Saturday 30 September 2017

Bryodelphax kristenseni: A new species of Tardigrade from the Sierra Nevada de Santa Marta Mountains of Colombia.

Tardigrades, or Water Bears, are a distinctive group of small (usually less than 1 mm) invertebrates related to Arthropods, Nematodes and Velvet Worms. They have a simple segmented body with four pairs of limbs, and are remarkably resilient to environmental stress, being able to withstand extremely high and low temperatures, complete desiccation and even exposure to vacuum. To date about 1200 species of Tardigrade have been described, from marine, freshwater and terrestrial environments. Of these, less than 250 have been described from South America, the majority of these from Chile, Argentina and Brazil. 

In a paper published in the journal ZooKeys on 27 September 2017, Oscar Lisi of the Grupo de Investigación MIKU at the Universidad del Magdalena, and the Dipartimento di Scienze Biologiche, Geologiche e Ambientali at the Università di Catania, Anisbeth Daza and Rosana Londoño, also of the Grupo de Investigación MIKU at the Universidad del Magdalena, and Sigmer Quiroga of the Programa de Biología at the Universidad del Magdalena, describe a new species of Tardegrade from the Sierra Nevada de Santa Marta Mountains of Colombia.

The new species is placed in the genus Bryodelphax, and given the specific name kristenseni, in honour of Reinhardt Møbjerg Kristensen, of the Natural History Museum of Denmark and University of Copenhagen, for his work on Tardigrade taxonomy. The species is described from eleven specimens collected from Lichen, Moss and Liverworts at two locations in the Sierra Nevada de Santa Marta Mountains. These range from 106 to 131 μm in length, are apparently eyeless and covered in armoured plates.

Drawings of the dorsal (A) and ventral (B) plates arrangement of Bryodelphax kristenseni. Lisi et al. (2017).

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Iowa woman dies from West Nile Virus infection.

Health officials in Iowa have reported the death of a woman in the southwest of the state earlier this month. The woman has not yet been named, but has been described as being between 41 and 60 years of age. Iowa has recorded seven cases of the disease this year, with this being the first fatality; three other possible infections have been reported. In 2016 37 cases of infection with the Virus were reported in Iowa, with a single fatality.

West Nile Virus is a Mosquito-born Flavivirus (the group of RNA Viruses that also includes the Yellow Fever, Zika and Hepatitis C Viruses), first diagnosed in the West Nile District in Uganda in 1937, and subsequently reported in a number of African and Middle Eastern countries. The first case in the US was was reported in New York City in 1999, and it has subsequently been reported in every continental state of America. Outbreaks have also been reported in some European countries.

The West Nile Virus is a zoonotic infection, that principally infects Birds, and is transferred to Humans by Mosquitoes or occasionally Ticks. Infections have also been reported in a wide range of Mammal species, as well as in Crocodiles. Around 80% of infected Humans show no symptoms, with those who do generally suffering only a minor fever. However in a small number of cases the Virus infects the nervous system, causing a meningitis- or encephalitis-like infection that can often prove fatal. There is currently no known treatment for the Virus, making suppression and avoidance of Mosquitoes the best way to minimise fatalities from the disease.

Neural tissue infected by West Nile Virus. Brian Davies/University of Washington.

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Jogger and truck fall into sinkhole in San Antonio, Texas.

A jogger and a police truck have fallen into a sinkhole that appeared in the Pecan Valley area of San Antonio, Texas, on Friday, 29 September 2017. The hole was first encountered by jogger Jeanette Berlanga, who was out running with her boyfriend when she stepped into what she assumed was a puddle in Southside Lions Park and found the pool was in fact a large hole. Shortly after she escaped a truck driven by an off-duty San Antonio Police officer returning home after a shift at work also encountered the hole. He was also able to escape, but the vehicle had to be towed out of the hole.

Truck trapped in a sinkhole in San Antonio, Texas, on 29 September 2017. Caleb Downs/My SA.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.

On this occasion the sinkhole is thought to have formed after a cast iron pipe carrying excess rainwater collapsed, allowing the water to escape and wash away soft sediments beneath the road, leading the road above to collapse into the void.

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One killed in landslide and three in flooding on Cebu Island, the Philippines.

An eleven-year-old boy has died after being burried in a landslide in the Barangay San Jose area of Mandaue City on Cebu Island in the Philippines on Thursday 28 September 2017. Kyle Ashley Barcoso and his grandfather, Juanito Barcoso, 62, were both buried when a hillslope above their lightly-constructed house collapsed onto the structure at about 8.45 p m local time. Both were quickly dug out by neighbours, but the boy was unconscious and died later on the way to hospital. The older man was treated for injuries to his leg.

The approximate location of the 28 September 2017 Barangay San Hose landslide. Google Maps.

The incident is reported to have happened following heavy rainfall in the area. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall. Cebu has a wet and dry tropical climate, with a long rainy season that lasts from May to January. 
In a related incident three people drowned in Cebu City on the morning of Friday 29 September, when a footbridge over the Guadalupe River collapsed. The river was in flood due to the high rainfall, and a little over a meter higher than its normal level. The dead in this incident have been named as brothers John Carlo Taran, 8, and Juros Taran, 9, and Arturo Cabradilla, 26.

Rescue workers recovering the body of a boy who drowned in the River Guadeloupe in Cebu City on 29 September 2017. Alan Tangcawan/Superbalita Cebu.

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Asteroid 2017 SN2 passes the Earth.

Asteroid 2017 SN2 passed by the Earth at a distance of about 8 460 000 km (21.6 times the average distance between the Earth and the Moon, or 5.66% of the distance between the Earth and the Sun), slightly before 3.00 am GMT on Saturday 23 September 2017. There was no danger of the asteroid hitting us, though were it to do so it would have presented a significant threat. 2017 SN2 has an estimated equivalent diameter of 110-340 m (i.e. it is estimated that a spherical object with the same volume would be 110-340 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 3500-100 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater about 1.5-5 km in diameter and devastation on a global scale, as well as climatic effects that would last decades or even centuries.

The calculated orbit of 2017 SN2. Minor Planet Center.

2017 SN2 was discovered on 17 September 2017 (six days before its closest approach to the Earth) by the Atlas MLO Telescope at Mauna Loa Observatory in Hawaii. The designation 2017 SN2 implies that the asteroid was the 63rd object (object N2) discovered in the second half of September 2017 (period 2017 S).  

2017 SN2 has an 1086 day orbital period and an eccentric orbit tilted at an angle of 22.9° to the plane of the Solar System, which takes it from 1.05 AU from the Sun (i.e. 105% of he average distance at which the Earth orbits the Sun) to 3.09AU from the Sun (i.e. 3.09% of the average distance at which the Earth orbits the Sun, or slightly over twice the distance at which the planet Mars orbits the Sun). It is therefore classed as an Amor Group Asteroid (an asteroid which comes close to the Earth, but which is always outside the Earth's orbit).As an asteroid probably larger than 150 m in diameter that occasionally comes within 0.05 AU of the Earth, 2017 SN2 is also classified as a Potentially Hazardous Asteroid (it comes no closer to the Sun than 105% of the average distance at which the Earth orbit's the Sun, but the Earth's orbit is not completely circular).

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Friday 29 September 2017

Lithochrysa borealis: A new species of Green Lacewing from the Eocene of British Columbia.

The Neuroptera, or Net-winged Insects, first appeared in the Permian and reached their maximum diversity in the Permian, when they were the most numerous Insects in many ecosystems. They are non-metamorphic Insects, in that they do not go through a dramatic metamorphosis on reaching maturity in the way that Butterflies or Wasps do, but rather the larvae grow progressively more like the adults with each molt Nevertheless the larvae are often quite different from the adults and may have quite different ecological roles. Today the Neuroptera are somewhat of a relic group, with many of the Jurassic groups having become extinct and most of the surviving groups having much lower diversity. One group that are still very successful today are the Green Lacewings, Chrysopidae, with around 2000 species in about 85 genera found living around the world. This group was already well established by the Eocene, with 21 species described, all from North America.

In a paper published in the journal Zootaxa on 27 September 2017, Bruce Archibald of the Department of Biological Sciences at Simon Fraser University and Vladimir Marakin of the Federal Scientific Center of the East Asia Terrestrial Biodiversity of the Far East Branch of the Russian Academy of Sciences, describe a new species of Green Lacewing from an Early Eocene lacustrine shale exposed in the Driftwood Canyon Provincial Park of British Colombia.

The new species is placed in the genus Lithochrysa, which contains one previously described species, from the Eocene of Colorado, and given the specific name borealis, meaning 'northrn'. The species is described from an overlapping partial forewing and hindwing (fossil Insect species are often described from their wings, the venation of which is highly diagnostic).

 Wings of Lithochrysa borealis. (A) Specimen as preserved, a crumpled forewing overlaying a partial hind wing; (B) forewing venation (hind wing not shown). Scale bar is 1 mm. Archibald & Makarin (2017).

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Magnitude 5.0 Earthquake in the Jizzax Region of Uzbeckistan.

The United States Geological Survey recorded a Magnitude 5.0 Earthquake at a depth of 20.0 km in the Jizzakh Region of Uzbeckistan, close to the border with Tajikistan, slightly before 6.50 pm local time (slightly before 1.50 pm GMT) on Friday 29 September 2017. There are no reports of any damage ot casualties associated with this event, but it was felt in Tashkent and Dushanbe.

The approximate location of the 29 September 2017 Jizzakh Earthquake. USGS.

The Jizzakh Region lies to the north of the boundary between the Indian and Eurasian tectonic plates, which runs through northern Afghanistan. The Indian Plate is moving northward relative to the Eurasian Plate, causing folding and uplift along this boundary, which has led to the formation of the Hindu Kush Mountains of Afghanistan, The Pamirs in Tajikistan, the Himalayas and the other mountain ranges of Central Asia., and which makes the nations in this boundary zone prone to Earthquakes.

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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Thursday 28 September 2017

British tourist killed by rockfall on El Capitan, Yosemite National Park.

A British tourist has been killed and his female companion, also British, has been seriously injured, following a rockfall on El Capitan, a mountain in Yosemite National Park, California, on Wednesday 27 September 2017. The couple were initially thought to have been climbing the peak when the incident occurred, but are now known to have been walking beneath a cliff popular with climbers when a chunk of rock about 40 m high, 20 m wide and 3 m thick, and estimated to weigh about 1170 tonnes, fell from the rockface. The couple will not be named until relatives in the UK can be contacted. About 30 climbers were on the cliff-face when the incident occurred, though none of them are reported to have suffered any injuries.

Dust from a rockfall on El Capitan, Yosemite National Park, on 27 September 2017. Tom Evans/US National Park Service.

El Capitan is a granite outcrop reaching 2308 m above sea-level, and about 900 m above the valley bellow, in the Sierra Nevada Mountains. Mountains appear to be permanent structures to humans, but are actually dynamic active systems, being constantly uplifted (in the case of the Sierra Nevada by the subduction of the last chunks of the ancient Farallon Plate along the Pacific Coast of North America), and constantly worn down by erosion. The granite outcrops of the Sierra Nevada ate the remains of an ancient batholith, formed in the Cretaceous Period by a mantle plume that rose up beneath the area, but did not reach the surface to any great extent. This allowed the liquid magma of the plume to cool slowly, allowing the large mineral crystals that make up granite to form. This granite has been exposed at the surface by uplift and erosion over the last four million years. Because granite is made up of large crystals of different minerals, with different physical properties, it is particularly prone to erosion, as heating and cooling of the rock on a seasonal, or even daily, cycle, causes the minerals to expand at different rates, leading to the formation of cracks. These cracks can be further widened by water entering them and freezing, pushing them further open, and allowing more water to enter on the next cycle.

Granite from the Sierra Nevada, showing the large crystals that give it both its distinctive appearance and make it vulnerable to erosion. Roc Doc Travel.

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