Eruptive Activity on Great Sisken Island.

The Alaska Volcano Observatory reported a vapour plume rising 300 m about the summit of Great Sitkin, a volcanic island in the Andreanof Islands, part of the Aleutian Island chain, on Sunday 19 November 2017. This is the first observed eruptive activity on the volcano since February 1974, though it is not entirely unexpected, as there has been a steady increase in seismic activity beneath the island since July 2016. Seismic activity beneath volcanoes can be significant, as they are often caused by the arrival of fresh magma, which may indicate that a volcano is about to undergo an eruptive episode. A second small plume was spotted over the island by a satellite on Tuesday 21 November.

 Small plume over Great Siskin Island on 19 November 2017. Alaska Volcano Observatory.

  

The volcanoes of the Alaskan Peninsula and Aleutian Islands are fed by magma rising from the Pacific Plate, which is being subducted beneath the North American Plate to the south along the Aleutian Trench. As the subducting plate sinks into the Earth it is subjected to enormous heat and pressure, causing more volatile minerals to melt. These then rise through the overlying North American plate as magma, fuelling the Alaskan volcanoes.

 How the subduction of the Pacific Plate beneath the North American Plate fuels the volcanoes of Alaska. Alaska Volcano Observatory.

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Asteroid 2017 WG28 passes the Earth.

Asteroid 2017 WG28 passed by the Earth at a distance of about 644 500 km (1.68 times the average distance between the Earth and the Moon,  or 0.43% of the distance between the Earth and the Sun), at about 10.00 pm GMT on Friday 24 November 2017. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2017 WG28 has an estimated equivalent diameter of 5-18 m (i.e. it is estimated that a spherical object with the same volume would be 5-18 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 40 and 25 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2017 WG28. Minor Planet Center.

2017 WG28 was discovered on 27 November 2017 (three days after its closest approach to the Earth) by the University of Arizona's Mt. Lemmon Survey at the Steward Observatory on Mount Lemmon in the Catalina Mountains north of Tucson. The designation 2017 WG28 implies that the asteroid was the 807th object (object G28) discovered in the second half of November 2017 (period 2017 W). 

2017 WG28 has a 1458 day orbital period and an eccentric orbit tilted at an angle of 0.75° to the plane of the Solar System, which takes it from 0.99 AU from the Sun (i.e. 99% of he average distance at which the Earth orbits the Sun) to 4.04 AU from the Sun (i.e. 404% of the average distance at which the Earth orbits the Sun, more than twice the distance at which the planet Mars orbits). 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 2017 VC14 has occasional close encounters with the Earth, which it last came close to in January 2010. The asteroid also has occasional close encounters with the planet Mars, which is last passed in November 2010.

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Rockfall kills one and injures two in the Blue Mountains National Park, New South Wales.

An employee of the New South Wales National Parks and Wildlife Service has been killed and another two have been severely injured following a rockfall in the Blue Mountains National Park, on Wednesday 29 November 2017. The deceased worker has been identified as a 36-year-old man, but no further details have been released at this time. Both of the other victims are described as being in serious conditions, with multiple injuries including fractures to their legs. It is understood that all three were trapped beneath large rocks and that it took several hours to extract the injured men safely.

Rescue workers at the scene of the 29 November 2017 Blue Mountains rockfall. 9 News.

The men are understood to have been working on a section of trackway that had been closed to the public since August when concerns were raised about the safety of the area by geotechnical engineers. The incident is reported to have been caused by a large slab of sandstone detaching from a rockface. Sandstone is made up of large grains of crystal, typically quartz, held together by a matrix of another material, typically calcite (i.e two 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.

 Injured worker being airlifted to hospital following the 29 November 2017 rockfall. APP.

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Magnitude 4.9 Earthquake in Petorca Province, Chile.

The United States Geological Survey recorded a Magnitude 4.9 Earthquake at a depth of 69.7 km, 32 km to the northeast of the city of La Ligua in the Chilean province of Petorca at about 7.15 pm local time (about 10.15 pm GMT) on Sunday 26 November 2017. There are no reports of any damage or injuries associated with this event, but people have reported feeling the event across much of central Chile.

 

The approximate location of the 26 November 2017 Petorca Earthquake. USGS.

 

Chile is located on the west coast of South America, which is also the convergent margin between the Nazca and South American Plates. The Nazca Plate is being subducted beneath the South American Plate and is sinking beneath the South American Plate. This is not a smooth process, the rocks of the two plates continuously stick together then, as the pressure builds up, break apart again, causing Earthquakes. As the Nazca Plate sinks deeper it is partially melted by the heat of the Earth's interior. Some of the melted material then rises up through the overlying South American Plate as magma, fuelling the volcanoes of the Chilean Andes.

The subduction of the Nazca Plate beneath the South American Plate, and how it causes Earthquakes and volcanoes. Pacific Earthquake Engineering Research Center.

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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Bryozoas from the seamounts, islands, and continental slopes of the northeast Atlantic.

Bryozoans, or Moss Animals, are colonial filter-feeding invertebrates that form encrusting or weed-like colonies. The individual 'animals' are on average about 0.5 mm in length, and live inside a protective covering from which they extend a crown of cilia-covered tentacles called a lophophore. These are not true individuals though as they develop as buds on the colony and share nutrients; for this reason they are referred to as 'zooids'. The colonies produce sexually by means of reproductive zooids that have gonads, but lack feeding apparatus. Bryozoans are widespread globally, but are often overlooked because they are small and the colonies resemble plants.

In a paper published in the European Journal of Taxonomy on 31 August 2017, Björn Berling of the Oberösterreichisches Landesmuseum, and the Centro de Investigação em Biodiversidade e Recursos Genéticos, Jean-Georges Harmelin of the Mediterranean Institute of Oceanography at Aix-Marseille University, and Beate Bader of the Institut für Geowissenschaften at Christian-Albrechts-Universität, describe ten new species of Bryozoas from the seamounts, islands, and continental slopes of the northeast Atlantic.

The first new species described is named Atlantisina atlantis, in reference to the Atlantis Seamount, where it was found; it is considered to be sufficiently different from a previoulsy described Bryazoans to merit also being placed in a new family, the Atlantisinidae. This an encrusting Bryozoan, forming ribbon-like colonies by linear budding. It has a translucent frontal shield covered with densely packed irregular nodules, and six spines around its oral orifice. The species was found encrusting Coral skeletons at depths of between 275 and 460 m.

 Atlantisina atlantis, Atlantis Seamount. Overview of colony growing on a Stylasterid skeleton; note the biserial-branching growth. Scale bar is 1 mm. Berling et al. (2017).

The second new species described is also placed in the genus Atlantisina and given the specific name meteor, in reference to the Great Meteor Bank, where it was discovered. This species is similar to Atlantisina atlantis, but has a frontal shield covered in nodules with flattened tips and eight spines around its oral opening. This species was found encrusting shells, pebbles and fragments of Coral skeleton on the Grand Meteor Bank and the Irving and Hyères seamounts at depths of between 270 and 750 m.

Atlantisina meteor, Great Meteor Bank, several autozooids and ovicellate zooids. Scale bar is 300 μm. Berling et al. (2017).

The third new species described is again placed in the genus Atlantisina, and given the specific name inarmata, meaning 'unarmed' as it lacks a spike beneath its mouth opening, someting found in many species. The frontal shield of this species is porcelain white, and covered with flattened nodules, and it has six spines around its oral opening. This species was found growing on shells, pebbles and fragments of Coral skeleton around Gran Canaria in the Canary Islands, at depths between 345 and 485 m.

Atlantisina inarmata, Canary Islands. An autozooid with a borehole in the frontal shield (centre), presumably drilled by a predatory Microgastropod, and one with an intramural bud (at right), indicated by the presence of a secondary orifice rim. Scale bar is 100 μm. Scale bar is 300 μm. Berling et al. (2017).

The forth new species described is again placed in the genus Atlantisina and given the specific name seinensis, meaning 'from Seine', in reference to the Seine Seamount, where it was discovered. This species has a frontal shield with large flattened nodules, six oral spines and a plate with a large spike beneath the oral structure. The species was found encrusting rocks at a depth of 235–260 m.

Atlantisina seinensis, Seine Seamount. Lateral view showing the vertical dimensions of the suboral umbones. Scale bar is 200 μm. Berling et al. (2017).

The fifth new species described is again placed in the genus Atlantisina and given the specific name tricornis, in reference to the sub-oral plate, which has a triple spike. The frontal shield of this species has a pattern of raised ridges around polygonal depressions, and it has six oral spines. The species was found encrusting rocks, Brachiopods, and fragments of Coral and other skeletal elements at depths of between 450 and 1040 m on the Iberian continental slope and between 675 and 1700 m on Galicia Bank.

Atlantisina tricornis. Colony from Galicia Bank forming biserial ribbons; note the relatively broad ooecia. Scale bar is 300 μm. Berling et al. (2017).

The sixth new species described is once again placed in the genus Atlantisina and given the specific name lionensis, meaning 'from Lion' in reference to Lion Seamount, where it was discovered. The frontal shield of this species has a pattern of raised ridges around polygonal depressions, it has six oral spines, and a suboral plate with three-to-five irregularly shaped spikes. This species was found encrusting small rocks at depths of between 320 and 630 m, on the Lion and Seine seamounts.

Atlantisina lionensis, Lion Seamount. Ovicellate zooids at the colony growth margin. Scale bar is 100 μm. Berling et al. (2017).

The seventh new species described is once again placed in the genus Atlantisina and given the specific name gorringensis, meaning 'Gorringe' in reference to the Gorringe Bank, where it was discovered. This species has a small, frontal shield with a reticulate pattern of raised ridges encircling round to polygonal depressions, six oral spines and a suboral plate with up to eight spikes. This species was found encrusting small shells and pebbles at depths of 180 to 330 m, on Gorringe Bank and Ampère Seamount.

Atlantisina gorringensis, Gorringe Bank. Periancestrular region, the constricted oral region of the partly overgrown ancestrula is to the left. Scale bar is 300 μm. Berling et al. (2017).

The eighth new species is once again placed in the genus Atlantisina and given the specific name acantha, meaning 'thorny', in reference to its suboral plate, which is flared and has a variable number of large spikes. The species has a frontal shield with a reticulate pattern of raised ridges encircling round to polygonal depressions and six oral spines. It was found growing on small rocks at a depth of 660 m off the coast of Gran Canaria.

Atlantisina acantha, Canary Islands. Close-up of ooecium and the suboral crest. Scale bar is 100 μm. Berling et al. (2017).

The ninth new species described is named Bathycyclopora suroiti, where 'Bathycyclopora' is a combination of 'bathyal', meaning 'deep' and 'Hemicyclopora', a previously described genus which it superficially resembles, and 'suroiti' in honour of French research vessel ‘Le Suroît’. This species has a frontal shield with pronounced ridges and seven or eight oral spines. It is an encrusting Bryozoan, with colonies forming patches with the individual zooids separated by grooves. This species was found on Atlantis Seamont at depths of 275–460 m, encrusting fragments of shell and Coral.

Baythycyclopora suroiti, Atlantis Seamount. Overview of a partly damaged colony. Scale bar is 100 μm. Berling et al. (2017).

The final new species described is named Calvetopora otapostasis, where 'Calvetopora' in honour of the early twentieth century marine biologist Louis Calvet, for his work on Bryozoans, and 'otapostasis', meaning 'protuding ears', in reference to the two avicularia (modified zooids that are used as suplimentary mouthparts) on either side of the oral opening. This species has a frontal shield with a granular texture and six oral spines. It forms large, patch-shaped colonies, which sometimes overgrow themselves, and was found growing on fragments of coral skeleton at depths of 280 to 460 m on Atlantis Seamount.

Calvetopora otapostasis, Atlantis Seamount. Slightly oblique view of an autozooid at the growth margin showing the communication pores in the lateral walls as well as marginal areolar pores (black arrow) and the roughly crescentically arranged pseudopores (white arrows) in the frontal shield. Scale bar is 200 μm. Berling et al. (2017).

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Streptomyces asenjonii: A new species of Actinobacteria from the Atacama Desert.

Actinobacteria are Gram-positive, filamentous, aerobic Bacteria found in soils and aquatic ecosystems, where they play a significant role in the decomposition of Plant material and other organic matter, making them highly important in the formation and maintenance of soils. Some species of Actinobacteria are capable of 'fixing' nitrogen from the atmosphere (i.e. taking atmospheric nitrogen and using it to form nitrogen compounds that can be utilised by Plants). Members of the genus Streptomyces have long interested scientists for their ability to produce antibiotics and other potentially useful compounds, and recent discoveries of members of this genus living in extreme environments has opened up the possibility of further interesting discoveries.

In a paper published in the journal Antonie van Leeuwenhoek on 6 June 2017, Michael Goodfellow, Kanungnid Busarakam, and Hamidah Idris, of the School of Biology at Newcastle University, David Labeda of the National Centre for Agricultural Utilization Research, Imen Nouioui, and Roselyn Brown, also of the School of Biology at Newcastle University, Byung-Yong Kim of Seoul National University, Maria del Carmen Montero-Calasanz, again of the School of Biology at Newcastle University, Barbara Andrews of the Centre for Biotechnology and Bioengineering at the University of Chile, and Alan Bull of the School of Biosciences at the University of Kent at Canterbury, describe a new species of Streptomyces from the hyperarid Atacama Desert of Chile.

The species is named Streptomyces asenjonii, in honour of Juan Asenjo of the University of Chile, for his work on the Actinobacteria of the Atacama Desert. The species forms extensive colonies of branching filaments, with spiralling aerial hyphae that produce spores. It was able to grow at temperatures of between 10 and 50 °C and pH levels of between 5 and 11, though it grows best at a temperature of 37 °C and a pH of 7.5. 

Scanning electron micrograph of Streptomyces asenjonii showing hairy ornamented spores in open spirals following growth on oatmeal agar at 28 °C for 14 days. Scale bar is 1 μm. Goodfellow et al. (2017).

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