Sunday, 18 March 2018

Homoneura yanqingensis: A new species of Lauxaniid Fly from northern China.

Lauxaniid Flies are small True Flies, Diptera, that tend to have plain coloured bodies, patterned wings and large, often brightly coloured eyes. The larvae of these flies are saprotrophs (detritovores) that often play a role in soil formation, helping to break down fallen leaves and other material. Lauxaniids are commonest in the Asian and American tropics, being rarer in temperate regions, and uncommon in Africa.

In a paper published in the journal ZooKeys on 29 December 2017, Li Shi and Xuefeng Gao, of the College of Agronomy at the Inner Mongolia Agricultural University, and Wenliang Li of the College of Forestry at the Henan University of Science and Technology, describe a new species of Lauxaniid from northern China.

The new species is placed in the genus Homoneura and given the specific name yanqingensis, meaning 'from Yanqing' in reference to Yanqing County in the Beijing Municipal Area, where the species was first discovered. This species ranges from 3.8 to 4.3 mm in length and is yellow in colour with brown spots on the wings. The species was found in the Beijing Municipal Area and Shaanxi Province.

Homoneura yanqingensis, male specimen from Shaanxi Province. Shi et al. (2017).

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Magnitude Earthquake in Zambezia Province, Mozambique.

The United States Geological Survey recorded a Magnitude 4.9 Earthquake at a depth of 10.0 km in western Zambezia Province, Mozambique, about 22 km to the northeast of the town of Nsanje in Malawi which was hit by an Earthquake on 6 March, slightly after 5.10 pm local time (slightly after 3.10 pm GMT) on Saturday 17 March 2018. This is unlikely to have caused any damage or casualties, though it is large enough that it was probably felt locally, although there have been no reports of anybody having done so at this time.

 The approximate location of the 17 March 2018 Zambezia Earthquake. USGS.

Western Zambezia lies within the the of the Great Rift Valley, which is slowly splitting the African Plate in two along a line from the Red Sea through Ethiopia, and which includes the great lakes and volcanoes of east-central Africa. This has the potential to open into a new ocean over the next few tens of millions of years, splitting Africa into two new, smaller, continents; Nubia to the west and Somalia to the east.

 Movement on the African Rift Valley, with associated volcanoes. Rob Gamesby/Cool Geography.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.
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Microbial biodiversity around the Garga Hot Spring in southern Siberia.

Microbial mats are thought to be the oldest biological communities on Earth, with a fossil record that dates back at least 3.5 billion years. Today these communities rend to be found in extreme environments where other organisms cannot thrive, such as hot springs or hypersaline lakes. The Baikal Rift Zone in southern Siberia is home to a number of hot spring systems with unusually alkaline waters, which are likely to be host to unique communities of mat-forming microbes, but which are relatively understudied.

In a paper published in the journal BMC Evolutionary Biology on 28 December 2017, Alexey Sergeevich Rozanov and Alla Victorovna Bryanskaya of the Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Timofey Vladimirovich Ivanisenko, also of the Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, and of the Novosibirsk State University, and Tatyana Konstantinovna Malup and Sergey Evgenievich Peltek, again of the Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, present the results of a study of the biodiversity of microbial mats around the Garga Hot Spring in the Barguzin Valley of the Republic of Buryatia in southern Siberia, which has the most alkaline known waters of any hot spring in the Baikal Rift Zone, with pH values of between 8.0 and 9.0.

 (a) Eastern Siberia; (b, Eastern Baikal, Barguzin Valley, satellite photo. Red cross marks the location of the Garga hot spring (54°19′3.72″N, 110°59′38.4″E). Rozanov et al. (2017).

Rozanov et al sampled waters originating from the spring at four points. The first of there was close to the spring itself, with waters at temperatures in excess of 74°C, where there was a simple biofilm of white material was present. The second was located in a stream running from the spring towards the Barguzin River, where the waters were about 70°C, and a thicker biofilm with three distinct layers had developed. The upper two layers were yellowish, with the upper being dense and about 2 mm thick and the lower being thinner and about 2 cm. The bottom layer was about 1 cm thick, white, gelatinous and adhered to the substrate. The third point was further downstream, where the temperature had fallen to 55°C. Here the mat still had three layers, with the top layer being yellowish green and about 2 mm thick, the middle layer being membranous, gelatinous and whitish-green and about 2 cm thick, while the bottom layer was again 1 cm thick, gelatinous and white. The final point was further downstream, where the temperature had fallen to 45°C. Here there were again three layers, with the upper two layers being apparently identical to those at the third site, while the bottom layer as thinner, about 3-5 mm, and 'skin coloured'.

Microbial mats of the Garga hot spring. (a) Microbial mat of the upper reaches of the spring; red circle, second sampling point. (b) Microbial mat of the middle reaches; red circle, third sampling point. (c) Layers of the third sample. (d) Sampling scheme. Rozanov et al. (2017).

The sample taken from the first location contained a significant proportion of Archaeans (Prokaryotic micro-organisms resembling Bacteria, but only distantly related to them, and more closely related to Eukaryotes, about 20% of the sample, the highest proportion found at any site in the Baikal Rift Zone to date. Many of these belonged to the Crenarchaeota, a group widely associated with hot springs, with about 7.9% of the sample closely related to Thermopro teusuzonensis, a species isolated from acid hot springs on the Kamchatka Peninsula, and Vulcanis aetasouniana, a species from acidic springs in Japan. However, the sample also contained other, non-Crenarchaeote, Archaeans, with no apparent close relationships to any other described species.

The remaining three sites had essentially similar structures, with an upper layer dominated by Cyanobacteria (filament-forming photosynthetic Bacteria) of the genera Leptolyngbya, Synechococcus and Nostoc, all associated with hot springs in a variety of other locations around the world. The second layer contained lower numbers of Cyanobacteria, though they were still present, along with heterotrophic Bacteria (Bacteria that gain nutrition by consuming other Bacteria), principally Proteobacteria and Actinobacteria. The lowermost layer was anearobic and dominated by saprotrphic Bacteria such as Clostridia, obtain nutrition by breaking down organic material externally.

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Avalanche feared to have killed four skiers in Swiss Alps.

The bodies of two skiers have been recovered from under about six meters of snow, and a further two are missing, following an avalanche in the Vallon d'Arbi area near Riddes in the District of Martigny of Canton Valais in Switzerland on Friday 16 March 2018. All four skiers are said to be aged between 20 and 25 and from the Alsace Region of France.

The scene of an avalanche in Vallon d'Arbi on 16 March 2018. Valais Canton Police.

Avalanches are caused by the mechanical failure of snowpacks; essentially when the weight of the snow above a certain point exceeds the carrying capacity of the snow at that point to support its weight. This can happen for two reasons, because more snow falls upslope, causing the weight to rise, or because snow begins to melt downslope, causing the carrying capacity to fall. Avalanches may also be triggered by other events, such as Earthquakes or rockfalls. Contrary to what is often seen in films and on television, avalanches are not usually triggered by loud noises. Because snow forms layers, with each layer typically occurring due to a different snowfall, and having different physical properties, multiple avalanches can occur at the same spot, with the failure of a weaker layer losing to the loss of the snow above it, but other layers below left in place - to potentially fail later.

 Diagrammatic representation of an avalanche, showing how layering of snow contributes to these events. Expedition Earth.

The Alps have seen a number of avalanche related incidents this winter, largely due to high levels of snowfall. This is, in turn caused by warmer conditions over the Atlantic, which leads to higher rates of evaporation over the ocean, and therefore higher rates of precipitation over Europe, which falls as snow in cooler regions such as the Alps, where the moist air meets cold air fromt the east. This situation is likely to get worst this week after a significant cold front from the east brought plunging temperatures across Europe this week, which is expected to be replaced by a new wet front from the west over the weekend, depositing precipitation as more snow across the now cooler continent. 

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The March Equinox.

The March Equinox falls at 4.15 pm on Tuesday 20 March this year. The Earth spins on its axis at an angle to the plain of the Solar System. This means that the poles of the Earth do not remain at 90° to the Sun, but rather the northern pole is tilted towards the Sun for six months of the year (the northern summer), and the southern pole for the other six months (the southern summer). This means that twice a year neither pole is inclined towards the Sun, on days known as the equinoxes.

The tilt of the Earth relative to the incoming light of the Sun at the March Equinox. Przemyslaw Idzkiewicz/Wikimedia Commons.

The equinoxes fall each year in March and September, with the March Equinox being the Spring (or Vernal) Equinox in the Northern Hemisphere and the Autumn Equinox in the Southern Hemisphere, while the September Equinox is the Autumn Equinox in the Northern Hemisphere and the Spring Equinox in the Southern Hemisphere. On these two days the day and night are both exactly twelve hours long at every point on the planet, the only days on which this happens.

 The tilt of the Earth relative to the Sun at the planet's equinoxes and solstices. Astronomy Group/University of St Andrews.

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Saturday, 17 March 2018

Asteroid 2007 LU19 passes the Earth.

Asteroid 2007 LU19 passed by the Earth at a distance of about 7 851 000 km (20.4 times the average distance between the Earth and the Moon, or 5.25% of the distance between the Earth and the Sun), slightly after 9.20 pm GMT on Saturday 10 March 2018. There was no danger of the asteroid hitting us, though were it to do so it would have presented a significant threat. 2007 LU19 has an estimated equivalent diameter of 100-330 m (i.e. it is estimated that a spherical object with the same volume would be 100-330 m in diameter), and an object of this size would be predicted to be capable of passing through the Earth's atmosphere relatively intact, impacting the ground directly with an explosion that would be 225 to 120 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater 1-5 km in diameter and devastation on a global scale, as well as climatic effects that would last years or even decades.

The calculated orbit of 2007 LU19. Minor Planet Center.

2007 LU19 was discovered on 15 June 2007 by the Siding Spring Observatory near Coonabarabran in New South Wales. The designation 2007 LU19 implies that it was the 495th asteroid (asteroid U19) discovered in the first half of June 2007 (period 2007 L). 

2007 LU19 has a 1332 day orbital period and an eccentric orbit tilted at an angle of 2.60° to the plane of the Solar System, which takes it from 0.89 AU from the Sun (i.e. 89% of he average distance at which the Earth orbits the Sun) to 3.84 AU from the Sun (i.e. 384% of the average distance at which the Earth orbits the Sun, and more than twice as distant from the Sun than the planet Mars). It is therefore classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer). This means that close encounters between the asteroid and Earth are extremely common, with the last having occurred in June 2007 and the next predicted in March 2029. As an asteroid probably larger than 150 m in diameter that occasionally comes within 0.05 AU of the Earth, 2007 LU19 is also classified as a Potentially Hazardous Asteroid.

2007 LU19 also has frequent close encounters with the planets Mars, which it last came close to in March 1960 and is next predicted to pass in May 2098, and Jupiter which it last came close to in July 1987 and is next predicted to pass in August 2022. Asteroids which make close passes to multiple planets are considered to be in unstable orbits, and are often eventually knocked out of these orbits by these encounters, either being knocked onto a new, more stable orbit, dropped into the Sun, knocked out of the Solar System or occasionally colliding with a planet.
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Hundreds of artefacts stolen from Canterbury Archaeological Trust recovered.

Hundreds of artefact's stolen from the Canterbury Archaeological Trust in Kent, England, in January this year have been recovered by Kent Police. The artefact's were found in an abandoned building a few streets from where they were originally stolen. The recovered items include hundreds of beads and other Anglo-Saxon items from excavations in Canterbury and St Albans (Hertfordshire). Many items are still missing after the break-in, though it is thought that most of these are replica items, such as weapons and coins, from the Trust's educational loans collection, plus modern tools used during archaeological excavations, which may have proved easier for the thieves to sell.

 Members of the Canterbury Archaeological Trust with stolen artifacts recovered by the police this week. Kent Messenger.

The thieves broke into the charity's premises in Canterbury on the night of Thursday 22-Friday 23 January 2018, then again on the night of Friday 23-Saturday 24, causing extensive damage to the charity's building and collection, breaking power and water lines and exposing asbestos, which had to be dealt with by a specialist contractor before other work could proceed. As well as the stolen items, many other artifacts were scattered and mixed, and will take hundreds of hours work by specialist workers to re-identify and properly curate; archaeological artifacts without proper records of their origin are of little value. The recovered items will now have to be treated in the same way, requiring many hours of work by the Trust's employees and volunteers.

Kent Police are still hoping to apprehend the thieves and recover those items that are still missing. Anyone with any information can contact Kent Police on 01843 222289 (+44 1843 222289 from outside the UK) and quote incident number ZY/4200/18. Alternatively Kent Crimestoppers can be called anonymously on 0800 555111 from within the UK only, or online here from anywhere in the world.

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