Sunday, 1 May 2016

Baetis alpinus: Cryptic Diversity in Alpine Mayflies.

Alpine Mayflies, Baetis alpinus, are widespread around the headwaters of many European rivers, being found in swift-flowing stoney streams at altitudes of between 200 and 2600 m (possibly higher). Like other Mayflies they spend the majority of their lives as aquatic larvae, only emerging for two final, winged stages, the pre-reproductive subimago, which typically lasts for less than 24 hours, and the sexually reproductive imago stage. Male imagos form swarms over fast-flowing water, with females flying into these swarms to mate. Males die after mating, females live long enough to find a suitable egg laying site (typically an overhanging rock upstream of the mating site). This reproductive system leaves little oportunity for long distance dispersal, and a numer of other Mayfly species have been shown to be complexes of cryptic species, made up of morphologically distinct but reproductively isolated lineages thought to have become separatedduring the Pleistocene glaciations. Alpine Mayflies are considered to be highly variable, both in morphology, an in reproductive behavior, with populations varying in generation time from three generations per year to one generation every two years (though this variation is thought to be linked to altitude and temperature), making the species a prime candidate for the presence of cryptic lineages.

In a paper published in the journal BMC Evolutionary Biology on 12 April 2016, Marie Leys of the Department of Aquatic Ecology at the Swiss Federal Institute of Aquatic Science and Technology and the Institute of Integrative Biology in Zürich, Irene Keller of the Department of Clinical Research at he University of Bern and the Swiss Institute of Bioinformatics, Katja Räsänen, also of the Department of Aquatic Ecology at the Swiss Federal Institute of Aquatic Science and Technology and the Institute of Integrative Biology in Zürich, Jean-Luc Gattolliat of the Musée cantonal de Zoologie and Department of Ecology and Evolution at the University of Lausanne and Christopher Robinson, again of the Department of Aquatic Ecology at the Swiss Federal Institute of Aquatic Science and Technology, examine the genetic structures of Alpine Mayfly populations on the headwaters of several major European rivers in the Swiss Alps.

An Alpine Mayfly, Baetis alpinus. Evasion.

Leys et al. sampled 1591 Mayfly larvae from 24 sites in the upper parts of four major European river basins, the Rhine, Rhone, Danube and Po. Of these 112 specimens were found to bellong to Baetis melanonyx, a closely related species that resembles Baetis alpinus closely. The remaining 1479 specimens were found to belong to two separate lineages, identified as A and B. Of these 1001 were assigned to lineage A and 478 assigned to lineage B.

The specimens assigned to lineage B were found in all river basins except the Po, and were found most commonly in streams fed by groundwater, while those of lineage A were found most commonly in streams fed by glacial meltwater. Members of lineage A were also found to have on average a higher number of setae (hairs) at the apex of their maxilary palps (part of the mouth structure) and also more setae in the dorsal margins of their femora (third segments of the legs).

The two lineages appear to be reproductively isolated, but are more closely related to one-another than to any other species. However the Leys et al. do not formerly describe the lineages as separate species at this time, pending further study of the phylogeny of the species across its total range.

See also... new species of Mayfly from western Ecuador.                                                  Mayflies are an ancient group of insects related to the Dragonflies and Damselflies. They have a long aquatic larval stage followed by a short flying adult phase, which typically does not feed, simply...
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Thirteen dead after helicopter crashes during flight from Norwegian oilfield.

Thirteen people have died after a helicopter crashed to the west of Bergen, Norway, on Friday 29 April 2016, during a return flight from the Gullfaks Oil Field in the North Sea. The names of the deceased have not been released, though they have been identified as eleven Norwegian citizens, a Briton and an Italian; all eleven passenger are understood to have been working on Statoil operated facilities in the oilfield, though not all were directly employed by the company, the helicopter was operated by CHC Helicopter. Witnesses have reported hearing unusual engine noises from the helicopter, after which a small explosion was witnessed on board, followed by the helicopter falling approximately 640 m into the sea close to the island of Turoey, then undergoing a second, larger explosion. No survivors are expected following the incident.

A rescue ship recovering the fuselage of the helicopter. Oil and Gas People.

The crashed helicopter is understood to be an Airbus EC225LP (or Super Puma), a model widely used in the oil industry, which had undergone scheduled replacement of its rota blades in March and its gearbox in January this year (helicopter components are typically replaced after a set number of flying hours, regardless of whether they show wear or damage). However the helicopter is understood to have twice had delays to scheduled replacement of parts in 2015, amounting to a total of 200 hours of flying time. 

Footage of the 29 April 2016 North Sea helicopter crash. TV2.

The cause of the crash is still being investigated by the Norwegian Civil Aviation Authority with help from the British Civil Aviation Authority, who have previous experience of investigating Super Puma crashes (two of the helicopters crashed in Scotland in 2012, one on Shetland and one near Aberdeen). Both of the helicopter's black boxes (which store details of the helicopter's performance during a flight) have been recovered. All flights by Super Puma helicopters have been suspended in Norway while the cause of the crash is investigated, while the UK has banned all flights by the helicopters to oil instillation's, but is still allowing their use for other purposes.

The approximate location of the 29 April 2016 North Sea helicoper crash. BBC/Google Maps.

See also... least three dead following helicopter crash in Jubilee Oil Field off coast of Ghana.      Three people are known to have died in a helicopter crash off the Ghanaian coast during heavy rains on Thursday 8 May 2014. The... Sea oil rig partially evacuated following leak.                                                             The Cormorant Alpha oil rig, 161 km northeast of Lerwick, Shetland, was partially evacuated on Saturday 2 March 2012, following the discovery of a leak of hydrocarbons (oil) from one of its legs. 71...

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Saturday, 30 April 2016

Bright fireball meteor seen over Southern California.

The American Meteor Society has received reports of a bright fireball meteor being seen over much of southern California slightly at about 9.30 pm local time on Monday 23 April 2016 (about 4.30 am on Tuesday 24 April GMT). The fireball has been described as being greenish in colour, which may indicate it was caused by the explosion of a small meteorite with a high iron content, and was seen from the northern Baja California as far north as Mendocino County, and east to western Arizona, though the majority of sightings were in Southern California. 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.

 Fireball over Southern California on Monday 23 April 2016. CBS2.

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. It is possible that this object will have produced meteorites that reached the surface (an object visible in the sky is a meteor, a rock that falls from the sky and can be physically held and examined is a meteorite).

Witness reports can help astronomers to understand these events. If you witnessed this fireball you can report it to the American Meteor Society here

See also... 'fireball' meteor seen over much of England.                                                       The UK Meteor Observation Network has received reports of a bright fireball meteor being seen over much of southern England slightly after 3.15 am GMT... seen over southern France and northern Italy.                                                  A bright fireball was seen over much of southeast France and northern Italy at about 6.20 pm local time on Wednesday 17... unlikely to have killed man in Tamil Nadu.                                                         Indian newspaper The Hindu carried a report on Sunday 7 February 2016 in which the death of a man and injury of three other people as well as causing damage to several nearby buildings at the campus of a college in Vellore, Tamil Nadu, were described as...

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Friday, 29 April 2016

Understanding the role of Bears in enabling a Cherry tree to migrate up mountains.

The Earth's climate is known to fluctuate over time, requiring animals and plants to move in order to find suitable habitats. For animals this is a fairly easy task, since most animals constantly move in search of the optimum environments during their lives, however for plants this is much more problematic, as they live the majority of their lives rooted to a single spot, with dispersal only occuring during the seed stage. One way to track optimum conditions in a changing climate without traveling vast distances is to move up and down slopes, since on average a 100 m rise in altitude coresponds to a -0.65 °C drop in temperature. However, while a seed can easily move downslope throgh gravity or water dispersal, seeds cannot fall upslope, requiring the plant to find more creative ways to move seeds uphill.

In a paper published in the journal Current Biology on 25 April 2016 a team of scientists led by Shoji Naoe of the Forestry and Forest Products Research Institute examine the dispersal of the seeds of the Hill Cherry, Prunus verecunda, in Central Japan via two animal vectors, the Asiatic Black Bear, Ursus thibetanus and the Japanese Marten, Martes melampus.

Oxygen isotope ratios in plant tissue can be closely related to altetude, enabling Naoe et al. to estimate the altitude at which the trees that produced Cherry stones found in Bear and Marten droppings had been growing. Surprisingly they found that both species preferentially moved the seeds upwards, with Bears moving them an average of 749.5 m upslope and Martens 460.5 m, close to the maximum distance a foraging member of each species would be expected to travel between eating the fruit and excreting their stones.

The Hill Cherry produces fruit in spring-to-summer, with trees lower on the slope producing flowers, fruit and leaves earlier in the season. Bears, which were responsible for moving 80.3% of the Cherry seeds, have previously been shown to move upslope over the season enabling them to access fruit throughout the season. Naoe et al. suggest that the preferential movement of Bears and Martend uphill between consuming Cherries and defacating may reflect a daily feeding cycle, with the animals feeding first on the fruit, then moving upslope to forrage on herbs and young vegetation that cannot be accessed beneath the canopy of fruiting trees.

Vertical seed dispersal toward the mountain tops by mammals that are following the springto summer plant phenology. The spring-to-summer plant phenology proceeds from the foot to the top of mountains. Cherry fruits and young vegetation are no longer available in low altitudes, ripe fruits are available but young vegetation is no longer available in middle altitudes, and ripe fruits are unavailable but young vegetation is available in high altitudes. Naoe et al. (2016).

See also... kunmingensis: Peaches from the Late Pliocene of Yunnan Province.                 Peaches, Prunus persica, are widely grown and consumed fruit around the world today, with a total annual production of about 20 million tons. They have a long historical association with humans, particularly in East Asia, with the oldest known... in the diet of Brown Bears on Hokkaido.                                                           Expanding Human populations have been the major factor affecting almost all of the Earth’s ecosystems since the end of the last glaciation. Human activity has altered food... killed by Bear at Alberta oil sands site.                                                                   A worker was killed in an attack by a Bear at an oil sands excavation site operated by Suncor Oil, about 25 km north of Fort McMurray in Alberta Province, Canada, around mid-afternoon on Wednesday 7...

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Lacustrine Gastropods from the Late Miocene Turiec Basin of Slovakia.

The Turiec Basin of the Slovakian Carpathian mountains was home to a closed freshwater lake for several million years during the Late Miocene, a lake that developed in a half-graben system (an area where tectonic movements are drawing rocks apart at the surface, causing thining of the crust and subsidence) and which developed a unique flora and fauna of endemic species (species not found elsewhere). This has been studied since the nineteenth century, with some groups from the lake (such as Ostracods) being very well understood, while others are less well known. Mollsuscs from Lake Turiec were first recorded in the 1860s, and have been intermittently described ever since; however the group has been the subject of few systematic reviews and the work on it is known to contian many imprecise descriptions and misidentifications.

In a paper published in the journal Geologica Carpathia in April 2015, Thomas Nuebauer and Mathias Harzhauser of the Department of Geology & Paleontology at the Vienna Natural History Museum and Radovan Pipík of the Geological Institute of the Slovak Academy of Sciences review the Gastropods of Lake Turiec, in which they describe four new species.

The first new species described is placed in the genus Viviparus, a widespread group of freshwater Snails with a fossil record dating back to the Jurassic, and given the specific name pipiki, in honour of Radovan Pipík of the Slovak Academy of Sciences for his work on the geology of Lake Turiec. Snails assigned to the genus Viviparus have been described from the Lake Turied deposits since the 1920s (and Snails described earlier are now assigned to this genus today), but oppinions have varied as to the specific assignment of these Snails, which have been placed in a number of fossil and extant species, but which Nuebauer et al. conclude should be described as a unique species found only in the Turiec deposits.

(D-E) Viviparus pipiki, first specimen; (F-G) Viviparus pipiki, second specimen; (H-I) Viviparus pipiki, protoconchs; (J) Viviparus pipiki, juvenile specimen. All specimens from Martin Brickyard. Scale bars correspond to 100 μm (H-I), 1 mm (A-C, J), and 10 mm (D-G). Nuebauer et al. (2015).

Viviparus pipiki is broad and conical with a thick shell and up to six whorls. The shape of the shell changed considerably as they grew, with early whorls being broadly conical, weakly convex and having a wide, ovoid, apature, while later whorls are conical to weakly ovoid and strongly convex, with a tear-shaped appature with a small posterior notch.

The second new species described is placed in the genus Melanopsis, which is today found in Europe, Anatolia, North Africa and parts of Austrelasia and which first appeared in the Cretaceous, and given the specific name glaubrechti, in honour of Matthias Glaubrecht of the Museum für Naturkunde Berlin, an expert on Melanopsid Snails. This species is described from 30 whole and fragmentary specimens from the Martin Brickyard, which were described by Czech palaeontologist Remeš as specimens of Melanoptychia pseudoscalaria, a species known from the Early Miocene of Moravia, a diagnisis rejected by Nuebauer et al. Melanopsis glaubrechti has a slender drop-shaped shell with distinct ribs and up to nine whorls.

 (A, D) Melanopsis glaubrechti, specimen digitally recombined from two separate images; (B) Melanopsis glaubrechti, juvenile shell; (C) Melanopsis glaubrechti, holotype. Scale bars correspond to 1 mm (D), and 5 mm (A-C). Nuebauer et al. (2015).

The third new species described is placed in the genus Tournouerina, which previously contains a single Mio-Pliocene species, and is given the specific name turiecensis, meaninf 'from Turiec'. This species is described from 35 specimens from Martin Brickyard, previously assigned to the species Lithoglyphus nannus in 2012 by Nadežda Krstić, Ljubinko Savić, and Gordana Jovanović, a diagnosis again rejected by Nuebauer et al. Tournouerina turiecensis is a small Snail shell with up to six convex whorls separated by deep sutures. The final whorl has a large drop-shaped apature with a thickened posterior tip.

 (E) Tournouerina turiecensis, paratype 1; (F) Tournouerina turiecensis, holotype; (G) Tournouerina turiecensis, paratype 2; (H) Tournouerina turiecensis, paratype 3; (I) Tournouerina turiecensis, protoconch. Scale bars correspond to 100 μm (I) and 1 mm (E-H).  Nuebauer et al. (2015).

The fourth species described is placed in the genus Radix, airbreathing freshwater Snails found throughout the Northern Hemisphere today and known to have been present by the Miocene, and given the specific name kovaci, in honour of Michal Kováč of Univerzita Komenského, for his work on the sedimentary evolution and stratigraphy of the Pannonian Basin. The species is described from a series of previously undescribed specimens from different locations in the Turiec Basin (many from drill cores). The majority of these specimens are fragmentary, making a full description difficult, but this is a small shell with four whorls, the last of which expands rapidly to the appature, which is eliptical with a small notch at the base, where it contacts the penultimate whorl.

Radix kovaci. (A) Holotype, Mošovce; (B) Juvenile specimen, Horná Štubňa; (C) Paratype 1, Horná Štubňa; (D) Paratype 3, Mošovce; (E) Paratype 2, Horná Štubňa; (F) Sediment infills of apertures of two specimens, Mošovce. Scale bars correspond to 10 mm. Nuebauer et al. (2015).

In addition to the newly described species Nuebauer et al. refur several Gastropod specimens to the species Theodoxus postcrenulatus, transfer the species Kosovia compressa to the new genus Popovicia and specimens assigned to the genera Radix and Planorbis but which cannot be assigned to species level.

See also... nielseni: A new species of Periwinkle from the Pleistocene-Holocene of northern Chile.                                    Periwinkles, Littorinidae, are abundant shallow marine Gastropods, the shells of which are familiar from neaches around the world... Land Snails from the Late Pleistocene of south central Jamaica.                                     Jamaica is considered to be a biodiversity hotspot for Land Snails, with over 505 species considered to be endemic to the island (i.e. coming from the island... predation on Barnacles in the Late Pleistocene of southern South America. Muricid Gastropods (Murexes) are carnivorous Snails which...
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Asteroid 2016 HO passes the Earth.

Asteroid 2016 HO passed by the Earth at a distance of 808 600 km (2.10 times the average distance between the Earth and the Moon, or 0.54% of the average distance between the Earth and the Sun), slightly before 12.30 pm GMT on Sunday 24 April 2016. There was no danger of the asteroid hitting us, though had it done so it would have presented no threat. 2016 HO has an estimated equivalent diameter of 14-45 m (i.e. it is estimated that a spherical object with the same volume would be 14-45  m in diameter), and an object of this size would be expected to explode in an airburst (an explosion caused by superheating from friction with the Earth's atmosphere, which is greater than that caused by simply falling, due to the orbital momentum of the asteroid) in the atmosphere between 28 and 10 km above the ground, with only fragmentary material reaching the Earth's surface.

 The calculated orbit of  2016 HOJPL Small Body Database.

2016 HO was discovered on 24 April 2016 (the day of its closest approach to the Earth) by the Southern Observatory for Near Earth Asteroids Research (SONEAR) at Oliviera in Minas Gerais State, Brazil. The designation 2016 HO implies that it was the 14th asteroid (asteroid O) discovered in the second half of April 2016 (period 2016 H).

2016 HO has a 673 day orbital period and an eccentric orbit tilted at an angle of 1.56° to the plane of the Solar System that takes it from 1.01 AU from the Sun (i.e. 101 % of the average distance at which the Earth orbits the Sun) to 2.00 AU from the Sun (i.e. twice the average distance at which the Earth orbits the Sun, considerably outside the orbit of the planet Mars). 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). This means that close encounters between the asteroid and Earth are fairly common, with the most recent having occurred in June 2005 next predicted in June 2027. 2016 HO also has occasional close encounters with the planet Mars, with the last such encounter calculated to have occured in October 1962 and the next predicted for April 2024.

See also... 2016 GP221 passes the Earth. Asteroid 2016 GP221 passed by the Earth at a distance of 592 000 km (1.54 times the average distance between the Earth and the Moon, or 0.40% of the average distance between the Earth and the Sun), slightly after 6.20 am GMT on Monday 18 April... 2016 GO134 passes the Earth. Asteroid 2016 GO134 passed by the Earth at a distance of 332 000 km (0.86 times the average distance between the Earth and the Moon, or 0.22% of the average distance between the Earth and the Sun), slightly before 7.35 pm GMT on Friday 6 April... Meteors to be visible next week.        The Lyrid Meteors will be visible between Saturday 16 and Monday 25 April 2006, with peak acticity on Friday 22 April, when the number of meteors may exceed 20 per hour. However with the...
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Thursday, 28 April 2016

Populus × jrtyschensis: Understanding the origin of a hybrid Poplar population from Xinjiang Province, China.

Hybridization between species is rare in animals, but a fairly common occurrence in many plants, with related plant species often having hybridization zones between populations of related parent species. How such hybridization zones occur without the two species is a subject of ongoing discussion among botanists, with three main theories having emerged. The Tension Zone theory suggests that the hybrids are less genetically fit than either parent species, but that the hybridization zone persists because there is no bar to hybridization between the two parent species, so that new hybrids are constantly produced, even if these do not thrive and reproduce. The Bounded Hybrid Superiority Theory suggests that the hybrids are unfit in the habitats favored by their parent species, but that they are more fit than their parents in the habitat where they occur, enabling them to thrive in a specific environment that the parents do not colonize; this theory allows for a thriving hybrid population even if the hybrids are sterile. Mosaic Hybridization is thought to occur where two species have an overlapping ranges containing a patchwork of different environments; in such circumstances a range of hybrid species can co-exist with the parents, each being suited to a different habitat.

In a paper published in the journal BMC Plant Biology on 18 April 2016, Dechun Jiang of the State Key Laboratory of Grassland Agro-Ecosystem at Lanzhou University, Jianju Feng, also of the State Key Laboratory of Grassland Agro-Ecosystem at Lanzhou University and of the College of Plant Sciences of the Xinjiang Production & Construction Corps and the Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin at Tarimu University, and Miao Dong, Guili Wu, Kangshan Mao and Jianquang Liu, all of the State Key Laboratory of Grassland Agro-Ecosystem at Lanzhou University, discuss the origin of a naturally occurring hybrid Poplar, Populus × jrtyschensis, from Xinjiang Province in northwest China.

Poplars, Populus spp., (also known as Aspens and Cottonwoods) are a widespread group of flowering trees in the Willow Family (Salicaceae), known for producing a range of hybrids, with a number of established trees in the genus also thought to have originated as hybrids. Hybridization in Poplars has previously been studied in Europe and North America, but the phenomenon has to date been little studied in Asia. Populus × jrtyschensis occurs naturally on the floodplains of the Erqis River in the north of Xinjiang Province, where it forms forests in which neither of its presumed parent species is present. The species is also widely planted along agricultural drainage channels, being easily cultivated as a clone from cuttings.

Foliage of Populus × jrtyschensis. eFlora/Flora of China.

It is thought to be a hybrid of two distantly related species, the Black Poplar, Populus nigra, which is found from Europe and northwest Africa east to Central Asia, and which favors wet slopes near rivers at altitudes of 400-1000 m, and the Laurel-leafed Poplar, Populus laurifolia, which is found in Northern Asia south into parts of Central Asia, and favors dry slopes in the mountainous parts of river valleys, occurring from 400-1800 m, these tow species co-concurring in parts of Xinjiang Province. Although these species prefer different environments, they flower at the same time of year, April-May, and are wind-pollinated as well as having wind-distributed seeds, leading to the possibility of both hybridization and the colonization of environments not favored by either parent by the resulting hybrid young.

A Black Poplar, Populus nigra. L'Orto botanico d'Italia.

Jiang et al. took chloroplast and nuclear DNA samples from 566 trees from 45 different populations of the three different species in order to determine their relationships. They found that the chloroplast DNA (which is passed only through the female line) of Populus nigra and Populus laurifolia were easily distinguished, with 94% of Populus × jrtyschensis trees having Populus laurifolia chloroplast DNA (indicating descent from a female Populus laurifolia plant) and the remaining 6% having Populus nigra chloroplast DNA. Sequencing of the nuclear DNA of Populus × jrtyschensis suggested that 84% of these trees were first generation hybrids between parents of the two other species, while 6% were crosses between first generation hybrids and one of the parent species, and 10% were more difficult to ascribe parental backgrounds. Two trees were found to be clones, suggesting that one or both had grown vegetatively from a detached part of a first generation hybrid.

A stand of Laurel-leafed Poplar, Populus laurifolia. Илья Смелянский/Определитель растени.

This suggests strongly that the population of Populus × jrtyschensis is maintained by a continuous supply of new hybrids between (usually male) Populus nigra and (usually female) Populus laurifolia flowers (Poplars usually produce separate male and female flowers on the same tree), with the trees themselves apparently having low fertility. However they had a distinct ecological niche, separate to that favored by either parent, growing on the floodplains of river valleys rather than higher on the side slopes. Examination of the sites where these trees grew revealed that the soil in which they grew also had far lower nitrogen levels than could normally be tolerated by either parent species, re-enforcing the idea that these trees have a unique ecological niche.

See also... kunmingensis: Peaches from the Late Pliocene of Yunnan Province.                 Peaches, Prunus persica, are widely grown and consumed fruit around the world today, with a total annual production of about 20 million tons. They have a long historical association with humans, particularly in East Asia, with the oldest known... pyneei: A new species of Myrtle from Mauritius.                                                        The genus Syzygium is the largest within the Myrtle family, Myrtaceae, with over 1200 described species from across the tropical and subtropical regions of the Old World, including fifteen previously described species from Mauritius. new species of Rhododendron from Guizhou Province, China.              Rhododendrons, Rhododendronspp., are a large group of flowering shrubs and trees found in East and Southeast Asia and across Indonesia to northern Australia, and widely introduced elsewhere...
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