernicus Publications (EGU)
    Details
    Publication Date: 2023-02-08
    Description: The largest and commercially appealing mineral deposits can be found in the abyssal seafloor of the Clarion-Clipperton Zone (CCZ), a polymetallic nodule province, in the NE Pacific Ocean, where experimental mining is due to take place. In anticipation of deep-sea mining impacts, it has become essential to rapidly and accurately assess biodiversity. For this reason, ophiuroid material collected during seven scientific cruises from five exploration license areas within CCZ, one area protected from mining (APEI3, Area of Particular Environmental Interest) in the periphery of CCZ and the DIS-turbance and re-COLonisation (DISCOL) Experimental Area (DEA), in the SE Pacific Ocean, was examined. Specimens were genetically analysed using a fragment of the mitochondrial cytochrome c oxidase subunit I (COI). Maximum Likelihood and Neighbour Joining trees were constructed, while four tree-based and distance-based methods of species delineation (ABGD, BINs, GMYC, mPTP) were employed to propose Secondary Species Hypotheses (SSHs) within the ophiuroids collected. The species delimitations analyses concordant results revealed the presence of 43 deep-sea brittle stars SSHs, revealing an unexpectedly high diversity and showing that the most conspicuous invertebrates in abyssal plains have been so far considerably under-estimated. The number of SSHs found in each area varied from 5 (IFREMER area) to 24 (BGR area), while 13 SSHs were represented by singletons. None of the SSHs was found to be present in all 7 areas, while the majority of species (44.2 %) had a single-area presence (19 SSHs). The most common species were Ophioleucidae sp. (Species 29), Amphioplus daleus (Species 2) and Ophiosphalma glabrum (Species 3), present in all areas except APEI3. The biodiversity patterns could be mainly attributed to POC fluxes that could explain the highest species numbers found in BGR (German contractor area) and UKSRL (UK contractor area) areas. The five exploration contract areas belong to a mesotrophic province, while in contrary the APEI3 is located in an oligotrophic province which could explain the lowest diversity as well as very low similarity with the other six study areas. Based on these results the representativeness and the appropriateness of APEI3 to meet its purpose of preserving the biodiversity of the CCZ fauna are questioned. Finally, this study provides the foundation for biogeographic and functional analyses that will provide insight into the drivers of species diversity and its role in ecosystem function.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Format: archive
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Evidence of eddy-related deep-ocean current variability in the northeast tropical Pacific Ocean induced by remote gap winds (2020)
    Copernicus Publications (EGU)
    Details
    Publication Date: 2023-02-08
    Description: 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: Article , PeerReviewed
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
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    Predicting meiofauna abundance to define preservation and impact zones in a deep-sea mining context using random forest modelling (2020)
    British Ecological Society | Wiley
    Details
    Publication Date: 2023-02-08
    Description: There is a strong economic interest in commercial deep‐sea mining of polymetallic nodules and therefore a need to define suitable preservation zones in the abyssal plain of the Clarion Clipperton Fracture Zone (CCZ). However, besides ship‐based multibeam data, only sparse continuous environmental information is available over large geographic scales. We test the potential of modelling meiofauna abundance and diversity on high taxonomic level on large geographic scale using a random forest approach. Ship‐based multibeam bathymetry and backscatter signal are the only sources for 11 predictor variables, as well as the modelled abundance of polymetallic nodules on the seafloor. Continuous meiofauna predictions have been combined with all available environmental variables and classified into classes representing abyssal habitats using k‐means clustering. Results show that ship‐based, multibeam‐derived predictors can be used to calculate predictive models for meiofauna distribution on a large geographic scale. Predicted distribution varies between the different meiofauna response variables. To evaluate predictions, random forest regressions were additionally computed with 1,000 replicates, integrating varying numbers of sampling positions and parallel samples per site. Higher numbers of parallel samples are especially useful to smoothen the influence of the remarkable variability of meiofauna distribution on a small scale. However, a high number of sampling positions is even more important, integrating a greater amount of natural variability of environmental conditions into the model. Synthesis and applications. Polymetallic nodule exploration contractors are required to define potential mining and preservation zones within their licence area. The biodiversity and the environment of preservation zones should be representative of the sites that will be impacted by mining. Our predicted distributions of meiofauna and the derived habitat maps are an essential first step to enable the identification of areas with similar ecological conditions. In this way, it is possible to define preservation zones not only based on expert opinion and environmental proxies but also integrating evidence from the distribution of benthic communities.
    Type: Article , PeerReviewed
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
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    Evaluating species richness using proteomic fingerprinting and DNA barcoding — a case study on meiobenthic copepods from the Clarion Clipperton Fracture Zone (2022)
    Springer
    Details
    Publication Date: 2024-01-08
    Description: The Clarion Clipperton Fracture Zone (CCZ) is a vast deep-sea region harboring a highly diverse benthic fauna, which will be affected by potential future deep-sea mining of metal-rich polymetallic nodules. Despite the need for conservation plans and monitoring strategies in this context, the majority of taxonomic groups remain scientifically undescribed. However, molecular rapid assessment methods such as DNA barcoding and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) provide the potential to accelerate specimen identification and biodiversity assessment significantly in the deep-sea areas. In this study, we successfully applied both methods to investigate the diversity of meiobenthic copepods in the eastern CCZ, including the first application of MALDI-TOF MS for the identification of these deep-sea organisms. Comparing several different species delimitation tools for both datasets, we found that biodiversity values were very similar, with Pielou’s evenness varying between 0.97 and 0.99 in all datasets. Still, direct comparisons of species clusters revealed differences between all techniques and methods, which are likely caused by the high number of rare species being represented by only one specimen, despite our extensive dataset of more than 2000 specimens. Hence, we regard our study as a first approach toward setting up a reference library for mass spectrometry data of the CCZ in combination with DNA barcodes. We conclude that proteome fingerprinting, as well as the more established DNA barcoding, can be seen as a valuable tool for rapid biodiversity assessments in the future, even when no reference information is available.
    Type: Article , PeerReviewed
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 7
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    Restoration experiments in polymetallic nodule areas (2022)
    Wiley | SETAC (Society of Environmental Toxicology and Chemistry)
    Details
    Publication Date: 2024-02-07
    Description: Deep-seabed polymetallic nodule mining can have multiple adverse effects on benthic communities, such as permanent loss of habitat by removal of nodules and habitat modification of sediments. One tool to manage biodiversity risks is the mitigation hierarchy, including avoidance, minimization of impacts, rehabilitation and/or restoration, and offset. We initiated long-term restoration experiments at sites in polymetallic nodule exploration contract areas in the Clarion-Clipperton Zone that were (i) cleared of nodules by a preprototype mining vehicle, (ii) disturbed by dredge or sledge, (iii) undisturbed, and (iv) naturally devoid of nodules. To accommodate for habitat loss, we deployed 〉2000 artificial ceramic nodules to study the possible effect of substrate provision on the recovery of biota and its impact on sediment biogeochemistry. Seventy-five nodules were recovered after eight weeks and had not been colonized by any sessile epifauna. All other nodules will remain on the seafloor for several years before recovery. Furthermore, to account for habitat modification of the top sediment layer, sediment in an epibenthic sledge track was loosened by a metal rake to test the feasibility of sediment decompaction to facilitate soft-sediment recovery. Analyses of granulometry and nutrients one month after sediment decompaction revealed that sand fractions are proportionally lower within the decompacted samples, whereas total organic carbon values are higher. Considering the slow natural recovery rates of deep-sea communities, these experiments represent the beginning of a ~30-year study during which we expect to gain insights into the nature and timing of the development of hard-substrate communities and the influence of nodules on the recovery of disturbed sediment communities. Results will help us understand adverse long-term effects of nodule removal, providing an evidence base for setting criteria for the definition of “serious harm” to the environment. Furthermore, accompanying research is needed to define a robust ecosystem baseline in order to effectively identify restoration success.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 8
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    Meiofauna in a Potential Deep-Sea Mining Area—Influence of Temporal and Spatial Variability on Small-Scale Abundance Models (2021)
    MDPI
    Details
    Publication Date: 2024-02-07
    Description: In large areas of the Clarion Clipperton Fracture Zone (northeast Pacific), exploration of deep-sea polymetallic nodules as a potential source of high-technology metals is ongoing. Deep-sea mining may have a severe impact on the benthic communities. Here, we investigated meiofauna communities in the abyss at the scale of a prospective mining operation area. Random forest regressions were computed to spatially predict continuous layers of environmental variables as well as the distribution of meiofauna abundance across the area. Significant models could be computed for 26 sediment and polymetallic nodule parameters. Meiofauna abundance, taxon richness and diversity were also modelled, as well as abundance of the taxon Nematoda. Spatial correlation is high if the predictions of meiofauna are either based on bathymetry and backscatter or include sediment and nodule variables; Pearson’s correlation coefficient varies between 0.42 and 0.91. Comparison of differences in meiofauna abundance between different years shows that spatial patterns do change, with an elevated abundance of meiofauna in the eastern part of the study area in 2013. On the spatial scale of a potential mining operation, distribution models prove to be a useful tool to gain insight into both temporal variability and the influence of potential environmental drivers on meiofauna distribution.
    Type: Article , PeerReviewed
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 9
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    Habitat heterogeneity enhances megafaunal biodiversity at bathymetric elevations in the Clarion Clipperton Fracture Zone (2023)
    Springer
    Details
    Publication Date: 2024-02-07
    Description: The Clarion Clipperton Fracture Zone (CCZ) in the northeast Pacific is a heterogeneous deep-sea environment, featuring abyssal plains as well as multiple seamounts and abyssal hills (bathymetric elevations) that harbour a highly diverse megabenthic fauna. Based on the analysis of seafloor photographic transects that were taken from elevated areas downslope into the abyssal plains in the eastern CCZ, a similar distribution of habitats was observed on five different bathymetric elevations including abyssal hills as well as the foothills of two seamounts. Rock outcrops occur at the summits, surrounded by an area with varying coverage and size of polymetallic nodules, which were divided into two different habitats characterized by large and small nodules, respectively, and followed by nodule-free sediments. Megafauna composition, density and diversity varies across these habitats. While density is the highest in areas with rock outcrops (1.4 individuals per m 2 ), the biodiversity is the highest when regarding all of the habitats combined. Regarded individually, nodule-covered areas are the most diverse, whereas sediment areas without hard substratum, i.e. nodule free sediments, show the lowest biodiversity and the lowest density (0.2 individuals per m 2 ). The multinomial species classification method (CLAM) shows that most of the observed megafauna morphotypes have to be regarded as rare. The large differences between the megafaunal communities at bathymetric elevations and the abyssal plain reported from previous studies might partly be explained by the multiplicity of habitats. This high heterogeneity can lead to a more diversified community at elevations, although most habitats can also be observed in the abyssal plain.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 10
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    Numerical Simulation of Deep-Sea Sediment Transport Induced by a Dredge Experiment in the Northeastern Pacific Ocean (2021)
    Frontiers
    Details
    Publication Date: 2024-02-07
    Description: 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: Article , PeerReviewed , info:eu-repo/semantics/article
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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