Physiological constraints will be investigated by examining in-situ respiration of selected fauna and tissue concentrations of such protein stabilizers as trimethylamine oxide TMAO , and the structural adaptations of macromolecules.
We feel these objectives represent an achievable and powerful combination of current technological capability, scientific understanding and theory, and the expertise of an international consortium of scientists.
Given the historical knowledge of trenches around the world and ongoing research within our consortium, our objectives are best met when focussed on conducting them in the Kermadec Trench.
The Kermadec Trench SW Pacific is a hadal environment that provided data for the earliest appreciations of trench ecosystems Wolff and where some of the most recent trench research has been and is being undertaken Blankenship et al. The Kermadec Trench has a gradient in depth both across its axis and along its length, and lies in close proximity to a variety of other habitat types in the Kermadec region seamounts, ridges, slope, and abyssal plain. As such, extensive comparisons between these habitats and the trench and abyssal environments can be made, placing the hadal fauna in a direct ecological context for the first time.
Advancing knowledge of trench and hadal ecosystems, informing stewardship of the deep ocean. The oceans are home to millions of Earth's plants and animals—from tiny single-celled organisms to the gargantuan blue whale , the planet's largest living animal.
Fish, octopuses, squid, eels, dolphins, and whales swim the open waters while crabs, octopuses, starfish, oysters, and snails crawl and scoot along the ocean bottom. Life in the ocean depends on phytoplankton, mostly microscopic organisms that float at the surface and, through photosynthesis, produce about half of the world's oxygen. Other fodder for sea dwellers includes seaweed and kelp, which are types of algae, and seagrasses , which grow in shallower areas where they can catch sunlight.
The deepest reaches of the ocean were once thought to be devoid of life, since no light penetrates beyond 1, meters 3, feet. But then hydrothermal vents were discovered. These chimney-like structures allow tube worms, clams, mussels, and other organisms to survive not via photosynthesis but chemosynthesis, in which microbes convert chemicals released by the vents into energy.
Bizarre fish with sensitive eyes, translucent flesh , and bioluminescent lures jutting from their heads lurk about in nearby waters, often surviving by eating bits of organic waste and flesh that rain down from above, or on the animals that feed on those bits.
Despite regular discoveries about the ocean and its denizens, much remains unknown. More than 80 percent of the ocean is unmapped and unexplored , which leaves open the question of how many species there are yet to be discovered. At the same time, the ocean hosts some of the world's oldest creatures: Jellyfish have been around more than half a billion years , horseshoe crabs almost as long.
Other long-lived species are in crisis. The tiny, soft-bodied organisms known as coral , which form reefs mostly found in shallow tropical waters, are threatened by pollution, sedimentation, and global warming. Researchers are seeking ways to preserve fragile, ailing ecosystems such as Australia's Great Barrier Reef. Human activities affect nearly all parts of the ocean. Lost and discarded fishing nets continue to lethally snare fish , seabirds, and marine mammals as they drift.
Ships spill oil and garbage; they also transport critters to alien habitats unprepared for their arrival, turning them into invasive species. Mangrove forests are cleared for homes and industry.
Our garbage— particularly plastic —chokes the seas, creating vast " garbage patches " such as the Great Pacific Garbage Patch.
Ocean trench es are long, narrow depression s on the seafloor. These chasm s are the deepest parts of the ocean—and some of the deepest natural spots on Earth.
In particular, ocean trenches are a feature of convergent plate boundaries, where two or more tectonic plate s meet. At many convergent plate boundaries, dense lithosphere melts or slides beneath less-dense lithosphere in a process called subduction , creating a trench. Ocean trenches occupy the deepest layer of the ocean, the hadalpelagic zone. The intense pressure, lack of sunlight, and frigid temperatures of the hadalpelagic zone make ocean trenches some of the most unique habitat s on Earth.
When the leading edge of a dense tectonic plate meets the leading edge of a less-dense plate, the denser plate bends downward. This place where the denser plate subducts is called a subduction zone. Oceanic subduction zones almost always feature a small hill preceding the ocean trench itself. This hill, called the outer trench swell , marks the region where the subducting plate begins to buckle and fall beneath the more buoyant plate.
Some ocean trenches are formed by subduction between a plate carrying continental crust and a plate carrying oceanic crust. Continental crust is always much more buoyant than oceanic crust, and oceanic crust will always subduct. Ocean trenches formed by this continental-oceanic boundary are asymmetric al. On the inner slope continental side , the trench walls are much more steep. The types of rocks found in these ocean trenches are also asymmetrical.
The oceanic side is dominate d by thick sedimentary rock s, while the continental side generally has a more igneous and metamorphic composition. Some of the most familiar ocean trenches are the result of this type of convergent plate boundary. The Peru-Chile Trench off the west coast of South America is formed by the oceanic crust of the Nazca plate subducting beneath the continental crust of the South American plate.
The Ryukyu Trench, stretching out from southern Japan, is formed as the oceanic crust of the Philippine plate subducts beneath the continental crust of the Eurasian plate. More rarely, ocean trenches can be formed when two plates carrying oceanic crust meet. The Mariana Trench, in the South Pacific Ocean, is formed as the mighty Pacific plate subducts beneath the smaller, less-dense Philippine plate. In a subduction zone, some of the molten material—the former seafloor—can rise through volcanoes located near the trench.
However, measuring the value of ecosystem services provided by the deep sea and making it conceivable by putting a monetary value to it might increase awareness.
Preserving the biodiversity of the deep sea may not be of the highest priority to policy makers and the general public but this is a dangerous gamble. Very little is known about the ecosystem, such as its key species, which species rely on each other, and any rare species responsible in maintaining the habitat Herring, Hence, we cannot make reliable estimates of our impact and the implications of human disturbance.
As humans have a direct impact on the deep sea, a thorough inspection of the implications for the environment must be made. As in all other environments, there is a mitigation hierarchy to consider when planning any project that has an impact on any environment as established first for the US wetlands mitigation framework McKenney and Kiesecker, It applies equally to the deep sea and is even more difficult to reach there since so little is known about the environmental variables.
The first consideration must always be avoidance. It is important to note that the Nature already made clear that economic advantages should never come before ecological considerations, which applies heavily to deep-sea mining European Commission, If the advantages outweigh the environmental impact, the second step in the hierarchy must be applied: minimizing the impact McKenney and Kiesecker, In the deep-sea environment, examples for minimizing are to reduce sediment plumes resulting from heavy machinery used on the ocean floor Niner et al.
Unfortunately, in the context of deep-sea mining, current technology is unable to protect biodiversity, which renders the minimization objective useless Niner et al. The last resort of the hierarchy is remediation, or offsetting the damage done to outbalance the negative effects. This would encompass attempts to restore the natural biodiversity in the habitat by recolonizing it with larvae from similar environments, or providing a substrate suitable for the naturally occurring organisms to attach after removing the natural hard substrate e.
However, in the deep-sea context, it remains to be seen if remediation is possible, and we are not able to say with confidence what a good remediation project looks like in the deep sea.
While the deep sea might seem like an extreme environment to us, life is highly adapted to this environment just as it is in dark caves, deserts, and on high mountain ranges. More and more evidence is emerging that our expectations for the extreme nature of the organisms there is really exaggerated, and the ecological concepts we know from other ecosystems also apply McClain et al.
This may help us decide how to mitigate effects such as ocean temperature or acidity changes. Unfortunately, it is difficult to gain traction when discussing why biodiversity in the deep sea is important, as it seems far removed to our daily lives.
This is a misconception; the deep sea does offer goods and services whose loss would impact our daily lives. For example, the deep sea is an important carbon sink and provides us with resources such as fish, oil, or gas Armstrong et al. The deep sea is not only an important player in climate change mitigation, it also has the potential to provide us with important pharmaceutical compounds and cycle nutrients that make life on Earth possible Figure 5. Figure 5. Ecosystem services of the deep sea as discussed in Armstrong et al.
In general, the same problems occur in the deep sea that are worrisome in the shallow oceans as well, including the effects of climate change on the biodiversity of the habitat. Humans are already exploiting deep-sea fish stocks and are planning to exploit other deep-sea resources in the near future for material needs.
This will without a doubt have lasting effects on the affected ecosystems, which should in itself be a serious deterrent for humans. While this may not be enough, research into the effects of the entire ocean ecosystem has to be stimulated, to highlight the importance of the deep sea as a habitat and an environment worth preserving. With regards to deep-sea mining, it is still possible to halt large-scale exploitation of the ocean floor, however, if any metals are mined, it is critical to guarantee that they are used responsibly.
With an expected increase in renewable energy usage around the globe, we need to be aware that these technologies rely heavily on metals Kleijn et al. Consequently, we need to assure that any mined metals are used for such technologies, decreasing our carbon footprint overall and fighting climate change.
In addition, no-take zones need to be established that are close-by and where biodiversity is similar to the mined areas—this is instrumental in aiding recovery through recolonization and increasing resilience of the habitat Jones et al.
While there are many publications highlighting the threats of deep-sea mining and how this may affect biodiversity, few studies aim to illuminate the effects of fishing on the deep sea. Gauging resilience in a habitat such as the deep sea is difficult, since long-term studies are expensive and experiments showing the influence of deep-sea mining are scarce and in no relation to large-scale mining operations planned in the future.
Current research on artificial nodules deployed in the CCZ will determine whether colonization of artificial substrates is possible and within a reasonable timeframe De Stigter et al. We have only just begun researching the deep sea, and long-term studies are desperately needed to truly understand resilience and recovery rates from disturbances. There are many knowledge gaps about the deep-sea environment, but we can say one thing for sure—we are currently damaging the delicate balance of the largest ecosystem on earth, with unknown implications for our own survival and other closely interwoven environments.
EP drafted and critically reviewed the article based on the comments and suggestions of two anonymous peer reviewers. The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Amon, D. Insights into the abundance and diversity of abyssal megafauna in a polymetallic-nodule region in the eastern Clarion-Clipperton Zone.
Anderson, T. Deserts on the sea floor: edward Forbes and his azoic hypothesis for a lifeless deep ocean. Endeavour 30, — Google Scholar. Armstrong, C.
Services from the deep: steps towards valuation of deep sea goods and services. Ashford, O. Investigating the environmental drivers of deep-seafloor biodiversity: a case study of peracarid crustacean assemblages in the Northwest Atlantic Ocean. Baillon, S. Deep cold-water corals as nurseries for fish larvae.
Bebber, D. Predicting unknown species numbers using discovery curves. B Biol. Billett, D. Deep Sea Res. Pt II 57, — Seasonal sedimentation of phytoplankton to the deep-sea benthos. Nature , — Bodil, B. Diversity of the arctic deep-sea benthos. Boehlert, G. A review of the effects of seamounts on biological processes. Boucher, G.
Ecological biodiversity of marine nematodes in samples from temperate, tropical, and deep-sea regions. Bowden, D. Clark, M. Consalvey, and A. Rowden Chichester: Wiley-Blackwell , — Brito-Morales, I. Climate velocity reveals increasing exposure of deep-ocean biodiversity to future warming. Brondizio, E. Brotz, L. Increasing jellyfish populations: trends in large marine ecosystems. Hydrobiologia , 3— Brown, A. Explaining bathymetric diversity patterns in marine benthic invertebrates and demersal fishes: physiological contributions to adaptation of life at depth.
Browne, M. Microplastic moves pollutants and additives to worms, reducing functions linked to health and biodiversity. Burney, D. Fifty millennia of catastrophic extinctions after human contact. Trends Ecol. Butman, C. Whaling effects on deep-sea biodiversity. Ceballos, G. Accelerated modern human—induced species losses: entering the sixth mass extinction. Choy, C.
The vertical distribution and biological transport of marine microplastics across the epipelagic and mesopelagic water column. Christiansen, B. Fisheries for orange roughy Hoplostethus atlanticus on seamounts in New Zealand. Acta 22, — Are deepwater fisheries sustainable?
Fish Res. Consalvey, M. Cooke, R. Projected losses of global mammal and bird ecological strategies. Corliss, B. Deep-sea benthic diversity linked to seasonality of pelagic productivity. Pt I 56, — Costello, M. Ocean depths: the mesopelagic and implications for global warming. Creasey, S. Population genetics of bathyal and abyssal organisms. Danovaro, R. Deep-sea biodiversity in the mediterranean sea: the known, the unknown, and the unknowable. PLoS One 5:e The deep-sea under global change.
Biodiversity response to climate change in a warm deep sea. Dayton, P. Role of biological disturbance in maintaining diversity in the deep sea. Deep Res. De Stigter, H. Des Roches, S. The ecological importance of intraspecific variation. Deudero, S. Mediterranean marine biodiversity under threat: reviewing influence of marine litter on species. Devine, J. Fisheries: deep-sea fishes qualify as endangered.
Nature Life history traits of Hoplostethus mediterraneus Pisces: Beryciformes from the north-western ionian sea Mediterranean Sea. Drazen, J. Opinion: midwater ecosystems must be considered when evaluating environmental risks of deep-sea mining. A , — Durden, J. Abyssal hills - hidden source of increased habitat heterogeneity, benthic megafaunal biomass and diversity in the deep sea. Etter, R. Population differentiation decreases with depth in deep-sea bivalves.
Evolution 59, — European Commission Brussels: European Commission. Fisher, C. How did the deepwater horizon oil spill impact deep-sea ecosystems? Oceanography 29, — Folkersen, M. Depths of uncertainty for deep-sea policy and legislation. Fossi, M. Bioindicators for monitoring marine litter ingestion and its impacts on Mediterranean biodiversity.
Environ Pollut , — Fujii, T. Deep-sea amphipod community structure across abyssal to hadal depths in the peru-chile and kermadec trenches.
Gage, J. A comparison of the deep-sea epibenthic sledge and anchor-box dredge samplers with the van Veen grab and hand coring by diver. Cambridge: Cambridge University Press.
Gallucci, F. Active colonisation of disturbed sediments by deep-sea nematodes: evidence for the patch mosaic model. Gerringer, M. Pseudoliparis swirei sp. Zootaxa , — Glover, A.
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