Deep-sea ecosystems and hydrothermal vents

Vertically distinct microbial communities in the Mariana and Kermadec trenches

Peoples LM, Donaldson S, Osuntokun O, Xia Q, Nelson A, Blanton J, Allen EE, Church MJ, Bartlett DH. Vertically distinct microbial communities in the Mariana and Kermadec trenches Smidt H. PLOS ONE [Internet]. 2018 ;13(4):e0195102. Available from: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0195102
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Hadal trenches, oceanic locations deeper than 6,000 m, are thought to have distinct microbial communities compared to those at shallower depths due to high hydrostatic pressures, topographical funneling of organic matter, and biogeographical isolation. Here we evaluate the hypothesis that hadal trenches contain unique microbial biodiversity through analyses of the communities present in the bottom waters of the Kermadec and Mariana trenches. Estimates of microbial protein production indicate active populations under in situ hydrostatic pressures and increasing adaptation to pressure with depth. Depth, trench of collection, and size fraction are important drivers of microbial community structure. Many putative hadal bathytypes, such as members related to the MarinimicrobiaRhodobacteraceaeRhodospirilliceae, and Aquibacter, are similar to members identified in other trenches. Most of the differences between the two trench microbiomes consists of taxa belonging to the Gammaproteobacteria whose distributions extend throughout the water column. Growth and survival estimates of representative isolates of these taxa under deep-sea conditions suggest that some members may descend from shallower depths and exist as a potentially inactive fraction of the hadal zone. We conclude that the distinct pelagic communities residing in these two trenches, and perhaps by extension other trenches, reflect both cosmopolitan hadal bathytypes and ubiquitous genera found throughout the water column.

Long-Term Stability of Back-Arc Basin Hydrothermal Vents

Preez CDu, Fisher CR. Long-Term Stability of Back-Arc Basin Hydrothermal Vents. Frontiers in Marine Science [Internet]. 2018 ;5. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2018.00054/full
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Since the discovery of hydrothermal vents 40-years ago, long-term time-series have focused on mid-ocean ridge systems. Based on these studies, hydrothermal vents are widely considered to be dynamic, ephemeral habitats. Under this premise, national, and international regulatory bodies are currently planning for the commercial mining of polymetallic sulfide deposits from hydrothermal vents. However, here we provide evidence of longevity and habitat stability that does not align with historic generalizations. Over a 10-year time-series focused on the back-arc basin systems off the west coast of the Kingdom of Tonga (South Pacific), we find the hydrothermal vents are remarkably stable habitats. Using high-resolution photo mosaics and spatially explicit in situ measurements to document natural changes of five hydrothermal vent edifices, we discovered striking stability in the vent structures themselves, as well as in the composition and coverage of the vent-associated species, with some evidence of microdistribution permanence. These findings challenge the way we think about hydrothermal vent ecosystems and their vulnerability and resilience to deep-sea mining activities.

Exploring the Ecology of Deep-Sea Hydrothermal Vents in a Metacommunity Framework

Mullineaux LS, Metaxas A, Beaulieu SE, Bright M, Gollner S, Grupe BM, Herrera S, Kellner JB, Levin LA, Mitarai S, et al. Exploring the Ecology of Deep-Sea Hydrothermal Vents in a Metacommunity Framework. Frontiers in Marine Science [Internet]. 2018 ;5. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2018.00049/full
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Species inhabiting deep-sea hydrothermal vents are strongly influenced by the geological setting, as it provides the chemical-rich fluids supporting the food web, creates the patchwork of seafloor habitat, and generates catastrophic disturbances that can eradicate entire communities. The patches of vent habitat host a network of communities (a metacommunity) connected by dispersal of planktonic larvae. The dynamics of the metacommunity are influenced not only by birth rates, death rates and interactions of populations at the local site, but also by regional influences on dispersal from different sites. The connections to other communities provide a mechanism for dynamics at a local site to affect features of the regional biota. In this paper, we explore the challenges and potential benefits of applying metacommunity theory to vent communities, with a particular focus on effects of disturbance. We synthesize field observations to inform models and identify data gaps that need to be addressed to answer key questions including: (1) what is the influence of the magnitude and rate of disturbance on ecological attributes, such as time to extinction or resilience in a metacommunity; (2) what interactions between local and regional processes control species diversity, and (3) which communities are “hot spots” of key ecological significance. We conclude by assessing our ability to evaluate resilience of vent metacommunities to human disturbance (e.g., deep-sea mining). Although the resilience of a few highly disturbed vent systems in the eastern Pacific has been quantified, these values cannot be generalized to remote locales in the western Pacific or mid Atlantic where disturbance rates are different and information on local controls is missing.

Scientific Considerations for the Assessment and Management of Mine Tailings Disposal in the Deep Sea

Vare LL, Baker MC, Howe JA, Levin LA, Neira C, Ramirez-Llodra EZ, Reichelt-Brushett A, Rowden AA, Shimmield TM, Simpson SL, et al. Scientific Considerations for the Assessment and Management of Mine Tailings Disposal in the Deep Sea. Frontiers in Marine Science [Internet]. 2018 ;5. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2018.00017/full
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Deep-sea tailings disposal (DSTD) and its shallow water counterpart, submarine tailings disposal (STD), are practiced in many areas of the world, whereby mining industries discharge processed mud- and rock-waste slurries (tailings) directly into the marine environment. Pipeline discharges and other land-based sources of marine pollution fall beyond the regulatory scope of the London Convention and the London Protocols (LC/LP). However, guidelines have been developed in Papua New Guinea (PNG) to improve tailings waste management frameworks in which mining companies can operate. DSTD can impact ocean ecosystems in addition to other sources of stress, such as from fishing, pollution, energy extraction, tourism, eutrophication, climate change and, potentially in the future, from deep-seabed mining. Environmental management of DSTD may be most effective when placed in a broader context, drawing expertise, data and lessons from multiple sectors (academia, government, society, industry, and regulators) and engaging with international deep-ocean observing programs, databases and stewardship consortia. Here, the challenges associated with DSTD are identified, along with possible solutions, based on the results of a number of robust scientific studies. Also highlighted are the key issues, trends of improved practice and techniques that could be used if considering DSTD (such as increased precaution if considering submarine canyon locations), likely cumulative impacts, and research needed to address current knowledge gaps.

The State of Deep‐Sea Coral and Sponge Ecosystems of the United States

Hourigan TF, Etnoyer PJ, Cairns SD. The State of Deep‐Sea Coral and Sponge Ecosystems of the United States. Silver Spring, MD: National Oceanic and Atmospheric Administration; 2017. Available from: https://deepseacoraldata.noaa.gov/library/2017-state-of-deep-sea-corals-report
Freely available?: 
Yes
Summary available?: 
No
Type: Report

Corals and sponges create the most important biogenic habitats in the deep sea, and support ecosystems of incredible variety and biodiversity. In 2007, the United States National Oceanic and Atmospheric Administration (NOAA) published the first peer‐reviewed report on the State of Deep Coral Ecosystems of the United States (Lumsden et al. 2007). The 2017 report on the State of Deep‐Sea Coral and Sponge Ecosystems of the United States updates information on deep‐sea coral ecosystems and management efforts to protect them over the last decade, and presents a first summary of information on U.S. deep‐sea sponge ecosystems. It consists of an introduction, six regional chapters with accompanying on‐line resources, and six spotlight chapters that highlight advances on crosscutting themes.

Incidence of disturbance and damage to deep-sea corals and sponges in areas of high trawl bycatch near the California and Oregon border

Yoklavich MM, Laidig TE, Graiff K, M. Clarke E, Whitmire CE. Incidence of disturbance and damage to deep-sea corals and sponges in areas of high trawl bycatch near the California and Oregon border. Deep Sea Research Part II: Topical Studies in Oceanography [Internet]. 2017 . Available from: http://www.sciencedirect.com/science/article/pii/S0967064517300966
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $39.95
Type: Journal Article

We evaluated disturbance and damage to deep-sea corals and sponges (DSCS) in areas of longtime (>65 years) bottom trawling off southern Oregon and northern California. The incidence of disturbance was quantified from video and still images collected along strip transects conducted with underwater vehicles operating at depths of 600-2,100 m. All DSCS were identified, counted, and measured, condition (healthy, unhealthy, or dead) was determined, and associated seafloor substratum types were designated. Physical disturbance and damage were classified as DSCS with broken or missing parts, overturned, or detached from the seafloor. Overall frequency of disturbance to DSCS throughout the study area was 2% of the total number observed; most of these were coral colonies while sponges were rarely damaged. There was notable disturbance to corals, particularly to bamboo corals of the family Isididae (45% of 873 colonies were impacted), at depths of 1100–1150 m in our most northern study site off southern Oregon and the southern site off Cape Mendocino, California. Nearly 20% (n=78) of disturbed bamboo corals were sheared off at the base, leaving only small stumps to be counted. Height of intact undisturbed bamboo coral colonies ranged from 5 to 185 cm. The Mendocino Ridge area had the highest incidence of coral bycatch in research bottom trawls conducted between 2001 and 2015. Using visual survey tools, we now have a better understanding of the extent of damage and disturbance to DSCS. Conservation areas have been implemented off the U.S. West Coast to protect seafloor habitats, but DSCS in our study site remain vulnerable to impacts from bottom-contact fishing gears.

Invertebrate population genetics across Earth's largest habitat: The deep-sea floor

Taylor ML, Roterman CN. Invertebrate population genetics across Earth's largest habitat: The deep-sea floor. Molecular Ecology [Internet]. 2017 . Available from: http://onlinelibrary.wiley.com/doi/10.1111/mec.14237/abstract
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Despite the deep sea being the largest habitat on Earth, there are just 77 population genetic studies of invertebrates (115 species) inhabiting non-chemosynthetic ecosystems on the deep-sea floor (below 200 m depth). We review and synthesize the results of these papers. Studies reveal levels of genetic diversity comparable to shallow-water species. Generally, populations at similar depths were well connected over 100s–1,000s km, but studies that sampled across depth ranges reveal population structure at much smaller scales (100s–1,000s m) consistent with isolation by adaptation across environmental gradients, or the existence of physical barriers to connectivity with depth. Few studies were ocean-wide (under 4%), and 48% were Atlantic-focused. There is strong emphasis on megafauna and commercial species with research into meiofauna, “ecosystem engineers” and other ecologically important species lacking. Only nine papers account for ~50% of the planet's surface (depths below 3,500 m). Just two species were studied below 5,000 m, a quarter of Earth's seafloor. Most studies used single-locus mitochondrial genes revealing a common pattern of non-neutrality, consistent with demographic instability or selective sweeps; similar to deep-sea hydrothermal vent fauna. The absence of a clear difference between vent and non-vent could signify that demographic instability is common in the deep sea, or that selective sweeps render single-locus mitochondrial studies demographically uninformative. The number of population genetics studies to date is miniscule in relation to the size of the deep sea. The paucity of studies constrains meta-analyses where broad inferences about deep-sea ecology could be made.

Microplastic pollution identified in deep-sea water and ingested by benthic invertebrates in the Rockall Trough, North Atlantic Ocean

Courtene-Jones W, Quinn B, Gary SF, Mogg AOM, Narayanaswamy BE. Microplastic pollution identified in deep-sea water and ingested by benthic invertebrates in the Rockall Trough, North Atlantic Ocean. Environmental Pollution [Internet]. 2017 ;231:271 - 280. Available from: http://www.sciencedirect.com/science/article/pii/S0269749117312885
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $35.95
Type: Journal Article

Microplastics are widespread in the natural environment and present numerous ecological threats. While the ultimate fate of marine microplastics are not well known, it is hypothesized that the deep sea is the final sink for this anthropogenic contaminant. This study provides a quantification and characterisation of microplastic pollution ingested by benthic macroinvertebrates with different feeding modes (Ophiomusium lymani, Hymenaster pellucidus and Colus jeffreysianus) and in adjacent deep water > 2200 m, in the Rockall Trough, Northeast Atlantic Ocean. Despite the remote location, microplastic fibres were identified in deep-sea water at a concentration of 70.8 particles m−3, comparable to that in surface waters. Of the invertebrates examined (n = 66), 48% ingested microplastics with quantities enumerated comparable to coastal species. The number of ingested microplastics differed significantly between species and generalized linear modelling identified that the number of microplastics ingested for a given tissue mass was related to species and not organism feeding mode or the length or overall weight of the individual. Deep-sea microplastics were visually highly degraded with surface areas more than double that of pristine particles. The identification of synthetic polymers with densities greater and less than seawater along with comparable quantities to the upper ocean indicates processes of vertical re-distribution. This study presents the first snapshot of deep ocean microplastics and the quantification of microplastic pollution in the Rockall Trough. Additional sampling throughout the deep-sea is required to assess levels of microplastic pollution, vertical transportation and sequestration, which have the potential to impact the largest global ecosystem.

Stakeholder perspectives on the importance of rare-species research for deep-sea environmental management

Turner PJ, Campbell LM, Van Dover CL. Stakeholder perspectives on the importance of rare-species research for deep-sea environmental management. Deep Sea Research Part I: Oceanographic Research Papers [Internet]. 2017 . Available from: http://www.sciencedirect.com/science/article/pii/S0967063716304356
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $39.95
Type: Journal Article

The apparent prevalence of rare species (rarity) in the deep sea is a concern for environmental management and conservation of biodiversity. Rare species are often considered at risk of extinction and, in terrestrial and shallow water environments, have been shown to play key roles within an ecosystem. In the deep-sea environment, current research focuses primarily on abundant species and deep-sea stakeholders are questioning the importance of rare species in ecosystem functioning. This study asks whether deep-sea stakeholders (primarily scientists) view rare-species research as a priority in guiding environmental management. Delphi methodology (i.e., an iterative survey approach) was used to understand views about whether or not ‘deep-sea scientists should allocate more resources to research on rare species in the deep sea, even if this means less resources might be available for abundant-species research.’ Results suggest little consensus regarding the prioritization of resources for rare-species research. From Survey 1 to Survey 3, the average participant response shifted toward a view that rare-species research is not a priority if it comes at a cost to research on abundant species. Participants pointed to the need for a balanced approach and highlighted knowledge gaps about even the most fundamental questions, including whether rare species are truly ‘rare’ or simply under-sampled. Participants emphasized the lack of basic biological knowledge for rare and abundant species, particularly abundant meio- and microscopic species, as well as uncertainty in the roles rare and abundant species play in ecosystem processes. Approaches that jointly consider the role of rare and abundant species in ecosystem functioning (e.g., biological trait analysis) may help to clarify the extent to which rare species need to be incorporated into deep-sea environment management in order to maintain ecosystem functioning.

Deep-sea genetic resources: New frontiers for science and stewardship in areas beyond national jurisdiction

Harden-Davies H. Deep-sea genetic resources: New frontiers for science and stewardship in areas beyond national jurisdiction. Deep Sea Research Part II: Topical Studies in Oceanography [Internet]. 2017 ;137:504 - 513. Available from: http://www.sciencedirect.com/science/article/pii/S0967064516301059
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $39.95
Type: Journal Article

The deep-sea is a large source of marine genetic resources (MGR), which have many potential uses and are a growing area of research. Much of the deep-sea lies in areas beyond national jurisdiction (ABNJ), including 65% of the global ocean. MGR in ABNJ occupy a significant gap in the international legal framework. Access and benefit sharing of MGR is a key issue in the development of a new international legally-binding instrument under the United Nations Convention on the Law of the Sea (UNCLOS) for the conservation and sustainable use of marine biological diversity in ABNJ. This paper examines how this is relevant to deep-sea scientific research and identifies emerging challenges and opportunities. There is no internationally agreed definition of MGR, however, deep-sea genetic resources could incorporate any biological material including genes, proteins and natural products. Deep-sea scientific research is the key actor accessing MGR in ABNJ and sharing benefits such as data, samples and knowledge. UNCLOS provides the international legal framework for marine scientific research, international science cooperation, capacity building and marine technology transfer. Enhanced implementation could support access and benefit sharing of MGR in ABNJ. Deep-sea scientific researchers could play an important role in informing practical new governance solutions for access and benefit sharing of MGR that promote scientific research in ABNJ and support deep-sea stewardship. Advancing knowledge of deep-sea biodiversity in ABNJ, enhancing open-access to data and samples, standardisation and international marine science cooperation are significant potential opportunity areas.

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