Oil spill on the coast of Tobago, following wreck of mystery barge.

An oil slick has spread over 160 km on the Caribbean Sea following the wreck of a barge off the coast of the island of Tobago on 7 February 2024. The wreck was not reported by the barge's owners, but instead was spotted by beachgoers who reported it to the Tobago Emergency Management Authority. The barge has capsized on Cove Reed, off the southern coast of the island, and oil from it has spread over reefs and beaches along the southern tip of the island, as well as spreading across the Caribbean Sea towards Grenada and Venezuela.

An aerial image of the capsized barge. Office of the Chief Secretary of Tobago.

The barge appears to have been an unmanned and unpowered vessel, and has the word 'Gulfstream' painted on its side. As an unmanned, unpowered vessel it would not have been required to register with the International Maritime Organization, nor to carry an Automatic Identification System tracker, although it would have been partnered with a manned tugboat, which should (in theory) have complied with both of these requirements.

Before and after satellite images from the Copernicus Sentinel-1 mission show the scale of the oil spill that occurred off the shores of Trinidad and Tobago’s coastline earlier this week. The vessel, identified as the Gulfstream, ran aground and overturned off the southern shores of Tobago Island. The final image of the animation, captured at 10.18 pm GMT on 14 February, shows the oil spill has travelled over 160 km westwards. The spill is moving out of Trinidad and Tobago’s marine area and into Grenada’s southernmost marine area – which could affect neighbouring Venezuela. Satellite radar is particularly useful for monitoring the progression of oil spills because the presence of oil on the sea surface dampens down wave motion. Since radar basically measures surface texture, oil slicks show up well – as black smears on a grey background. European Space Agency.

An investigation by the Trinidad and Tobago Coast Guard found that a barge identified as the Gulfstream left Panama en route for Guyana coupled to a tug called the Solo Creed on 12 January 2024, and that authorities in Guyana reported that neither vessel arrived there. The Solo Creed, identified by the Vessel Finder website as a Tanzanian registered towing vessel, which visited Aruba on 20 January, and was last detected off the coast of Venezuela on 4 February.

An image of the capsized barge on 10 February 2023. Tobago House Assembly/AFP.

The Bellingcat investigative agency has identified a double-hulled barge capable of carrying 60 000 barrels of oil (i.e. 9.5 million litres) called the Gulfstream which was coupled to a tugboat called the Marlin, operating within the United States until 2012, which appears to be a good physical match for the vessel off the coast of Tobago. The Marlin was sold to the Panamanian San Martin Group in 2014, and while there are no official records of the Gulfstream after this, Bellingcat has found photographic evidence of the two vessels operating together between Panama and Venezuela between 2015 and 2020. The Marlin was sold on to another Panamanian company, Star Goods Petroleum, in 2021, and has not transmitted its position since. The Gulfstream was observed in the Astinave shipyard in Ecuador in February 2022, but has not been sighted since. Bellingcat suspect that the renamed Marlin and Gulfstream may still be operating together, as part of a 'ghost fleet' carrying embargoed Iranian oil to Venezuela. Many oil-carrying vessels operating out of Venezuela are considered to be poorly maintained to the point of being dangerous, and the Marlin and Gulfstream, if still operating together, would be 60- and 58-years-old respectively; both vessels would have been built with a planned lifetime of 30 years.

Oil spills are potentially harmful to marine life in a variety of ways. Most obviously it can coat the outside of organisms, causing damage to external structures such as the feathers of Birds and fur of Mammals, as well as smothering many marine invertebrates and plants. It also contains a variety of chemicals which can be directly toxic upset the hormonal balance of many animals. Oil also impedes the feeding of marine organisms, coating both food and feeding organs, but provides an excellent food source for Bacteria, which can lead to Eutrophication events - dramatic increases in Bacteria numbers, which then use all the oxygen in the water, leading other organisms to asphyxiate.

Workers from state own Heritage Petroleum Oil and Gas Company, the state oil company of Trinidad and Tobago, clean up an oil spill that reached Rockly Bay beach, in Scarborough, south western Tobago. Akash Boodan/AP.

Many fishermen on the southern part of Tobago are reporting vessels and equipment damaged by exposure to oil, and beaches across the southern part of the island being forced to close to tourists at the height of the tourist season. Volunteers and local specialists have recovered about 2000 barrels of oil from beaches on Tobago, but the vessel is still leaking and will probably need to be emptied of oil before it can be refloated and the damage repaired.

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Magnitude 5.2 Earthquake between Tobago and Grenada.

The United States Geological Survey recorded a Magnitude 5.2 Earthquake at a depth of 31.0 km roughly half way between the islands of Tobago and Grenada,  slightly after 11.25 pm local time on Monday 6 April 2020 (slightly after 3.25 am on Tuesday 7 April GMT). There are no reports of any casualties or damage associated with this event, though the quake was felt over a large area, with people reporting feeling it across Tobago, Grenada, Trinidad, and St Vincent and the Grenadines.

The approximate location of the 6 April 2020 Tobago and Grenada Earthquake. USGS.

The Lesser Antilles Islands, including Grenada and Tobago are located at the eastern fringe of the Caribbean Tectonic Plate. The Atlantic Plate (strictly speaking, an extension of the South American Plate which runs to the northeast of the Caribbean) is being subducted beneath this, and as it sinks into the Earth, is melted by the heat of the planets interior. Some of the melted material then rises up through the overlying Caribbean Plate as magma, fuelling the volcanoes of the Lesser Antilles Volcanic Arc. The subduction of the Atlantic Plate beneath the Caribbean Plate is not a smooth process, with the two plates constantly sticking together then breaking apart as the tectonic pressure builds up, causing Earthquakes in the process, though since the boundary between the two plates is some way to the east of the islands, Earthquakes in the Lesser Antilles tend to be both deep and offshore, which lessens their destructive potential.

 The subduction of the Atlantic Plate beneath the Caribbean Plate fuels the volcanoes of the Lesser Antilles Volcanic Arc. George Pararas-Carayannis.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The University of the West Indies is interested in hearing from people who have felt Earthquake events in the region; if you felt such a quake then you can report it here. 

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Erythrolamprus pseudoreginae: A new, cryptic, species of False Coral Snake from Tobago.

The genus Erythrolamprus currently contains 50 species of highly variable Colubroid Snakes from Central America, the Caribbean, and northern South America. The genus comprises a large number of species formerly assigned to other genera, as it has been shown by genetic studies that several different morphologies and colour patterns have repeatedly evolved within the group in response to similar environmental conditions; the group takes its name from the first described genus of these Snakes, which was originally used to include several Coral Snake-mimics, hence the common name False Coral Snakes. This high diversity and repeated convergent evolution means that the genus is thought highly likely to include numerous cryptic species (species that closely resemble other species, and cannot be separated by simple, non-invasive examination).

In a paper published in the journal ZooKeys on 15 January 2019,  John Murphy of Science and Education at the Field Museum of Natural History, Alvin Braswell of the North Carolina State Museum of Natural Sciences, Stevland Charles of the Department of Biology at Howard University, Renoir Auguste of the Department of Life Science at the University of the West Indies, Gilson Rivas of the Museo de Biologia at the Universidad del Zulia, Amaël Borzée of the Division of EcoScience and the Interdisciplinary Program of EcoCreative at Ewha Womans University, Richard Lehtinen of the Department of Biology at The College of Wooster, Michael Jowers of the Centro de Investigação em Biodiversidade e Recursos Genéticos at the Universidade do Porto, and the Korean National Institute of Ecology, describe a new species of Erythrolamprus from the island of Tobago.

As well as being an island of the Caribbean, Tobago forms part of the Cordillera de Costa, a sky island archipelago that extends 925 km in an east-west orientation from western Venezuela, across the Northern Range of Trinidad to the island. The Cordillera de Costa forms a distinct upland ecosystem made up of islands that have been periodically separated by either lowlands or ocean, depending on the sealevel, since at least the Miocene and possibly the Cretaceous, it is currently separated from the nearest area of similar uplands, the Guyana Shield by the Llanos Grasslands of northern Venezuela, with Trinidad separated from the Peninsula de Paria in Venezuala by the Gulf of Paria, and the island of Tobago separated from Trinidad by 35 km of open water. Despite these distances the uplands of Trinidad and Tobago form part of a continuous biome with the other parts of the Cordillera de Costa, with plants and animals there more closely related to those of other parts of the sky archipelago than the surrounding lowlands. This biome is a diversity hotspot for members of the genus Erythrolamprus, with sixteen species recorded in the Venezualan part of the range (eight of which are also found on the Guyanan Shield) and seven in Trinidad and Tobago.

The new species is named Erythrolamprus pseudoreginae, as it is described from a population previously assigned to the species Erythrolamprus reginae, which is otherwise found on the Guyanan Shield (a population previously assigned to this species on the Cordillera de Costa of Venezuala and Trinidad has already been described as a separate species. Adult specimens of this species ranged from 436 to 539 mm in length, with the longest specimen found having suffered damage to the tail, which suggests it was formerly somewhat larger. This species lacks the 'Coral Snake' colouration, being brown with black markings, a yellow stripe on the side and a white underside and an olive face.

Erythrolamprus pseudoreginae, living specimen. Murphy et al. (2019).

Erythrolamprus reginae has a very limited range, being found only in the forested ravines along the crest of the Main Ridge, a rocky ridge about 16 km long and covered with lower montane rain forest on schist soil, reaching elevations of 487–576 m above sealevel, with a steep terrain with deep gullies and fast-moving streams. This area lies entirely within the Main Ridge Forest Reserve, which has had protected status since 1776, making it the oldest protected forest in the Americas. As such the species is not thought to be under any immediate threat from Human activities, though it could potentially be threatened by future climate change.

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Magnitude 5.9 Earthquake off the coast of Tobago.

The United States Geological Survey recorded a Magnitude 5.9 Earthquake at a depth of 34.8 km roughly 22 km southeast of Scarborough,  the capital of Tobago, slightly after 5.40 pm local time (slightly after 9.40 pm GMT) on Tuesday 6 December 2016. This was a large quake, but at some depth as well as some way offshore, and there are no reports of any casualties or serious damage, though the quake was felt over a large area, with people reporting feeling it across much of northeast Venezuela, as well as in Trinidad and Tobago, Grenada, St Vincent and the Grenadines and St Lucya.

 

 Goods shaken from the shelves of a supermarket in Trinidad and Tobago. DownaYaad.

 

Trinidad and Tobago form part of the southern margin of the Caribbean Plate, which is moving eastward compared to the South American Plate to the south. This is not a smooth process, the two plates constantly stick together, then break apart as the pressure builds up, causing Earthquakes in the process. 

 

 The approximate location of the 6 December 2016 Tobago Earthquake. Google.

 

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

 

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Pachycara caribbaeum: A new species of Eelpout from vent fields in the Caribbean.

Eelpout, Zoarcidae., are bottom-dwelling Eel-like marine fish related to Sticklebacks and Scorpionfish. Members of the genus Pachycara are found at bathyal to abyssal depths (between one and six kilometers below the surface of the sea) in all oceans except the Arctic. There are currently twenty seven described species, of which three have been described from hydrothermal vent fields, areas where superheated water laden with minerals that has percolated through hot volcanic rocks reaches the surface, supporting whole ecosystems that get their energy from chemotrophic Bacteria (Bacteria that gain energy by breaking down chemicals from the vents rather than photosynthesis).

In a paper published in the journal Zootaxa on 13 January 2016, Eric Anderson of the South African Institute for Aquatic Biodiversity, Russell Somerville of Ocean and Earth Science at the University ofSouthampton and Jonathan Copely also of Ocean and Earth Science at the University of Southampton and of the Natural History Museum, describe a new species of Pachycara from the Von Damm Vent Field on the Mid-Cayman Spreading Centre and an un-named methane seep (area where methane is escaping from sedimentary rocks on the sea-floor, also often supporting ecosystems based upon chemotrophic Bacteria) close to Tobago.

The new species is named Pachycara caribbaeum, in reference to the area where it was found. The species is described from two male and one female specimens recovered from the Von Damm Vent Field at depths of 2309-2313 m by deep-sea submersibles, none of which are judged to be mature. The males are 117 and 199 mm in length, the female 197 mm.

Pachycara caribbaeum in the Von Damm Vent Field. Anderson et al. (2016).

Pachycara caribbaeum was found close to areas of visible diffuse flow venting in the Von Damm Vent Field, with temperatures ranging from 5-20ºC with several potential prey species in the vicinity. This suggests that the species does not have the tolerance of high temperatures seen in some vent-dwelling organisms and avoids areas of higher temperatures. He species was also observed at a methane seep close to Tobago, though the individuals seen here were not as large or as numerous as those seen in the Von Damm Vent Field, suggesting this was a less optimal environment. The species has not been seen on the roughly 2000 km of seafloor that separates the two sites, nor in the Beebe Vent Field which lies close to the Von Damm Vent Field (about 30 km) away, but much deeper (about 5 km compared to the 2.3 km depth at the Von Damm Vent Field.

Locations (indicated by stars) of Pachycara caribbaeu; West, Von Damm Vent Field (depth ca.2300 m), east, methane seep near Tobago (depth 1049 m). Scale bar is 1000 km. Anderson et al. (2016).

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