Fine-scale monitoring of fish movements and multiple environmental parameters around a decommissioned offshore oil platform : A pilot study in the North Sea

Acknowledgements The authors would like to thank OSPAR for providing data for offshore structures in the North Sea, and Imants G. Priede (University of Aberdeen), Stewart Chalmers (University of Aberdeen), John Polanski (University of Aberdeen), Thomas O’Donoghue (University of Aberdeen), and Michelle Horsfield (BP), Anne Walls (BP), Peter Evans (BP), Alwyn Mcleary (BP) and all the crew members of the Miller platform for invaluable advice and support in conducting this research project. This work was coordinated by Oceanlab, University of Aberdeen and supported by the BP Fellowship in Applied Fisheries Programme.Peer reviewedPublisher PD

HOT : Hadal Zones of our Overseas Territories

HOT: Hadal zones of our Overseas Territories is a multi-disciplinary program that will deliver a step-change in our understanding of the fundamental ecological and geological processes in the South Sandwich Trench (SST). The SST reaches water depths of 8266 m ±13m at a location known as Meteor Deep, named after the German research vessel who first sounded it in 1926, and uniquely is the only sub-zero hadal environment on Earth. This Darwin Plus (Round 7) funded project will improve understanding of marine biodiversity and geodiversity to fill an identified knowledge gap supporting the existing Marine Protected Area and obligations under the Convention of Biological Diversity. The South Georgia and the South Sandwich Islands Marine Protected Area (MPA) is one of the largest MPAs on Earth covering >1 million km2 and includes the SST. Predicting trench habitats and their fauna cannot be extrapolated from shallower systems as they exhibit stark ecotones and abrupt changes in geology, making MPA management at depths >6000m at best difficult. The MPA is designed to ensure the protection and conservation of the region’s rich and diverse marine life, whilst allowing sustainable and carefully regulated fisheries. Key outcomes of the 5-year review of the MPA (November 2017) included: a need to enhance bathymetric knowledge around the region; recognition there is a lack of data on the abyssal and hadal ecosystems; that more information is needed on assemblages versus biodiversity, ecosystem processes and function; and general information on how to record long-term change to factors such as climate change. This project will make use of high-resolution bathymetric maps of the South Sandwich Trench acquired using the latest generation full-ocean-depth EM124 by the Five Deeps Expedition (www.fivedeeps.com). These data form a primary dataset for geological and geomorphological analysis and provide the context for research into the biological communities of these deeps. With the newly collected invertebrate samples from the SST, this project will utilise specimens of scavenging amphipods including: new species from the genus Hirondellea, and Bathycallisoma schellenbergi. These species are model species for understanding the historical and present connectivity of the hadal zone and its effects on speciation. The remoteness and uniqueness of the low temperatures and high pressures of the South Sandwich Trench makes these recent findings highly important in resolving ultra-deep sea speciation on a large geographical scale. Geological and geomorphological interpretation and map production was funded by a grant awarded through the Darwin Initiative funded by the UK Government: Hadal Zones of our Overseas Territories (DPLUS093). STEWART, H, JAMIESON, A. 2019. HOT: Hadal zones of our overseas territories. [Poster] In: SAGES ’19 Global Challenges for a Blue Economy: scientific evidence; its relevance; societal solutions, Edinburgh, UK, 27-28th November 2019 (p 74 of abstract booklet). (doc) Poster presentation by H Stewart. DOI: 10.13140/RG.2.2.10374.6048

Bioaccumulation of persistent organic pollutants in the deepest ocean fauna

The Kermadec and Mariana ‘HADES’ expeditions (RV Thomas G. Thompson TN309, and RV Falkor FK141109) were funded through the National Science Foundation (NSF-OCE nos 1130712 and 1140494) and the Schmidt Ocean Institute. S.B.P. was supported by a Fellowship from the Leverhulme Trust. The analytical costs were supported by the Total Foundation (France) and the Marine Alliance for Science and Technology, Scotland (MASTS) through a Deep Sea Forum small grant award.Peer reviewedPostprin

Habitat heterogeneity of hadal trenches: considerations and implications for future studies

The hadal zone largely comprises a series of subduction trenches that do not form part of the continental shelf-slope rise to abyssal plain continuum. Instead they form geographically isolated clusters of deep-sea (6000-11000 m water depth) environments. There is a growing realization in hadal science that ecological patterns and processes are not driven solely by responses to hydrostatic pressure, with comparable levels of habitat heterogeneity as observed in other marine biozones. Furthermore, this heterogeneity can be expressed at multiple scales from inter-trench levels (degrees of geographical isolation, and biochemical province), to intra-trench levels (variation between trench flanks and axis), topographical features within the trench interior (sedimentary basins, ridges, escarpments, ‘deeps’, seamounts) to the substrate of the trench floor (seabed-sediment composition, mass movement deposits, bedrock outcrop). Using best available bathymetry data combined with the largest lander-derived imaging dataset that spans the full depth range of three hadal trenches (including adjacent slopes); the Mariana, Kermadec and New Hebrides trenches, the topographic variability, fine-scale habitat heterogeneity and distribution of seabed sediments of these three trenches have been assessed for the first time. As well as serving as the first descriptive study of habitat heterogeneity at hadal depths, this study also provides guidance for future hadal sampling campaigns taking into account geographic isolation, total trench particulate organic matter flux, maximum water depth and area

Large effective population size masks population genetic structure in Hirondellea amphipods within the deepest marine ecosystem, the Mariana Trench

Acknowledgements This work was supported by NERC (NBAF884 to AJJ and NE/N01149X/1 to SBP), the Leverhulme Trust (to SBP) and the Schmidt Ocean Institute, USA (SBP and AJJ). We are grateful to the captain and crew of the RV Falkor, Professor Jeff Drazen (University of Hawaii) as Principal Scientist for cruise FK141109 and Dr Thomas Linley (Newcastle University) for assistance in lander operations. We thank Edinburgh Genomics for RAD genotyping services, and Heather Ritchie for useful discussions.Peer reviewedPublisher PD

In situ observations of trophic behaviour and locomotion of Princaxelia amphipods (Crustacea, Pardaliscidae) at hadal depths in four West Pacific Trenches

Peer reviewedPublisher PD

The five deeps: the location and depth of the deepest place in each of the world's oceans

The exact location and depth of the deepest places in each of the world's oceans is surprisingly unresolved or at best ambiguous. Out of date, erroneous, misleading, or non-existent data on these locations have propagated uncorrected through online sources and the scientific literature. For clarification, this study reviews and assesses the best resolution bathymetric datasets currently available from public repositories. The deepest place in each ocean are the Molloy Hole in the Fram Strait (Arctic Ocean; 5669 m, 79.137° N/2.817° E), the trench axis of the Puerto Rico Trench (Atlantic Ocean; 8408 m 19.613° N/67.847° W), an unnamed deep in the Java Trench (Indian Ocean; 7290 m, 11.20° S/118.47° E), Challenger Deep in the Mariana Trench (Pacific Ocean; 10,925 m, 11.332° N/142.202° E) and an unnamed deep in the South Sandwich Trench (Southern Ocean; 7385 m, 60.33° S/25.28° W). However, discussed are caveats to these locations that range from the published coordinates for a number of named deeps that require correction, some deeps that should fall into abeyance, deeps that are currently unnamed and the problems surrounding variable and low-resolution bathymetric data. Recommendations on the above and the nomenclature and definition of deeps as undersea features are provided

Hadal zones of the Northwest Pacific Ocean

Understanding the extent of the hadal ecosystem (habitats exceeding 6000 m water depth) is convoluted due to the complexity of seafloor geomorphology that accounts for 45% of the total ocean depth range. Furthermore, at such great depths, features such as fracture zones and basins, although numerous, are less prominent and therefore have drawn less focus compared to the conspicuous subduction trenches that are typically associated with hadal science. Here we focus on the Northwest Pacific Ocean, where the majority of hadal features are located, to evaluate the true extent of the deepest marine ecosystem. This analysis has highlighted that the Mariana Trench, in terms of continuous hadal habitat, is in fact five isolated areas, with the most northern being what Russian scientists used to call the Volcano Trench. Conversely, we identified that there are no physical partitions either north or south of the Japan Trench to isolate it from the neighbouring Kuril-Kamchatka or Izu-Bonin trenches respectively, thus it forms one continuous hadal habitat. By evaluating the frequency and distribution of smaller features, such as basins and fracture zones, we conclude that in the northwest Pacific, the total area occupied by depths > 6000 m is 2,793,011 km2, which is considerably larger than the 686,114 km2 accounted for by subduction trenches alone. These results demonstrate not only that the hadal ecosystem may be far larger than previously anticipated but that the geomorphology is crucial in understanding the distribution and genetic connectivity of endemic hadal species that inhabit these great depths

Loss of APC induces polyploidy as a result of a combination of defects in mitosis and apoptosis

Mutations in the adenomatous polyposis coli (APC) tumor suppressor gene initiate a majority of colorectal cancers. Acquisition of chromosomal instability is an early event in these tumors. We provide evidence that the loss of APC leads to a partial loss of interkinetochore tension at metaphase and alters mitotic progression. Furthermore, we show that inhibition of APC in U2OS cells compromises the mitotic spindle checkpoint. This is accompanied by a decrease in the association of the checkpoint proteins Bub1 and BubR1 with kinetochores. Additionally, APC depletion reduced apoptosis. As expected from this combination of defects, tetraploidy and polyploidy are consequences of APC inhibition in vitro and in vivo. The removal of APC produced the same defects in HCT116 cells that have constitutively active β-catenin. These data show that the loss of APC immediately induces chromosomal instability as a result of a combination of mitotic and apoptotic defects. We suggest that these defects amplify each other to increase the incidence of tetra- and polyploidy in early stages of tumorigenesis

High‐resolution multibeam sonar bathymetry of the deepest place in each ocean

Over the course of 10 months, the global Five Deeps Expedition (2018–2019) mapped ~550,000 km2 of seafloor of which 61% comprised new coverage over areas never before surveyed and ~30% was acquired from some of the ocean's deepest trenches and fracture zones. The deepest points of each ocean were mapped using a latest-generation, full-ocean depth Kongsberg EM 124 multibeam echosounder. These extreme depths were corrected using Conductivity, Temperature and Depth (CTD) data from sea surface to full ocean depth. The deepest place in each ocean were identified as the Brownson Deep, Puerto Rico Trench in the Atlantic Ocean (8,378 ± 5 m), an unnamed deep within the South Sandwich Trench in the Southern Ocean (7,432 ± 13 m), an unnamed deep within the Java Trench in the Indian Ocean (7,187 ± 13 m), Challenger Deep within the Mariana Trench in the Pacific Ocean (10,924 ± 15 m), and the Molloy Hole in the Arctic Ocean (5,551 ± 14 m). As part of the overarching mission of the Five Deeps Expedition, and to clarify beyond doubt the deepest point in the Indian, Pacific and Southern oceans, other sites were visited that had been postulated as potential deepest locations. This study has confirmed that the Horizon Deep within the Tonga Trench is the second deepest point in the Pacific Ocean (10,816 ± 16 m), the Dordrecht Deep within the Diamantina Fracture Zone is not the deepest point in the Indian Ocean (7,019 ± 17 m) and that in accordance with the guidelines of the Antarctic Treaty and International Hydrographic Organisation, although the Meteor Deep is the deepest point in the South Sandwich Trench (8,265 ± 13 m) it is located within the waters of the Atlantic Ocean and not the Southern Ocean