Characterization of Deep-sea Macrofauna in the Korean Exploration Claim Area in the Clarion-Clipperton Fracture Zone, Northeastern Pacific Ocean

Yu, Ok Hwan; Lee, Hyung-Gon; Kim, Dongsung; Wi, Jin Hee; Kim, Kyeong Hong; Yoo, Changsik

doi:10.1007/s12601-018-0029-8

Cited by 12 publications

(8 citation statements)

References 26 publications

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“…Food supply, sediment grain size and the density of nodules are the three main environmental factors that seem to drive the structure and composition of polychaete assemblages in the CCFZ. The abundance of polychaetes per box core was positively correlated with nodule density, which is consistent with previous studies showing that nodules enhance macrofaunal densities and polychaete diversity (De Smet et al, 2017;Yu et al, 2018). Nodules may have antagonistic influences on different size groups of benthic communities.…”

Section: Major Forces Driving Local-and Regional-scale Patterns In Cosupporting

confidence: 91%

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

2020

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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.

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Section: Major Forces Driving Local-and Regional-scale Patterns In Cosupporting

confidence: 91%

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

2020

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“…Nodules however increase habitat heterogeneity, providing hard substrate for sessile organisms and generally enhancing the standing stocks of both sessile and vagile megafauna Vanreusel et al, 2016;Simon-Lledó et al, 2019). Similarly, nodules seem to enhance macrofaunal density (De Smet et al, 2017) and diversity (Yu et al, 2018). Our results support the reported positive and significant relationship between polychaete abundance and nodule density (De Smet et al (2017).…”

Section: Major Forces Driving Local-and Regional-scale Patterns In Cosupporting

confidence: 85%

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

Bonifácio¹,

Martinez-Arbizu²,

Menot³

2019

Preprint

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Abstract. In the abyssal Equatorial Pacific Ocean, most of the seafloor of the Clarion-Clipperton Fracture Zone (CCFZ), a 6&#8201;million&#8201;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 &#8211; albeit very limited &#8211; 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 <q>Ecological aspects of deep-sea mining</q>, 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&#8201;km in the eastern CCFZ. Between 3 and 8 quantitative box cores (0.25&#8201;m2; 0&#8211;10&#8201;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&#8201;% 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&#8201;species&#8201;km&#8722;1 and an average species range of 25&#8201;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&#8201;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.

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“…Even though using individual cores from the same MUC deployment as replicates (sometimes called parallel samples) can sometimes show a higher spatial variance in comparison with cores from independent deployments (Montagna et al 2017), this strategy is statistically not ideal, since these cores are not collected independently. They are considered pseudo-replicates and may therefore lead to false conclusions of densities and biodiversity (Colegrave and The low densities of benthic biota (meiofauna about 50-500 ind/10 cm 2 and macrofauna about 100-200 ind m À2 ) in the CCFZ (Hessler and Jumars 1974;Yu et al 2018;Uhlenkott et al 2020), in combination with high species richness, results in the requirement for large sample sizes, usually not allowing to subsample boxcores or cores from a MUC. This stresses the need to increase replication in order to collect sufficient specimens to fully characterize the biodiversity of the present fauna (De Smet et al 2017;Pape et al 2017).…”

Section: Sampling Design and Replicationmentioning

confidence: 99%

“…While both polychaetes and tanaidaceans showed highest diversity at the highest productivity site, this trend was reversed for Isopoda (Wilson 2017). At the local scale, nodule density also influences the composition of polychaete assemblages (Bonifácio et al 2019) and was reported to have either a positive (Yu et al 2018) or no (Pasotti et al 2020) influence on macrofaunal densities.…”

Section: The Ccfz Nodule Province and Its Associated Faunamentioning

confidence: 99%

“…This upper size limit of the meiofauna does not match with the lower size limit of the macrofauna. In the deep sea, the lower size limit for macrofauna is normally set to 250 or 300 μ m (e.g., Hessler and Jumars 1974; Dinet et al 1985; De Smet et al 2017; Montagna et al 2017; Yu et al 2018). This overlap in size limits is due to an overlap in the size distribution of the two groups where the adults of the larger meiofaunal species are in the macrofaunal size‐range while juveniles of macrofauna are in the meiofaunal size range.…”

Section: Size Limits For Meio‐ and Macrofaunamentioning

confidence: 99%

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Toward a reliable assessment of potential ecological impacts of deep‐sea polymetallic nodule mining on abyssal infauna

Lins

Zeppilli

Menot

et al. 2021

Limnology & Ocean Methods

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The increasing demand for metals is pushing forward the progress of deep-sea mining industry. The abyss between the Clarion and Clipperton Fracture Zones (CCFZ), a region holding a higher concentration of minerals than land deposits, is the most targeted area for the exploration of polymetallic nodules worldwide, which may likely disturb the seafloor across large areas and over many years. Effects from nodule extraction cause acute biodiversity loss of organisms inhabiting sediments and polymetallic nodules. Attention to deep-sea ecosystems and their services has to be considered before mining starts but the lack of basic scientific knowledge on the methodologies for the ecological surveys of fauna in the context of deep-sea mining impacts is still scarce. We review the methodology to sample, process and investigate metazoan infauna both inhabiting sediments and nodules dwelling on these polymetallic-nodule areas. We suggest effective procedures for sampling designs, devices and methods involving gear types, sediment processing, morphological and genetic identification including metabarcoding and proteomic fingerprinting, the assessment of biomass, functional traits, fatty acids, and stable isotope studies within the CCFZ based on both first-hand experiences and literature. We recommend multi-and boxcorers for the quantitative assessments of meio-and macrofauna, respectively. The assessment of biodiversity at species level should be focused and/or the combination of morphological with metabarcoding or proteomic fingerprinting techniques. We highlight that biomass, functional traits, and trophic markers may provide critical insights for biodiversity assessments and how statistical modeling facilitates predicting patterns spatially across point-source data and is essential for conservation management.

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Characterization of Deep-sea Macrofauna in the Korean Exploration Claim Area in the Clarion-Clipperton Fracture Zone, Northeastern Pacific Ocean

Cited by 12 publications

References 26 publications

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

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

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

Toward a reliable assessment of potential ecological impacts of deep‐sea polymetallic nodule mining on abyssal infauna

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