Sunday 26 February 2023

Outbreak of Marburg Virus in Equatorial Guinea claims nine lives.

On 7 February 2023, the Ministry of Health and Social Welfare of Equatorial Guinea reported the deaths of a number of individuals with suspected hemorrhagic fever, according to a press release issued by the World Health Organization on 25 February 2023. On 12 February 2023, one sample was confirmed positive for Marburg Virus by real-time polymerase chain reaction, at the Institut Pasteur in Dakar, Senegal. Investigations are ongoing to find additional cases. The World Health Organization is supporting the response by strengthening contact tracing, case management, infection prevention and control, laboratory, risk communication and community engagement, and assesses the risk posed by the outbreak as high at the national level, moderate at the regional level and low at the global level. This is the first Marburg Virus Disease outbreak reported in Equatorial Guinea.

On 7 February 2023, the Ministry of Health and Social Welfare of Equatorial Guinea reported at least eight deaths that occurred between 7 January and 7 February 2023, in two villages located in the district of Nsock Nsomo, in eastern the province of Kie-Ntem, in the Río Muni Region. According to the ongoing epidemiological investigation, the cases presented with fever, followed by weakness, vomiting, and blood-stained diarrhoea; two cases also presented with skin lesions and otorrhagia (bleeding from the ear).

On 9 February 2023, eight blood samples were collected from contacts and sent to the Centre Interdisciplinaire de Recherches Médicales de Franceville in Gabon, where they tested negative for both Ebola and Marburg viruses by real-time polymerase chain reaction.

An additional eight blood samples were collected from other contacts and sent to the Institute Pasteur in Dakar, Senegal, on 12 February 2023. One of these samples was taken from a suspected case that was confirmed positive for Marburg virus by real-time polymerase chain reaction. This case presented with fever, non-bloody vomiting, bloody diarrhoea, and convulsions and died on 10 February 2023 at Ebebiyin District Hospital. The case also had epidemiological links to four deceased cases from one of the villages in Nsoc-Nsomo district.

As of 21 February 2023, the cumulative number of cases is nine, including one confirmed case, four probable cases and four suspected cases. All the cases have died, one in a health facility and the other eight in the community. There are no cases among healthcare workers. Thirty-four contacts are currently under follow-up.

Marburg Virus is the causative agent of Marburg Virus Disease, which has a case-fatality ratio of up to 88%. Marburg Virus Disease was initially detected in 1967 after simultaneous outbreaks in Marburg and Frankfurt in Germany, and in Belgrade, Serbia.

Negative stained transmission electron micrograph of a number of filamentous Marburg Virions, which had been cultured on Vero cell cultures, and purified on sucrose, rate-zonal gradients. Erskine Palmer/Russell Regnery/Centers for Disease Control and Prevention/Wikimedia Commons.

The Egyptian Fruit Bat, Rousettus aegyptiacus is considered to be the natural host for Marburg Virus, from which the Virus is then transmitted to Humans. Marburg spreads through Human-to-Human transmission via direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids. Healthcare workers have previously been infected while treating patients with suspected or confirmed Marburg Virus Disease. Burial ceremonies that involve direct contact with the body of the deceased can also contribute to the transmission of Marburg.

The incubation period varies from two to 21 days. Illness caused by Marburg Virus begins abruptly, with high fever, severe headache and severe malaise. Severe watery diarrhoea, abdominal pain and cramping, nausea and vomiting can begin on the third day. Severe haemorrhagic manifestations appear between five and seven days from symptoms onset, and fatal cases usually have some form of bleeding, often from multiple areas. In fatal cases, death occurs most often between eight and nine days after symptom onset, usually preceded by severe blood loss and shock.

In the early course of the disease, the clinical diagnosis of Marburg Virus Disease is difficult to distinguish from many other tropical febrile illnesses due to the similarities in the clinical symptoms. Other viral haemorrhagic fevers need to be excluded, including Ebola Virus Disease, as well as Malaria, Typhoid Fever, Leptospirosis, Rickettsial infections, and Plague. Laboratory confirmation can be made by different tests, such as antibody-capture enzyme-linked immunosorbent assay, antigen-capture detection tests, serum neutralization test, reverse transcriptase polymerase chain reaction assay, electron microscopy, and Virus isolation by cell culture. 

Although no vaccines or antiviral treatments are approved to treat the Virus, supportive care, rehydration with oral or intravenous fluids, and treatment of specific symptoms improve survival. A range of potential treatments are being evaluated, including blood products, immune therapies, and drug therapies.

This is the first time that Equatorial Guinea has reported an outbreak of Marburg Virus Disease, and the World Health Organization assesses that the country's capacity to manage the outbreak is insufficient. The most recently reported outbreak of Marburg Virus Disease was in Ghana in 2022 (three confirmed cases). Other Marburg Virus Disease outbreaks have been previously reported in Guinea (2021), Uganda (2017, 2014, 2012, 2007), Angola (2004-2005), the Democratic Republic of the Congo (1998 and 2000), Kenya (1990, 1987, 1980) and South Africa (1975).

Based on available information, all nine deceased cases were in contact with a relative with the same symptoms or participated in a burial of a person with symptoms compatible with Marburg Virus Disease. At this stage it cannot be ruled out that all Marburg Virus Disease cases have been identified, therefore there could be transmission chains that have not been tracked. To date, most of the contacts of the nine deceased cases have not been identified.

It should also be noted that with the exception of one case who died in a health facility, the other eight died in the community and their burial conditions are unknown.

Cross-border population movements are frequent, and the borders are very porous, between Ebebiyin and Nsock Nsomo districts (Equatorial Guinea), Cameroon and Gabon. This constitutes a risk of cross-border spread. Considering the above described scenario, the risk is considered high at the national level, moderate at the regional level and low at the global level.

Marburg Virus Disease outbreak control relies on using a range of interventions, namely case management, surveillance including contact tracing, a good laboratory service, infection prevention and control including safe and dignified burials, and social mobilization. Community engagement is key to successfully controlling Marburg Virus Disease outbreaks. Raising awareness of risk factors for Marburg infection and protective measures that individuals can take is an effective way to reduce Human transmission.

Communities affected by Marburg should make efforts to ensure that the population is well informed, both about the nature of the disease itself and about necessary outbreak containment measures.

Outbreak containment measures include prompt, safe and dignified burial of the deceased cases, identifying people who may have been in contact with someone infected with Marburg and monitoring their health for 21 days, isolating and providing care to confirmed patients and maintaining good hygiene and a clean environment.

Healthcare workers caring for patients with or suspected of Marburg Virus Disease should apply additional infection control measures in addition to standard precautions to avoid contact with patients’ blood and body fluids and with surfaces and objects contaminated.

The World Health Organization recommends that male survivors of Marburg Virus Disease practice safer sex and hygiene for 12 months from onset of symptoms or until their semen twice tests negative for Marburg Virus. Contact with body fluids should be avoided and washing with soap and water is recommended. The World Health Organization does not recommend isolation of male or female convalescent patients whose blood has tested negative for Marburg Virus, nor the implementation of any restrictions on travel and/or trade to Equatorial Guinea based on available information for the current outbreak.

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Analyzing the contents of a 500-year-old medicine horn from Eastern Cape Province, South Africa.

The discovery of organic residues in or on ancient artifacts presents exciting opportunities for archaeologists. Analysis of such residues has suggested purposes as cosmetics, adhesives, medicines and even poisons, with the majority apparently derived from Plants. The earliest organic residues date from about 200 000 years ago, and apparently reflect Plants chosen for the Insect-repellent smoke they produced when burned,. This marks the beginning of a long history of Humans utilizing the chemical properties of Plants, which has enabled us to move out of Africa and colonise every continent except Antarctica. The oldest of these studied residues come from Southern Africa, where we have a record of Human Plant usage spanning almost the entire history of our species, and including a wide range of uses, though, surprisingly, including very few residues associated with medicines.

Traditional African medicine is still widely used on the continent, and is heavily dependent on Plants, something which was recorded by the earliest European visitors to the continent, and which therefore was probably the case long before their arrival. Unfortunately, from an anthropological point of view, traditional African medicine practitioners are flexible and adaptable in their approach to Plant selection, and today use many Plants imported from other parts of the world, something which makes it hard to assess which Plants might have been used in medicine in the remote past. This is complicated by the fact that not all traditional medicines are effective, with only 33 of the 166 Plants used in traditional medicine in Eastern Cape Province today having been shown to have pharmacological effects. This is not simply a sign of incompetence on the behalf of the practitioners of this medicine, but rather a slightly different perspective on how Plants are used, with much medicine being used to protect against, or treat the effects of, harmful magic rather than disease.

The lack of archaeological evidence makes it hard to assess how old modern traditional medicine practices are, and how (or if) they have changed over time. The remains of Plants which would be considered to have medicinal properties today have been found associated with archaeological sites dating back to the Middle Stone Age in South Africa (i.e. more than 130 000 years old), although it not possible to say if they were being used for medicinal purposes, or how they were used if they that was their purpose.

In a paper published in the South African Journal of Science on 31 January 2023, Justin Bradfield of the Palaeo-Research Institute at the Universityof Johannesburg, Stephan Woodborne of iThemba LABS, Jeremy Hollmann of the Rock Art Research Institute at the University of the Witwatersrand, and Ian Dubery of the Research Centre for PlantMetabolomics and the Departmentof Biochemistry at the University of Johannesburg, describe a 500-year-old medicine horn found in a rock shelter on a farm in Eastern Cape Province, South Africa, the results of an analysis of its contents.

The horn was discovered on a farm called La vie D’Antan, in the Langkloof Mountains, about 40 km to the north of Plettenberg Bay, and about 40 km to the east of Uniondale. The object is a Cattle horn sealed with  leaves, which contained a solid residue, thought likely to have been a liquid or gel when the horn was deposited, due to its orientation. This residue was readily soluble, making it suitable for gas chromatography-mass spectrometry analysis.

The horn container after excavation (large inset) and at two stages of the recovery of the parcel: (A) the parcel tightly bundled with Boophane disticha leaves and grass, wrapped together with plant fibre rope and (B) partially unwrapped exposing the horn container. (C) and (D) The location of the rock shelter on the farm La vie D’Antan. Bradfield et al. (2023).

The site from which the horn was recovered is a rock shelter with rock art, about 3 m high and cutting 3 m deep into the conglomerate Enon Formation. The shelter has a shallow floor deposit, which is only a few centimetres thick, within which the horn had been deposited. The horn was discovered after apparently being exposed by Animal activity, and removed by a passer-by to prevent further damage. It was sealed with a bundle of Century Plant, Boophane disticha, leaves and Grass, which were attached to the horn by a twisted Plant-fibre rope. The leaves of the Century Plant are known to have antiseptic properties, which may have helped to preserve the horn and its contents; the same leaves were used to bind the 2000-year-old Kouga Mummy, which was discovered about 10 km from the La vie D'Antan site. The site also produced a few shards of ceramic, but no signs of ever having been occupied, The area around the site contained numerous Everlasting Plants, Helichrysum spp., and Ragworts, Senecio spp., both of which are sometimes used to make teas in Southern Africa.

The rock shelter is within a conglomerate made up of sandstone boulders, which is covered by between 20 and 30 paintings, executed in red and yellow ochre paints, apparently made with a brush (with the exception of some handprints), and depicts Human figures armed with hunting equipment, and a range of Animals, most of which are hard to identify, but which include at least one Eland and one Antelope. This art is fairly typical of the San people who occupied the region before being largely driven out by Dutch settlers in the late eighteenth century; similar art has been found at two other rock shelters within 2 km of the site.

Examples of rock art from La vie D’Antan and neighbouring sites. Images have been digitally enhanced using colour deconvolution. The original colour is a red hue. Bradfield et al. (2023).

Prior to the eighteenth century, the area was occupied by hunter gatherers who belonged to the San ethnic group, and pastoralists from the Khoi ethnic group, who typically owned large herds of Sheep and Cattle. By 1775 much of the land had been partitioned among Dutch settlers, with the few remaining Inqua Khoi largely being employed as herdsmen on Dutch owned farms. A mixed population, descended from San and Khoi refugees and deserters from the Dutch army (which included non-European conscripts from colonies in Africa and Asia) may have survived in the mountains as late as the 1880s, but the last independent San bands disappeared in the 1760s. Little is known about this hunter gatherer population, though they were resident in the area for at least 10 000 years, and used a technology which modern archaeologists classify as Later Stone Age.

The Kouga Mummy was found about 10 km from the La vie D'Antan rockshelter, and comprises a man aged between 30 and 40 and thought to be a member of the San ethnic group due to his stature, and dated to about 1930 years before the present. The Mummy was wrapped in the leaves of a Century Plant, and covered with a mass of twigs and branches, which may have formed a burial basket. Within the leaf-bindings were found some Century Plant bulbs, as well as some beads made from marine shells. The feet of the Mummy had been bound, and the last joint of the left little finger removed, both burial customs known to have been practiced by some San societies. The burial site was covered by a painted stone slab.

The Kouga Mummy. Albany Museum.

The use of horns as medicine containers is fairly common across Africa as a whole, but somewhat unusual in Southern Africa, where the shells of Tortoises or the eggs of Ostriches have been the favoured traditional containers. A number of Cattle horn snuff containers attributed to Sotho or Shona makers are housed in the collection of the British Museum, but these date from the nineteenth century. The Harvard Peabody Museum has similar containers, reportedly from southern Tanzania or northern Zimbabwe, but again from the nineteenth century. Bradfield et al. also note having found reference to a medicine horn collected in the Belgian Congo between 1890 and 1930, on which they could find no further information, possibly in reference to this specimen from the Welcome Collection. They also note that some San groups living in the Kalahari use horns to store medicine, as do the Bemba of Zimbabwe, althought the Kalahari San generally use Duiker horns to store medicine used against witchcraft, while the Bemba use  a variety of Antelope horns, including Duiker and Bushbuck, 

Bradfield et al. first examined the contents of the horn under a light microscope, finding a mixture of Insect and Plant remains in the surface layer. The majority of the Insect remains could not be identified with any confidence, but were not inconsistent with having come from Dermestid Beetles (Skin Beetles) a group which are known to have been attacking the Horn and its contents when it was found, though some scales of Lepidopteran Insect (Butterfly or Moth) wings were also found. Beneath the surface the residue contained no Insect or Plant remains, and comprised a shiny brown crystalline substance which dissolved readily in water and smells faintly of Liquorice. 

Micrographs showing (A) Insect epithelial tissue; the glossy, reflective surface and absence of visible phytolith structures under ultraviolet light suggest Insect origin rather than Plant; (B), (C) elongated tissue structure, possible Plant tracheids; (D) fragment of an Insect wing; (E)–(G) Lepidoptera wing scales; (H)–(K) probable Insect setae; (L), (M) crystalline-looking fragments of the tacky main container residue; and (N), (O) the solute of the tacky residue after dissolving in water. Note the absence of other obvious tissue structures. Bradfield et al. (2023).

Gas chromatography-mass spectrometry analysis of the brown residue revealed it to be a mixture of organic compounds, with the largest proportion being mono-methyl inositol and its isomers, as well as lupeol, and lesser amounts of  di- and tri-terpenes, a sterol derivative and fatty acid methyl ester. Curiously, no volatile aromatic associated with a Liquorice smell was found.

Inositol is a natural polysaccharide sugar synthesized in plant cells and used in the production of plasma lipo-proteins to aid cell growth. It is produced by a range of Plants, including Legumes and Citrus fruits, and used in medicines used to control diabetes, and treat  high cholesterol, bronchopulmonary dysplasia and various mood disorders, as well as to reduce the symptoms of polycystic ovarian syndrome. Importantly, it is considered to be a pharmacologically stable compound, upon which it is impossible to overdose.

Mono-methyl inositol and inositol isomers are produced by a number of Southern African plants used medicinally, including the Balloon Pea, Sutherlandia frutescens, an antioxidant which has traditionally been used to wash wounds and treat eye infections, as well as as a tonic to treat rheumatism and pulmonary ailments and boost immune function, the Honeybush, Cyclopia intermedia, from which an antioxidant rich tea is made, which is held to have anti-inflammatory and possibly cancer-fighting effects,  Lotonius laxa, and Bluebellvine, Clitoria ternatea, which is not used in medicine in Southern Africa today, but which is used in Asia to treat sexually transmitted diseases and anxiety.

Lupeol is a pentacyclic triterpenoid produced by a wide range of Plants, and is commonly a constituent of resins and plant waxes. Medicinally, it has anti-inflammatory and antimicrobial properties, and is used in some cancer treatments. In Southern Africa it is produced by a number of Plants, including the Namaqua Rock Fig, Ficus cordata, the Kokilaksha, Asteracantha longifolia, which is used by the Pedi people of northern South Africa as a treatment for rheumatism, urinary tract infections, and jaundice, as well as an aphrodisiac, as well as by a number of species of Euphorbia

Kaurenoic acid is an antibacterial compound produced by a variety of Plants, which is particularly effective against Gram-positive Bacteria such as Listeria, Staphylococcus and Streptococcus. It has also been shown to offer some protection against liver damage. Again, this is produced by a number of Plants found in Southern Africa, including the Bears Foot, Arctopus sp., the medicinal use of which has been recorded since the 1770s, as a treatment for gout, various infections and respiratory ailments, Alepidea sp., which has been used to treat colds, coughs, sore throats, influenza, and abdominal cramps, and Aster bakeranus, which has been used to treat venereal diseases, urinary tract infections, chronic coughs, and intestinal complaints.

Another chemical present is cyclolanostenol acetate, which can be produced by a variety of Dicotyledonous Plants and Animals. Notably, in Southern Africa, it is produced by Rafnia amplexicaulis, which has been used to make a tea used to treat pulmonary conditions, and as a substitute for liquorice. 

Small amounts of three decanoic acids were found within the resin. These are are produced by a range of Plants held to have medicinal compounds. Also present were hexadecane and octadecanoic acid, both of which have antifungal, antibacterial, and antioxidant properties.

While all of the identified chemicals are produced by a range of Plants across Southern Africa, Bradfield et al. feel confident in narrowing the field to plants found close to the site where the horn was discovered. When this is done, three species stand out as being highly likely to have contributed to the contents of the horn; the Prostrate Purslane, Corbichonia decumbens, which comprises 75% mono methyl inositol, 17% hexadecenoic acid and 16% octadecanoic acid, and which is liquefied for use as an emetic by members of the Zulu people today, the Liquorice Plant, Glycyrrhiza glabra, which contains 28% of mono-methyl inositol, 3.4% octadecanoic acid, and 4.9% hexadecenoic acid, which is widely used by traditional medicine practitioners across Africa, but which has generally been assumed to have been introduced to the continent by Europeans, and the Horse Gram, Macrotyloma uniflorum, which also contains mono-methyl inositol, hexadecanoic acid and octadecanoic acid, and which, while not used in African traditional medicine today, is used in India as an antioxidant and a treatment for insulin resistance. Another possibility is Mikania sp., which contains lupeol and kaurenoic acid, and which is used to treat Snake bites and venereal disease today.

Bradfield et al. conclude that the horn contains a mixture of extracts from at least two plants, almost certainly intended to have a medicinal use. The major components of this mixture are used to treat a wide range of ailments today, either by drinking or applying as an ointment; San people today often apply ointments to small cuts intentionally made for that purpose, which may also have been the case when the horn medicine was in use. There is no way to know what ailment(s) the mixture found in the horn was actually intended to treat, or whether that treatment would have been of any benefit to the patient. The medicine contains a number of active ingredients, but the medicine maker is likely to have had a world view very different to our own, including a belief in supernatural as well as (or instead of( physical causes for ailments, which would have affected the choice of ingredients to be used in a medicinal potion in ways difficult for us to understand.

Notably, two plants found to be growing abundantly in the area around the rock shelter today, Helichrysum sp. and Senecio sp., are both used in traditional medicine today to treat both physical and spiritual ailments, are unlikely to have been components of the medicine, based upon the gas chromatography-mass spectrometry analysis, although both the medicine and Helichrysum sp. have a Liquorice-smell, so it is possible that this was a component of the medicine but not detected instrumentally for some reason. The alternative explanation, that the Liquorice-smell derives from the Liquorice Plant, Glycyrrhiza glabra, runs counter to the current belief that the Plant was introduced to Africa by Europeans, although this Plant matches the chemical contents of the horn much more closely, and other Plants thought to have been introduced to Africa by Europeans have subsequently been shown to have been on the continent before Europeans arrived. 

The careful wrapping and burial of the horn and its contents implies that this was a valued object. It is likely that it was buried in the rock shelter with the intention that its owner would return and retrieve it at some point, but never did so. Similar finds of items probably buried for storage purposes have been found elsewhere in Southern Africa, for example a full hunting kit was found  Eland Cave in the Drakensberg Mountains. Other than this item, the rock shelter contains only a few ceramic shards and the rock paintings, with no indication that it was ever used as a dwelling. 

As far as Bradfield et al. are aware, the horn from the La vie D'Antan rock shelter is the oldest medicine container ever discovered in Southern Africa. The occupation of the region where the horn was found appears to have been ephemeral after about 2000 years ago, with nearby rock shelters at Boomplaas, Nelson Bay Cave and Matjes River, all of which were once occupied, having been abandoned during the first millennium AD. The information available does not allow the identification of the medicine-maker. The art in the rock shelter is clearly of San origin, but there is no evidence that the horn and the paintings were contemporary in origin. The choice of a Domestic Cattle horn would seem to imply the medicine was left by a Khoi herder, but there is no real reason to assume this. The San people sometimes kept Cattle, and even if this was not the case, the horn could have been acquired by a San medicine maker through scavenging, theft, or trade. Bradfield et al. note that nineteenth century records from the Western Cape state that the Khoi and San peoples there shared a belief in a mythical being called the Water Bull, which resembled a Domestic Bull, and which had horns with magical healing properties. 

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Saturday 25 February 2023

Magnitude 3.7 Earthquake in Gwent, South Wales.

The British Geological Survey recorded a Magnitude 3.7 Earthquake at a depth of about 3 km, beneath the town of Brynmawr in Gwent, South Wales, slightly before midnight GMT on Friday 24 February 2023. There are no reports of any damage or casualties associated with this event, and nor would they be expected with an Earthquake this small, but the quake was felt by a large number of people within 40 km of the epicentre, with several reports of people feeling it further afield in Wales and the Midlands region of England.

The approximate location of the 24 February 2023 Brynmawr Earthquake. British Geological Survey.

Earthquakes become more common as you travel north and west in Great Britain, with the west coast of Scotland being the most quake-prone part of the island and the northwest of Wales being more prone  to quakes than the rest of Wales or most of England.
The precise cause of Earthquakes in the UK can be hard to determine; the country is not close to any obvious single cause of such activity such as a plate margin, but is subject to tectonic pressures from several different sources, with most quakes probably being the result of the interplay between these forces.

The precise cause of Earthquakes in the UK can be hard to determine; the country is not close to any obvious single cause of such activity such as a plate margin, but is subject to tectonic pressures from several different sources, with most quakes probably being the result of the interplay between these forces.

(Top) Simplified diagram showing principle of glacial rebound. Wikipedia. (Bottom) Map showing the rate of glacial rebound in various parts of the UK. Note that some parts of England and Wales show negative values, these areas are being pushed down slightly by uplift in Scotland, as the entire landmass is quite rigid and acts a bit like a see-saw. Climate North East. 

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. If you felt this quake, or were in the area but did not (which is also useful information) then you can report it to the British Geological Survey here.  

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Cyclone Freddy makes landfall in Mozambique after killing seven people in Madagascar.

Cyclone Freddy made landfall in the coastal town of Vilanculos in southern Mozambique on Friday 24 February 2023, brining with it windspeeds of 113 km per hour, as well as high rainfall levels. The rain is predicted to be the bigger part of the problem for the country, which is already suffering from widespread flooding following exceptionally high seasonal rains, and may also cause problems in neighbouring Malawi, Zimbabwe, and northern South Africa. While the storm is likely to bring severe problems to the country, it is hoped that the number of casualties will be kept low, with thousands of people having been evacuated from the path of the cyclone as part of the World Meteorological Organization's Early Warnings for All Programme. The storm has already claimed seven lives in Madagascar, as well as causing damage to property on the islands of Mauritius and La Reunion.

Meteosat-9 image of Cyclone Freddy making landfall in Mozambique on Friday 24 February 2023. NOAA/AP.

Tropical storms, called Cyclones in the Indian Ocean and South Pacific, are caused by solar energy heating the air above the oceans, which causes the air to rise leading to an inrush of air. If this happens over a large enough area the inrushing air will start to circulate, as the rotation of the Earth causes the winds closer to the equator to move eastwards compared to those further away (the Coriolis Effect). This leads to tropical storms rotating clockwise in the southern hemisphere and anticlockwise in the northern hemisphere. These storms tend to grow in strength as they move across the ocean and lose it as they pass over land (this is not completely true: many tropical storms peter out without reaching land due to wider atmospheric patterns), since the land tends to absorb solar energy while the sea reflects it..

The formation of a tropical cyclone. Natural Disaster Management.

Cyclone Freddy is particularly unusual in that it formed off the coast of Australia, tracking its way across the entire southern Indian Ocean before hitting Madagascar and Mozambique. It is only the fourth time a storm has been recorded doing this, with the previous examples being cyclones Litanne in 1994 and Leon–Eline and Hudah in 2000. This long journey allowed Freddy to gain considerable energy, hitting Madagascar as a Category 5 Cyclone (i.e. a storm with sustained winds in excess of 252 km per hour). The storm lost most of its energy passing over the island, but regained some of this passing over the Mozambique Channel.

Track map of Severe Tropical Cyclone Freddy The points show the location of the storm at 6-hour intervals. The colour represents the storm's maximum sustained wind speeds as classified in the Saffir–Simpson scale, with warmer colours representing higher wind speeds. Wikimedia Commons.

Despite the obvious danger of winds of this speed, which can physically blow people, and other large objects, away as well as damaging buildings and uprooting trees, the real danger from these storms comes from the flooding they bring. Each drop millibar drop in air-pressure leads to an approximate 1 cm rise in sea level, with big tropical storms capable of causing a storm surge of several meters. This is always accompanied by heavy rainfall, since warm air over the ocean leads to evaporation of sea water, which is then carried with the storm. These combined often lead to catastrophic flooding in areas hit by tropical storms. 

The formation and impact of a storm surge. eSchoolToday.

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Friday 24 February 2023

The threats facing Great Salt Lake, Utah, and finding ways to address them.

Terminal lakes occur in semi-arid regions of continental interiors where precipitation is sufficient to allow the formation of surface waters, but not sufficient to create waterways which flow to the sea, leading to the formation of an ecosystem where wetlands are maintained by the balance between precipitation and evaporation. The largest such lake in North America is Great Salt Lake in Utah, a major driver of biodiversity and economic activity in the western United States. Great Salt Lake is estimated to generate about US$2.5 billion in economic activity each year, and to support about 9000 jobs, in fields such as mineral extraction, recreation, and Brine Shrimp harvesting. Evaporation from the lake is estimated to contribute 5-10% of the snowfall onto nearby mountains, generating a further US$1.8 billion in economic activity, and supporting a further 20 000 jobs.

Great Salt Lake provides a vital link in the 'Pacific Flyway' Bird migration route, creating a food-rich habitat used by about 10 million migratory Birds each year. About 350 species of Birds are thought to depend on Great Salt Lake and its associated wetlands, including Eared Grebes, Tundra Swans, Snowy Plovers, American Avocets, and multiple species of Ducks, Phalaropes, Owls, and Blackbirds. The widespread loss of wetlands across the western United States is has made this environment an even more vital resource for wildlife.

Great Salt Lake also provides a range of ecosystem services of direct importance to Humans, including the protection of air quality, removing water pollutants, and moderating the local climate. It is also of significant cultural importance to the people of Utah, and has inspired numerous countless scientists, pioneers, artists, writers, photographers, and recreationists. As such good stewardship of the lake is important not only because of its ecological, environmental, and economic importance, but also because of its central place in the culture of the state.

However, in recent years, the extraction of water by Humans has driven the lake far beyond the natural fluctuations that it has endured over the past millennia, pushing the lake-associated ecosystems into structural decline. Since 2020 Great Salt Lake has lost over 1.2 billion cubic metres of water per year, a trend which could see the lake disappear completely by 2028. The lake is currently 3.5 m lower and 7.4 billion cubic metres short of its minimum healthy level, and has reached this minimum on only a single occasion since 2002.

In a report published by Plant and Wildlife Services at Bingham Young University on 4 January 2024, a team of scientists headed by Benjamin Abbott of Bigham Young University, lay out the current threats faced by Great Salt Lake, and discuss the measures that could be taken to address them.

A bridge where the Bear River used to flow into Great Salt Lake. EcoFlight in Abbott et al. (2023).

The nature of saline lakes is highly dependent on the relationship between precipitation and evaporation. If there is to little rainfall or two much evaporation, then the lake becomes to saline to support the micro-organisms at the base of its food chain. Conversely, if there is to much rainfall, or to little evaporation, then the lake becomes less saline, altering the community which can live there. Water extracted from the lake or its watershed for use in agriculture can alter this balance, harming the lake's delicate ecology. Water extraction for agriculture is known to have been affecting Great Salt Lake since the mid-1800s, becoming the dominant controlling force in the watershed in the twentieth century. During this period, numerous federal and state projects, including dams, canals, and pipelines, took water from the watershed for use in agriculture, industry, and municipal purposes. This high extraction caused water levels in Great Salt Lake to fall precipitously from the 1960s, although a 'pluvial' period of high rainfall in the 1980s enabled it to recover somewhat.

Elevation, extent, and volume of Great Salt Lake from 1985 to 2022. The mean natural values were determined from estimated 1850-2016 values without Human water use. The 1985 lake level is close to the long-term natural average of 4207 foot (1313 m) above sealevel, providing a useful comparison. Abbott et al. (2023).

During the past three years Great Salt Lake has received less than a third of its natural water-input, due to excessive water extraction for Human purposes. In 2022 the lake surface dropped to its lowest ever recorded elevation, 4188 foot (1276 m) above sealevel. These figures do not include groundwater extraction or levels, making it likely that the situation in the Great Salt Lake Basin is even more severe; the loss from the lake represents about 32 billion cubic metres, but it is likely that twice as much has been loss from the basin's aquifers, which will slow the lake's recovery even if the waterflow is restored.

Ten of the 338 bird species known to feed, breed, or seek refuge at Great Salt Lake. Mary Anne Karren, Jeff Beck, Jeremy Bekker, Russell Hatch, Travis McCabe, and Chuck Castleton in Abbott et al. (2023).

The watershed for Great Salt Lake spreads across four states, and includes the Bear, Jordan, and Weber basins. Six percent of this watershed is covered by agricultural land, drawing its irrigation from the lake's water supply; 63% of this agricultural land lies in Utah, with 31% in Idaho, 5% in Wyoming, and 1% in Nevada. Another 3% of the watershed is covered by urban development, 93% of which lies in Utah.

Map of the Great Salt Lake watershed, including the most extensive land uses (agricultural and urban). Abbott et al. (2023).

Agriculture is the single largest consumer of water from the Great Salt Lake watershed, with about 75% of the water extracted going to irrigate Alfalfa and other crops, while 5-10% is lost during transport within irrigation systems. About 9% of the extracted water is consumed during mineral extraction from the lake, while another 9% is used for domestic and urban purposes, with 90% of that estimated to be spent on outdoor water use, such as watering lawns and ornamental Plants; the amount used for internal domestic purposes is negligible, as most of this is returned to the lake via wastewater treatment plants. The remaining extracted water is used in thermoelectric power generation, industry, and mining.

Evaporation ponds on the east side of the lake seen from the International Space Station. Water is taken from the lake to accelerate evaporation and extract potash fertilizer, magnesium, sulphate, table salt, and other minerals. Alexander Gerst/European Space Agency in Abbott et al. (2023).

Climate change is also affecting Great Salt Lake, with average temperatures in Utah having risen by 2°C since 1900, which is exacerbating draughts across the southwestern United States. This climate change is thought to be responsible for about 9% of the decline in water within Great Salt Lake. This trend is likely to continue for the foreseeable future, requiring Utah's Human population to plan for a drier future.

Saline lake ecosystems are being destroyed by excess water extraction for agriculture on every continent except Antarctica. This excess water extraction has been shown to trigger a sequence of ecological and economic consequences, which are almost impossible to reverse. The circumstances of this vary from site to site, but generally involve pollution of both the water and air supply, collapse of agriculture and industry, economic depression, and a breakdown of the lake and wetland ecosystems.

Even without complete loss of the lake, exposure of large areas of the former lake bed can cause problems, as this exposes sediments often laden with large amounts of pollutants, harmful minerals, and toxins. The sediments at Great Salt Lake have been shown to contain : arsenic, cadmium, mercury, nickel, chromium, lead, copper, selenium, organic contaminants, and cyanotoxins. When exposed these substances are easily picked up and distributed by the wind, as the average particle size is about 10μm. Exposure to these substances in air pollution has been linked to a number pf medical conditions, including reproductive disfunction, developmental defects, cognitive impairment, cardiovascular damage, and cancer. At a time when awareness of the problems of air pollution have risen globally, and almost all urban communities have taken steps to improve air quality, exposed lake beds can rapidly undermine improvements that took decades to achieve. Such dusts can also damage agricultural land, damaging crops and undermining soil fertility, as well as building up on top of snow packs, where their dark colour enables them to absorb thermal energy which would normally be reflected by the white snow, leading to premature melting.

Dust from drying saline lakes. (Left) Mar Chiquita, Argentina. (Upper right) Owens Lake, California. (Lower right) Dust darkens snowpack in the Rockies causing early melt.  Jeff Schmaltz, Brian Russell, and NASA in Abbott et al. (2023).

The damage to the local ecology from the loss of a saline lake is also typically severe. Changes in the water coverage and depth affect local Plant and Animal communities, and tend, in the case of salt lakes, to be accompanied by changes in the water chemistry, which can have profound impacts across wide areas. The loss of evaporative water coming from the former lake can aridify the local climate, leading to desertification, wider swings in temperature, and lower rainfall within the catchment area, leading to further aridification. This in turn profoundly affects Human populations dependent on the lake, causing industries to collapse, loss of property values, and eventually mass migration away from the area, which in turn can lead to social conflicts and a loss of social identity.

Great Salt Lake is already showing signs of developing many of these problems, and is likely to proceed further along this path without urgent action. The salinity of the lake has already begun to rise, and ,currently sits at about 19%. At this level the micro-organisms upon which the Brine Shrimps (a vital food-source for migratory Birds) depend are becoming much less productive, and the Brine Shrimps themselves are beginning to suffer metabolic problems. The lake suffered a catastrophic crash in its Brine Fly population in 2022, and the same is currently predicted to happen to the Brine Shrimp this year (2023). Several Bird species using the lake, including Wilson’s Phalaropes and Eared Grebes, are protected by federal regulations, which might lead to the enforced stopping of some economic activities on the lake if they become threatened. Even if this does not happen, the falling water levels are predicted to make mineral extraction from the lake non-viable in 2023 or 2024. At the moment the drying lake is forming salty evaporite crusts over newly exposed sediments, but if these remain exposed for long, they are likely to be a source of dust storms; dust from the lake is already reaching areas from southern Utah to Wyoming, with the majority of dust falling in the Wasatch Front area now derived from the lake. Salt-laden dust storms can lead to severe pollution levels, and are damaging to agricultural land.

A juvenile Gull feeds on Brine Flies, which depend on microbialite habitat that is being destroyed by desiccation and salination. Mary Anne Karren in Abbott et al. (2023.

The worst problems facing Great Salt Lake can be seen in the lake's North Arm, which was cut off by a railway causeway in 1959, and now receives almost no water input. This has led to salt in the water here reaching evaporation point, which in turn has killed off all the Algae in this part of the lake and causing the food web here to collapse. In addition, water circulation in the North Arm of the lake has broken down, causing pollutants to build up, giving this part of the lake the highest methylmercury levels recorded anywhere in the United States. 

Gunnison Island and the receding hypersaline water of Great Salt Lake’s North Arm. With the island connected to the mainland, predators can access the island’s colony of American White Pelicans, which is one of the largest in the world. EcoFlight in Abbott et al. (2023).

Recent changes to legislation in Utah have favoured conservation of water within natural waterways as as something to be valued in itself, allowing farmers to leave water in streams without losing water rights. In addition, the state government has significantly raised the funding available for conservation projects in 2022, and plans to do the same again in 2023. Similar changes to federal legislation has secured extra funding for the conservation of Great Salt Lake. Furthermore, many cities, towns, and districts within the Great Salt Lake basin have introduced their own water conservation projects, and many businesses and community groups are now also seeking to play an active role in the conservation of Great Salt Lake.

All of these changes are likely to have a positive impact on the lake's survival over the next few decades - as long as the lake can survive the immediate crisis, though they are probably not sufficient to avert that crisis. All of the water conservation efforts combined in 2022 is only estimated to have increased water-flow into Great Salt Lake by 123 million square metres.

Abbott et al. call for an emergency rescue plan to be put into plan for Great Salt Lake, which should be taking steps within the first half of 2023 in order to protect the lake from catastrophic changes. The lake is currently more than three metres below its minimum healthy level, a shortfall of over 7.5 billion cubic metres of water. It will require a dramatic increase in the amount of water flowing into the lake in 2023 and 2024 in order to give the lake any hope of recovery.

Abbott et al. calculate that the minimum acceptable amount of water flowing into the lake should be three billion cubic metres per year. Analysis of the past behaviour of the lake suggests that this is the point at which the water level in the lake begins to rise rather than falling. It is also roughly 1.25 billion cubic metres per year more than is currently flowing into the lake. How much water will need to be conserved each year in order to achieve this is somewhat dependent on the weather, but Abbot et al. estimate it to be between 865 million and 1.48 billion cubic metres of water per year, which would require water use within the watershed to be cut by between 30 and 50%.

A child explores rock formations on the shore of Great Salt Lake. Angie Hatch in Abbot et al. (2023).

The first instinct of planners, when faced with water scarcity, has often been to increase the supply using 'hard' engineering solutions, such as dams or pipelines. However, over the past century numerous studies have shown that this is generally the worst answer to such problems. Abbott et al. suggest that the correct way to address water shortages is to study the natural system of the water basin in question, conserve as much water as possible, and only augment the water flow with engineered solutions as a last resort.

The reasons for doing this are not purely ecological; large scale infrastructure projects such as dams are extremely expensive, and notoriously prone to both overrunning their predicted budgets and underachieving their aims, as well as often producing risks and problems which were not anticipated at the planning phase. Even when the construction phase of such projects is successful they are often unable to cope with natural changes in the hydrological cycle or variations in water demand, which can quickly make them obsolete, particularly if they are combined with overallocation of water, changes in landuse, or variations in the climate. Notably, moving water from one area to augment the supply in another can lead the area from which water is extracted facing shortfalls of its own. 

A family enjoys the buoyancy of Great Salt Lake’s saline water. Kevin Hehl in Abbott et al. (2023).

The Great Salt Lake watershed is littered with such hard engineered water projects, including three huge pumping stations and a system of reservoirs which is calculated to lose as much water each year as the total domestic consumption within the watershed. An inter-basin transfer system also exists, which has been linked to the decline of the Colorado River water-system. However, many other proposed engineering solutions to the watershed's problems have been rejected, which Abbott et al. suggest indicates a degree of wisdom on the part of environmental managers.

Abbott et al. believe that decreasing water demand is always a better solution than trying to maintain water supplies through engineered solutions, both because it costs considerably less, and because it provides more resilience to changes in the water cycle. Careful pricing of water and caps on its usage can deliver reductions in water consumption quite quickly, and with relatively little expense. Estimates of the costs that would be associated with restoring the Great Salt Lake through water conservation alone vary between US$14 and US$96 million, or between US$5 and US$32 for every person living in the watershed, while the use of a water market system, which would give inhabitants the right to buy and sell water, could lower the cost to between US$6 and US$48 million, or between US$2 and US$14 per person living in the watershed. 

More heavily modified water-systems tend to require more maintenance than more natural, less modified systems. This is currently the case with Great Salt Lake, where almost every aspect of the ecosystem, water-flow regime, and even lake chemistry is currently controlled by Humans, While all of these controls were put in place with good intent, collectively they are responsible for the majority of the problems facing the lake today.

Abbott et al. note that returning the lake to a 'pristine', pre-Human intervention state would be neither possible nor desirable, but do believe the natural state of the lake should be a major consideration when planning future changes. Such an approach should reduce the risk of harmful side-effects occurring when well-intentioned projects are put into place, increasing the likelihood of such projects are undertaken. Particular attention should be paid to maintaining the amount of water flowing into the lake, and also the seasonal nature of such water flow, as well as to the establishing a conservation buffer zone around the lake, where natural ecosystem-processes are allowed to take precedence over infrastructure projects. Efforts should be made to keep the lakes level above its natural lowest level (1282 m above sealevel). Abbott et al. believe that restoring a more natural hydrology to Great Salt Lake will have a knock-on effect, helping to restore more natural systems to upstream environments such as Utah Lake, Jordan River, Weber River, Logan River, and Farmington Bay.

Complex dikes and flow control structures in the wetlands around the lake. EcoFlight in Abbot et al. (2023).

Environmental concerns and the maintenance of natural water systems have traditionally been given a low legal priority in western cultures. This has failed to take into account that Humans often need these natural ecosystems in order to survive and flourish. Changing the allocation of water usage between different consumer groups can deal with short term problems, but fails to address the underlying problems of water supply. Abbot et al. believe that in order for Utah to establish a maintain a sound ecological foundation upon which its Human prosperity can be based, Great Salt Lake itself must be permanently allocated a large portion of the water flowing into its watershed. Current law in the state relies on the principle that users who can establish that they have been utilizing water for longer have precedence over other users, something which Abbott et al. believe should be extended to the lake itself as an entity. If the lake is accorded such status, then a the water required to maintain the natural system would be allocated ahead of that required by Human users, thereby insuring the continuance of the lake and associated water systems.

This would mean reducing the amount of water available for Human users, but would introduce a degree of security into the system, which would be of benefit to the Human occupants of the watershed. Once the lake's needs were met any excess water could then be distributed via a system of prior application (earliest Human users first), or divided equally among users. The later system has been deployed successfully in Nevada, while the former aligns more closely with standing law in Utah. 

Abbott et al. also note that in strongly religious Utah, recognizing the Great Salt Lake as part of God's creation entrusted to Human stewardship, which therefore should have a right to continue to exist, is not at odds with the customs or beliefs of much of the population.

Great Salt Lake and its watershed seen from the International Space Station. Alexander Gerst in Abbott et al. (2023).

Abbott et al. recommend that the federal government makes more funds available for water conservation in the Great Salt Lake watershed, and takes an active role in coordinating water usage agreements across state lines. They further recommend that the federal government increases monitoring of the hydrology and climate of the basin, and that federal agencies work closely with state agencies on the monitoring and maintenance of the basin's ecosystems.

Livestock and water Infrastructure in the Heber Valley. Ben Abbott in Abbott et al. (2023).

Abbot et al. further recommend that the state authorities in Utah release water held in reservoirs in order to increase the streamflow into Great Salt Lake during 2023 and 2024, if necessarily leasing, purchasing or using emergency mandate powers to obtain water from wholesalers (although they do stress that private organizations holding water should be compensated for such seizures). They further recommend that the state establish a long-term target lake-level, using the framework suggested in previous state reports, with a well-defined, and legally binding, timeline for reaching key goals in the restoration of the ecosystem. Furthermore, they recommend that the state develops a high-profile website dedicated to promoting the wellbeing of the lake, which highlights individuals and organizations doing the most to help conserve water, and also directly contacts all water users in the watershed, as well as community, church, and agricultural groups to ensure that they are kept up to date on the progress of the program, why it is being undertaken, and any changes to the legal structure through which water allocation is handled and how it will affect users.

A Tundra Swan looks for water at the former shoreline of Great Salt Lake. Mary Anne Karren in Abbott et al. (2023).

Furthermore, Abbott et al. recommend that the state authorities should offer farmers in the watershed compensation for not growing crops this year, and provide aid to help them transition to less water-intensive crops. The state should also seek to extend develop water markets across the entire watershed, using models previously developed for the management of saline lake watersheds. The state should work with the Utah Water Task Force and other organizations to establish a 'law of the lake' framework within each of the major watershed basins, following the pattern used in the early 2000s to resolve water conflicts in the Bear River Basin. The state should be responsible for ensuring any water saved by state and federal programs is permanently assigned for the benefit of the lake, expand turf-removal programs to encourage less water-consumptive gardening practices in urban and country communities, hire more employees to work on all of these projects, and implement a system of tiered water pricing, as well as removing subsidies for water use.

An American Avocet forages for food among desiccated microbialites. Mary Anne Karren in Abbott et al. (2023).

Abbott et al. also recommend that local authorities within the Great Salt Lake watershed should coordinate with both state and federal programs to raise awareness of the problems facing the lake and its watershed, and to promote water conservation by cities, businesses, and individuals. In particular local authorities should convene homeowner and home-builder associations, who should be kept briefed on any changes to the rules regarding water management, and encouraged to take an active role in water conservation. Local authorities should also work with community groups to remove turf from public spaces, and promote less water-intensive forms of gardening, including the planting of vegetation native to the region, as well as introducing tiered charging for different water uses (in particular lower charges for indoor water use than outdoor).

Boaters, birders, and hunters access the lake’s wetlands and shallow bays. Chandler Rosenberg in Abbott et al. (2023).

Abbott et al. also make a number of recommendations for individuals and community groups within the Great Salt Lake watershed, including actively spreading information about the crisis facing the lake and the efforts being made to tackle it, sharing information about water conservation techniques, changing the vegetation in gardens and other outdoor spaces to types which need little or no irrigation, encouraging local, state, and federal authorities to adopt conservation measures, and maintaining or removing sprinkler systems.

An Eared Grebe looks to us for leadership. Mary Anne Karren in Abbott et al. (2023).

As well as a list of recommendations for things that should be done, Abbot et al. strongly advise that a number of actions be avoided. The first of these is not attempting to prevent natural evaporation from the lake (something which is often done with reservoirs) as this will effect precipitation in areas downwind of the site, and impact the natural water/mineral balance of the lake. Secondly, Abbot et al. advice against cloud seeding to try to resolve water shortage problems, noting that this is (at best) an unreliable technology, and again has the potential to upset rainfall patterns in neighbouring areas. Thirdly, Abbot et al. recommend against the building of more infrastructure, observing that reservoirs and piping systems are major causes of the current problem, and that building more it unlikely to solve the situation. Fourthly, Abbott et al. strongly advise against simply waiting for rain, noting that, while this did work briefly in the 1980s when a short pluvial interval restored much of the water to an already drying lake system, that was regarded at the time as a once-in-a-thousand-years event, and that since then a warming global climate has shifted conditions in the Great Salt Lake watershed, making a repeat of the event even less likely. Finally, Abbott et al. advise strongly against simply abandoning the lake or any part thereof (something they refer to as the Aral Sea solution). Recent speculation has been made about the possibility of abandoning the North Arm of Great Salt Lake, which was cut off by the building of a railway causeway in 1959, and now naturally receives little natural irrigation, in order to conserve water for the rest of the lake. However, this course of action would mean allowing the Pelican colony on Gunnison Island to go extinct, sacrificing a valuable mineral extraction industry on this arm of the lake, and risking the creation of a major source of toxic dusts, including methyl mercury.

Sunset over an exposed microbialite reef. Mary Anne Karren in Abbott et al. (2023).

Finally, Abbott et al. suggest that what has ultimately been missing from the Great Salt Lake watershed has been not water but trust. Water conservation measures are present throughout the watershed, but the various users have not trusted each other enough to allow conserved water back into the lake. Abbott et al. concede that the proposed changes will have the most impact on farmers and rural communities within the Great Salt Lake watershed, but stress that the majority of the authors of the report come from such backgrounds, and that they are keen to see proper support, financial, legal, and technical, for farming communities during any change within the watershed.

A woman gazes across the lake. Jared Tamez in Abbott et al. (2023).

The Great Salt Lake ecosystem is currently facing an unprecedented ecological collapse, and addressing this will require equally unprecedented changes in the way water conservation is managed within the Great Salt Lake watershed. However, Abbot et al. suggest that bold, collective action is not unprecedented in the history of Utah, and that they believe the people of the state are capable of rising to face the challenge before them. 

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