scholarly journals Recovery of Paleodictyon patterns after simulated mining activity on Pacific nodule fields

2021 ◽  
Vol 51 (6) ◽  
Author(s):  
Lilian Boehringer ◽  
Sofia P. Ramalho ◽  
Yann Marcon ◽  
Antje Boetius ◽  
Daphne Cuvelier ◽  
...  
Keyword(s):  
Deep Sea ◽  
Image Data ◽  
Camera System ◽  
Polymetallic Nodule ◽  
Disturbed Areas ◽  
The Pacific ◽  
Mode Of Life ◽  
Irregular Form ◽  
The Pacific Ocean ◽  
Clarion Clipperton Fracture Zone

AbstractSince the late 1980s, various experiments have been conducted in polymetallic nodule fields of the Pacific Ocean to assess the potential environmental impacts of future mining, specifically in two areas: the Peru Basin and the Clarion-Clipperton Fracture Zone (CCZ). Two expeditions, SO242/2 in 2015 (Peru Basin) and SO268/1 + 2 in 2019 (CCZ), deployed a towed camera system to collect imagery from both areas. These expeditions aimed to assess recovery of fauna in the short (few weeks) and long term (several years) following physical seafloor disturbance actions designed to mimic potential mining, by ploughs, dredges and epibenthic sleds. Within the collected image data, several strikingly hexagonal hole patterns were observed and identified as Paleodictyon nodosum, and an irregular form of Paleodictyon traces, both on undisturbed and disturbed areas of seafloor. Recent forms occur abundantly in various deep-sea regions, but their origin, and how they represent the mode of life of the forming organism, remains unknown. In this study, the imaged occurrences of Paleodictyon traces on disturbed seafloor sheds light on the lifecycle of the forming organism, demonstrating that they can recolonize disturbed habitat and produce the trace network in a few weeks. Nevertheless, the density of these patterns on disturbed substrates was lower than observed on undisturbed substrates in both nodule regions. We therefore hypothesize that, along with other benthic deep-sea fauna, these structures and the forming organism are impacted by physical seafloor disturbance, and even 26 years after disturbance, densities on disturbed sediments have not recovered to undisturbed levels.

Taxonomy and biogeography of Molgolaimus Ditlevsen, 1921 (Nematoda: Chromadoria) with reference to the origins of deep sea nematodes

2006 ◽  
Vol 18 (1) ◽  
pp. 23-50 ◽  
Author(s):  
Gustavo Fonseca ◽  
Ann Vanreusel ◽  
Wilfrieda Decraemer
Keyword(s):  
Deep Sea ◽  
Tail Length ◽  
Species Level ◽  
Weddell Sea ◽  
Similar Species ◽  
Disturbed Areas ◽  
The Pacific ◽  
Morphometric Features ◽  
Total Community ◽  
The Pacific Ocean

Molgolaimus is a genus of free-living marine nematodes which is found in high densities (10–35% of the total community) up to 2000 m depth. Its occurrence is often associated with organically enriched and recently disturbed areas. Currently, only 16 species have been described, mainly from shallow waters. The present study contributes 17 new species mainly from the Weddell Sea but also from the Pacific Ocean, and provides an illustrated polytomous identification key to species level. The 33 Molgolaimus species described can be identified based on just a few morphometric features: spicule length, body length, anal body diameter, tail length and pharynx length. A first insight into the biogeography of this deep sea genus at species level is presented. A comparison of morphometric characteristics between species suggests that the most similar species co-occur in the same geographical region, rather than within the same bathymetric zones or similar ecosystems separated over long distances. These observations suggest that deep sea nematodes may not have a common origin but might have derived “recently” from shallow water taxa. Therefore, global distribution of nematodes could be explained by means of palaeogeographical events.

scholarly journals From the Surface to the Deep-Sea: Bacterial Distributions across Polymetallic Nodule Fields in the Clarion-Clipperton Zone of the Pacific Ocean

2017 ◽  
Vol 8 ◽  
Author(s):  
Markus V. Lindh ◽  
Brianne M. Maillot ◽  
Christine N. Shulse ◽  
Andrew J. Gooday ◽  
Diva J. Amon ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Deep Sea ◽  
Polymetallic Nodule ◽  
The Pacific ◽  
The Pacific Ocean

scholarly journals Larval assemblages over the abyssal plain in the Pacific are highly diverse and spatially patchy

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7691 ◽  
Author(s):  
Oliver Kersten ◽  
Eric W. Vetter ◽  
Michelle J. Jungbluth ◽  
Craig R. Smith ◽  
Erica Goetze
Keyword(s):  
Human Impacts ◽  
Abyssal Plain ◽  
Benthic Boundary Layer ◽  
Parasitic Copepods ◽  
Polymetallic Nodule ◽  
Disturbed Areas ◽  
Pelagic Larvae ◽  
The Pacific ◽  
Clarion Clipperton Fracture Zone ◽  
Nodule Mining

Abyssal plains are among the most biodiverse yet least explored marine ecosystems on our planet, and they are increasingly threatened by human impacts, including future deep seafloor mining. Recovery of abyssal populations from the impacts of polymetallic nodule mining will be partially determined by the availability and dispersal of pelagic larvae leading to benthic recolonization of disturbed areas of the seafloor. Here we use a tree-of-life (TOL) metabarcoding approach to investigate the species richness, diversity, and spatial variability of the larval assemblage at mesoscales across the abyssal seafloor in two mining-claim areas in the eastern Clarion Clipperton Fracture Zone (CCZ; abyssal Pacific). Our approach revealed a previously unknown taxonomic richness within the meroplankton assemblage, detecting larvae from 12 phyla, 23 Classes, 46 Orders, and 65 Families, including a number of taxa not previously reported at abyssal depths or within the Pacific Ocean. A novel suite of parasitic copepods and worms were sampled, from families that are known to associate with other benthic invertebrates or demersal fishes as hosts. Larval assemblages were patchily distributed at the mesoscale, with little similarity in OTUs detected among deployments even within the same 30 × 30 km study area. Our results provide baseline observations on larval diversity prior to polymetallic nodule mining in this region, and emphasize our overwhelming lack of knowledge regarding larvae of the benthic boundary layer in abyssal plain ecosystems.

scholarly journals Copper-binding ligands in deep-sea pore waters of the Pacific Ocean and potential impacts of polymetallic nodule mining on the copper cycle

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sophie A. L. Paul ◽  
Rebecca Zitoun ◽  
Ann Noowong ◽  
Mythili Manirajah ◽  
Andrea Koschinsky
Keyword(s):  
Pacific Ocean ◽  
Deep Sea ◽  
Organic Ligand ◽  
Copper Binding ◽  
Pore Waters ◽  
Potentially Toxic Metals ◽  
Polymetallic Nodule ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Nodule Mining

AbstractThe release of potentially toxic metals, such as copper (Cu), into the water column is of concern during polymetallic nodule mining. The bioavailability and thus toxicity of Cu is strongly influenced by its speciation which is dominated by organic ligand (L) complexation in seawater, with L-complexes being considered less bioavailable than free Cu2+. The presence of CuL-complexes in deep-sea sediments has, however, not been systematically studied in the context of deep-sea mining. We thus analyzed the Cu-binding L concentration ([L]) in deep-sea pore waters of two polymetallic nodule provinces in the Pacific Ocean, the Peru Basin and the Clarion-Clipperton-Zone, using competitive ligand equilibration–adsorptive stripping voltammetry. The pore-water dissolved Cu concentration ([dCu]) ranged from 3 to 96 nM, generally exceeding bottom water concentrations (4–44 nM). Based on fitting results from ProMCC and Excel, Cu was predominantly complexed by L (3–313 nM) in bottom waters and undisturbed pore waters. We conclude that processes like deep-sea mining are unlikely to cause a release of toxic Cu2+ concentrations ([Cu2+]) to the seawater as > 99% Cu was organically complexed in pore waters and the [Cu2+] was < 6 pM for 8 of 9 samples. Moreover, the excess of L found especially in shallow pore waters implied that even with a Cu release through mining activities, Cu2+ likely remains beneath toxic thresholds.

scholarly journals Are seamounts refuge areas for fauna from polymetallic nodule fields?

2019 ◽  
Author(s):  
Daphne Cuvelier ◽  
Pedro A. Ribeiro ◽  
Sofia P. Ramalho ◽  
Daniel Kersken ◽  
Pedro Martinez Arbizu ◽  
...  
Keyword(s):  
Fracture Zone ◽  
Deep Sea ◽  
Soft Sediment ◽  
Sea Floor ◽  
Polymetallic Nodule ◽  
Refuge Area ◽  
Clipperton Fracture Zone ◽  
Clarion Clipperton Fracture Zone ◽  
Refuge Areas ◽  
Hard Substrata

Abstract. Seamounts are abundant and prominent features on the deep-sea floor and intersperse with the nodule fields of the Clarion-Clipperton Fracture Zone (CCZ). There is a particular interest in characterising the fauna inhabiting seamounts in the CCZ because they are the only other ecosystem in the region to provide hard substrata besides the abundant nodules on the soft sediment abyssal plains. It has been hypothesised that seamounts could provide refuge for organisms during deep-sea mining actions or that they could play a role in the (re-)colonisation of the disturbed nodule fields. This hypothesis is tested by analysing video transects in both ecosystems, assessing megafauna composition and abundance. Nine video transects (ROV dives) from two different license areas and one Area of Particular Environmental Interest in the eastern CCZ were analysed. Four of these transects were carried out as exploratory dives on four different seamounts in order to gain first insights in megafauna composition. The five other dives were carried out in the neighbouring nodule fields in the same areas. Variation in community composition observed among and along the video transects was high, with little morphospecies overlap on intra-ecosystem transects. Despite these observations of considerable faunal variations within each ecosystem, differences between seamounts and nodule fields prevailed, showing significantly different species associations characterising them, thus questioning their use as a possible refuge area.

scholarly journals A biogeographic network reveals evolutionary links between deep-sea hydrothermal vent and methane seep faunas

2016 ◽  
Vol 283 (1844) ◽  
pp. 20162337 ◽  
Author(s):  
Steffen Kiel
Keyword(s):  
Pacific Ocean ◽  
Deep Sea ◽  
Hydrothermal Vents ◽  
Subduction Zones ◽  
Continental Margins ◽  
Stepping Stones ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Active Continental Margins ◽  
Ocean Ridge

Deep-sea hydrothermal vents and methane seeps are inhabited by members of the same higher taxa but share few species, thus scientists have long sought habitats or regions of intermediate character that would facilitate connectivity among these habitats. Here, a network analysis of 79 vent, seep, and whale-fall communities with 121 genus-level taxa identified sedimented vents as a main intermediate link between the two types of ecosystems. Sedimented vents share hot, metal-rich fluids with mid-ocean ridge-type vents and soft sediment with seeps. Such sites are common along the active continental margins of the Pacific Ocean, facilitating connectivity among vent/seep faunas in this region. By contrast, sedimented vents are rare in the Atlantic Ocean, offering an explanation for the greater distinction between its vent and seep faunas compared with those of the Pacific Ocean. The distribution of subduction zones and associated back-arc basins, where sedimented vents are common, likely plays a major role in the evolutionary and biogeographic connectivity of vent and seep faunas. The hypothesis that decaying whale carcasses are dispersal stepping stones linking these environments is not supported.

scholarly journals Are seamounts refuge areas for fauna from polymetallic nodule fields?

2020 ◽  
Vol 17 (9) ◽  
pp. 2657-2680 ◽  
Author(s):  
Daphne Cuvelier ◽  
Pedro A. Ribeiro ◽  
Sofia P. Ramalho ◽  
Daniel Kersken ◽  
Pedro Martinez Arbizu ◽  
...  
Keyword(s):  
Fracture Zone ◽  
Deep Sea ◽  
Soft Sediment ◽  
Sea Floor ◽  
Polymetallic Nodule ◽  
Refuge Area ◽  
Clipperton Fracture Zone ◽  
Clarion Clipperton Fracture Zone ◽  
Refuge Areas ◽  
Hard Substrata

Abstract. Seamounts are abundant and prominent features on the deep-sea floor and intersperse with the nodule fields of the Clarion-Clipperton Fracture Zone (CCZ). There is a particular interest in characterising the fauna inhabiting seamounts in the CCZ because they are the only other ecosystem in the region to provide hard substrata besides the abundant nodules on the soft-sediment abyssal plains. It has been hypothesised that seamounts could provide refuge for organisms during deep-sea mining actions or that they could play a role in the (re-)colonisation of the disturbed nodule fields. This hypothesis is tested by analysing video transects in both ecosystems, assessing megafauna composition and abundance. Nine video transects (ROV dives) from two different license areas and one Area of Particular Environmental Interest in the eastern CCZ were analysed. Four of these transects were carried out as exploratory dives on four different seamounts in order to gain first insights into megafauna composition. The five other dives were carried out in the neighbouring nodule fields in the same areas. Variation in community composition observed among and along the video transects was high, with little morphospecies overlap along intra-ecosystem transects. Despite the observation of considerable faunal variations within each ecosystem, differences between seamounts and nodule fields prevailed, showing significantly different species associations characterising them, thus calling into question their use as a possible refuge area.

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