{{short description|Fracture zone of the Pacific Ocean seabed}} {{Use dmy dates|date=March 2017}} {{Infobox body of water | name = Clarion-Clipperton zone | location = Eastern and Central Pacific Ocean | coordinates = {{Coord|11.4543|-135.76346|type:waterbody_region:CA-BC|display=inline,title}} | length = {{cvt|7,240|km}} | area = {{cvt|4,500,000|km2}} | depth = {{cvt|3000|-|6000|m}} | image_map = {{maplink|frame=yes|frame-align=center|frame-width=310|frame-height=175|frame-long=-130|frame-lat=12.5|zoom=2|raw=[{{Wikipedia:Map data/Fracture zone}},{ "type": "Feature", "properties": { "marker-size": "small", "marker-color": "#0000ff", "marker-symbol": "landmark-JP", "title": "Clarion-Clipperton Zone" }, "geometry": {"type": "Point", "coordinates":[-135.76346, 11.4543]} }]|text=The marker indicates approximate location Clarion-Clipperton zone related to surface projection of fracture zones.{{collapsible list|title=Key: |{{legend-inline|#f717f7|Clipperton and Clarion fracture zones}} |{{legend-inline|#f787f7|Probable extension of Clipperton and Clarion fracture zones}} |{{legend-inline|#f38d27|Other fracture zones}} |{{legend-inline|#f7aa87|Probable extension of other fracture zones}} |{{legend-inline|#def0f2|Mid-oceanic ridges}} |{{legend-inline|#b9d4ee|Sea}} |{{legend-inline|#ffffff|Land}} |Clicking on the rectangle icon enables full window and mouse-over with text detail.<ref name=FZmaplink>General citations for named fracture zones are at page Wikipedia:Map data/Fracture zone and specific citations are in interactive detail.</ref>}} }} }}
thumb|320px|Major Pacific trenches (1–10) and fracture zones (11–20). The '''Clipperton fracture zone''' (15) is the nearly horizontal line below the '''Clarion fracture zone''' (14), and the Middle America Trench is the deep-blue line No. 9.
The '''Clarion–Clipperton zone'''<ref name=":02" /> ('''CCZ''') or '''Clarion–Clipperton fracture zone<ref name=":12">{{cite web |title=Clarion–Clipperton Fracture Zone {{!}} International Seabed Authority |url=https://www.isa.org.jm/clarion-clipperton-fracture-zone |archive-url=https://web.archive.org/web/20180321205102/https://www.isa.org.jm/clarion-clipperton-fracture-zone |archive-date=2018-03-21 |website=www.isa.org.jm}}</ref>''' is an environmental management area of the eastern and central Pacific Ocean, lying between Hawaii and Mexico. It is one of the world's largest known fields of polymetallic nodules and is administered by the International Seabed Authority (ISA) under the United Nations Convention on the Law of the Sea (UNCLOS).<ref>{{Cite web |title=Marine Regions · Clarion Clipperton Zone (ISA Environmental Management Area) |url=https://marineregions.org/gazetteer.php?p=details&id=64222 |access-date=2023-10-22 |website=marineregions.org}}</ref> The region includes the Clarion fracture zone and the Clipperton fracture zone, geological submarine fracture zones. Clarion and Clipperton are two of the five major lineations of the northern Pacific floor. They were discovered by the Scripps Institution of Oceanography in 1954.<ref name=":325">Galka, Jonathan M. ''In the Nodule Provinces: A History of the Ocean that Minerals Promised'', Harvard University, United States -- Massachusetts, 2025''. ProQuest.''</ref>
The CCZ extends around 4,500 miles (7,240 km) East to West<ref name="EB" /> and spans approximately {{Convert|4,500,000|km2|mi2|abbr=}}.<ref>{{Cite web |last= |first= |date= |title=The Clarion-Clipperton Zone |url=https://pew.org/2o4se1P |access-date=2019-11-27 |website=Pew Charitable Trusts}}</ref> The fractures themselves are unusually mountainous topographical features. Depths across the CCZ generally range from 3,000 to 6,000 metres (9,800 to 19,700 ft).<ref name=":34">International Seabed Authority. ''A Geological Model of Polymetallic Nodule Deposits in the Clarion–Clipperton Fracture Zone and Prospector's Guide for Polymetallic Nodule Deposits in the Clarion–Clipperton Fracture Zone''. Technical Study No. 6. Kingston, Jamaica: International Seabed Authority, 2010.</ref>
The Clarion-Clipperton Zone is regularly considered for deep-sea mining due to the rich deposits of manganese, nickel, copper, and cobalt.<ref name=":5" /> Scientific surveys, however, have found the CCZ contain an abundance and diversity of life – more than half of the species collected were new to science.<ref name=":63">{{Cite journal |last1=Amon |first1=Diva J. |last2=Ziegler |first2=Amanda F. |last3=Dahlgren |first3=Thomas G. |last4=Glover |first4=Adrian G. |last5=Goineau |first5=Aurélie |last6=Gooday |first6=Andrew J. |last7=Wiklund |first7=Helena |last8=Smith |first8=Craig R. |date=2016-07-29 |title=Insights into the abundance and diversity of abyssal megafauna in a polymetallic-nodule region in the eastern Clarion-Clipperton Zone |journal=Scientific Reports |language=en |volume=6 |issue=1 |doi=10.1038/srep30492 |issn=2045-2322 |pmc=4965819 |article-number=30492 |pmid=27470484 |bibcode=2016NatSR...630492A }}</ref> These findings have led to significant environmental and governance debates, particularly centering ISA permits regarding mining regulations, like the operation of the "two-year rule", and international calls for a precautionary pause or moratorium on commercial seabed mining.<ref name=":325" />
== Etymology == The Clarion fracture zone is named after Clarion Island, a volcanic island in the Revillagigedo Archipelago west of Mexico. Similarly, the Clipperton fracture zone is named after Clipperton Island located along the same latitude as the feature.<ref name="jstor" />
The combined term "Clarion-Clipperton Zone" was later adopted by the International Seabed Authority to represent the larger environmental regulated region that includes both the fracture zones and surrounding abyssal plain.<ref name=":325" />
== Geography == thumb|320px|Location of the Clarion–Clipperton zoneThe fractures can be divided into four parts:
*The first, 127°–113° W, is a broad, low welt of some {{convert|900|miles}}, with a central trough {{convert|10 to 30|miles}} wide; *The second, 113°-107° W, is a volcano enriched ridge, {{convert|60|miles}} wide and {{convert|330|miles}} long; *The third, 107°-101° W, is a low welt with a central trough {{convert|1,200–2,400|feet}} deep which transects the Albatross Plateau; and *The fourth, 101°-96° W, contains the Tehuantepec Ridge which extends {{convert|400|miles}} northeast to the continental margin.<ref name="jstor">{{cite journal |author=H. W. Menard and Robert L. Fisher |year=1958 |title=Clipperton Fracture in the Northeastern Equatorial Pacific |journal=The Journal of Geology |volume=66 |issue=3 |pages=239–253 |bibcode=1958JG.....66..239M |doi=10.1086/626502 |jstor=30080925 |s2cid=129268203}}</ref>
The Nova-Canton Trough is often seen as an extension of the fractures.<ref name="Oceanography1972">{{cite book|title=Contributions – Scripps Institution of Oceanography|url=https://books.google.com/books?id=2JHzAAAAMAAJ|access-date=17 November 2011|year=1972|publisher=Scripps Institution of Oceanography|page=69}}</ref>
The underlying crust in the CCZ consists mainly of Mid-Eocene to Early Miocene basaltic seafloor, forming extensive abyssal hills and plains. The seafloor is capped by a sequence of deep-sea sediments.<ref name=":4">{{Cite journal |last1=Parianos |first1=John |last2=O'Sullivan |first2=Anthony |last3=Madureira |first3=Pedro |date=2022-12-01 |title=Geology of parts of the central and eastern Clarion Clipperton Zone |url=https://doi.org/10.1080/17445647.2022.2035267 |journal=Journal of Maps |volume=18 |issue=2 |pages=232–245 |doi=10.1080/17445647.2022.2035267 |bibcode=2022JMaps..18..232P |doi-access=free }}</ref> With the thick layers of Mid-Eocene at the bottom, there are recent chalks (the Marquesas Oceanic Formation) and siliceous clay-ooze (the Clipperton Formation) that may reach 20-30 metres thick.<ref name=":4" /> Local geomorphology includes knoll seamounts, potholes formed in chalk units, and mobile sediment drifts. Together, the seabed captures a diverse microhabitat, and the region's geological heterogeneity is thought to contribute to variations in benthic biodiversity and ecosystem structure.<ref name=":4" />
The zone contains nodules made up of valuable rare-earth and other minerals. Some of these play an essential role for the energy transition to a low carbon economy.<ref>{{cite book |last1=Church |first1=Clare |last2=Crawford |first2=Alec |series=Lecture Notes in Energy |title=The Geopolitics of the Global Energy Transition |date=2020 |volume=73 |publisher=Springer International Publishing |location=Cham |isbn=978-3-030-39066-2 |pages=279–304 |chapter-url=https://link.springer.com/chapter/10.1007/978-3-030-39066-2_12 |access-date=28 January 2021 |language=en |chapter=Minerals and the Metals for the Energy Transition: Exploring the Conflict Implications for Mineral-Rich, Fragile States|doi=10.1007/978-3-030-39066-2_12 |s2cid=226561697 }}</ref> These nodules form around bone fragments or shark teeth. Micronodules then further aggregate and accrete into the clumps targeted for harvesting.<ref name=":2">{{Cite news |last1=Imbler |first1=Sabrina |last2=Corum |first2=Jonathan |date=2022-08-29 |title=Deep-Sea Riches: Mining a Remote Ecosystem |language=en-US |work=The New York Times |url=https://www.nytimes.com/interactive/2022/08/29/world/deep-sea-riches-mining-nodules.html |access-date=2023-04-12 |issn=0362-4331}}</ref>
=== Clipperton fracture zone === The Clipperton fracture zone is the southernmost of the north east Pacific Ocean lineations. It begins east-northeast of the Line Islands and ends in the Middle America Trench off the coast of Central America,<ref name="EB">{{cite web |title=Clipperton Fracture Zone |url=http://www.britannica.com/EBchecked/topic/121879/Clipperton-Fracture-Zone |access-date=17 November 2011 |publisher=Encyclopædia Britannica}}</ref><ref name="Keating1987">{{cite book |last=Keating |first=Barbara H. |url=https://books.google.com/books?id=wKCYe5haiCUC&pg=PA156 |title=Seamounts, islands, and atolls |publisher=American Geophysical Union |year=1987 |isbn=978-0-87590-068-1 |page=156 |access-date=17 November 2011 }}{{Dead link|date=December 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref name="jstor" /> forming a rough line on the same latitude as Kiribati and Clipperton Island, from which it gets its name.
=== Clarion fracture zone === The Clarion fracture zone is the next Pacific lineation north of Clipperton FZ. It is bordered on the northeast by Clarion Island, the westernmost of the Revillagigedo Islands, from which it gets its name. Both fracture zones were discovered by the U.S. research vessels "Horizon" and "Spencer F. Baird" in 1954.<ref>{{Cite web |title=Marine Regions · Clarion Fracture Zone (Fracture Zone) |url=https://marineregions.org/gazetteer.php?p=details&id=7454 |access-date=2023-10-22 |website=marineregions.org}}</ref>
== Deep sea mining == thumb|Polymetallic nodules on the seafloor in the CCZ The Clarion–Clipperton Zone lies within "the Area," meaning the portions of seabed beyond national jurisdiction, as defined under the United Nation Convention on the Law of Sea (UNCLOS).<ref name=":325" /> The Area is legally designated as the Common Heritage of Mankind (CHM), proposed by Arvid Pardo in 1967, and mineral explorations in the CCZ are under the regulation of the International Seabed Authority.<ref name=":325" /> Governance of the CCZ emerged from late twentieth-century debates on deep-sea resource rights, specifically discussions comparing treatment of seabed and economic exclusive zone (EEZ).<ref name=":325" />
Since the 2000s, large areas of the CCZ have been surveyed for mineral and environmental assessments. 173,000 km<sup>2</sup> of the region has been mapped in seven regions associated with the NORI, TOML, and Marawa exploration contract areas.<ref name=":4" /> These mapped zones span roughly 2,000 km longitudinally (116°–134.5° W) and 700 km latitudinally (10°–16° N). The ISA has also designated thirteen Areas of Particular Environmental Interest (APEIs) intended to preserve representative ecosystems across the CCZ.<ref name=":622" /> However, some biodiversity surveys indicate that many known species have been observed exclusively outside of APEIs, raising debates regarding their representativeness.<ref name=":723" /> Approximately {{convert|1,000,000|km2|mi2|abbr=}} of the region has been claimed by 16 mining regions.<ref name=":02">{{Cite web |last= |first= |date= |title=DeepCCZ: Deep-sea Mining Interests in the Clarion–Clipperton Zone |url=https://oceanexplorer.noaa.gov/explorations/18ccz/background/mining/mining.html |url-status=live |archive-url=https://web.archive.org/web/20190214022631/https://oceanexplorer.noaa.gov/explorations/18ccz/background/mining/mining.html |archive-date=14 February 2019 |access-date=2019-11-27 |website=NOAA Office of Ocean Exploration and Research |language=EN-US}}</ref> A further nine areas, each covering {{convert|160,000|km2|mi2|abbr=}}, have been set aside for conservation.<ref name=":02" />
The International Seabed Authority (ISA) estimates that the total amount of polymetallic nodules in the Clarion–Clipperton zone exceeds 21 billion tons (Bt), containing about 5.95 Bt of manganese, 0.27 Bt of nickel, 0.23 Bt of copper and 0.05 Bt of cobalt.<ref name=":34" /> Geochemical surveys show that nodule composition varies significantly across the region: Mn/Fe ratios, Ni and Cu content, and Co/Ni patterns differ between eastern and western sub-domains.<ref name=":5">{{Cite journal |last1=Menendez |first1=Amaya |last2=James |first2=Rachael H. |last3=Lichtschlag |first3=Anna |last4=Connelly |first4=Douglas |last5=Peel |first5=Kate |date=2019-03-01 |title=Controls on the chemical composition of ferromanganese nodules in the Clarion-Clipperton Fracture Zone, eastern equatorial Pacific |url=https://www.sciencedirect.com/science/article/pii/S0025322717306096 |journal=Marine Geology |volume=409 |pages=1–14 |doi=10.1016/j.margeo.2018.12.004 |bibcode=2019MGeol.409....1M |issn=0025-3227|url-access=subscription }}</ref> These differences have been linked to variations in sedimentation rate, bottom-water oxygenation, and the relative contributions of hydrogenetic and diagenetic formation processes.<ref name=":5" /> The nodules are generally cultivated within the geochemically active interface, below the calcite lysocline, where chalk strata are overlain by mobile siliceous clay-ooze. Acoustic surveys show higher than average seabed backscatter in zones with larger and more abundant nodules. The ISA has issued 19 licences for mining exploration within this area.<ref>{{Cite web |title=Exploration Contracts {{!}} International Seabed Authority |url=https://www.isa.org.jm/exploration-contracts |access-date=2021-11-30 |website=www.isa.org.jm}}</ref> Exploratory full-scale extraction operations were set to begin in late 2021.<ref name=":12"/> ISA aimed to publish the deep sea mining code in July 2023. Commercial license applications were to be accepted for review thereafter.<ref>{{Cite news |last=Reid |first=Helen |date=2021-10-29 |title=New deep-sea mining rules set to miss 2023 deadline, Latam and Caribbean countries say |url=https://www.reuters.com/business/sustainable-business/un-deep-sea-mining-rules-unlikely-be-completed-by-2023-deadline-latam-countries-2021-10-28/ |access-date=2021-12-07 |work=Reuters |language=en}}</ref> By 2021, the ISA has granted 18 exploration contracts.<ref>{{Cite journal |last1=Bribiesca-Contreras |first1=Guadalupe |last2=Dahlgren |first2=Thomas G. |last3=Horton |first3=Tammy |last4=Drazen |first4=Jeffrey C. |last5=Drennan |first5=Regan |last6=Jones |first6=Daniel O. B. |last7=Leitner |first7=Astrid B. |last8=McQuaid |first8=Kirsty A. |last9=Smith |first9=Craig R. |last10=Taboada |first10=Sergio |last11=Wiklund |first11=Helena |last12=Glover |first12=Adrian G. |date=2021-07-27 |title=Biogeography and Connectivity Across Habitat Types and Geographical Scales in Pacific Abyssal Scavenging Amphipods |journal=Frontiers in Marine Science |language=English |volume=8 |article-number=705237 |doi=10.3389/fmars.2021.705237 |bibcode=2021FrMaS...805237B |doi-access=free |issn=2296-7745|hdl=11250/3135023 |hdl-access=free }}</ref>
Seabed mining at CCZ often involves seafloor collector vehicles that use riser pipes to extract nodules systematically to the surface. These operations typically generate two types of sediment plumes.<ref name=":22">{{Cite web |date=2021-08-07 |title=Researchers Observe Potential Impacts of Seafloor Mining {{!}} Scripps Institution of Oceanography |url=https://scripps.ucsd.edu/news/researchers-observe-potential-impacts-seafloor-mining |access-date=2025-12-01 |website=scripps.ucsd.edu |language=en}}</ref> Vehicle movement approximate to the seafloor will create near-bottom collector plumes, and the extraction process will cause mid-water discharge plumes.<ref name=":22" /> A field experiment done by Scripps Institution of Oceanography has shown that discharge plumes become rapidly diluted but consist of fine particles capable of long-distance transport, and subsequently built a model to inform environmental guidelines regarding potential damage from sediment plumes.<ref name=":22" /> Considering sediment plumes being one of the main pathways for potential environmental harm in seabed mining, the International Seabed Authority (ISA) is actively developing science-based discharge thresholds to regulate plume concentration, spatial scales and duration through operational limits, real-time monitoring, and precautionary thresholds.<ref>{{Cite journal |last1=Hitchin |first1=B. |last2=Smith |first2=S. |last3=Kröger |first3=K. |last4=Jones |first4=DOB |last5=Jaeckel |first5=A. |last6=Mestre |first6=NC |last7=Ardron |first7=J. |last8=Escobar |first8=E. |last9=van der Grient |first9=J. |last10=Amaro |first10=T. |date=2023-03-01 |title=Thresholds in deep-seabed mining: A primer for their development |url=https://www.sciencedirect.com/science/article/pii/S0308597X23000325 |journal=Marine Policy |volume=149 |article-number=105505 |doi=10.1016/j.marpol.2023.105505 |bibcode=2023MarPo.14905505H |issn=0308-597X|doi-access=free }}</ref>
The two-year rule states that before regulations are passed, a member nation has the authority to notify ISA that it wants to mine. This starts a two-year clock during which the ISA can come up with rules. If it fails to do so, the mining is implicitly approved. Nauru gave notice in July 2021, creating a deadline of July 9, 2023. ISA's next meeting, however, begins a day later, on July 10.<ref name=":2" />
== Biodiversity in the CCZ == The Clarion-Clipperton Zone (CCZ) is habitat to diverse marine wildlife. More than 400 described species are recorded and 42% of known deep-sea species were first discovered in CCZ.<ref name=":622">{{Cite web |title=Deep-Sea Mining May Harm Thousands of Species—Before They Are Even Discovered |url=https://pew.org/44aaylk |access-date=2025-12-01 |website=pew.org |language=en}}</ref> Yet, environmental assessments have highlighted that biodiversity in the CCZ remains incompletely characterized.<ref name=":622" /> Surveys have suggested that 88-92% benthic metazoan species may remain undescribed, and Rarefaction curves show that sampling is not yet saturated, with each new survey tending to record extra discoveries.<ref name=":622" /> In addition, a large proportion of species in the CCZ are known from a single record, implying the proportion of unexplored biodiversity.<ref name=":622" />
Researchers have begun to refine this picture at smaller spatial scales. One survey of a single 30 x 30 km study box in the UK-1 exploration area documented 42 mollusc records representing 21 species, including one described new species and more than twelve potentially undescribed taxa.<ref name=":723" /> The discovered genetic pull is found to have no genetic matches in public reference databases, and the authors also showed that several morphologically similar molluscs are genetically distinct.<ref name=":723" /> In contrast to previously held apparent cosmopolitan distributions based on morphology alone, this research suggests that a high degree of endemism might exist in the CCZ.<ref name=":723" />
One species that inhabits the fracture zone are xenophyophores. A 2017 study found 34 novel species in the area. Xenophyophores are highly sensitive to human disturbances, such that mining may adversely affect them. They play a keystone role in benthic ecosystems such that their removal could amplify ecological consequences.<ref>{{Cite journal |last1=Gooday |first1=Andrew J. |last2=Holzmann |first2=Maria |last3=Caulle |first3=Clémence |last4=Goineau |first4=Aurélie |last5=Kamenskaya |first5=Olga |last6=Weber |first6=Alexandra A.-T. |last7=Pawlowski |first7=Jan |date=2017-03-01 |title=Giant protists (xenophyophores, Foraminifera) are exceptionally diverse in parts of the abyssal eastern Pacific licensed for polymetallic nodule exploration |journal=Biological Conservation |language=en |volume=207 |pages=106–116 |doi=10.1016/j.biocon.2017.01.006 |bibcode=2017BCons.207..106G |issn=0006-3207 |doi-access=free}}</ref> The nodules are considered "critical for food web integrity".<ref>{{Cite journal |last1=Stratmann |first1=Tanja |last2=Soetaert |first2=Karline |last3=Kersken |first3=Daniel |last4=van Oevelen |first4=Dick |date=2021-06-10 |title=Polymetallic nodules are essential for food-web integrity of a prospective deep-seabed mining area in Pacific abyssal plains |journal=Scientific Reports |language=en |volume=11 |issue=1 |page=12238 |doi=10.1038/s41598-021-91703-4 |issn=2045-2322 |pmc=8192577 |pmid=34112864 |bibcode=2021NatSR..1112238S }}</ref> The zone hosts corals, sea cucumbers, worms, dumbo octopuses and many other species.<ref name=":222">{{Cite news |last1=Imbler |first1=Sabrina |last2=Corum |first2=Jonathan |date=2022-08-29 |title=Deep-Sea Riches: Mining a Remote Ecosystem |url=https://www.nytimes.com/interactive/2022/08/29/world/deep-sea-riches-mining-nodules.html |access-date=2023-04-12 |work=The New York Times |language=en-US |issn=0362-4331}}</ref>
Along with the xenophyophores, many types of species reside in the Clarion–Clipperton zone: protists, microbial prokaryotes, and various fauna including megafauna, macrofauna, and meiofauna, each distinguished by size.<ref>NORI D Collector Test EIS – Final – Chapter 6. (2022). In The Metals Company.</ref> Due to the lack of historical research in the region—in large part because of the inaccessibility, monetary, and physical cost without modern technology—very little is known about life in the CCZ. The increasing tests in the region have led to the discovery of many new species, suggesting both a high species richness and high species rarity within the CCZ. It seems that polymetallic nodules in the region, the target of much deep-sea mining, are crucial for fostering a high level of biodiversity on the sea floor. Even so, there are many gaps in the current understanding of the ecosystem roles played, life history traits, sensitivities, spatial or temporal variabilities, and resilience of these species.<ref name="auto12" />
Some studies have suggested that polymetallic nodules form "nodule provinces" that provide distinctive hard-substrate habitat in an otherwise sediment-dominated abyssal plain.<ref name=":325" /> Studies have shown abundant infaunal species such as Nucula profundorum inhabit in these soft sediments, as well as nodule-attached molluscs and other epifauna, indicating that nodules add structural complexity and increase the diversity of available microhabitats at the seafloor.<ref name=":723">{{Cite journal |last1=Wiklund |first1=Helena |last2=Taylor |first2=John D. |last3=Dahlgren |first3=Thomas G. |last4=Todt |first4=Christiane |last5=Ikebe |first5=Chiho |last6=Rabone |first6=Muriel |last7=Glover |first7=Adrian G. |date=2017-10-10 |title=Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Mollusca |journal=ZooKeys |language=en |issue=707 |pages=1–46 |doi=10.3897/zookeys.707.13042 |doi-access=free |issn=1313-2970 |pmc=5674146 |pmid=29118626 |bibcode=2017ZooK..707....1W }}</ref> Geological heterogeneity has been proposed as another important driver of biodiversity in the CCZ.<ref>{{Cite journal |last1=Uhlenkott |first1=Katja |last2=Simon-Lledó |first2=Erik |last3=Vink |first3=Annemiek |last4=Martínez Arbizu |first4=Pedro |date=2023-07-19 |title=Habitat heterogeneity enhances megafaunal biodiversity at bathymetric elevations in the Clarion Clipperton Fracture Zone |url=https://doi.org/10.1007/s12526-023-01346-z |journal=Marine Biodiversity |language=en |volume=53 |issue=4 |pages=55 |doi=10.1007/s12526-023-01346-z |bibcode=2023MarBd..53...55U |issn=1867-1624|doi-access=free }}</ref> The region contains abyssal hills, knolls, potholes, seamounts, sediment drifts and nodule-rich plains, accompanied with layers of chalk and clay-ooze formations.<ref name=":4" /> Researchers note that sediment type, relief, or bedrock exposure may play a vital rule in the composition of benthic communities, and habitat diversity and resource distribution may be more closely linked than previously thought.<ref name=":34" />
== Environmental concerns == Researchers associated with International Seabed Authority observers, including those at the Massachusetts Institute of Technology and TU Delft, have examined potential environmental impacts of nodule collection and compared it to the environmental and human impact of terrestrial mining.<ref>{{cite web |last1=Gallagher |first1=Mary Beth |title=Understanding the impact of deep-sea mining |url=https://news.mit.edu/2019/understanding-impact-deep-sea-mining-1206 |access-date=28 January 2021 |website=MIT News {{!}} Massachusetts Institute of Technology |date=6 December 2019 |publisher=Massachusetts Institute of Technology |language=en}}</ref><ref>[https://blueharvesting-project.eu/ 9 European partners work together to help the maturation of a hydraulic nodule collector, while minimizing its environmental footprint], blueharvesting-project.eu</ref> In April 2021, scientists from JPI oceans project carried out in depth studies into mining technology and its possible effect on the seabed.<ref>{{Cite web |title=Assessing the Impacts of Nodule Mining on the Deep-Sea Environment |url=https://www.jpi-oceans.eu/news-events/news/assessing-impacts-nodule-mining-deep-sea-environment |access-date=2021-12-07 |website=www.jpi-oceans.eu |language=en}}</ref>
Much of what is known about the potential environmental impact is a result of a dredging pilot test conducted in 1978. In the years since the tests, the region has been monitored. Many species here are more susceptible to the negative effects of environmental shifts as change at these depths is atypical. Specifically looking at nematodes, it has been determined that there is a lower species richness and lower total biomass in the area where the dredging occurred as compared to the neighboring spaces. Additionally, the composition of species and the frequencies at which they are found change with human interference. The removal of polymetallic nodules, as proposed through deep-sea mining, would decrease suitable habitat as many species of nematodes reside within the upper five centimeters where nodules exist, too. Even those species that do remain will face changes to their habitat conditions as the new top layer of sediment after the removal of the nodules will be significantly denser. The low sedimentation levels and minimal currents show that disruption in the CCZ would have long-lasting effects on the environment; the upturned sediment remains unsettled even decades later.<ref name="auto">Miljutin, Dmitry & Miljutina, Maria & Martinez Arbizu, Pedro & Galéron, Joëlle. (2011). Deep-sea nematode assemblage has not recovered 26 years after experimental mining of polymetallic nodules (Clarion–Clipperton fracture zone, Tropical Eastern Pacific). Deep Sea Research Part I: Oceanographic Research Papers. 58. 10.1016/j.dsr.2011.06.003.</ref>
In addition, Seabed mining may lead to prolonged impact to the nodule provinces.<ref name=":63" /> Polymetallic nodules in the CCZ grow extremely slowly, at rates of approximately 1–10 millimeters per million years.<ref name=":34" /> Polymetallic nodules are classified in three morphologies, smooth (S-type), rough (R-type), and mixed (S–R) .<ref name=":34" /> Their formation is conditioned by a combination of metal supply, availability of nuclei, benthic currents, sediment–water interface conditions, biological mixing (bioturbation), and internal stratigraphic layering, which makes it difficult to reproduce quickly.<ref name=":34" /> The species directly dependent on them, and all of their subsequent linkages or environmental functions would see vast changes that could not be quickly restored after the damage is complete.<ref name="auto12">Amon, D.; Gollner, S.; Morato, T.; Smith, C.; Chen, C.; Christiansen, S., et al. (2022). Assessment of scientific gaps related to the effective environmental management of deep-seabed mining. UC San Diego. Report #: ARTN 105006. http://dx.doi.org/10.1016/j.marpol.2022.105006 Retrieved from https://escholarship.org/uc/item/0w48f05q</ref> Beyond direct physical contact with equipment, organisms may be affected by sediment plumes, change in resource availability, and noise and light pollution associated with mining operations; the latter effect remain largely unknown.<ref name="auto" /><ref>{{Cite journal |last=Schriever |first=G. |date=2009-05-04 |title=SS Ocean Mining: Development of Environmental Research related to future Deep Sea Mining - Are Concerns justified and what should be done? |journal=All Days |article-number=OTC-19935-MS |publisher=OTC |doi=10.4043/19935-ms}}</ref>
Some scholars have raised environmental concerns regarding legal and governance issues in the CCZ. While UNCLOS requires that activities in the Area provide "effective protection" of the marine environment, the ISA simultaneously administers mineral development and environmental protection.<ref name=":325" /> Surveys of extensive undescribed biodiversity and environmental effects have led some commentators and governments to argue that the current ecological baselines are limited. Accompanied with ongoing debates over draft mining regulations, implementation of environmental thresholds, and the role of precaution in the ISA's decision-making processes, mining activities remain controversial at the CCZ.<ref name=":325" />
==References== {{Reflist}}
== Links == * {{cite web | url = https://www.scientificamerican.com/article/deep-sea-mining-could-begin-soon-regulated-or-not/ | title = Deep-Sea Mining Could Begin Soon, Regulated or Not | last1= Heffernan | first1 = Olive |date = 2023-10-23 | publisher = Scientific American}} * {{cite web | url = https://www.youtube.com/watch?v=pf1GvrUqeIA | title = The race to mine the bottom of the ocean | author = Laura Bult (producer) | date = 2023-10-11 | publisher = Vox }}
{{DEFAULTSORT:Clarion-Clipperton zone}} Category:Fracture zones Category:Pacific Ocean Category:Mining Category:Environmental conservation