A road map for defining Good Environmental Status in the deep-sea

The development of tools to assess the Good Environmental Status (GES) in the Deep Sea (DS) is one of the aspects that ATLAS WP3 is addressing. GES assessment in the DS is challenging due to 1) the lack of baseline data, 2) the remoteness of the DS ecosystems, and 3) the limitations of the sampling methods currently available. Throughout the duration of the project, ATLAS will develop a suitable approach to address GES in the DS. During the 2nd General Assembly, we will present a draft for a “road map” to address GES in the DS as well some of the aspects discussed during the 2017 ICES WG on Deep Sea Ecosystems. The temporal and spatial scale at which GES should be assessed in the deep-sea is an important aspect to be considered. Due to the data limited situation and challenges posed to monitoring, it may well be the case that GES will have to be assessed at large spatial and temporal scales when comparing the shallower waters of the European Seas. For similar reasons, the type of indicators to be used may have to be simplified and likely be based on high-level analyses related to traits, pressures/risks, and habitat /ecosystem resilience. Ultimately, the results of the combined analyses of GES descriptors might bring to a potential refining or redefinition of the GES concept for the deep-sea

Tuna Longline Fishing around West and Central Pacific Seamounts

BACKGROUND: Seamounts have been identified as aggregating locations for pelagic biodiversity including tuna; however the topography and prevailing oceanography differ between seamounts and not all are important for tuna. Although a relatively common feature in oceanic ecosystems, little information is available that identifies those that are biologically important. Improved knowledge offers opportunities for unique management of these areas, which may advance the sustainable management of oceanic resources. In this study, we evaluate the existence of an association between seamounts and tuna longline fisheries at the ocean basin scale, identify significant seamounts for tuna in the western and central Pacific Ocean, and quantify the seamount contribution to the tuna longline catch. METHODOLOGY/PRINCIPAL FINDINGS: We use data collected for the Western and Central Pacific Ocean for bigeye, yellowfin, and albacore tuna at the ocean basin scale. GLMs were applied to a coupled dataset of longline fisheries catch and effort, and seamount location information. The analyses show that seamounts may be associated with an annual longline combined catch of 35 thousand tonnes, with higher catch apparent for yellowfin, bigeye, and albacore tuna on 17%, 14%, and 14% of seamounts respectively. In contrast 14%, 18%, and 20% of seamounts had significantly lower catches for yellowfin, bigeye and albacore tuna respectively. Studying catch data in relation to seamount positions presents several challenges such as bias in location of seamounts, or lack of spatial resolution of fisheries data. Whilst we recognize these limitations the criteria used for detecting significant seamounts were conservative and the error in identification is likely to be low albeit unknown. CONCLUSIONS/SIGNIFICANCE: Seamounts throughout the study area were found to either enhance or reduce tuna catch. This indicates that management of seamounts is important Pacific-wide, but management approaches must take account of local conditions. Management of tuna and biodiversity resources in the region would benefit from considering such effects

Ocean Circulation over North Atlantic underwater features in the path of the Mediterranean Outflow Water: Ormonde and Formigas seamounts, and the Gazul mud volcano

Seamounts constitute an obstacle to the ocean circulation, modifying it. As a result, a variety of hydrodynamical processes and phenomena may take place over seamounts, among others, flow intensification, current deflection, upwelling, Taylor caps, and internal waves. These oceanographic effects may turn seamounts into very productive ecosystems with high species diversity, and in some cases, are densely populated by benthic organisms, such corals, gorgonians, and sponges. In this study, we describe the oceanographic conditions over seamounts and other underwater features in the path of the Mediterranean Outflow Water (MOW), where populations of benthic suspensions feeders have been observed. Using CTD, LADPC and biochemical measurements carried out in the Ormonde and Formigas seamounts and the Gazul mud volcano (Northeast Atlantic), we show that Taylor caps were not observed in any of the sampled features. However, we point out that the relatively high values of the Brunt–Väisälä frequency in the MOW halocline, in conjunction with the slope of the seamount flanks, set up conditions for the breakout of internal waves and amplification of the currents. This may enhance the vertical mixing, resuspending the organic material deposited on the seafloor and, therefore, increasing the food availability for the communities dominated by benthic suspension feeders. Thus, we hypothesize that internal waves could be improving the conditions for benthic suspension feeders to grow on the slope of seamounts.En prens

Climate change considerations are fundamental to management of deep‐sea resource extraction

Climate change manifestation in the ocean, through warming, oxygen loss, increasing acidification, and changing particulate organic carbon flux (one metric of altered food supply), is projected to affect most deep‐ocean ecosystems concomitantly with increasing direct human disturbance. Climate drivers will alter deep‐sea biodiversity and associated ecosystem services, and may interact with disturbance from resource extraction activities or even climate geoengineering. We suggest that to ensure the effective management of increasing use of the deep ocean (e.g., for bottom fishing, oil and gas extraction, and deep‐seabed mining), environmental management and developing regulations must consider climate change. Strategic planning, impact assessment and monitoring, spatial management, application of the precautionary approach, and full‐cost accounting of extraction activities should embrace climate consciousness. Coupled climate and biological modeling approaches applied in the water and on the seafloor can help accomplish this goal. For example, Earth‐System Model projections of climate‐change parameters at the seafloor reveal heterogeneity in projected climate hazard and time of emergence (beyond natural variability) in regions targeted for deep‐seabed mining. Models that combine climate‐induced changes in ocean circulation with particle tracking predict altered transport of early life stages (larvae) under climate change. Habitat suitability models can help assess the consequences of altered larval dispersal, predict climate refugia, and identify vulnerable regions for multiple species under climate change. Engaging the deep observing community can support the necessary data provisioning to mainstream climate into the development of environmental management plans. To illustrate this approach, we focus on deep‐seabed mining and the International Seabed Authority, whose mandates include regulation of all mineral‐related activities in international waters and protecting the marine environment from the harmful effects of mining. However, achieving deep‐ocean sustainability under the UN Sustainable Development Goals will require integration of climate consideration across all policy sectors.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2020 The Authors. Global Change Biology published by John Wiley & Sons Lt

Biodiversity and benthic megafaunal communities inhabiting the Formigas Bank (NE Azores)

The Formigas Bank is an offshore seamount located in the easternmost part of the Azores archipelago (northeast Atlantic). It rises from abyssal depths to the surface, including a small set of islets. The bank holds multiple nature conservation designations, including a Natura 2000 Special Area of Conservation, an OSPAR Marine Protected Area, a RAMSAR site and a Nature Reserve declared under the Azores network of protected areas. The protection is based on the presence of sublittoral biotopes of high conservation interest, and importance as feeding grounds, spawning and nursery areas for many marine species, including fish, cetaceans and turtles. Although some information exists on the sublittoral communities occurring on the seamount summit (e.g., infralittoral Cystoseira and Laminaria beds, circalittoral hydrarian and sponge gardens, rich pelagic fauna), virtually no information was available on the deep-sea communities inhabiting the seamount flanks. Therefore, during the MEDWAVES cruise, the flanks of the Formigas bank have been surveyed using multibeam sonar, an ROV and oceanographic profiles, with the objective to characterise deep-sea biodiversity and megafaunal communities as well as the environment where they occur. This communication will present results from the video annotations of the ten dives made on the seamount slopes between ~500m and ~1,500 m depth. Diverse communities of sedentary suspension-feeding organisms were observed, with more than 20 cold-water coral species (mainly octocorals) being recorded, as well as many different sponge morphotypes. Dense coral garden habitats and sponge grounds were identified on several occasions, confirming the presence of vulnerable marine ecosystems (VMEs) and of ecologically or biologically significant areas (EBSAs). Differences in the abundance and composition of these habitats between the northern and southern dive transects are interpreted as reflecting substrate and geomorphological differences, as well as the potential influence of the Mediterranean Outflow Water (MOW). The new knowledge on deep-sea megafaunal communities reinforces the importance of this seamount as an area of high conservation interest

A framework for the development of a global standardised marine taxon reference image database (SMarTaR-ID) to support image-based analyses

Video and image data are regularly used in the field of benthic ecology to document biodiversity. However, their use is subject to a number of challenges, principally the identification of taxa within the images without associated physical specimens. The challenge of applying traditional taxonomic keys to the identification of fauna from images has led to the development of personal, group, or institution level reference image catalogues of operational taxonomic units (OTUs) or morphospecies. Lack of standardisation among these reference catalogues has led to problems with observer bias and the inability to combine datasets across studies. In addition, lack of a common reference standard is stifling efforts in the application of artificial intelligence to taxon identification. Using the North Atlantic deep sea as a case study, we propose a database structure to facilitate standardisation of morphospecies image catalogues between research groups and support future use in multiple front-end applications. We also propose a framework for coordination of international efforts to develop reference guides for the identification of marine species from images. The proposed structure maps to the Darwin Core standard to allow integration with existing databases. We suggest a management framework where high-level taxonomic groups are curated by a regional team, consisting of both end users and taxonomic experts. We identify a mechanism by which overall quality of data within a common reference guide could be raised over the next decade. Finally, we discuss the role of a common reference standard in advancing marine ecology and supporting sustainable use of this ecosystem

Influence of Water Masses on the Biodiversity and Biogeography of Deep-Sea Benthic Ecosystems in the North Atlantic

Circulation patterns in the North Atlantic Ocean have changed and re-organized multiple times over millions of years, influencing the biodiversity, distribution, and connectivity patterns of deep-sea species and ecosystems. In this study, we review the effects of the water mass properties (temperature, salinity, food supply, carbonate chemistry, and oxygen) on deep-sea benthic megafauna (from species to community level) and discussed in future scenarios of climate change. We focus on the key oceanic controls on deep-sea megafauna biodiversity and biogeography patterns. We place particular attention on cold-water corals and sponges, as these are ecosystem-engineering organisms that constitute vulnerable marine ecosystems (VME) with high associated biodiversity. Besides documenting the current state of the knowledge on this topic, a future scenario for water mass properties in the deep North Atlantic basin was predicted. The pace and severity of climate change in the deep-sea will vary across regions. However, predicted water mass properties showed that all regions in the North Atlantic will be exposed to multiple stressors by 2100, experiencing at least one critical change in water temperature (+2 ◦C), organic carbon fluxes (reduced up to 50%), ocean acidification (pH reduced up to 0.3), aragonite saturation horizon (shoaling above 1000 m) and/or reduction in dissolved oxygen (>5%). The northernmost regions of the North Atlantic will suffer the greatest impacts. Warmer and more acidic oceans will drastically reduce the suitable habitat for ecosystem-engineers, with severe consequences such as declines in population densities, even compromising their long-term survival, loss of biodiversity and reduced biogeographic distribution that might compromise connectivity at large scales. These effects can be aggravated by reductions in carbon fluxes, particularly in areas where food availability is already limited. Declines in benthic biomass and biodiversity will diminish ecosystem services such as habitat provision, nutrient cycling, etc. This study shows that the deep-sea VME affected by contemporary anthropogenic impacts and with the ongoing climate change impacts are unlikely to withstand additional pressures from more intrusive human activities. This study serves also as a warning to protect these ecosystems through regulations and by tempering the ongoing socio-political drivers for increasing exploitation of marine resources