Wednesday, 7 June 2023

Determining the origin of the silver in the bracelets of Queen Hetepheres.

Egypt lacks any notable silver deposits of its own, and silver objects were rare during the Old Kingdom, with the metal not becoming a commonly imported commodity until the early Middle Kingdom, about 1900 BC. Silver objects dating to the Old Kingdom are therefore extremely rare, and generally associated with high status royal burials. One of the most notable groups of silver objects is a collection of bracelets from the tomb of Queen Hetepheres, the wife of the Pharoah Sneferu, who was the first ruler of the Forth Dynasty and reigned from approximately 2613 to 2589 BC, and mother to Pharoah Khufu, who built the Great Pyramd at Giza. 

The origin of silver from this period is uncertain. It could potentially have come from local sources which have since been lost; the Ancient Egyptians are known to have mined gold extensively, and seams of silver in gold-bearing rocks are not unusual. Alternatively, silver could have been imported from one of the cities of what is now Syria, most likely Byblos on the southern coast, which Egypt had been trading with since at least the Naqada IIIA1 Period (about 3320 BC), although cities further north were also traded with, with Elba having been added to the trade network by the end of the Old Kingdom, about 2300 BC.

The tomb of Queen Hetepheres at Giza was uncovered in 1925, by a joint expedition of Harvard University and the Museum of Fine Arts. This tomb had been undisturbed till this point, and contained a trove of artefacts including gilded furniture, gold vessels and jewellery. Among this jewellery was the remains of a wooden box containing twenty silver 'deben' rings (a 'deben' was a unit of weight, although the value of this appears to have changed over time). The rings were in a variable state when uncovered (unlike gold, silver will corrode over time), and the whole collection was sent to the Egyptian Museum in Cairo. In 1947 two intact rings from this collection, along with a number of fragments of silver from rings which had disintegrated, was gifted by the Egyptian Museum to the Museum of Fine Arts.

When worn, these rings would have been bracelets, with five worn on each limb. They are made from thin sheets of silver folded into a cresent shape, so that there is a cavity on the inner side, and inlaid with turquoise, lapis lazuli and carnelian, in a style which clearly establishes their Egyptian origin. A metallurgical analysis of the metal was carried out in the 1920s, finding it to be 90.1% silver, 8.9% gold, and 1.0% copper, but the distribution of the gold was uneven, giving the bracelets yellowish patches. Since that time no further metalogical examination of the rings has taken place.

In a paper published in the Joutnal of Archaeological Science: Reports on 1 May 2023, Karin Sowada of the Department of History and Archaeology at Macquarie University, Richard Newman of the Museum of Fine Arts, Francis Albarède of the Ecole Normale Supérieure de Lyon, Gillan Davis of the Australian Catholic University, Michele Derrick, also of the Museum of Fine Arts, Timothy Murphy of the School of Natural Sciences at Macquarie University, and of Newspec Pty Ltd, and Damian Gore, also of Newspec Pty Ltd, present an updated metallurgical analysis of the silver from the bracelets of Queen Hetepheres, and discuss the implications of their results for the likely origin of this metal.

(A) Bracelets in the burial chamber of Tomb G 7000X as discovered by George Reisner in 1925 (Photographer: Mustapha Abu el-Hamd, August 25 1926) (B) Bracelets in restored frame, Cairo JE 53271–3 (Photographer: Mohammedani Ibrahim, August 11 1929) (C) A bracelet (right) in the Museum of Fine Arts, Boston, MFA 47.1700. The bracelet on the left is an electrotype reproduction made in 1947. Sowada et al. (2023).

The bracelets donated to the Museum of Fine Arts were not available for study, but Sowada et al. were able to access the fragmentary material given to the museum at the same time. These samples were analysed using X-ray fluorescence spectroscopy to analyse their elemental composition. Furthermore, trace amounts of lead recovered from the sample were anlalysed using Multicollector Inductively Coupled Plasma-Mass Spectrometry, in order to determine their isotopic composition, which is strongly linked to geogrsphical origin.

(A) Bag B1 of corroded bracelet fragments in the Museum of Fine Arts, Boston, MFA 47.1702. MFA 47.1702 B1P4 shown second from left, centre. (B) Detail of MFA 47.1702 B1P4 (C)–(D) Metallic fragment recto (left) and verso (right) MFA 47.1702 B2P1. Sowada et al. (2023).

Sowada et al. found that the bulk sample of metal fragments was 98% silver, with 1% gold, 0.4% copper, and 0.04% lead. Patches of corrosion are dominated by silver chloride. Some other elements appear to have accumulated on the surface of the sample, notably calcium, but also iron, probably in the form of iron oxide grains. Examined under an a scanning electron microscope, fragments of the silver seen in section showed a pattern of dark and light layers typical of metal which has been worked heavily while cold, something often seen in Old Kingdom copper samples. Mapping of the elements in these profile sections suggested that the material was in fact about 90% silver and about 10% gold.

(A) Back-scattered electron image of part of the polished cross section from MFA 47.1702 B2P1 (B) Detail from image A at higher magnification, showing the metal structure to consist of elongated islands of uncorroded solver metal ('A') intercalated with a more porous matrix ('B') transitioning to an open framework of corroded metal ('C'). (C) Concentrations of silver and gold in small regions (purple outlines) were determined and plotted in (D). The plots begin at the top of the area shown in (C) and end at the bottom. The final data point is for the larger rectangular area and can be considered the average for this part of the sample (about 89% silver and 9% gold). Note that gold has higher concentrations and silver lower in the more heavily corroded areas (data points in the middle of the plots). Sowada et al. (2023).

The lead within the samples was found to have a lead²⁰⁶/lead²⁰⁴ ratio of 18.8816. This was compared to a database containing the isotopic rations of lead ores from 7000 locations between Iran and the Atlantic Ocean. This analysis susgests that the silver is most likely to have come from the Cyclades Islands, in the Aegean Sea to the southeast of the Greek mainland, and that the second most likely point of origin is the Lavrion mines of Attica. 

Map of the north-east Mediterranean and western Asia, showing potential silver sources. The lead isotope composition of a sample from MFA 47.1702 B2P1 is compared with the compositions of nearly 7000 samples of galena (white dots) distributed from the Atlantic Ocean to the Indian Ocean from the Ecole Normale Supérieure de Lyon database. The distance (colour bar to the right) allows 128 galena samples with the closest lead isotope compositions relative to MFA 47.1702 B2P1 to be retained. Unlikely sources can be ignored. A black symbol colour indicates a high probability of provenance with the greatest density of ‘hits’ coming from Seriphos, Anafi, and Kea-Kithnos in the Cyclades, and to a lesser degree Lavrion. Red and orange symbols indicate less probable sources (Anatolia, Macedonia). The symbol sizes have been slightly jittered and enlarged to increase visibility of the less probable points. Sowada et al. (2023).

Silver is known to have been mined in the Aegean region from the very beginning of the Bronze Age, and to have increasingly been traded around the Mediterranean as time passed; nevertheless, finding it as far afield as Egypt during the early Fourth Dynasty is surprising. Silver is known to have been imported to the Old Kingdom, with records dating to the reign of the Pharoah Sneferu mentioning the metal as an import, although not where it was imported from. The earliest records which do mention a source date to the late Sixth Dynasty (around 2300 BC), and record silver being imported from Byblos, in southern Lebanon. At the same time, records from Elba, in northern Lebanon, report silver being exported from that city to Egypt.

Heterpheres was the wife of Sneferu, who ruled 300 years before the Sixth Dynasty records were made, at a time when there is no direct evidence for trade between Egypt and Lebanon. A jug believed to have come from Cilicia in the Taurus Region of southern Anatolia is known from a slightly later tomb, suggesting that the Egyptians were trading this far north. This has been taken as evidence that Egypt could have traded silver from the cities of Lebanon, it is also known that silver from the Aegean was being traded in Anatolia by this time.

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Sunday, 4 June 2023

A Lotus from the Early Cretaceous Crato Formation of northeastern Brazil, and its implications for the origin of the group.

Angiosperms, or Flowering Plants, are the most numerous and diverse Plant group today, dominating almost all terestrial environments. The ealiest Angiosperm fossils appear an the Early Cretaceous, around the shores of the Tethys Ocean, with many Angiosperm groups appearing sudenly, in forms apparently not much different to today, making it impossible to tell how these groups are related without molecular data.

Lotuses, Nelumbonaceae, are aquatic Plants, superficially similar to Water Lilies, to which they were once thought to be related. They grow annually from submerged rhizomatous roots, producing large flar leaves with hydrophobic coatings which lie flat upon the water surface. Surprisingly, molecular analysis of Angiosperm relationships has revealed that Lotuses not closely related to Water Lilies, which are related to Magnolias, but instead are members of the Order Proteales (Proteas), most closely related to Plane Trees. This is particularly surprising as all other members of the Proteales are woody shrubs and trees, while Lotuses are aquatic annual herbs lacking any woody tissue. 

In a paper published in ths journal Scientific Reports on 2 June 2023, William Vieira Gobo of the Departamento de Paleontologia e Estratigrafa at the Universidade Federal do Rio Grande do Sul,  Lutz Kunzmann of the Abteilung Museum für Mineralogie und Geologie, Roberto Iannuzzi and Thamiris Barbosa dos Santos, also of the Departamento de Paleontologia e Estratigrafa at the Universidade Federal do Rio Grande do Sul, Domingas Maria da Conceição of the Museu dePaleontologia Plácido Cidade Nuvens at the Universidade Regional do Cariri, Daniel Rodrigues do Nascimento and Wellington Ferreira da Silva Filho of the Departamento de Geologia at the Universidade Federal do CearáJulien Bachelier and Clément Coifard of the Structural and Functional PlantDiversity Group at the Freie Universität Berlin, describe a new species of Lotus from the Early Cretaceous Crato Formation of Ceará State, Brazil.

The new species is described from pits to the southwest of Nova Olinda in the Araripe Basin of northeastern Brazil, and now in the collections of the Museum für Naturkunde in Berlin and the Senckenberg Forschungsinstitut und Naturmuseum in Frankfurt am Main. The authors acknowledge that there are currently unresolved issues concerning fossils from the Crato deposits, with the Brizilian government regarding all removal of the fossils from the country as illegal, and asking that collections in other parts of the world return them, but note that the Brazilian members of the team were invited by the German institutions to come and study the material. The Plant is named Notocyamus hydrophobus, where 'Notocyamus' means 'Southern Bean' in Greek, a refernce to the term 'Egyptian Bean' used by Teophrastos of Eresos to refer to Lotus seeds, and 'hydrophobus' refers to the hydrophobic leaves of Lotus Plants.

Notocyamus hydrophobus (holotype, MB. Pb. 2002/1047). (A) Overview of the whole plant, with roots, rhizome, leaves, and aggregate fruit in organic connection. A black arrow points to the part of the peduncle used to make the thin sections. (B) Details of higher-order venation. (C) Close-up of palinactinodromous venation and the marginal lamina attachment. (D) Close-up on the enlarged receptacle showing two globose fruitlets (presumed nutlets). Scale bars are 1 cm. Gobo et al. (2023).

The holotype specimen is about 30 cm high and about 25 cm wide, and comprises a rhizome with about 30 roots, 13 leaves, and a single fruiting body. Leaves are 60 to 95 cm long and 60 to 100 mm wide, and oval to eliptical in shape. They are attached to petiole stems 120-200 mm long and 5-10 mm wide. The cells of the leaves are discernable, larger on the upper side than on the lower with each cell bearing a single papilla (hair), agian larger above than below.

Notocyamus hydrophobus (paratype, SMF SM.B 16.522). (A) Isolated leaf. (B), (C) Close-ups of the pattern of venation. Note that abundant structures interpreted as galls occur along the lamina and petiole (arrows point to some of them). Scale bars are 5 mm. Gobo et al. (2023).

The fruiting body is borne on a peduncle stem 22.5 cm long and 4 mm wide. Notably, this peduncle has in inner pith layer surrounded by xylem (wood), a tissue not seen in any modern Lotus, but present in all other members of the Order Proteales. 

Notocyamus hydrophobus (holotype, MB. Pb. 2002/1047). (A)–(B) Transversal section of the peduncle. (A) Overview displaying homoxylic wood with abundant fbers interspersed with parenchymatous rays. Te dashed outline shows the rays connecting with primary xylem that form bundles near the pith. On the periphery, remains of the cambial zone occur in a discontinuous layer that is followed by new vascular increments. (B) Close-up of region near pith showing the primary xylem bundles and their connection with the rays. Abbreviations: pi. pith; px, primary xylem; sx, secondary xylem; r, ray; cz, cambial zone; vi, vascular increments; pxb, primary xylem bundles. Scale bars: (A) 1 mm; (B) 250 µm. Gobo et al. (2023).

The xylum tissue comprises an inner layer of 18 (or possibly 19) primary bundles, surrounded by a secondary homoxylic (vesselless) layer. No growth rings are present, and the whole is surrounded by an ounter layer thought to be the remains of the cambium (bark).

Notocyamus hydrophobus (holotype, MB. Pb. 2002/1047). Radial (A)–(G) and tangential (H) sections of the peduncle. (A) Overview of region adjacent to the pith (to the far right) showing vessels in the xylem followed by the secondary xylem with ray and fber cells (to the far left). (B) Primary xylem cells with helical thickenings and fbers of secondary xylem. (C) A vessel element with scalariform-like pits and simple perforation plates (arrows). (D) Close-up of a fiber showing simple (black arrow) and slit-like pits (white arrow). (E) Ray cells with slit-like pit apertures. (F) Overview of region near cambial zone (dashed outline) showing fber and ray cells in the secondary xylem followed by the layer that gives rise to the new vascular increments. (G) Fusiform and compressed cells from the cambial zone followed by tracheary elements with scalariform-like pits. (H) Ray cells in between fbers of secondary xylem. Abbreviations: v, vessels; px, primary xylem; r, ray; f, fber; cz, cambial zone; vi, vascular increments. Scale bars: (A), (F) 200 µm; (B), (C), (E), (G) 50 µm; (D) 25 µm; (H) 100 µm. Gobo et al. (2023).

The Crato Formation has not been dated precisely, but is thought to be slightly more than 120 million years old, which, if correct, would make Notocyamus hydrophobus the oldest known member of the Nelumbonaceae. Molecular dating techniques have suggested that the Nelumbonaceae branched from theit closest relatives, the Platanaceae (Plane Trees) between 83 and 123 million years ago. Since dates at the younger end of this range can be ruled out by other, more modern-looking fossil Lotuses it is not unreasonable to assume that the group dates from the earlier part of this bracket, or possibly a little older. Either way, the assumption that Notocyamus hydrophobus is a very early member of the group, still showing some similarities to non-Lotus relatives, is not unreasonable.

Reconstruction of Notocyamus hydrophobus in its likely environment. Rebecca Dart in Gobo et al. (2023).

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Friday, 2 June 2023

Queensland Fireball confirmed as largest meteor seen over Australia in 35 years.

A bright fireball seem over northern Queensland on 20 May 2023 has been declared to have been the largest meteor seen over Australia since records began in 1988. Planetary scientist Ellie Sanson of the Desert Fireball Network at Curtin University made the conclusion after examining satellite data of the meteor's passage provided by NASA. The satellite images revealed the object was travelling at about 28 km per second when it exploded, about 29 km above the town of Croydon. This implies that the object was about 3.5 m in diameter, and would have had a mass of about 8 tonnes. 

The Queensland Meteor, just before exploding on 20 May 2023. Cairns Airport/ABC News.

A fireball is defined as a meteor (shooting star) brighter than the planet Venus. These are typically caused by pieces of rock burning up in the atmosphere, but can be the result of man-made space-junk burning up on re-entry. In this case many witnesses have described the object as being green in colour, probably implying an iron-nickel composition. Since the object exploded less than 35 km above the ground, it is thought highly likely that material from it will have reached the ground, and scientists from Curtin University are planning to organise a search of the object, along with researchers from other universities and members of the general public. 

Heat map showing areas where sightings of the meteor were reported (warmer colours indicate more sightings)and the apparent path of the object (blue arrow). American Meteor Society.

Objects of this size probably enter the Earth's atmosphere several times a year, though unless they do so over populated areas they are unlikely to be noticed. They are officially described as fireballs if they produce a light brighter than the planet Venus. The brightness of a meteor is caused by friction with the Earth's atmosphere, which is typically far greater than that caused by simple falling, due to the initial trajectory of the object. Such objects typically eventually explode in an airburst called by the friction, causing them to vanish as an luminous object. However, this is not the end of the story as such explosions result in the production of a number of smaller objects, which fall to the ground under the influence of gravity (which does not cause the luminescence associated with friction-induced heating).

These 'dark objects' do not continue along the path of the original bolide, but neither do they fall directly to the ground, but rather follow a course determined by the atmospheric currents (winds) through which the objects pass. Scientists are able to calculate potential trajectories for hypothetical dark objects derived from meteors using data from weather monitoring services.

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Thursday, 1 June 2023

Neonatal Enterovirus infection leads to seven deaths in France.

France has reported an increase in cases of severe neonatal sepsis associated with the Echovirus-11 Enterovirus, according to a press release issued by the World Health Organization on 31 May 2023. A total of nine cases of neonatal sepsis with hepatic impairment and multi-organ failure were reported between July 2022 and April 2023 from four hospitals in three regions of France. As of 5 May 2023, seven cases have died and two were still hospitalized in neonatal unit.

The current increase in incidence and severity in neonates, associated with a recombinant lineage of Echovirus-11 that previously was not detected in France, and is considered unusual due to the extremely rapid deterioration and associated case fatality rate amongst the affected babies. 

Based on the limited information available, the World Health Organization assesses the public health risk for the general population to be low, despite the concerning nature of the increase.

Of the nine cases of severe neonatal sepsis reported, eight were preterm (born before 38 weeks of gestation). Four pairs of twins were affected and presented with late-onset neonatal sepsis (occurring after one week of birth to three months).

The cases were reported from four hospitals in three regions between July 2022 and April 2023. Of the nine reported cases, six were reported in 2022 (two cases each in July, October, and December) and three were reported in 2023 (one case in January and two cases in April).

All cases presented with one or more clinical signs less than seven days after birth, suggesting a mother-to-child transmission route. The clinical presentation of these cases was considered to be atypical due to their extremely rapid deterioration and the associated case fatality rate. As of 5 May 2023, seven cases have died and two were still hospitalized in the neonatal unit; their short-term prognosis is no longer threatened.

Enterovirus reverse transcription polymerase chain reaction testing of all nine cases (including blood samples, throat swabs, nasopharyngeal swabs, cerebrospinal fluid samples, and/or post-mortem biopsies) confirmed the presence of Enterovirus, typed as Echovirus-11. Echovirus-11 maternal infection was confirmed by reverse transcription polymerase chain reaction testing and enterovirus genotyping by analyzing blood samples from four out of five mothers. All tested mothers presented with gastrointestinal signs or fever within the three days before or at delivery.

Sequence analyses of all typed Enterovirus infections in 2022 showed the circulation of at least two lineages of recombinant origin, of which the predominant one included all the sequences associated with the nine cases together with sequences associated with non-neonatal or non-severe neonatal infections. Further genetic analyses are ongoing.

According to historical data from 2016 to 2021, Echovirus-11 represented 6.2% (3 of 48) of reported severe neonatal infections with known Enterovirus type while this proportion increased to 55% (11 of 20) in 2022.

Enteroviruses are a group of Viruses that can cause various infectious illnesses and are responsible for annual epidemics. Illness is usually mild but has been found to affect neonates differently and sometimes more severely than older children and adults. There are multiple transmission routes, particularly in the neonatal period, including intrapartum by exposure to maternal blood, secretions, and/or stool, or postnatally from close contacts with infected caregivers. Echovirus 11 is a positive-strand RNA Virus belonging to the Genus Enterovirus of the Family Picornaviridae.

Structure of an Echovirus. Wang et al. (2020).

Echovirus 11 infections can cause severe inflammatory illnesses in neonates, including severe acute hepatitis with coagulopathy. 

On 28 April 2023, the French National Reference Centre for Enteroviruses and Parechoviruses informed clinicians and virologists involved in the care of newborns, to reinforce the diagnosis and surveillance of Enterovirus infection in neonates with severe sepsis through a professional network. In particular, the message focused on what to do in newborns with a picture of severe sepsis of indeterminate aetiology to sensitize about the risk of transmission. Clinicians were invited to systematically consider Enterovirus infection in neonates with severe liver failure, enterocolitis, meningoencephalitis, or myocarditis. Close monitoring of liver function, cardiac function, neurological function, and risk of enterocolitis were recommended in neonates with severe neonatal sepsis of undetermined cause.  Clinicians were also invited to undertake an early notification of referral hospitals in order to discuss potential therapeutic options. The risk of maternal transmission of Echovirus 11 was raised and recommendations made to monitor the infant closely for at least 7 days if the mother was known to have had an infection before or during childbirth. Emphasis was placed on importance of collecting additional samples (blood, stool, and nasopharyngeal samples) in newborns and mothers for Enterovirus, as was the importance of genotyping Enterovirus-positive samples: Clinical virologists were invited to send Enterovirus-positive samples in a prospective manner, especially from patients presenting with severe clinical signs. Samples are sent to the National Reference Laboratories for genotyping and genome studies.

Continuous information sharing regarding this event among France and other Member States (through the European Non-Polio Enterovirus Network), the European Centre for Disease Prevention and Control and World Health Organization is ongoing. To date, no comparable increase of Echovirus 11 cases associated with neonatal sepsis has been observed in countries that have reported to the European Centre for Disease Prevention and Control (Belgium, Denmark, Netherlands, Norway, and Spain) in 2022 and 2023.

A review of the epidemiological data collected from 2016 to 2022 in France through routine surveillance of Enterovirus infections among hospitalized patients showed a significant increase in incidence and mortality for all severe neonatal infections associated with Echovirus 11, defined as infections with at least one organ failure and/or requiring admission to intensive care.

A total of 443 Enterovirus neonatal infections (severe and non-severe types) including seven deaths (a case fatality rate of 1.6%) were reported in France in 2022. Of these, 72% (317 cases) had a known Enterovirus type. Echovirus 11 was the predominant circulating Enterovirus type (all ages included) and was identified in 30.3% (96 of 317) of neonatal infections (severe and non-severe) with known Enterovirus type. It has been continuously detected since June 2022.

Of the reported neonatal infections in 2022, 4.5% (22 of 443) were classified as severe. Of these 20 had known Enterovirus types. Echovirus 11 represented 55% (11 of 20) of these cases as compared to 6.2% (3 of 48) of cases with known Enterovirus type out of the total reported severe neonatal infections (62 cases) between 2016 to 2021. 

In 2022, there were seven deaths (case fatality rate, a case fatality ratio of 1.6%) out of the cumulative 443 Enterovirus neonatal infections recorded in 2022 (six associated with Echovirus 11), compared to seven deaths (a case fatality ratio of 0.4%), out of 1774 neonatal infections from 2016 to 2021 (none associated with Echovirus 11). There have also been seven deaths so far in 2023.

Sequence analyses showed the circulation of at least two lineages of recombinant origin, of which the predominant one included all the sequences associated with the nine severe cases together with sequences associated with non-neonatal or non-severe neonatal infections. This new variant of Echovirus 11 had not been observed in France before July 2022, nor elsewhere based on available sequences on the GenBank database, as of 28 April 2023. As of 5 May 2023, Echovirus 11 sequences retrieved from samples collected in 2023 all belong to this predominant lineage. Although higher pathogenicity of this new lineage cannot be excluded, the severity of infections may also be explained by the young age, prematurity, and the absence of maternal immunity. Further analyses are warranted to delineate the characteristics of this recombinant Virus.

Based on the limited information available, the World Health Organization assesses the public health risk for the general population to be low. However, asymptomatic carriage and shedding of infectious Viruses are a feature of Enterovirus infection. Echovirus infection was confirmed in four out of five mothers by analyzing blood samples three days before or at delivery. There have been previous reports of severe Echovirus 11 infection in twin neonates, however, the observation of four sets of twins amongst nine cases is more than expected. As non-Polio Enterovirus infection is often not a notifiable disease in Member States, additional cases of severe neonatal Enterovirus infection may have gone undiagnosed and/or unreported.

Non-Polio Enteroviruses are common and distributed worldwide. Although infections often are asymptomatic, some may present with respiratory tract infections. Symptoms include fever, runny nose, and body weakness. These Viruses are also associated with occasional outbreaks in which an unusually high proportion of patients develop clinical disease, sometimes with serious and fatal consequences. The World Health Organization recommends that clinicians managing neonates and young infants presenting with circulatory shock should consider an underlying diagnosis of sepsis and perform appropriate diagnostic investigations, including testing for Enteroviruses.

The World Health organization further recommends that health and care workers working with samples suspicious of non-Polio Enteroviruses should be properly trained to collect, store, and transport various samples. If samples are referred domestically and/or internationally for confirmation, typing, or sequencing purposes, appropriate national and international regulations on the transport of infectious substances should be strictly followed. Laboratories that perform sequencing should consider sharing genetic sequence data through publicly accessible databases.

No specific antiviral therapy for Echovirus infection is available, and treatment focuses on preventing complications. Health facilities caring for neonate populations in France should familiarize themselves with the signs and symptoms of Enterovirus and maintain vigilance for potential healthcare-associated infection cases and outbreaks in wards providing neonatal care. 

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Wednesday, 31 May 2023

Estimating biodiversity in the Clarion-Clipperton Zone.

The Clarion-Clipperton Zone is an area of the Pacific seafloor bounded by the Clarion and Clipperton fracture zones to the north and south, and the 115°W and 160°W longitude lines. It has an area of about 6 million km², making it roughly twice the size of India, and is located between Hawai'i, Kiribati, and Mexico, but lies entirely outside the jurisdiction of any nation. Throughout this region the seafloor is between 4000 and 6000 m deep, and mostly covered with muddy sediments with a scattering of Potato-sized polymetalic nodules, making the zone attractive to prospective deep-sea miners. The seafloor here is known to host a diverse community of benthic organisms, albeit at a much lower density than is found on the continental shelves or in coastal regions.

The Clarion-Clipperton Zone has been explored for mineral extraction since the 1960s, a process formalized by the formation of the International Seabed Authority in the 1980s, although the possibility of actual mining operations is only becoming possible now. There are currently 17 mining concessions granted within the Clarion-Clipperton Zone, covering an area of about 1.2 million km². 

Despite decades of exploration work being carried out within the Clarion-Clipperton Zone, very little taxonomic work has been carried out, with large-scale environmental surveys in the 1970s, 1980s and 1990s producing lists of informally named taxa only; i.e. differentiated by morphological or molecular data, but not formally described. This presents challenges for anyone trying to understand the biodiversity of the region, particularly as deep ocean benthic environments are known to be rich in cryptic species, as the constraints of the environment push members of different taxonomic groups towards similar morphologies and lifestyles.

To make matters worse, the data that has been collected isn't to any method, with sampling and data recording being carried out in different ways in different studies. Furthermore, many studies that have been carried out within the Clarion-Clipperton Zone have concentrated on particular taxa, ecological groups or size classes, and have usually covered only small parts of the zone. This greatly hampers the establishment of any overall understanding of biodiversity within the region, making to almost impossible to come up with a coherent environment management policy plan. Without any meaningful understanding of the biodiversity of the area, it is essentially impossible to calculate the range or environmental requirements of individual species, nor to tell which species are common and widespread and which are rare and tied to very specific environments. 

In a paper published in the journal Current Biology on 25 May 2023, Muriel Rabone of the Deep-Sea Systematics and Ecology Group at the Natural History MuseumJoris Wiethase of the Department of Biology of the University of YorkErik Simon-Lledo of the National Oceanography CentreAidan Emery, also of the Deep-Sea Systematics and Ecology Group at the Natural History Museum, Dan Jones, also of the National Oceanography Centre, Thomas Dahlgren, of the Department of Marine Sciences at the University of Gothenburg, and the Norwegian Research CentreGuadalupe Bribiesca-Contreras, again of the Deep-Sea Systematics and Ecology Group at the Natural History Museum, Helena Wiklund, again of the Deep-Sea Systematics and Ecology Group at the Natural History Museum and the Norwegian Research Centre, Tammy Horton, again of the National Oceanography Centre, and Adrian Glover, once again of the Deep-Sea Systematics and Ecology Group at the Natural History Museum, present a synthesis of Metazoan biodiversity within the Clarion-Clipperton Zone, aimed to convey the best currently available information to all stakeholders, ahead of the start of any mining operation within the zone.

Rabone et al. synthesized data from seven different data sources, producing over 100 000 individual records. Although these were assembled over several decades, the majority of the taxonomic work is recent, and much less than five years old. A total of 219 taxa new to science (including species, genera, and families) have been described from the Clarion-Clipperton Zone, again mostly in the recent past; only seven were described prior to the year 2000. The checklist of Animal species assembled by Rabone et al. includes 436 species found within the Clarion-Clipperton Zone, including 185 which were first described from within the zone (31 new genera and 3 new families were also described from within the zone). Of these 185 species, only six have subsequently been discovered living in other areas; two Sea Cucumbers, a Nematode, a Carnivorous Sponge, a Crinoid, and an Antipatharian Coral.

All geolocated published records of benthic Metazoa from the literature and databases Areas of Particular Environmental Interest and exploration mining contract areas, both active and reserved, are shown in outline. The type localities of all species described from the Clarion-Clipperton Zone to date are also shown (185 in total). Rabone et al. (2023).

A total of 27 phyla of Animals have been recorded in the Clarion-Clipperton Zone, as well as 49 classes, 163 orders, 501 families, and 1119 genera. Of the 436 Animals identified to species level, 185 (i.e. 42%) have been identified on the basis of both molecular and morphological data, with 217 (50%) identified only by their morphology. The remaining 34 species were listed with no method of identification given. Of the species described from the Clarion-Clipperton Zone, 51% were identified solely on the basis of morphology; this rises to 86% for meiofauna (species larger than 150 μm but smaller than 300 μm). For the most abundant groups within the Clarion-Clipperton Zone, Tanaid and Isopod Crustaceans and Polychaete Worms, 23% of the species identified were originally described from outside the zone, including some species from other ocean basins. A total of 5367 unnamed species were recorded, although 3.9% of these are species Rabone et al. believe to have been named erroneously; if these are taken out of the equation the number is 5142.

Rates of species descriptions in the Clarion-Clipperton Zone; proportion of species diversity in the Clarion-Clipperton Zone that is undescribed. (A) Rates of new descriptions and publications in the Clarion-Clipperton Zone. Cumulative totals of new taxa (families, genera, and species combined) and new species described from the Clarion-Clipperton Zone and taxonomic publications per year, over the period 1980–2022. Yearly totals of new descriptions also shown. (B) Proportion of recorded benthic Metazoan diversity from the Clarion-Clipperton Zone that is undescribed: named species recorded in red (both those described from the Clarion-Clipperton Zone and elsewhere), unnamed species shown in blue (‘unassigned’ are records not identified to phylum). Depictions of some of the new Clarion-Clipperton Zone species by phyla: Annelida, Neanthes goodayi Drennan; Arthropoda, Siphonis aurreus; Brachiopoda, Oceanithyris juveniformis; Bryozoa, Pandanipora helix; Cnidaria, Abyssopathes anomala; Echinodermata, Psychropotes dyscrita; Kinorhyncha, Meristoderes taro; Loricifera, Fafnirloricus polymetallicus; Mollusca, Ledella knudseni; Nematoda, Odetenema gesarae; Porifera, Chaunoplectella megapora; and Tardigrada, Moebjergarctus clarionclippertonensis. Rabone et al. (2023).

Based upon identified species, the most abundant taxa in the Clarion-Clipperton Zone are the Arthropoda, comprising 27% of the total, followed by the Annelida, 18%, Nematoda, 16%, Echinodermata, 13%, and Porifera, 7%. The proportions appear to be similar for unnamed species, albeit with a slightly higher proportion of Annelid Worms. According to the World Register of Deep-Sea Species (part of the World Register of Marine Species) there are currently 36 579 named species of Animal known to live at depths of greater than 500 m, of which 31% belong to the Phylum Arthropoda, 17% to the Phylum Mollusca, 15% to the Phylum Chordata, and 10% each to the phyla Annelida and Echinodermata. Thus the Clarion-Clipperton Zone appears to have a significantly higher proportion of Annelid, Nematode, and Echinoderm species than the deep ocean as a whole, and slightly higher proportions of Sponges and Bryozoans than the deep ocean as a whole. Conversely, the Clarion-Clipperton Zone has a lower proportion of Molluscs, particularly Gastropods, and Chordates, particularly Teleost Fish. Also notable is that Holothurans (Sea Cucumbers) make up a higher proportion of the total number of Echinoderm species in the Clarion-Clipperton Zone, while Asteroids (Starfish) and Ophiuroids (Brittle Stars) are less numerous. There are also groups, such as the Pycnogonids (Sea Spiders) for which there are no recorded named species within the Clarion-Clipperton Zone, although unnamed species are known.

Classed by size, 50% of identified species from the Clarion-Clipperton Zone are macrofauna (larger than 300 μm but smaller than 10 mm), 28% are megafauna (larger than 10 mm), and 22% are meiofauna (smaller than 300 μm but larger than 150 μm). This reflects the nature of studies carried out in the area, with 46% concentrating on macrofauna, 30% on megafauna, and 22% on meiofauna, What is notable about the Clarion-Clipperton Zone is the nature of the substrate, with the combination of soft mud and hard nodules, meaning that 14% of named species and 13% of unnamed species are hard-substrate species living on nodules, while the remainder are soft substrate species living on or in the mud. Several species of megafauna (Cnidarians and Sponges) have recently been described from nodules in the Clarion-Clipperton Zone, though there have only been two quantitative studies of macrofaunal nodule dwellers to date, revealing that the majority of these are undescribed Sponges and Bryozoans. One monograph on nodule Bryozoans in the Clarion-Clipperton Zone has been published, which described sixteen new species, nine new genera, and two new families. 

Fauna from the Clarion-Clipperton Zone. (A)–(J) All fauna are species described from the region and illustrating a range of phyla and size classes. Row 1 (A) the Sea Cucumber, Psychropotes dyscrita , commonly known as the ‘Gummy Squirrel’ (scale bar is 5 cm); (B) the Primnoid Coral, Abyssoprimnoa gemina, (scale bar is 5 mm); (C) the Antipatharian Coral, Abyssopathes anomala, (scale bar is 2 cm); and (D) the Hexactinellid Sponge, Sympagella clippertonae, (scale bar is 1 cm). Row 2, (E) the Cyclostomatid Bryozoan, Pandanipora helix, (scale bar is 500 μm); (F) the Isopod, Macrostylis metallicola, (scale bar is 0.2 mm); (G) the Polychaete, Neanthes goodayi, and (H) the Mollusc, Ledella knudseni, (scale bar is 0.5 mm). Row 3, (I) the Nematode, Odetenema gesarae, (scale bar is 100 μm); (J) the Kinorhynch, Meristoderes taro, (scale bar is 10 μm); (K) the Loriciferan, Fafnirloricus polymetallicus, (scale bar is 100 μm), and (L) the Copepod, Siphonis aurreus, (scale bar is 100 μm), Rabone et al. (2023).

Rabone et al. used several different mathematical models to attempt to predict the total number of Animal species within the Clarion-Clipperton Zone, producing answers which ranged from 6109 to 8514, with between 947 and 1034 genera, and 406-544 families. Thus, although there are clearly many unidentified species left within the zone, the picture appears to be much more complete for higher level taxonomic categories.

Rabone et al. estimate that 92% of species within the Clarion-Clipperton Zone remain unidentified. The proportion of unidentified species is thought to vary considerably from group to group, with 99.4% of Taneid Crustacean species though to be unidentified, along with 96.6% of Isopod Crustaceans and 87% of Polychaete Worms. An estimate of 92% of species being unidentified is also in line with higher estimates for the proportion of unidentified species in the total ocean.

Sampling efforts cross the Clarion-Clipperton Zone have note been even, with the majority of studies having been carried out in the central and eastern parts of the area, while portions of the zone remain almost totally unexplored. There is a similar unevenness in the depth of sampling, with the majority of sampling having taken place at depths of about 4200 m and about 5000 m. Both the depth and geographical data relate to areas where mining exploration contracts have been granted, mostly in the east-central part of the zone. Data on numbers do not exist for all recorded species, but where they do, 37% are known only from a single specimen, which implies significant undersampling. Again, 91% of the single specimen species have been recorded in areas where mining concessions have been granted, with the area known from Areas of Particular Environmental Interest. Overall, 95% of species recorded (named and unnamed) are unknown in the declared Areas of Particular Environmental Interest.

Heatmap of sampling effort as the density of unique sampling sites. Sampling effort is displayed as two-degree polygons. Rabone et al. (2023).

Rabone et al.'s study provides an estimate of the known and unknown species richness for benthic Animals across the Clarion-Clipperton Zone. This shows sampling to be very incomplete at the species level, but likely to be complete or very nearly complete at the family level. 

Density of sampling by depth. Number of samples by depth, grouped by 10 sample quantiles, all taxa combined. Rabone et al. (2023).

Diversity estimates can be seriously distorted when specimens of the same species are recorded as different species, a problem Rabone et al. believe was present in one of the sources they consulted,, the DeepData Database of the International Seabed Authority, where they suggest about a quarter of records represent duplicates. Further duplications could potentially be present and undetected within the remaining data.

Rabone et al. note that some regions of and habitats within the Clarion-Clipperton Zone remain almost totally unsampled. There have been, for example, only six studies of rocky outcrops and seamounts within the zone, habitats which are known to typically have very different faunas to other deep sea environments. The Clarion-Clipperton Zone is a highly variable area compared to much of the oceans' abyssal plains, with numerous rocky outcrops, and extensive fields of polymetallic nodules. Such a diverse environment ought to support a diverse community of organisms, with a lack of sampling almost certainly leading to a significant deficiency in the available data on biodiversity in the region.

A number of other factors could potentially cause estimates of species richness to be inflated or underestimated. Notably, within the Clarion-Clipperton Zone, many species have been recorded by informal names only, allowing for multiple synonyms for a single species, and variation in naming practices over time. A proportion of the informal names within the consulted data sources will no doubt be wrong; but it is impossible to do more that estimate this inaccuracy.

For the most abundant groups within the Clarion-Clipperton Zone, Tanaid and Isopod Crustaceans, 23% of identified species have type localities outside the zone, many within other ocean basins. These groups are known to include many widespread species, but it is still quite possible that this record could include many cryptic species (i.e. species which appear morphologically identical, but which are genetically distinct) or species complexes (groups of closely related cryptic species), which are known to be particularly prevalent in the deep oceans. Resolving this would require genetic sampling of both specimens from the type locality and the Clarion-Clipperton Zone population(s); without this the diversity of these groups may be underestimated by 20-25%. Most of the new species described from within the Clarion-Clipperton Zone have been described since the advent of molecular taxonomy as a standard method, but 51% are named from morphological data only. This is particularly true for smaller species, with 86% of meiofaunal species described from the Clarion-Clipperton Zone described only on the basis of morphological data. 

Rabone et al. suspect that their figure of 92% of species being unidentified within the Clarion-Clipperton Zone includes an overestimation of the number of species due to different informal names being used for the same species, but an underestimation of the number of species due to undersampling of some regions, and the presence of cryptic species. 

Rabone et al's study produces a species composition for the Clarion-Clipperton Zone with differs from the World Register of Deep-Sea Species estimate for the deep ocean, even at phylum level. Some of the trends produced in the study are likely to be real, such as the higher diversity of Sea Cucumbers in the World Register of Deep-Sea Species than in the deep ocean as a whole, but others are likely to be the result of problems such as uneven sampling within the zone and a shortage of experts working on some taxonomic groups. Rabone et al. also note that the majority of species identified within the Clarion-Clipperton Zone, both named and unnamed, fall into the macrofauna category, which has been the subject of the most studies within the region. Megafauna, which are hard to sample using remote-operated vehicles, are rarely collected, and therefore seldom identified. Meiofauna are thought to make up the majority of the biomass of organisms in the deep sea, but are also thought to be significantly undersampled. This situation is not unique to the Clarion-Clipperton Zone, and the World Register of Deep-Sea Species probably also contains significant biases, given the lack of sampling across much of the deep ocean floor.

Very few estimates of biodiversity across large areas of the deep ocean floor have been carried out. A study of the deep sea floor of the Southern Ocean found 674 species of Isopod Crustacean, 87% of which were new to science. Rabone et al. estimate that 96% of Isopod species within the Clarion-Clipperton Zone will be undescribed from elsewhere, i.e. the 23 species already described from within the zone, plus an estimated 474 species yet to be described. Estimates of the total number of marine Animal species range from 300 000 (likely to be a significant underestimate) to 10 million (likely to be a significant overestimate). Rabone et al. estimate the proportion of undescribed species within the Clarion-Clipperton Zone at 92%, while the number for the total deep ocean has been estimated at 87%, a comparable figure. The named species within the Clarion-Clipperton Zone currently represent about 1% of the total estimated deep sea biodiversity for the planet, while the total number of species probably represents about 15% of that total.

The biodiversity of the Clarion-Clipperton Zone is currently significantly under-described. Thirty one new genera and three new families have been described from the zone to date, and Rabone et al. are aware of several new general and at least one new family of Animals- awaiting description from samples collected within the zone. The area clearly contains a significant amount of unique evolutionary lineages. The Clarion-Clipperton Zone is known to be home to significant Echinoderm novelty not known from elsewhere, and the same is probably true of other groups. Life histories unknown from elsewhere have also been recorded within the Clarion-Clipperton Zone, including organisms associated with the stalks of Sponges, as well as Nematodes, Isopods, and Polychaetes from groups otherwise associated with infaunal sediment-dwelling lifestyles which have adapted to live on the hard surfaces of polymetallic nodules. Suspension feeders are also particularly likely to be associated with nodules, with 60-80% of megafauna (the size range dominated by suspension feeders) within the Clarion-Clipperton Zone living on the surface of nodules. How these nodule-dwelling species (and species living in the nearby sediments) would be affected by deep-sea mining efforts targeting the nodules has never been the subject of any specific study. Little is known about the life-histories of these nodule-dwelling organisms, and any such study is likely to be extremely difficult, given that a third of such species have been observed only once.

Studies of individual taxa within the Clarion-Clipperton Zone have estimated that the proportion of undescribed taxa is in excess of 80%. Rabone et al.'s study provides the first estimate of the area's total biodiversity, and estimates the number of undescribed species to be between 88% and 92%. Despite decades of study in the region, taxonomic studies have only recently begun, leaving much work to be completed, something which Rabone et al. should be treated as a matter of some urgency, given the likelihood of mining operations commencing in the zone in the near future. Biodiversity is often assumed to be low in deep marine environments, but this assumption is at least partly driven by low sampling levels rather than low diversity. The United Nations Convention on the Law of the Sea states that marine mining efforts should cause 'no serious harm', but this term is not defined, and in the absence of reliable data on deep marine ecosystems, could easily become meaningless. 

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