New insights from the deep: Meiofauna in the Kuril-Kamchatka Trench and adjacent abyssal plain

Schmidt, Christina; Sattarova, Valentina V.; Katrynski, Laura; Arbizu, Pedro Martínez

doi:10.1016/j.pocean.2019.02.010

Cited by 20 publications

(17 citation statements)

References 70 publications

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“…Even though, abundance of kinorhynchs was very low and small sample size might have important implication on the assessment of kinorhynchs diversity, our results are in line with other hadal studies. It has already been documented that trenches and their adjacent abyssal plain can differ significantly in their macrobenthic (Jamieson et al, 2011;Fujii et al, 2013;Gallo et al, 2015) and meiobenthic communities (Kitahashi et al, 2013;Leduc et al, 2016;Schmidt et al, 2019), due to the combination of environmental conditions at trenches floor that are not found in any other deep-sea environment. However, these geographical and depth gradients do not act as sharp boundaries but rather as transitional zones (Jamieson et al, 2011), thus still the hadal zone can share few fauna species with abyssal communities, but less likely with bathyal ones (Eustace et al, 2016;Brandt et al, 2019).…”

Section: Hadal Vs Abyssal and Bathyal Depthsmentioning

confidence: 99%

Hadal Mud Dragons: First Insight Into the Diversity of Kinorhyncha From the Atacama Trench

et al. 2021

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Deep-sea trenches are one of the last frontiers for deep-sea exploration and represent a large reservoir of undiscovered biodiversity. This applies in particular to organisms belonging to smaller-size classes, such as meiofauna. Among different meiofauna taxa, kinorhynchs represent a large gap in our knowledge about global marine biodiversity in general, but primarily in extreme deep-sea environments. Out of the more than 300 known mud dragon species, only a single species has ever been described from hadal depths (> 6000 m), i.e., Echinoderes ultraabyssalis from the Kuril-Kamchatka Trench. The results presented in this paper are based on material collected during a research expedition in 2018 investigating the Atacama Trench environment. We provide a first overview and comparison of the diversity and abundance of mud dragons in the Atacama Trench, the adjacent abyssal plain and continental slope off Chile. The study revealed six species of Echinoderes. Of these, Echinoderes mamaqucha sp. nov. is described as a new species and morphological data of three undescribed species are given. Because of the low number of available specimens, we provide only a brief description of these three species and comparison with their morphologically closest congeners, but formal descriptions are not given. Moreover, Echinoderes juliae and Echinoderes pterus were also recovered. Echinoderes juliae was described from the abyssal plain off Oregon and along the continental rise off California, at 2702 to 3679 m depth. Echinoderes pterus is known from the high Arctic, the North Atlantic, and the Mediterranean Sea, and has also been reported to show a wide bathymetric distribution, from 675 to 4403 m. Interestingly, E. mamaqucha sp. nov. dominated at the trench stations and it reached its highest abundance at the deepest station, at 8085 m water depth. The only other single individual that was found in the Atacama Trench was Echinoderes sp.1. The remaining four species were all found at the abyssal and slope stations. The obtained results seem to confirm previous hypotheses about geographic isolation of deep-sea trenches and relatively low connectivity with other habitats, reflected by limited diversity of sediment dwelling fauna, particularly in the deepest parts of trenches.

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Section: Hadal Vs Abyssal and Bathyal Depthsmentioning

confidence: 99%

Hadal Mud Dragons: First Insight Into the Diversity of Kinorhyncha From the Atacama Trench

et al. 2021

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“…However, when including additional stations, care must be taken to include stations which will likely include similar species as doing otherwise may again lead to inclusion of further singleton species. Regarding Harpacticoida for instance, deep‐sea studies frequently deal with low‐frequency occurrences of species and numerous singletons (Schmidt et al ). In such cases, analyzing stations individually would inevitably lead to high errors that have to be taken into account when working with the results.…”

Section: Discussionmentioning

confidence: 99%

Unsupervised biodiversity estimation using proteomic fingerprints fromMALDI‐TOF MSdata

Rossel

Arbizu

2020

Limnology & Ocean Methods

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Species identification using matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) data strongly relies on reference libraries to differentiate species. Because comprehensive reference libraries, especially for metazoans, are rare, we explored the accuracy of unsupervised diversity estimations of communities using MALDI-TOF MS data in the absence of reference libraries to provide a method for future application in ecological research. To discover the best analysis strategy providing high congruence with true community structures, we carried out a simulation with more than 30,000 analyses using different combinations of data transformations, dimensionality reductions, and cluster algorithms. Species profile, Hellinger, and presence/absence transformations were applied to raw data and dimensions were reduced using principal component analysis (PCA), t-distributed stochastic neighbor embedding, and uniform manifold approximation and projection. To estimate biodiversity, data were clustered making use of partitioning around medoids, modelbased clustering, and K-means clustering. The analyses were carried out on published mass spectrometry data of harpacticoid copepods. Most successful combinations (Hellinger transformation + PCA or raw data + partitioning around medoids) returned good values even for difficult species distributions containing numerous singleton species. Nevertheless, errors occurred most frequently because of such singleton taxa. Hence, replicative sampling in wide sampling areas for analysis is emphasized to increase the minimum number of specimens per species, thus reducing putative sources of errors. Our results demonstrate that MALDI-TOF MS data can be used to accurately estimate the biodiversity of unknown communities using unsupervised learning methods. The provided approach allows the biodiversity comparison of sampled regions for which no reference libraries are available. Hence, especially data on groups which demand a time-consuming identification or are highly abundant can be analyzed within short working time, accelerating ecological studies.

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“…Depth has been proven to be one of the strongest environmental factors affecting megafaunal communities in deep sea environments, including continental slope, seamounts, and the hadal trenches (Carney, 2005;Blankenship et al, 2006;Lacey et al, 2016;Linley et al, 2017;Schmidt et al, 2019). However, the boundary between the abyssal and hadal zones is still controversial.…”

Section: Vertical Zonation Patterns Of Megafauna From the Abyssal To mentioning

confidence: 99%

“…There is a growing realization in hadal science that ecological patterns and processes are not driven solely by responses to hydrostatic pressure (Stewart and Jamieson, 2018), with comparable levels of habitat heterogeneity as observed in other more accessible marine habitats cold seeps (Levin et al, 2016), hydrothermal vents (van Dover, 2000, sub-marine canyons (e.g., Amaro et al, 2016;Fernandez-Arcaya et al, 2017) and seamounts (e.g., Rowden et al, 2005). It had been hypothesized that higher seafloor heterogeneity supports larger variability of megabenthic assemblages (De Leo et al, 2010;Lacharité and Metaxas, 2017;Schmidt et al, 2019).…”

Section: Habitat Heterogeneitymentioning

confidence: 99%

Megafaunal Community Structure From the Abyssal to Hadal Zone in the Yap Trench

et al. 2021

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Hadal trenches remain one of the unexplored ocean ecosystems due to the challenges of sampling at great depths. It is still unclear how a faunal community changes from the abyssal to the hadal zone, and which environmental variables are the key impacting factors. In this study, nine dives of the Human Occupied Vehicle (HOV) “JIAOLONG” were conducted from abyssal to hadal depths (4,435–6,796 m) in the Yap Trench on the southeastern boundary of the Philippine Sea Plate in the western Pacific, divided into 48,200 m video transects, to describe the megafaunal communities and reveal their relationship with environmental factors. A total of 1,171 megafauna organisms was recorded, 80 morphospecies (msps) from 8 phyla were identified based on the video data, most of which were reported for the first time in the Yap Trench. Arthropoda was the most abundant phylum and Echinodermata was the most diverse phylum of the megafaunal community. The faunal abundance increased with depth, whereas the Shannon diversity index decreased with depth. Cluster analysis suggested seven assemblages, with five abyssal groups, one mixed group, and one hadal dominant group. Although megafaunal communities changed gradually from abyssal zone to hadal zone, both PERMANOVA and PERMDISP analyses revealed that the communities are significantly different between abyssal zone and hadal zone, indicating 6,000 m as the boundary between the two depth zones. Depth, substrate, slope, and latitude were identified as four important environmental factors with significant influence on megafaunal community structure. This study proposed a transition pattern from the abyssal to hadal zone in the Yap Trench, highlighted the importance of habitat heterogeneity in structuring megafaunal community in a hadal trench.

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New insights from the deep: Meiofauna in the Kuril-Kamchatka Trench and adjacent abyssal plain

Cited by 20 publications

References 70 publications

Hadal Mud Dragons: First Insight Into the Diversity of Kinorhyncha From the Atacama Trench

Hadal Mud Dragons: First Insight Into the Diversity of Kinorhyncha From the Atacama Trench

Unsupervised biodiversity estimation using proteomic fingerprints fromMALDI‐TOF MSdata

Megafaunal Community Structure From the Abyssal to Hadal Zone in the Yap Trench

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