Deep-sea ecosystems and hydrothermal vents

A new classification scheme of European cold-water coral habitats: implications for ecosystem-based management of the deep sea

Davies JS, Guillaumont B, Tempera F, Vertino A, Beuck L, Ólafsdóttir SH, Smith C, Fosså JH, van den Beld IMJ, Savini A, et al. A new classification scheme of European cold-water coral habitats: implications for ecosystem-based management of the deep sea. Deep Sea Research Part II: Topical Studies in Oceanography [Internet]. 2017 . Available from: http://www.sciencedirect.com/science/article/pii/S0967064517301303
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $39.95
Type: Journal Article

Cold-water coral (CWC) habitats can form complex structures which provide refuge, nursery grounds and physical support for a diversity of other living organisms, but despite their ecological significance, CWCs are still vulnerable to human pressures such as fishing, pollution, ocean acidification and global warming

Providing coherent and representative conservation of vulnerable marine ecosystems including CWCs is one of the aims of the Marine Protected Areas networks being implemented across European seas and oceans under the EC Habitats Directive, the Marine Strategy Framework Directive and the OSPAR Convention. In order to adequately represent ecosystem diversity these initiatives require a standardised habitat classification that organises the variety of biological assemblages and provides consistent and functional criteria to map them across European Seas (Howell 2010). One such classification system, EUNIS, enables a broad level classification of the deep sea based on abiotic and geomorphological features. More detailed lower biotope-related levels are currently under-developed, particularly with regards deep-water habitats (>200 m depth).

This paper proposes a hierarchical CWC biotope classification scheme that could be incorporated by existing classification schemes such as EUNIS. The scheme was developed within the EU FP7 project CoralFISH to capture the variability of CWC habitats identified using a wealth of seafloor imagery datasets from across European seas and oceans. Depending on the resolution of the imagery being interpreted, this hierarchical scheme allows data to be recorded from broad CWC biotope categories down to detailed taxonomy-based levels, thereby providing a flexible yet valuable information level for management. The CWC biotope classification scheme identifies 81 biotopes and highlights the limitations of the classification framework and guidance provided by EUNIS, the EC Habitats Directive, OSPAR and FAO; with limited categories for identifying and classifying these CWC habitats.

Major impacts of climate change on deep-sea benthic ecosystems

Sweetman AK, Thurber AR, Smith CR, Levin LA, Mora C, Wei C-L, Gooday AJ, Jones DOB, Rex M, Yasuhara M, et al. Major impacts of climate change on deep-sea benthic ecosystems. Elem Sci Anth [Internet]. 2017 ;5:4. Available from: https://www.elementascience.org/article/10.1525/elementa.203/
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The deep sea encompasses the largest ecosystems on Earth. Although poorly known, deep seafloor ecosystems provide services that are vitally important to the entire ocean and biosphere. Rising atmospheric greenhouse gases are bringing about significant changes in the environmental properties of the ocean realm in terms of water column oxygenation, temperature, pH and food supply, with concomitant impacts on deep-sea ecosystems. Projections suggest that abyssal (3000–6000 m) ocean temperatures could increase by 1°C over the next 84 years, while abyssal seafloor habitats under areas of deep-water formation may experience reductions in water column oxygen concentrations by as much as 0.03 mL L–1 by 2100. Bathyal depths (200–3000 m) worldwide will undergo the most significant reductions in pH in all oceans by the year 2100 (0.29 to 0.37 pH units). O2 concentrations will also decline in the bathyal NE Pacific and Southern Oceans, with losses up to 3.7% or more, especially at intermediate depths. Another important environmental parameter, the flux of particulate organic matter to the seafloor, is likely to decline significantly in most oceans, most notably in the abyssal and bathyal Indian Ocean where it is predicted to decrease by 40–55% by the end of the century. Unfortunately, how these major changes will affect deep-seafloor ecosystems is, in some cases, very poorly understood. In this paper, we provide a detailed overview of the impacts of these changing environmental parameters on deep-seafloor ecosystems that will most likely be seen by 2100 in continental margin, abyssal and polar settings. We also consider how these changes may combine with other anthropogenic stressors (e.g., fishing, mineral mining, oil and gas extraction) to further impact deep-seafloor ecosystems and discuss the possible societal implications. 

Conservation of deep-sea ecosystems within offshore oil fields on the Brazilian margin, SW Atlantic

Almada GVaz de Mel, Bernardino AFraga. Conservation of deep-sea ecosystems within offshore oil fields on the Brazilian margin, SW Atlantic. Biological Conservation [Internet]. 2017 ;206:92 - 101. Available from: http://www.sciencedirect.com/science/article/pii/S0006320716311089
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

The exploration of deep-sea mineral resources on continental margins is increasing worldwide. In the SW Atlantic, Campos Basin has been Brazil's main deep-sea area for oil and gas extraction since the 1980′s, with currently over 11,000 km2 of leased blocks below 200 m depth. The historical record of exploration and the lack of a basin-wide management for the offshore industry in the SW Atlantic threaten the biodiversity and ecological function of vulnerable deep-sea ecosystems. This study identified habitats of biological interest on the Campos Basin and proposes relevant areas for conservation (EBSAs) that could be included in the first deep-sea Marine Protected Area (MPA) network in the South Atlantic. A total of 42 benthic habitats were mapped including cold-water coral reefs, submarine canyons, soft sediment slope and a seamount. Those habitats fill conservation criteria to be proposed as EBSAs along Campos Basin and could support a MPA network with a 5.5% overlap (2330 km2) to current leased blocks. If implemented, the MPA network would cover 31% of the Campos Basin and offer 31–100% protection of EBSAs with minimal interference on industry. This study is the first to identify EBSAs in a deep-sea basin of major economic importance in Brazil's EEZ and their conservation would also protect areas at two biogeographic provinces in the South Atlantic. Furthermore, the methods demonstrated here could be widely applied to other offshore oil and gas areas that lack environmental management measures at early stages of bidding rounds or during the process of environmental licensing.

The distribution of deep-sea sponge aggregations in the North Atlantic and implications for their effective spatial management

Howell K-L, Piechaud N, Downie A-L, Kenny A. The distribution of deep-sea sponge aggregations in the North Atlantic and implications for their effective spatial management. Deep Sea Research Part I: Oceanographic Research Papers [Internet]. 2016 ;115:309 - 320. Available from: http://www.sciencedirect.com/science/article/pii/S0967063716300097
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

Sponge aggregations have been recognised as key component of shallow benthic ecosystems providing several important functional roles including habitat building and nutrient recycling. Within the deep-sea ecosystem, sponge aggregations may be extensive and available evidence suggests they may also play important functional roles, however data on their ecology, extent and distribution in the North Atlantic is lacking, hampering conservation efforts. In this study, we used Maximum Entropy Modelling and presence data for two deep-sea sponge aggregation types, Pheronema carpenteriaggregations and ostur aggregations dominated by geodid sponges, to address the following questions: 1) What environmental factors drive the broad-scale distribution of these selected sponge grounds? 2) What is the predicted distribution of these grounds in the northern North Atlantic, Norwegian and Barents Sea? 3) How are these sponge grounds distributed between Exclusive Economic Zones (EEZs) and High Seas areas? 4) What percentage of these grounds in High Seas areas are protected by the current High Seas MPA network? Our results suggest that silicate concentration, temperature, depth and amount of particulate organic carbon are the most important drivers of sponge distribution. Most of the sponge grounds are located within national EEZs rather than in the High Seas. Coordinated conservation planning between nations with significant areas of sponge grounds such as Iceland, Greenland and Faroes (Denmark), Norway (coastal Norway and Svalbard), Portugal and the UK, should be implemented in order to effectively manage these communities in view of the increasing level of human activity within the deep-sea environment.

Ecosystem status of the deep Black Sea, soft sediment, benthic community

Collins PC, Carlsson J, Rowcroft P, Tibbles B. Ecosystem status of the deep Black Sea, soft sediment, benthic community. Marine Policy [Internet]. 2016 ;73:216 - 223. Available from: http://www.sciencedirect.com/science/article/pii/S0308597X16304833
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

The deep soft sediment Black Sea benthic community is dominated by cold seep habitats formed by the microbial breakdown of phytoplankton. The deep Black Sea benthic ecosystem is chemosynthetic with methanogenesis and the sulfate-driven anaerobic oxidation of methane acting as the primary metabolic pathways. Due to the depth and lack of metazoan life the deep Black Sea benthic ecosystem is generally regarded to be at low risk from anthropogenic impact and has little legislation pertaining directly to the preservation of the chemosynthetic habitats. The principal ecosystem services provided by the Black Sea include carbon sequestration and preservation of historical artefacts. Compared to other ecosystems, information on microbial biodiversity and ecosystem services in the deep Black Sea is lacking, and we highlight a need to plan and implement research programmes to address significant gaps and to enhance scientific understanding of this environment.

A synthesis of genetic connectivity in deep-sea fauna and implications for marine reserve design

Baco AR, Etter RJ, Ribeiro PA, von der Heyden S, Beerli P, Kinlan BP. A synthesis of genetic connectivity in deep-sea fauna and implications for marine reserve design. Molecular Ecology [Internet]. 2016 ;25(14):3276 - 3298. Available from: http://onlinelibrary.wiley.com/doi/10.1111/mec.13689/abstract
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

With anthropogenic impacts rapidly advancing into deeper waters, there is growing interest in establishing deep-sea marine protected areas (MPAs) or reserves. Reserve design depends on estimates of connectivity and scales of dispersal for the taxa of interest. Deep-sea taxa are hypothesized to disperse greater distances than shallow-water taxa, which implies that reserves would need to be larger in size and networks could be more widely spaced; however, this paradigm has not been tested. We compiled population genetic studies of deep-sea fauna and estimated dispersal distances for 51 studies using a method based on isolation-by-distance slopes. Estimates of dispersal distance ranged from 0.24 km to 2028 km with a geometric mean of 33.2 km and differed in relation to taxonomic and life-history factors as well as several study parameters. Dispersal distances were generally greater for fishes than invertebrates with the Mollusca being the least dispersive sampled phylum. Species that are pelagic as adults were more dispersive than those with sessile or sedentary lifestyles. Benthic species from soft-substrate habitats were generally less dispersive than species from hard substrate, demersal or pelagic habitats. As expected, species with pelagic and/or feeding (planktotrophic) larvae were more dispersive than other larval types. Many of these comparisons were confounded by taxonomic or other life-history differences (e.g. fishes being more dispersive than invertebrates) making any simple interpretation difficult. Our results provide the first rough estimate of the range of dispersal distances in the deep sea and allow comparisons to shallow-water assemblages. Overall, dispersal distances were greater for deeper taxa, although the differences were not large (0.3–0.6 orders of magnitude between means), and imbalanced sampling of shallow and deep taxa complicates any simple interpretation. Our analyses suggest the scales of dispersal and connectivity for reserve design in the deep sea might be comparable to or slightly larger than those in shallow water. Deep-sea reserve design will need to consider the enormous variety of taxa, life histories, hydrodynamics, spatial configuration of habitats and patterns of species distributions. The many caveats of our analyses provide a strong impetus for substantial future efforts to assess connectivity of deep-sea species from a variety of habitats, taxonomic groups and depth zones.

Deep Sea Coral Research and Technology Program 2016 Report to Congress

Anon. Deep Sea Coral Research and Technology Program 2016 Report to Congress. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service; 2016 p. 58. Available from: http://www.habitat.noaa.gov/pdf/NOAA_DSC_Report_2016.pdf
Freely available?: 
Yes
Summary available?: 
No
Type: Report

Deep-sea coral and sponge habitats support the richest and most complex biological communities in the deep sea. NOAA’s Deep Sea Coral Research and Technology Program is providing the first systematic effort to discover and understand these ecosystems, combining science and information-sharing to help ocean managers conserve valuable habitats. The Program proudly announces its 2016 Report to Congress, highlighting exciting scientific research conducted over the past two-year period and historic conservation measures that have been proposed and enacted based on our Program’s results. The report spans the globe, from the remote Johnston Atoll in the middle of the Pacific Ocean to previously unknown coral gardens teeming with redfish only 25 miles off the coast of Maine. The Deep Sea Coral Research and Technology Program’s website also provides fieldwork reports and a searchable map in the nation’s most comprehensive online database of deep-sea corals and sponges. Armed with such information, the Mid-Atlantic Fishery Management Council is the most recent council to propose measures to protect deep-sea coral habitat from impacts of fishing. The Gulf of Maine also earns a spotlight because its deep-sea coral gardens are a major discovery – in addition to reading the report, take a virtual dive into this offshore habitat!

The impacts of deep-sea fisheries on benthic communities: a review

Clark MR, Althaus F, Schlacher TA, Williams A, Bowden DA, Rowden AA. The impacts of deep-sea fisheries on benthic communities: a review. ICES Journal of Marine Science [Internet]. 2016 ;73(suppl 1):i51 - i69. Available from: http://icesjms.oxfordjournals.org/content/73/suppl_1/i51.abstract?etoc
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Deep-sea fisheries operate globally throughout the world's oceans, chiefly targeting stocks on the upper and mid-continental slope and offshore seamounts. Major commercial fisheries occur, or have occurred, for species such as orange roughy, oreos, cardinalfish, grenadiers and alfonsino. Few deep fisheries have, however, been sustainable, with most deep-sea stocks having undergone rapid and substantial declines. Fishing in the deep sea not only harvests target species but can also cause unintended environmental harm, mostly from operating heavy bottom trawls and, to a lesser extent, bottom longlines. Bottom trawling over hard seabed (common on seamounts) routinely removes most of the benthic fauna, resulting in declines in faunal biodiversity, cover and abundance. Functionally, these impacts translate into loss of biogenic habitat from potentially large areas. Recent studies on longline fisheries show that their impact is much less than from trawl gear, but can still be significant. Benthic taxa, especially the dominant mega-faunal components of deep-sea systems such as corals and sponges, can be highly vulnerable to fishing impacts. Some taxa have natural resilience due to their size, shape, and structure, and some can survive in natural refuges inaccessible to trawls. However, many deep-sea invertebrates are exceptionally long-lived and grow extremely slowly: these biological attributes mean that the recovery capacity of the benthos is highly limited and prolonged, predicted to take decades to centuries after fishing has ceased. The low tolerance and protracted recovery of many deep-sea benthic communities has implications for managing environmental performance of deep-sea fisheries, including that (i) expectations for recovery and restoration of impacted areas may be unrealistic in acceptable time frames, (ii) the high vulnerability of deep-sea fauna makes spatial management—that includes strong and consistent conservation closures—an important priority, and (iii) biodiversity conservation should be > balanced with options for open areas that support sustainable fisheries.

Deep Sea Coral Research and Technology Program 2014 Report to Congress

Anon. Deep Sea Coral Research and Technology Program 2014 Report to Congress. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service; 2014 p. 54. Available from: http://www.habitat.noaa.gov/protection/corals/deepseacorals.html
Freely available?: 
Yes
Summary available?: 
No
Type: Report

This report features an overview of the Program’s continuing regional three-year field studies. Accompanying the details of the fieldwork are stunning video footage and still photos of this unique marine life in all regions of the U.S.

Throughout the country, the Councils are increasingly engaged in developing methods to manage potential impacts of fisheries to deep-sea coral areas, recognizing these habitats’ role in the ecosystem. And yet, the geographic distribution of deep-sea corals and the full extent of their function as fish habitats have not been adequately studied, thus limiting some Councils’ ability to design management measures. In 2012 and 2013, the Program made considerable progress in filling these knowledge gaps by locating and characterizing deep-sea coral sites and submitting the findings to the Councils.

At $2.46 million in fiscal year 2012 and $2.37 million in fiscal year 2013, NOAA’s Deep Sea Coral Research and Technology Program is cost-effective in generating information of immediate use to Regional Fishery Management Councils and other resource managers in conserving structurally complex habitats formed by deep-sea corals.

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