Sciency Thoughts: Nicaragua

Showing posts with label Nicaragua. Show all posts

Wednesday, 21 December 2022

Deamia funis: A new species of epiphytic Cactus from Nicaragua.

The genus Deamia currently contains three species of climbing and epiphytic Cacti from Central America and Mexico. These Cacti show determinate growth (i.e. flowers are produced on the tips of the main stems), have stems covered by a thick, waxy coating, and produce spines on their flowers. Their fruit are red with a white pulp.

In a paper published in the journal Phytotaxa on 20 December 2022, Barry Hammel of the Missouri Botanical Garden and Salvador Arias of the Jardín Botánico at the Universidad Nacional Autónoma de México, describe a new species of Deamia from the Atlantic dry forests of Nicaragua.

The new species is named Deamia funis, in reference to the long, dangling, rope-like stems common in this species when found growing on horizontal branches of trees ('funis' is Latin for 'rope'). It is a root-climbing or trailing epiphyte, with strait, cylindrical, usually pendulous (dangling) stems up to 10 m long and 0.6-1.1 cm in diameter.

Deamia funis, vegetative characters. (A)–(C) Habitat and habit. (D) Close-up of stem showing cracks in epidermal wax. Olga Martha Montiel in Hammel & Arias (2022).

The flowers of Deamia funis are produced in the local dry season (January to April). These are funnel shaped structures at the tips of the stem, 8-10 cm long, with at green outer pericarpel with numerous areoles (spine clusters) producing hair-like spines. The flowers open at night, revealing a white interior. Curiously, the stigma (pollen-receptive part of the female sex organs) of Deamia funis project beyond the anthers (pollen producing male organs), an unusual state in Cacti.

Deamia funis, reproductive characters (A) Side-view of flower on specimen. (B) Side-view of flower in life. (C) Front-view of flower in life (arrow at stigma). (D) Close-up of base of flower in life. (E) Submature fruit, in life. Barry Hammel, Olga Martha Montiel, & Claudia Lucía Chamorro in Hammel & Arias (2022).

Deamia funis has only been observed growing at elevations of between 322 and 423 m above sealevel in the fog-zones of dry, seasonal forests on the Atlantic watershed of central Nicaragua, although Hammel and Arias note that this ecosystem extends into neighbouring Honduras, and the species could potentially live there also. All three areas where the species has been seen growing are outside of protected zones, and the total distribution of the species probably covers less than 5000 km². Furthermore, all of this habitat is considered to be at risk from the expansion of Cattle ranching in the area, for which reasons Hammel and Arias consider that Deamia funis should be considered to be Endangered under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species.

Thursday, 21 April 2022

Magnitude 6.7 Earthquake off the coast of Nicaragua.

The United States Geological Survey recorded a Magnitude 6.7 Earthquake at a depth of 25.3 km, about 58 km off the coast of the town of Masachapa in Managua Department, Nicaragua, slightly after 1.40 am local time (slightly after 7.40 am GMT) on Thursday 21 April 2022. There are no reports of any damage or casualties associated with this event, though it was felt across Nicaragua as well as in parts of El Salvador, Honduras, and Costa Rica.

The approximate location of the 21 April 2022 Nicaragua Earthquake. USGS.

Nicaragua is located on the southern part of the Caribbean Plate, close to its boundary with the Cocos Plate, which underlies part of the east Pacific. The Cocos Plate is being pushed northwards by expansion of the crust along the East Pacific Rise, and is subducted beneath the Caribbean Plate along the Middle American Trench, which runs parallel to the south coast of Central America, passing under the peninsula as it sinks into the Earth's interior. This is not a smooth process, the plates tend to stick together, breaking apart again once the pressure from the northward movement of the Cocos Plate builds up to much, triggering Earthquakes.

Friday, 6 November 2020

Landslides kill more than 50 in Guatemala, as Hurricane Eta sweeps across Central America.

More than fifty people are thought to have died in a series of landslides in Guatemala, with around half the deaths associated with a single event in the town of San Cristobal Verapaz, where a mudslide swept away about 20 houses. Elsewhere, another ten people were killed in a landslide in Huehuetenango Department, two children died when their home was destroyed by a landslide in Santa Barbara Department in the north of the country and a second pair of children died in another landslide incident in Quiche Department, also in the north, while a third pair of children died in a separate landslide in the south of the country. Another landslide in the south has left one person dead and another two missing, while another person died in a landslide close to Guatemala City. All of these landslides have been brought on by heavy rains associated with Hurricane Eta. 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. Despite not being directly hit by the storm, Guatemala has suffered badly because of it, with flooding across much of the country, and at least five major bridges, and numerous roads, swept away.

Flooding in Guatemala City associated with Hurricane Eta. Johan Ordonez/AFP.

Across central America about 70 people are thought to have died in incidents related to Hurricane Eta, which was a Category 4 Hurricane when it made landfall, bringing with it winds of up to 225 km per hour, to the south of the city of Puerto Cabezas. Two people are known to have died in Nicaragua as a result, and two in Honduras. In Panama, five people were killed when a landslide buried their homes in Chiriqui Province, close to the border with Costa Rica, while in Costa Rica a 71-year-old American citizen and his 51-year-old Costa Rican wife died in a landslide at Coto Brus in Puntarenas Province. El Salvador has also reported a number of landslides, though no fatalities at the current time.

The aftermath of a landslide in Chiriqui Province, Panama, caused by heavy rainfall associated with Hurricane Eta. AFP.

Hurricane Eta has lost energy as it has passed over Central America, and been downgraded from a hurricane to a tropical storm, but it is expected to travel northwest over the next few days, gaining strength again as it passes over the Caribbean, and potentially threatening the populations of Cuba and Florida. The casualty rate was probably been kept down by the evacuation of about 20 000 people from its path in Nicaragua, and Honduras.

The path and strength of Hurricane Eta. Thick line indicates the past path of the storm (till 3.00 am GMT on Friday 6 August 2020), while the thin line indicates the predicted future path of the storm, and the dotted circles the margin of error 9, 21, 33, 45, 69, 93 and 117 hours ahead. Colour indicated the severity of the storm. Tropical Storm Risk.

Tropical storms 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.

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.