Role of Siliceous Fossil Dissolution in Downcore Variations of Grain Size and Water Content: Western Margin of Clarion-Clipperton Fracture Zone, NE Equatorial Pacific

2001 ◽  
Vol 19 (3) ◽  
pp. 181-195
Author(s):  
Hoi-Soo Jung ◽  
Kap-Sik Jeong ◽  
Yong-Shik Chu ◽  
Sung-Hyun Park ◽  
Ki-Hyune Kim
Keyword(s):  
Grain Size ◽  
Water Content ◽  
Fracture Zone ◽  
Equatorial Pacific ◽  
Western Margin ◽  
Clipperton Fracture Zone ◽  
Clarion Clipperton Fracture Zone

scholarly journals Alpha and beta diversity patterns of polychaete assemblages across the nodule province of the eastern Clarion-Clipperton Fracture Zone (equatorial Pacific)

2020 ◽  
Vol 17 (4) ◽  
pp. 865-886 ◽  
Author(s):  
Paulo Bonifácio ◽  
Pedro Martínez Arbizu ◽  
Lénaïck Menot
Keyword(s):  
Fracture Zone ◽  
Beta Diversity ◽  
Species Turnover ◽  
Regional Scale ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean ◽  
Species Ranges ◽  
Diversity Patterns ◽  
Clipperton Fracture Zone ◽  
Clarion Clipperton Fracture Zone

Abstract. In the abyssal equatorial Pacific Ocean, most of the seafloor of the Clarion-Clipperton Fracture Zone (CCFZ), a 6 million km2 polymetallic nodule province, has been preempted for future mining. In light of the large environmental footprint that mining would leave and given the diversity and the vulnerability of the abyssal fauna, the International Seabed Authority has implemented a regional management plan that includes the creation of nine Areas of Particular Environmental Interest (APEIs) located at the periphery of the CCFZ. The scientific principles for the design of the APEIs were based on the best – albeit very limited – knowledge of the area. The fauna and habitats in the APEIs are unknown, as are species' ranges and the extent of biodiversity across the CCFZ. As part of the Joint Programming Initiative Healthy and Productive Seas and Oceans (JPI Oceans) pilot action “Ecological aspects of deep-sea mining”, the SO239 cruise provided data to improve species inventories, determine species ranges, identify the drivers of beta diversity patterns and assess the representativeness of an APEI. Four exploration contract areas and an APEI (APEI no. 3) were sampled along a gradient of sea surface primary productivity that spanned a distance of 1440 km in the eastern CCFZ. Between three and eight quantitative box cores (0.25 m2; 0–10 cm) were sampled in each study area, resulting in a large collection of polychaetes that were morphologically and molecularly (cytochrome c oxidase subunit I and 16S genes) analyzed. A total of 275 polychaete morphospecies were identified. Only one morphospecies was shared among all five study areas and 49 % were singletons. The patterns in community structure and composition were mainly attributed to variations in organic carbon fluxes to the seafloor at the regional scale and nodule density at the local scale, thus supporting the main assumptions underlying the design of the APEIs. However, the APEI no. 3, which is located in an oligotrophic province and separated from the CCFZ by the Clarion Fracture Zone, showed the lowest densities, lowest diversity, and a very low and distant independent similarity in community composition compared to the contract areas, thus questioning the representativeness and the appropriateness of APEI no. 3 to meet its purpose of diversity preservation. Among the four exploration contracts, which belong to a mesotrophic province, the distance decay of similarity provided a species turnover of 0.04 species km−1, an average species range of 25 km and an extrapolated richness of up to 240 000 polychaete species in the CCFZ. By contrast, nonparametric estimators of diversity predict a regional richness of up to 498 species. Both estimates are biased by the high frequency of singletons in the dataset, which likely result from under-sampling and merely reflect our level of uncertainty. The assessment of potential risks and scales of biodiversity loss due to nodule mining thus requires an appropriate inventory of species richness in the CCFZ.

scholarly journals Fractionation Trends and Variability of Rare Earth Elements and Selected Critical Metals in Pelagic Sediment from Abyssal Basin of NE Pacific (Clarion-Clipperton Fracture Zone)

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 320 ◽  
Author(s):  
Dominik Zawadzki ◽  
Łukasz Maciąg ◽  
Tomasz Abramowski ◽  
Kevin McCartney
Keyword(s):  
Grain Size ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Fracture Zone ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Critical Metals ◽  
Icp Ms ◽  
Clipperton Fracture Zone ◽  
Clarion Clipperton Fracture Zone

The geochemical and mineralogical characteristics of pelagic sediments collected from the Interoceanmetal Joint Organization (IOM) claim area, located in the eastern part of the Clarion-Clipperton Fracture Zone (CCFZ; eastern tropical Pacific), are described in this paper. The concentrations of rare earth elements (REE), as well as other selected critical elements contained in 135 sediment samples of siliceous clayey silts, are presented. The vertical and spatial variabilities of elements, with particular emphasis on REE as well as metals of the highest economic interest such as Cu, Ni, and Co, are detailed. The applied methods include grain size analysis by laser diffraction, geochemistry examination using ICP-MS, XRF, AAS, and CNS spectrometry, and XRD analysis of mineral composition (Rietveld method). Additionally, statistical methods such as factor analysis (FA) and principal components analysis (PCA) were applied to the results. Finally, a series of maps was prepared by geostatistical methods (universal kriging). Grain size analysis showed poor sorting of the examined fine-grained silts. ICP-MS indicated that total REE contents varied from 200 to 577 ppm, with a mean of 285 ppm, which is generally low. The contents of critical metals such as Cu, Ni, and Co were also low to moderate, apart from some individual sampling stations where total contents were 0.15% or more. Metal composition in sediments was dominated by Cu, Ni, and Zn. A mineral composition analysis revealed the dominance of amorphous biogenic opaline silica (27–58%), which were mostly remnants of diatoms, radiolarians, and sponges associated with clay minerals (23% to 48%), mostly Fe-smectite and illite, with mixed-layered illite/smectite. The high abundance of diagenetic barite crystals found in SEM−EDX observations explains the high content of Ba (up to 2.4%). The sediments showed complex lateral and horizontal fractionation trends for REE and critical metals, caused mostly by clay components, early diagenetic processes, admixtures of allogenic detrital minerals, or scavenging by micronodules.

scholarly journals Alpha and beta diversity patterns of polychaete assemblages across the nodule province of the Clarion-Clipperton Fracture Zone (Equatorial Pacific)

2019 ◽  
Author(s):  
Paulo Bonifácio ◽  
Pedro Martinez-Arbizu ◽  
Lénaïck Menot
Keyword(s):  
Fracture Zone ◽  
Beta Diversity ◽  
Species Turnover ◽  
Regional Scale ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean ◽  
Species Ranges ◽  
Diversity Patterns ◽  
Clipperton Fracture Zone ◽  
Clarion Clipperton Fracture Zone

Abstract. In the abyssal Equatorial Pacific Ocean, most of the seafloor of the Clarion-Clipperton Fracture Zone (CCFZ), a 6 million km2 polymetallic nodule province, has been preempted for future mining. In light of the large footprint that mining would leave, and given the diversity and the vulnerability of the abyssal fauna, the International Seabed Authority has implemented a regional management plan that includes the creation of nine areas of particular environmental interest (APEIs) located at the periphery of the CCFZ. The APEIs were defined based on the best – albeit very limited – scientific knowledge for the area. The fauna and habitats in the APEIs are unknown, as are species' ranges and the extent of biodiversity across the CCFZ. As part of the Joint Programming Initiative Healthy and Productive Seas and Oceans (JPI Oceans) pilot action Ecological aspects of deep-sea mining, the SO239 cruise aimed at improving species inventories, determining species ranges, identifying the drivers of beta diversity patterns and assessing the representativeness of an APEI. Four exploration contract areas and an APEI (APEI#3) were sampled along a gradient of sea-surface primary productivity that spanned a distance of 1440 km in the eastern CCFZ. Between 3 and 8 quantitative box cores (0.25 m2; 0–10 cm) were sampled in each study area, resulting in a large collection of polychaetes that were morphologically and molecularly (COI and 16S genes) analyzed. A total of 275 polychaete morphotypes were identified. Only one morphotype was shared among all five study areas and 49 % were singletons. The patterns in community structure and composition were mainly attributed to variations in food fluxes at the regional scale and nodule density at the local scale. The four exploration contract areas belong to a mesotrophic province. The distance-decay of similarity among the four areas provides an estimated species turnover of 0.04 species km−1 and an average species range of 25 km. The polychaete assemblage in APEI#3 showed the lowest densities, lowest diversity as well as very low, distant-independent similarity with the other four study areas. Given that APEI#3 is located in an oligotrophic province and separated from the CCFZ by the Clarion Fracture Zone, our results call into question the representativeness and the appropriateness of APEI#3 to meet its purpose of preserving the biodiversity of the CCFZ fauna. Two methods for estimating the total number of polychaete species gave estimates that ranged from 498 to 240 000 species. Both methods are biased by the high frequency of singletons in the dataset, which likely result from under-sampling; our estimates thereby merely reflect our level of uncertainty. The assessment of potential risks and scales of biodiversity loss due to nodule mining thus requires an appropriate inventory of species richness in the CCFZ.

New species of Cirratulidae (Annelida, Polychaeta) from abyssal depths of the Clarion-Clipperton Fracture Zone, North Equatorial Pacific Ocean

Zootaxa ◽  
2019 ◽  
Vol 4629 (2) ◽  
pp. 151-187
Author(s):  
JAMES A. BLAKE
Keyword(s):  
New Species ◽  
Fracture Zone ◽  
Manganese Nodule ◽  
Equatorial Pacific ◽  
Depth Range ◽  
Equatorial Pacific Ocean ◽  
Clipperton Fracture Zone ◽  
The Family ◽  
Clarion Clipperton Fracture Zone ◽  
Deposit Feeding

Abyssal polychaetes of the family Cirratulidae were collected as part of reconnaissance and benthic impact experimental surveys at Clarion-Clipperton Fracture Zone manganese nodule sites in 1984 and 1993–1994. All specimens were collected from the 4500–4900 m depth range. Twelve species of Cirratulidae were identified, of which 11 are new to science. Aphelochaeta abyssalis n. sp., A. clarionensis n. sp., A. clippertonensis n. sp., A. spargosis n. sp., A. tanyperistomia n. sp., A. wilsoni n. sp., Caulleriella bathytata n. sp., Chaetozone akaina n. sp., C. grasslei n. sp., C. truebloodi n. sp. and Tharyx hessleri n. sp. Most of these species are small deposit-feeding threadlike worms that reside in the upper 5 cm of the sediment and represent a unique assemblage of abyssal taxa. 

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