Saturday, 13 August 2022

Cyne barcelonae: A new species of Showy Mistletoe from the Philippines.

Showy Mistletoes, Loranthaceae, are specialist members of the Sandlewood order, Santalales, which superficially resemble the Mistletoes of the northern temperate regions (to which they were formerly thought to be related), but with a distribution in the Southern Hemisphere and tropical regions, and more showy and brightly coloured flowers. Like the True Mistletoes, the Showy Mistletoes are hemiparasitic, which is to say they produce chlorophyll and photosynthesise for themselves, but obtain many of their nutrients by sinking their roots into the xylem of other Plants.

In a paper published in the journal Phytotaxa on 11 August 2022, Daniel Nickrent of the Plant Biology Section at Cornell University, and Mark Gregory Rule of the Department of Environmental Studies at Mindanao University and the Philippine Taxonomic Initiative describe a new species of Showy Mistletoe from Dinagat and Bucas Grande Island off the northeast coast of Mindanao. 

The new species is placed in the genus Cyne, which has previously been found in the Philippines, the Moluccas Islands, and New Guinea, and given the specific name barcelonae, in honour of the Filipina botanist Julie Fenete Barcelona, for her work on Pteridophytes and Rafflesia

Cyne barcelonae. (A) Habit of mistletoe parasitic on Myrsine sp. (B) A young haustorial connection to host branch. Arrow indicates a new vegetative shoot forming on the flank of the haustorium. Note that no epicortical roots are present. (C) Terminal portion of vegetative shoot showing two lateral and the central stems assuming a pseudo-whorled appearance. Note the connation of the leaf bases. (D) Non-connate leaves subtending to young shoots with connate leaves, still unopened. (E) Young inflorescence with one of the connate leaves removed. Although two pairs of triads can be discerned, their decussate nature is obscure. (F) Flowering shoots of plant photographed on Dinagat Island. Meljan Demetillo & Mark Gregory Rule in Nickrent & Rule (2022).

Cyne barcelonae produces a stem directly from its host without epicortical runners (visible external roots). This stem then typically divides to form two branches. The bark darkens to reddish brown as it ages, leaves are waxy and oval. The branch tips have two terminal leaves, each surrounding two triads of flowers. These flowers are green and tubular, with red tips. Fruits are a orange-brown in colour.

Cyne barcelonae. (A) Flowers at anthesis. Note the green corolla with a dilated base as well as stamens with filaments. (B) Fruits young and mature with persistent calyculus and style base. (C) Young fruit longitudinal section showing seed inside ovary wall. (D) Capitulum arising from corky periderm of receptacle. Note the bracts and bracteoles adpressed to calyculus/ovary. (E) Portion of inflorescence with two triads, one with calyculus/ovaries removed to show the laciniate bracts and bracteoles. (F) Corky periderm removed from receptacle. Nickrent & Rule (2022).

This Mistletoe has been observed growing on trees belonging to the genera MyrsineSterculia, and  Timonius, always on ultramafic soils within 20 m of a stream; other Mistletoes were observed in the same areas targeting the same host-trees. The species was found on two islands. Bucas Grande is part of the Siargao Islands Protected Landscape and Seascape, and in theory enjoys a high level of protection. However, the area where Cyne barcelonae was found growing as actually a fragment of remnant forest within a community-operated resort, and while their are regulations on Human activities here, firewood-collection and commercial tree cultivation do occur. Furthermore, the Plants were observed before the passage of Typhoon Rai through the area in December 2021, and has not been revisited by scientists since. Dinagat Island is currently considered to be severely threatened by mining, despite being recognised as an area of great importance for Plant biodiversity, with about half of the island's forests in areas which are currently covered by Mineral Production Sharing Agreements. Some protection may be offered by the Dinagat Island Conservation Program, which has recently been initiated by the provincial government, and which is intended to exclude areas of great biological significance from mineral extraction.

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Friday, 12 August 2022

Looted artefacts returned to Cambodia by the US.

The United States has formally handed back 30 looted artefacts to Cambodia in a ceremony in New York on Monday 8 August 2022. The artefacts, which were looted during civil conflicts within the country which lasted from the 1960s to the 1990s, include a 10th century statue of the Hindu god Skanda riding a Peacock, and a four ton statue of the god Ganesaha, which was too large to bring to the ceremony, both looted from the ancient Khmer capital Koh Ker, and other sculptures dating from as far back as the Bronze Age.

Damian Williams, US Attorney for the Southern District of New York, stands between two sandstone Bhudas during a ceremony in which these, and other looted artefacts, were returned to the Kingdom of Cambodia, on Monday 8 August 2022. International Consortium of Concerned Journalists.

The artefacts were smuggled into the US by Douglas Latchford, a British-born, Bangkok-based antiquities dealer who had been under investigation by the United States Department of Homeland Security Investigations from 2019 until the time of his death in August 2020. They were in the collections of a number of museums and individuals, all of whom chose to surrender the objects voluntarily after being served with civil forfeiture claims.

A tenth century sandstone statue of the Hindu war god Skanda riding a Peacock, looted from the Khmer capitol of Koh Ker and officially handed back to the Kingdom of Cambodia by the US Government this week. Seth Wenig/AP.

Latchford is believed to have obtained antiquities in Bangkok from an organised network of smugglers who dealt in items looted from archaeological sites and temples with Cambodia. In Thailand Latchfod is alleged to have forged documents of provenance for the artefacts, allowing them to be sold on the international market. However, the network was exposed as part of the 'Pandora Papers' investigation by the International Consortium of Investigative Journalists, which exposed numerous offshore banking and illegal trade networks involving high ranking politicians and wealthy individuals around the world.

A tenth century sandstone statue returned to the Kingdom of Cambodia by the US Government this week after being looted and traded on the international black market. Andrew Kelly/Reuters.

As well as being of great historic and artistic value, many of the looted objects are considered to be sacred by the people of Cambodia. Once returned, they will be displayed in the National Museum of Cambodia in Phnom Penh.

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The Perseid Meteor Shower.

The Perseid Meteor Shower lasts from late July to early September each year, and are expected to be at a peak before dawn on Saturday 13 August 2022. Viewing will be poor for the Perseids this year, as the meteors peak slightly after the Full Moon on Friday 12 August. The Perseids get their name from the constellation of Perseus, in which the meteors have their radiant (the point from which they appear to originate).

The radiant point of the Perseid Meteors. Greg Smye-Rumsby/Astronomy Now.

Meteor showers are thought to be largely composed of material from the tails of comets. Comets are composed largely of ice (mostly water and carbon dioxide), and when they fall into the inner Solar System the outer layers of this boil away, forming a visible tail (which always points away from the Sun, not in the direction the comet is coming from, as our Earth-bound experience would lead us to expect). Particles of rock and dust from within the comet are freed by this melting (strictly sublimation, transforming directly from a solid to a gas due to the low pressure on it's surface) of the comet into the tail and continue to orbit in the same path as the comet, falling behind over time.

The Earth passing through a stream of comet dust, resulting in a meteor shower. Not to scale. Astro Bob.

The Perseid Meteors are caused by the Earth passing through the trail of the Comet 109P/Swift-Tuttle, and encountering dust from the tail of this comet. The dust particles strike the atmosphere at speeds of over 200 000 km per hour, burning up in the upper atmosphere and producing a light show in the process.

How the passage of the Earth through a meteor shower creates a radiant point from which they can be observed. In The Sky.

Comet 109P/Swift-Tuttle was discovered independently in July 1862 by the astronomers Lewis Swift and Horace Parnell Tuttle, after whom it is named. The number 109P implies that it was the 109th comet discovered (strictly speaking people had been observing comets for thousands of years, but it was not until the mid-eighteenth century that it was realised that they were predictable objects that returned cyclically), that it is a periodic comet (P - again, most comets are periodic, but the term 'periodic comet' is reserved for those with periods of less than 200 years, since these can be reliably predicted).

Comet 109P/Swift-Tuttle imaged in 1992 during its last visit to the Inner Solar System. The Planetary Society/NASA.

Comet 109P/Swift-Tuttle itself only visits the Inner Solar System once every 133 years, last doing so in 1992, on an eccentric orbit tilted at 113° to the plane of the Solar System (or 67° with a retrograde orbit - an orbit in the opposite direction to the planets - depending on how you look at it), that takes it from 0.95 AU from the Sun (95% of the distance at which the Earth orbits the Sun) to 51.22 AU from the Sun (51.22 times as far from the Sun as the Earth, more than three times as far from the Sun as Neptune and slightly outside the Kuiper Belt, but only scraping the innermost zone of the Oort Cloud). The comet is next expected to visit the Inner Solar System in 2126, reaching about 22 950 00 km (0.15 AU) from Earth in August of that year. As a comet with a period of more than 20 years but less than 200 years, 109P/Swift-Tuttle is considered to be a Periodic Comet, and a Halley-type Comet.

The orbit and current position of Comet 109P/Swift Tuttle. JPL Small Body Database Browser.

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Thursday, 11 August 2022

Wildfires in the Silurian.

Free oxygen first appeared in the Earth's atmosphere during the Great Oxidation Event, between 2.5 and 2.3 billion years ago, and has played a significant role in all biogeochemical cycles ever since. A soil-forming microbial cover is thought to have begun to form on the Earth's landmasses about 850 million years ago, which further contributed to the oxygen content of the atmosphere. Following this, atmospheric oxygen concentrations are thought to have remained fairly constant until the appearance of the first land Plants in the Ordovician. 

These first Plants emerged into a world already dominated by Fungi, a group which quickly acquired the ability to both break-down the tissues of dead plants, and to form mycorrhizal relationships with living ones, enhancing the flow of nutrients through these primitive terrestrial ecosystems, and causing another rise in oxygen levels. The oldest known Vascular Plant, Cooksonia, a leafless, dichotomously branching Plant reaching less than 10 cm high, appeared during the Wenlock Epoch of the Silurian, between 433.4 and 427.4 million years ago, and has been recorded from rocks in Ireland and the Czech Republic. However, Cooksonia is not the most common form in the deposits where it is found, it lived in a landscape dominated by Namatophytes, vegetative organisms comprised of aggregations of tubes and cuticles, which were almost certainly Fungi, and possibly Lichens, and fossils of which have been found around the world.

The appearance of terrestrial Plants is generally accepted to have provoked a rise in atmospheric oxygen levels, although the extent of this is hard to determine, and scientists have differing opinions upon when oxygen levels comparable to those seen today were first achieved. 

In a paper published in the journal Geology on 13 June 2022, Ian Glasspool and Robert Gastaldo of the Department of Geology at Colby College, attempt to reconstruct the oxygen content of the Silurian atmosphere, by using charcoal fragments from deposits in Wales and Poland as evidence of Silurian wildfires, which would have required a minimum level of oxygen to occur.

Charcoal can only form when the atmospheric oxygen pressure is between 70% and 140% of that of today's atmosphere. Lower than this, and plant matter will not combust, higher, and it will combust completely, turning all available carbon into CO₂. Charcoal first appears in the Ordovician, suggesting that the atmosphere had sufficient oxygen for it to form then, but disappears again in the (Early Devonian, 419.2-410.8 million years ago), and is absent for much of the the rest of the Devonian. 

Glasspool and Gastaldo examine microscopic charred plant fragments from the Middle Silurian Pen-y-lan Mudstone at Rumney in Wales, and which is about 10 million years older than the previous oldest charred vegetative material, from the Late Silurian Winnica Formation at Winnica in Poland.

Silurian palaeogeography with Rumney (Wales, UK) and Winnica (Poland) localities plotted against International Geological Congress time scale version 2021.7. Abbreviations: Ord., Ordovician; Sa, Sandbian; Ka, Katian; Hi, Hirnantian; Rh, Rhuddanian; Ae, Aeronian; Te, Telychian; Sh, Sheinwoodian; Ho, Homerian; Go, Gorstian; Lu, Ludfordian; Pd, Přídolí; Lo, Lochkovian; Pr, Pragian; Em, Emsian; Ei, Eifelian; Gi, Givetian; Fr, Frasnian; Fa, Famennian. Glasspool & Gastaldo (2022).

Organic material from Rumney is dominated by Nematophytes, and in particular members of the genus Pachytheca. Glasspool  and Gastaldo obtained charred vegetative fragments from rock samples obtained from a borehole, drilled by the British Geological Survey, at depths of between 314.71 and 316.3 m. 

Since the exact nature of Nematophytes is unclear, it was necessary to use proxies to estimate the temperature at which this material may have burned; previous research having found that charcoal can be made from wood at temperatures between 410 and 730°C, and from Bracket Fungi at between 440 and 940°C. Based upon the degree of charring, Glasspool  and Gastaldo conclude that the material from Rumney burned at an average of about 490°C if Namatophytes were woody, or about 540°C if they were Bracket Fungus-like, although the most charred were probably burned at about 640°C (if woody) or 820°C (if Bracket Fungus-like).

Select charred phytoclasts: Rumney (Wales, UK) Nematophytes in reflected light (A), (B) and scanning electron microscopy images of Nematophytes from Winnica (Poland) (C), (D). (A) High reflectance and brittle fracture in Prototaxites. (B) Outer cortex of Pachytheca. (C) Trilayered Nematophyte cf. Tristratothallus. (D) Aggregation of small and large tubes. Glasspool & Gastaldo (2022).

The development of an oxygen-rich atmosphere has been crucial for the development of life on Earth, and particularly so for the emergence of Animals onto land. However, there is no direct way of measuring the oxygen content of ancient atmospheres is impossible, forcing scientists to rely on proxies for this information. As the formation of charcoal requires atmospheric oxygen levels approaching those of today, charcoal is an excellent proxy for the development of an oxygen-rich atmosphere, and Glasspool and Gastaldo's evidence that this may have developed by the Wenlock Epoch of the Silurian Period. about 430 million years ago.

There are some significant carbon isotope excursions (short intervals in which the proportions of carbon isotopes in sedimentary rocks shift significantly) in the Silurian, including notable ones in the Wenlock to Přídolí epochs, which suggests that the Silurian carbon cycle was more prone to severe disruption than that of any other period of the Phanerozoic. While some fairly good models of oxygen fluctuations in the Silurian have been developed, these operate on a scale of tens of millions of years, and cannot provide helpful data on the sort of sudden, short lived events that would cause these isotope excursions. However, a stratigraphic model of fire intervals within the Silurian could potentially address this mystery, something Glasspool and Gastaldo propose creating.

Most current predictions of oxygen levels in the atmosphere suggest that the oxygen content remained below 15% from the Late Ordovician until the Early Devonian. However, this is inconsistent with evidence for wildfires in the Silurian, as an oxygen content of 16% or above is needed for the combustion of dry vegetative matter. One model (GEOCARBSULFOR) does allow for higher oxygen levels, but still below 18%, which would allow for small fires under very dry conditions, though Glasspool and Gastaldo question whether any Silurian Plant or Fungus was capable of surviving in such an environment. The deposits at Rumney record a fairly high proportion of charcoal in a marine sediment, which would generally imply a conflagration of some size, inconsistent with any current model of Silurian oxygen levels.

Most of the data from Rumney implies a fairly low temperature fire (how low depending on whether the vegetation was Plant- or Fungus-like), but there are charcoal fragments which formed at far higher temperatures, suggesting at least pockets of high temperature fire. This seems implausible given the nature of the fuel, though Glasspool and Gastaldo suggest it it more plausible if Nematophytes were Fungal in nature, as Fungi naturally burn at higher temperatures.

The limiting factor for vegetative growth in the Silurian was probably the availability of phosphorus. Fungi and Bacteria can liberate this from rock to some extent, enabling the growth of Lichens and Plants (the later through symbiotic mycorrhizal relationships), but the phosphorus then becomes locked into the Plant or Fungus body, even after it dies. Fires would have had the ability to free up phosphorus locked into dead vegetation, making it available for new growth on land and in the oceans, where it could prompt blooms of photosynthetic algae, further rising the oxygen level. However, too frequent or severe fires would have damaged the soil structure, killing off microbial communities and creating a sterile environment.

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Tuesday, 9 August 2022

Magnitude 5.6 Earthquake beneath East New Britain Province, Papua New Guinea.

The United States Geological Survey recorded a Magnitude 5.6 Earthquake at a depth of 35.0 km roughly 149 km to the southwest of the city of Kokopo in East New Britain Province, Papua New Guinea, slightly after 3.35 pm local time (slightly after 5.35 am GMT) on Monday 8 August 2022. There are no reports of any damage or casualties associated with this event, but people have reported feeling it locally. 

The approximate location of the 8 August 2022 East New Britain Earthquake. USGS.

New Britain is located on the South Bismarck Plate, north of the Solomon Sea Plate, which is being subducted beneath it. The plates do not pass over one-another smoothly, but constantly stick together then break apart as the pressure builds up, causing Earthquakes in the process.

The subduction of the Solomon Sea Plate beneath New Britain. Oregon State University.

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Monday, 8 August 2022

Horniman Museum in London agrees to return 72 objects looted from Benin City to Nigeria.

The Horniman Museum in London has agreed to return a collection of 72 objects looted from Benin City, in modern Edo State, Nigeria, according to a press release issued on 7 August 2022. The museum received a formal request for the return of the objects from the Nigerian National Commission for Museums and Monuments in January 2022, and, following a consultation with community members, visitors, schoolchildren, academics, heritage professionals and artists based in Nigeria and the UK, has decided to return the objects, stating that the objects were clearly obtained by force, and that it is both moral and appropriate to hand them back. Having received endorsement for this course of action from the Charity Commission (the body in the UK which ensures that charities do not misuse funds or assets), the museum will now go ahead with returning the objects.

A Brass plaque depicting Oba (King) Orhogbua. Horniman Museum.

The objects to be returned by the Horniman Museum include twelve brass plaques, a variety of brass and ivory ceremonial objects, including a brass cockerel alter piece and several brass bells, a key to the king's palace, and every day objects such as fans and baskets.

A ceremonial brass clapper bell. Horniman Museum.

The Kingdom of Benin dates back to at least the twelth century, and covered much of what is now southwest Nigeria. The Oba (King) of Benin ruled from his capital, Edo, which (slightly confusingly) is now the modern city of Benin in Edo State, Nigeria. By the 1890s the Benin had become a major exporter of Palm oil to British traders on the Niger Delta, but in 1896, following a dispute over taxes, the Oba (King) of Benin cut off this supply of oil. The Acting Consul-General of the Protectorate of Nigeria, James Robert Phillips, drew up plans to invade the state and overthrow the Oba, but these were rejected by the British Foreign Secretary, Lord Salisbury. Instead, Philips dispatched an expedition to 'negotiate' with the Oba, which included 250 soldiers and a pipe band. This force was interpreted as an invasion by the Iyase (commander in chief of the army) of Benin, who dispatched a force to intercept the party. The two forces met at Ughoton, with the British force being defeated and the majority of its leaders either killed or captured.

Brass plaque depicting an Oba's Emissaries. Horniman Museum.

This was used by Philips to justify a much larger 'punitive' expedition, under the command of Rear-Admiral Harry Rawson. On 9 February 1897 Rawson invaded Benin with a force of 1200 heavily armed soldiers and marines, with the city of Edo falling on 18 February. The city was subsequently lootied of its rich artwork, with individual soldiers, sailors and marines stripping not just the royal palaces and major temples of the city, but also smaller shrines and the homes of individual citizens. These artefacts were subsequently shipped back to the UK, and disposed of as their new owners saw fit, either being sold privately to museums or collectors, or retained as mementoes of the expedition. 

A bronze pendant from Benin. Horniman Museum. 

This essentially random looting and subsequent sale of artefacts from Benin makes it very hard to know how many objects were taken, and renders almost impossible any hope of understanding the original context of many of the artefacts. This kind of haphazard looting was fairly typical of European colonial forces in Africa (and elsewhere), something which was made worse by subsequent claims that African peoples, now stripped of much of their heritage, actually lacked any meaningful history. While the events surrounding the looting of Benin and other African cities cannot be undone, it is hoped that the return of African artworks and cultural objects will at least go some way towards undoing the perception that Africans were not capable of making these artefacts in the first place.

Carved wooden paddle from Benin. Horniman Museum.

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