Tuesday 31 March 2020

Landslide derails train in Hunan Province, China.

A train has derailed after hitting a landslide in Hunan Province, China, on Monday 30 March 2020. The driver of the train, a Guangzhou Railway Group operated service between Jinan and Guangzhou, attempted to brake when he saw the landslip, on the southbound section of rail between Matianxu and Qifengdu stations in Yongxing County, but was unable to prevent the collision. The incident resulted in six carriages derailing, one of which subsequently caught fire, one person dying, and 127 people being injured, four of them seriously.

Rescue workers attend a train derailment caused by a landslide in Hunan Province, China, on Monday 30 March 2020. Hunan Emergency Management Department Fire Rescue Bureau.

The incident is reported to have occurred following several days of heavy rain associated with the onset of the Monsoon Season, which typically lasts from the begining of April to the middle of August in Hunan. 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. 

Engineers begin the process of clearing the site of a train derailment in Hunan Province on 30 March 2020. AFP.

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate.

 Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.

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Monday 30 March 2020

Fodinicola acaciae: A novel Endophytic Actinomycete Fungi isolated from the roots of a Black Wattle Tree, Acacia mangium, in Thailand.

Endophytic Actinomycete Fungi colonise the internal plant tissues and usually have a beneficial effect to the host plant by promoting growth and protecting the plant from biotic and abiotic stresses without any damage or morphological changes to the plant. Isolation and identification of novel genus and species of Endophytic Actinomycetes is an attractive propostition for microbiologists since these organisms are potential sources for plant growth-promoting Bacteria and compounds. Substances isolated from Endophytic Actinomycetes have been shown to produce compounds which enhance plant growth, chelate iron and other elements, reduce plant stress ethylene, and solubilise of inorganic phosphate.

In a paper published in the journal Microorganisms on 25 March 2020, Huyền Thị Thanh Phạm of the Department of Genetics and Omics Center for Agriculture at Kasetsart University, Wipawadee Suwannapan, also of the Department of Genetics at Kasetsart University, Wilaiwan Koomsiri, again of the Department of Genetics and Omics Center for Agriculture at Kasetsart University, Yuki Inahashi of the Kitasato Institute for Life Sciences at Kitasato University, Akira Také of the Department of Microbiology at the Kitasato University School of Medicine, Atsuko Matsumoto, also of the Kitasato Institute for Life Sciences at Kitasato University, and Arinthip Thamchaipenet, once again of the Department of Genetics and Omics Center for Agriculture at Kasetsart University, describe a new species of Endophytic Actinomycete Fungi isolated from the roots of the Black Wattle Tree, Acacia mangium, growing in the grounds of Kasetsart University in Bangkok.

The new species is placed in the genus Fodinicola, which contains only one previously described species, Fodinicola feengrottensis, which was isolated from acidic metal-containing rocks of a medieval alum slate mine in Germany, and is given the specific name acaciae, which derives from 'Acacia', the generic name of the host plant. It is a gram-stain-positive, aerobic, non-motile, catalase-positive, oxidase-negative actinomycete that produces branched substrate mycelium and abundant aerial mycelium. Aerial hyphae break up into irregular rod-like elements. Colonies are wrinkled, beige to orange in colour. Growth occurs between 14 and 42 °C, good growth at 28 °C, and no growth below 14 °C or above 42 °C. Good growth occurs at pH 7.0 and pH 8.0, but no growth occurs at pH 3 nor pH 12. NaCl (salt) tolerance is up to 6%.

Scanning electron micrograph of fragmentation of aerial hyphae of Fodinicola acaciae on agar at 28 °C after 21 days. Scale bar is 2 μm. Pham et al. (2020).

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Latimeria chalumnae: A live Coelocanth seen living off the KwaZulu-Natal South Coast, South Africa.

When a living coelacanth was trawled off East London, South Africa, at a depth between 72 m and 100 m on 22 December 1938, it caused an international sensation. The specimen was saved for science by the young curator of the East London Museum, Marjorie Courtenay-Latimer and identified by JLB Smith of Rhodes University College. Smith named it Latimeria chalumnae, after Courtenay-Latimer and the river off which it was caught. JLB Smith, who was a keen angler and had an excellent knowledge of Fish anatomy, behaviour and habitat preferences, predicted that the East London Fish was a stray from relatively shallow rocky reefs further north on the tropical east coast of Africa. Latimeria chalumnae has since been found in the Comoros (over 200 specimens), Mozambique (one specimen), Madagascar (over 13 specimens), Kenya (one specimen), and Tanzania (over 70 specimens), and a colony was discovered in the iSimangaliso Wetland Park in northern Zululand, South Africa, in 2000. Another species of living Coelacanth, Latimeria. menadoensis, was found on the other side of the Indian Ocean off North Sulawesi Island in Indonesia in 1997.this species is smaller than Latimeria chalumnae and its body, which is also covered with white spots, is brown rather than blue.

In a paper published in the South African Journal of Science on 26 March 2020, Michael Fraser of Pumula in KwaZulu-Natal, Bruce Henderson and Pieter Carstens of Somerset West in Western Cape Province, Alan Fraser, also of Pumula in KwaZulu-Natal, Benjamin Henderson and Marc Dukes, also of Somerset West in Western Cape Province, and Michael Bruton of the South African Institute for Aquatic Biodiversity, describe the sighting of a living Coelocanth, Latimeria chalumnae, off the KwaZulu-Natal South Coast Region, and present a review of Coelocanth sightings off the African coast and in the western Indian Ocean.

The first scientist to observe a living Coelacanth was Jacques Millot of France who briefly examined a dying immature female Fish (142 cm, 41 kg) in a flooded wooden boat at Mutsamudu on Anjouan Island in the Comoros in 1954. The Fish was captured at 8.00 pm on 12 November 1954 and was kept alive in the sunken boat from about 11.30 pm until 3.30 pm on 13 November 1954. The Fish was stressed and exhibited only feeble movements.

Several Coelacanths that were subsequently caught by traditional fishermen in the Comoros (mainly Grand Comoro), and brought to the attention of scientists, survived for periods of 1–42 hours, (usually less than 11 hours), near the water surface where they could be observed by divers.

Hans Fricke and his team from Germany were the first to study the living Coelacanth in detail from their research submersible Jago. They compiled an extraordinary data series on the living Coelacanth in the Comoros spanning 21 years and including 145 specimens that had been individually identified using the unique patterns of white spots on their bodies.

On 28 October 2000, mixed-gas divers Pieter Venter, Peter Timm and Etienne le Roux discovered Coelacanths living at a depth of 104 m in Jesser Canyon at Sodwana Bay in the newly proclaimed iSimangaliso Wetland Park in Maputaland; the shallowest sighting of Coelacanths at that time. On 27 November 2000 they filmed three coelacanths at a depth of 106 m in Jesser Canyon. These discoveries led to the establishment of the African Coelacanth Ecosystem Programme in April 2002 which aimed to initiate and promote a new phase of multidisciplinary research on the coelacanth and its habitats.

The South African Institute for Aquatic Biodiversity in Makhanda (previously Grahamstown) was appointed as the lead organisation for African Coelacanth Ecosystem Programme, which has been carried out in three phases: 2001–2006, 2007–2011 and 2012–2015. From 2002 to 2004, Professor Hans Fricke and his team returned to South Africa with the Jago submersible to study Coelacanths in the iSimangaliso Wetland Park from the FRS Algoa as part of African Coelacanth Ecosystem Programme. They carried out 47 survey dives with a total bottom time of 166 hours at depths ranging from 46 m to 359 m. Initially, 24 Coelacanths were identified in three submarine canyons at depths from 96 m to 133 m along a 48 km stretch of coast in the iSimangaliso Wetland Park. This number was later increased to 32 individuals. Over time the African Coelacanth Ecosystem Programme extended its research programme further north into other countries in East Africa and the Western Indian Ocean Islands using the FRS Algoa and other motherships, the Jago submersible and a Sea-Eye Falcon underwater remotely operated vehicle.

On 15 February 2004, mixed-gas diver Christo van Jaarsveld observed a coelacanth at a depth of about 54 m in Diepgat Canyon south of Sodwana Bay in the iSimangaliso Wetland Park. This sighting is the shallowest on record for a healthy adult Coelacanth and was the 19th specimen known from the iSimangaliso Wetland Park, but it has not been seen again. Christo van Jaarsveld has subsequently seen and filmed another specimen on 7 August 2018 in the iSimangaliso Wetland Park; this Fish has also not been seen since.

At about 9.00 am on 22 November 2019, a team of divers observed and filmed a single Coelacanth at a depth of 69 m off the village of Umzumbe (between Hibberdene and Pumula) on the South Coast of KwaZulu-Natal. This site is about 325 km south of the iSimangaliso Wetland Park. The divers, Mike Fraser and Alan Fraser from Pumula and Bruce Henderson and Pieter Carstens from Somerset West, launched from the Injambili launch site at Pumula, with Benjamin Henderson and Marc Dukes acting as surface support in the boat. Bruce Henderson and Pieter Carstens used open circuit trimix and Mike and Alan Fraser used rebreathers with trimix diluent.

Coelacanth off Pumula on the KwaZulu-Natal South Coast, South Africa, on 22 November 2019. Bruce Henderson in Fraser et al. (2020).

Mike and Alan Fraser are keen anglers and have fished the reef on which the Coelacanth was found for many years. They are also avid scuba divers who have been using AP diving rebreathers for the past 9 years and are familiar with the underwater terrain on this coast. Mike and Alan Fraser had previously speculated that the Umzumbe River Canyon would be an ideal place to spot a Coelacanth, because the caves and cracks seen on the sonar would offer good shelter from predators.

The reef on which the dive took place (the longitude and latitude coordinates for the discovery site are known but are being kept confidential in order to safeguard the Coelacanth) is about 1 km from the continental shelf edge and is washed by strong currents. The Coelacanth was first found by Alan Fraser who was swimming ahead of the other divers. On the video recorded during the dive he can be heard shouting for Bruce Henderson, who had the GoPro 7 video camera with a 150 m underwater housing. The maximum depth of the dive was 72 m and the total bottom time 15 minutes, of which about half was spent with the Coelacanth. Bruce Henderson filmed the Coelacanth at a depth of 69 m.

This is the original footage of the Coelacanth discovered off the coast of Pumula at 70m on 22 November 2019. It was filmed by Bruce Henderson and discovered by Alan Fraser. They were accompanied by Mike Fraser and Pieter Carstens. Ben Henderson and Marc Dukes were the top men for the dive. Wreckless Divers/YouTube.

The single Coelacanth that was sighted remained relatively motionless under an overhang despite the attentions of the four divers and their strobe lights. It maintained a head-down position, slowly moving its paired fins. Although the epicaudal ridge along the middle of the tail was prominent, the fin rays on the epicaudal lobe of the tail fin did not extend beyond the curve of the rays on the dorsal and ventral portions of the fin, as in the second Coelacanth, which JLB Smith initially thought was a separate species.

The size of the Coelacanth was estimated to be 180–200 cm and about 100 kg by comparing its dimensions with those of the divers, although it is difficult to estimate a Fish’s size accurately under water. It would almost certainly have been a female individual as male Coelacanths rarely exceed 150 cm in length.

This estimated size is comparable to the largest Coelacanths on record which include a 179 cm, 98 kg female caught off Pebane in Mozambique, a 183 cm female caught off Mutsamudu, Anjouan, a 187 cm, 85 kg individual caught off Toliara in Madagascar, and a 190 cm female caught off Chiconi, Anjouan.

What is the significance of the Pumula coelacanth discovery? It indicates that Coelacanths live along our coast further south than the iSimangaliso Wetland Park in Maputaland and raises the possibility that they may live elsewhere along the KwaZulu-Natal coast and even further south along the Transkei coast into the Eastern Cape. If this is the case, then the first Coelacanth that was caught off East London over 80 years ago may not have been a stray but a member of a resident population. Instead of being washed southwards from the tropics by the south-flowing Mozambique current, as JLB Smith had suggested; Coelacanths may have moved purposefully over time into suitable habitats further south than their optimal range in the tropics.

Dives conducted using the research submersible Jago off the Eastern Cape coast near East London and Port Elizabeth in 1991 by Hans Fricke, Jurgen Schaüer, Mike Bruton and others revealed that underwater habitats there were suboptimal, with only small overhangs and no deep caves. On these dives large ambush predators, such as the Wreckfish, Polyprion americanus, seemed to fill the Coelacanth’s niche.More suitable habitats for Coelacanths along the Eastern Cape coast have since been found in the Chalumna Canyon by Kerry Sink of the African Coelacanth Ecosystem Programme using remotely operated vehicles near the capture site of the first specimen in December 1938.

The depth preferences of Coelacanths throughout their range extends from about 54 m to over 800 m, shallow by marine standards as the average depth of the ocean is 3688 m. The Pumula Coelacanth record is therefore the second shallowest yet recorded for a healthy, non-pregnant adult Coelacanth. Coelacanth specimens, and the data associated with their capture, are well documented; the latest edition of the Coelacanth inventory compiled by Rik Nulens for the Coelacanth Conservation Council lists 323 specimens caught to date.

Dead or dying Coelacanths, some with their guts full of plastic, one with a Tetradon Blaasop Pufferfish stuck in its mouth, have been found floating at the water surface off Tanzania. A large Coelacanth (179 cm, 98 kg) pregnant with 26 pups, was caught between 40 m and 44 m on the continental shelf off Pebane in northern Mozambique in August 1991.

The discovery of a Coelacanth at a depth of only 69 m off Pumula (and at 54 m in the Diepgat Canyon) suggests that they may live shallower than previously thought, at least at the southern end of their range, which means that they may be more accessible to mixed-gas divers, as well as to shallow-water remotely operated vehicles and research submersibles, for study. Many aspects of Coelacanth biology and behaviour have not been documented, including whether they guard their young after birth and the diet and habitat preferences of the young.

The shallower depths at which Coelacanths appear to live off South Africa, compared to the Comoros, Tanzania or Madagascar, may be a consequence of their relatively low tolerance of high water temperatures and low oxygen saturations. As oxygen saturations are lower in warmer water, they may tend to live deeper in the warmer waters of the tropics and shallower in the cooler subtemperate waters off South Africa’s east coast. Mike Fraser has reported that, although the surface water temperature on the day of the discovery (22 November 2019) was about 25 °C, there was a marked thermocline at about 15 m from the bottom where the recorded temperature fell to 17 °C.

The discovery of a living Coelacanth off the South Coast of KwaZulu-Natal also reveals how little we know about marine life off our coast, despite intensive research, increasingly intense deep diving ventures and longterm commercial and recreational fishing pressure. That Coelacanths have been living undiscovered off the heavily fished south coast of KwaZulu-Natal, despite the high profile of the Fish over the past 80 years, suggests that many remarkable discoveries remain to be made in our oceans.

The African Coelacanth Ecosystem Programme and other programmes that promote and facilitate multi-disciplinary research in our marine environment should therefore continue to receive priority financial and logistical support, and recreational divers should be encouraged to collaborate with scientists so that their valuable observations can be included in the scientific dialogue. More effort should also be made to create organised platforms that make it possible for ‘citizen scientists’, especially deep divers, to participate meaningfully in scientific research. The possibility of creating an offshore Marine Protected Area off Pumula, without unduly impacting on the activities of recreational anglers, also needs to be considered.

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Asteroid 2020 FX4 passes the Earth.

Asteroid 2020 FX4 passed by the Earth at a distance of about 18 206 000 km (47.4 times the average distance between the Earth and the Moon, or 12.2% of the distance between the Earth and the Sun), slightly after 0.10 am GMT on Wednesday 25 March 2020. There was no danger of the asteroid hitting us, though were it to do so it would have presented a considerable threat. 2020 FX4 has an estimated equivalent diameter of 88-280 m (i.e. it is estimated that a spherical object with the same volume would be 88-280 m in diameter), and an object at the upper end of this range 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 60 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater over 4 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 2020 FX4. JPL Small Body Database.
2020 FX4 was discovered on 24 March 2020 (the day before its closest encounter with the Earth) by the University of Hawaii's PANSTARRS telescope. The designation 2012 DJ61 implies that it was the 119th asteroid (asteroid X4 - in numbering asteroids the letters A-Y, excluding I, are assigned numbers from 1 to 24, with a number added to the end each time the alphabet is ended, so that A = 1, A1 = 25, A2 = 49, etc., which means that X4 = 23 + (24 X 4) = 119) discovered in the second half of March 2020 (period 2020 F).

2020 FX4 has a 1389 day (3.80 year) orbital period, with an elliptical orbit tilted at an angle of 9.88° to the plain of the Solar System which takes in to 0.97 AU from the Sun (97% of the distance at which the Earth orbits the Sun) and out to 3.90 AU (3.9% of the distance at which the Earth orbits the sun and more than twice as from the Sun as the planet Mars). This means that close encounters between the asteroid and Earth are fairly common, with the last thought to have happened in April 2001 and the next predicted in March 2043. 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). As an asteroid probably larger than 150 m in diameter that occasionally comes within 0.05 AU of the Earth, 2020 FX4 is also classified as a Potentially Hazardous Asteroid.
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