Halloween special VII: A story of Darkness and Climate Change.

In April of 1815 the eruption of Mount Tambora released two million tons of debris and sulphur components into the atmosphere. The following year was known as “the year without summer”. The eruption produced famine, riots, and disease outbreak. Charles Lyell describes the eruption in his Principles of Geology: “Great tracts of land were covered by lava, several streams of which, issuing from the crater of the Tomboro Mountain, reached the sea. So heavy was the fall of ashes, that they broke into the Resident’s house at Bima, forty miles east of the volcano, and rendered it, as well as many other dwellings… The darkness occasioned in the daytime by the ashes in Java was so profound, that nothing equal to it was ever witnessed in the darkest night.”

The 1815 eruption of Tambora volcano (Sumbawa island, Indonesia) was the largest volcanic eruption in the last 500 years. The dust, gas, rock and pyroclastic flows hitted the surronding sea hard enough to set off moderate-sized tsunami that struck the shores of various islands in the Indonesian archipelago. Over 71 000 people died during, or in the aftermath of, the eruption near Sumbawa and the island of Lombok. The nothern hemisphere experienced severe weather. Summer temperatures across much of western and central Europe were 1–2°C cooler than the average for the period 1810–1819.

The Villa Diodati. Image from Finden’s Landscape & Portrait Illustrations to the Life and Works of Lord Byron, vol. 2 (London: John Murray, 1832).

The event inspired the great romantic poet Lord Byron to wrote “Darkness”:

I had a dream, which was not all a dream.
The bright sun was extinguish’d, and the stars
Did wander darkling in the eternal space,
Rayless, and pathless, and the icy earth
Swung blind and blackening in the moonless air;
Morn came and went—and came, and brought no day,
And men forgot their passions in the dread…”
The poem, with a vision of an icy Earth full of desolation and despair was published in 1816. At the time, after a failed marriage, scandalous affairs and huge debts, Byron left England and never returned. He traveled to Switzerland whith his physician, Dr John William Polidori, where he met up with Percy Bysshe Shelley and Mary Wollstonecraft Godwin (she married Shelley later that year) at the Villa Diodati on the banks of Lake Geneva. The meeting was organized by Clare Clairmont, Mary’s step-sister and a former lover of Lord Byron, because Shelley wanted to meet the great poet.
Years later, Mary Shelley wrote about their stay at Geneva: “it proved a wet, ungenial summer, and incessant rain often confined us for days to the house. Some volumes of ghost stories translated from the German into French, fell into our hands. There was the History of the Inconstant Lover, who, when he thought to clasp the bride to whom he had pledged his vows, found himself in the arms of the pale ghost of her whom he had deserted. There was the tale of the sinful founder of his race, whose miserable doom it was to bestow the kiss of death on all the younger sons of his fated house, just when they reached the age of promise.” 

Illustration from the frontispiece of the 1831 edition of Frankestein.

Byron proposed a ghost story contest. They all agreed. Byron wrote a short, fragmentary vampire tale. Shelley wrote a tale inspired by his childhood. Polidori used Byron’s tale and wrote The Vampyre. The story was first published in April 1819 in Henry Colburn’s New Monthly Magazine. Byron himself was the model for the vampire character, Lord Ruthven. The story was an immediate popular success and influenced Bram Stoker’s Dracula.
Mary’s contribution was Frankenstein: “I busied myself to think of a story, —a story to rival those which had excited us to this task. One which would speak to the mysterious fears of our nature, and awaken thrilling horror—one to make the reader dread to look round, to curdle the blood, and quicken the beatings of the heart.”
As in “Darkness”, Frankenstein deal with desolation and despair. Both are notable examples of the narrative of the climate disaster and the trauma unfolding around them in the Tambora years of 1816-18.
Mount Tambora continued rumbling intermittently at least up to August 1819. Once it was similar in stature to Mont Blanc. And of course, Mer de Glace, on the slope of the mountain, is where Victor Frankenstein reunited with his Creature: “From the side where I now stood Montenvers was exactly opposite, at the distance of a league; and above it rose Mont Blanc, in awful majesty…. The sea, or rather the vast river of ice, wound among its dependant mountains, whose aerial summits hung over its recess….” (Mary Shelley, Frankenstein, 1818)
Oppenheimer, C. (2003). Climatic, environmental and human consequences of the largest known historic eruption: Tambora volcano (Indonesia) 1815. Progress in Physical Geography, 27(2), 230–259. doi:10.1191/0309133303pp379ra
Shelley, Mary. (1818) Frankenstein or, The Modern Prometheus. [via Gutenberg Project.]
Polidori, John. (1819) The Vampyre and Other Tales of the Macabre. [via Gutenberg Project.]

Mutagenesis in land plants during the end-Triassic mass extinction


A basaltic lava flow section from the Middle Atlas, Morocco. From Wikimedia Commons.

During the last 540 million years five mass extinction events shaped the history of the Earth. The End-Triassic Extinction at 201.51 million years (Ma) is probably the least understood of these events. Most mammal-like reptiles and large amphibians disappeared, as well as early dinosaur groups. In the oceans, this event eliminated conodonts and nearly annihilated corals, ammonites, brachiopods and bivalves. In the Southern Hemisphere, the vegetation turnover consisted in the replacement to Alisporites (corystosperm)-dominated assemblage to a Classopollis (cheirolepidiacean)-dominated one.

The mass extinction event was likely caused by the eruption of the Central Atlantic Magmatic Province (CAMP), a large igneous province emplaced during the initial rifting of Pangea. Data indicates that magmatic activity started c. 100,000 years before the endTriassic event and continued in pulses for 700,000 years. The CO2 emissions caused global warming. The SO2 emissions on mixing with water vapour in the atmosphere, caused acid rain, which in turn killed land plants and caused soil erosion.

A normal fern spore compared with mutated ones from the end-Triassic mass extinction event. Image credit: S LINDSTRÖM, GEUS

Volcanoes are also a primary source of mercury (Hg) in the global atmosphere. Mercury can cause morphologically visible abnormalities in plants and their reproductive cells (spores and pollen). A new study led by Sofie Lindström of the Geological Survey of Denmark and Greenland analized various types of abnormalities in the reproductive cells of ferns, with focus in two morphogroups: LTT-spores (laevigate, trilete fern spores with thick exine), and LCT-spores (laevigate, circular, trilete spores). The LTT-spores were produced primarily by the fern families Dipteridaceae, Dicksoniaceae, and Matoniaceae, while LCT spores were primarily produced by ferns belonging to Osmundaceae and Marattiales.

The elevated concentrations of mercury (Hg) in sedimentary rocks in North America, Greenland, England, Austria, Morocco, and Peru are linked to CAMP eruptions. This pulse of mercury also correlate with high occurrences of abnormal fern spores, indicating severe environmental stress and genetic disturbance in the parent plants. Three negative organic C-isotope excursions (CIEs) have being recognized at the end-Triassic: the Marshi, the Spelae, and the top-Tilmanni CIEs. Malformations in LTT-spores first occur sporadically in the lower pre-Marshi interval. LCT-spores are present but are generally rare in this interval. During the Spelae CIE, the occurrences of moderate to severe malformations increased and aberrant forms can encompass as much as 56% of the counted LTT-spores. This interval is associated with marked global warming, recorded by stomatal proxy data.




Sofie Lindström et al. Volcanic mercury and mutagenesis in land plants during the end-Triassic mass extinction, Science Advances (2019). DOI: 10.1126/sciadv.aaw4018}

Grasby, S. E., Them, T. R., Chen, Z., Yin, R., & Ardakani, O. H. (2019). Mercury as a proxy for volcanic emissions in the geologic record. Earth-Science Reviews, 102880. doi:10.1016/j.earscirev.2019.102880

Ocean acidification and the end-Cretaceous mass extinction

Heterohelix globulosa foraminifera isolated from the K-Pg boundary clay at Geulhemmerberg in the Netherlands. Image credit: Michael J. Henehan/PNAS

The Cretaceous–Paleogene extinction that followed the Chicxulub impact was one of the five great Phanerozoic mass extinctions. Three-quarters of the plant and animal species on Earth disappeared, including non-avian dinosaurs, pterosaurs, marine reptiles, ammonites, and planktonic foraminifera. The impact released an estimated energy equivalent of 100 teratonnes of TNT, induced earthquakes, shelf collapse around the Yucatan platform, and widespread tsunamis that swept the coastal zones of the surrounding oceans. The event also produced high concentrations of dust, soot, and sulfate aerosols in the atmosphere. Global forest fires might have raged for months. Photosynthesis stopped and the food chain collapsed. The impacto also caused sudden ocean acidification, impacting marine ecosystems and the carbon cycle. Around the time of the impact, 23,000 to 230,000 cubic miles of magma erupted out of the mid-ocean ridges, all over the globe. One of the largest eruptive events in Earth’s history. This pulse of global marine volcanism played an important role in the environmental crisis at the end of the Cretaceous. Marine volcanism also provides a potential source of oceanic acidification, but a new study by Yale University indicates that the sudden ocean acidification was caused by the Chicxulub bolide impact (and not by the volcanic activity) that vaporised rocks containing sulphates and carbonates, causing sulphuric acid and carbonic acid to rain down. The evidence came from the shells of planktic and benthic foraminifera.

Foraminifera are crucial elements for our understanding of past and present oceans. Their skeletons take up chemical signals from the sea water, in particular isotopes of oxygen and carbon. Over millions of years, these skeletons accumulate in the deep ocean to become a major component of biogenic deep-sea sediments. Ocean acidification in the geological record is often inferred from a decrease in the accumulation and preservation of CaCO3 in marine sediments, potentially indicated by an increased degree of fragmentation of foraminiferal shells. In the early 1990’s it was recognised that the boron isotopic composition of marine carbonates was determined largely by ocean pH. Usingy the boron isotope-pH proxy to planktic and benthic foraminifera, the new study determinated the ocean pH drop following the Chicxulub impact.

The Cretaceous/Palaeogene extinction boundary clay at Geulhemmerberg Cave. Image credit: Michael J. Henehan

The boron isotope composition of carbonate samples obtained from a shallow-marine sample site (Geulhemmerberg Cave, The Netherlands) preserved sediments from the first 100 to 1000 years after the asteroid’s impact. The data from the Geulhemmerberg Cave indicate a marked ∼0.25 pH unit surface ocean acidification event within a thousand years. This change in pH corresponds to a rise in atmospheric partial pressure of CO2 (pCO2) from ∼900 ppm in the latest Maastrichtian to ∼1,600 ppm in the immediate aftermath of bolide impact.

Ocean acidification was the trigger for mass extinction in the marine realm. Acidification affects the biogeochemical dynamics of calcium carbonate, organic carbon, nitrogen, and phosphorus in the ocean and interferes with a range of processes including growth, calcification, development, reproduction and behaviour in a wide range of marine organisms like planktonic coccolithophores, foraminifera, echinoderms, corals, and coralline algae. Additionaly, ocean acidification can intensify the effects of global warming, in a dangerous feedback loop.

Anthropogenic climate change and ocean acidification resulting from the emission of vast quantities of CO2 and other greenhouse gases pose a considerable threat to ecosystems and modern society. Since the Industrial Revolution the pH within the ocean surface has decreased ~0.1 pH and is predicted to decrease an additional 0.2 – 0.3 units by the end of the century. This underlines the urgency for immediate action on global carbon emission reductions.




Michael J. Henehan el al., “Rapid ocean acidification and protracted Earth system recovery followed the end-Cretaceous Chicxulub impact,” PNAS (2019). www.pnas.org/cgi/doi/10.1073/pnas.1905989116

Kump, L.R., T.J. Bralower, and A. Ridgwell. 2009. Ocean acidification in deep time. Oceanography 22(4):94–107, https://doi.org/10.5670/oceanog.2009.100.


The Last Mammoths

Mammuthus primigenius, Royal British Columbia Museum. From Wikipedia Commons

During the Late Pleistocene and early Holocene, most of the terrestrial megafauna became extinct. It was a deep global-scale event. The extinction was notably more selective for large-bodied animals than any other extinction interval in the last 65 million years. Among them, the mammoths offers a very complete fossil record, and their evolution is usually presented as a succession of chronologically overlapping species, including (from earliest to latest) M. meridionalis (southern mammoths), M. trogontherii (steppe mammoths), and M. columbi (Columbian mammoths) and M. primigenius (woolly mammoths).

Wrangel Island coast. From Wikipedia Commons

From Siberia to Alaska, mammoths were widespread in the northern hemisphere and their remains inspired all types of legends. Their lineage arose in Africa during the late Miocene, and first appeared in Europe almost three million years ago. The iconic M. primigenius arose in northeastn Siberia from the steppe mammoth (Mammuthus trogontherii) and their extinction has inspired an impressive body of literature. Multiple explanatory hypotheses have been proposed for this event: climatic change, overhunting, habitat alteration, and the introduction of a new disease.

The world’s last population of woolly mammoths lived on Wrangel Island going extinct around 4,000 years ago. In contrast the mammoth population from Russia disappeared about 15,000 years ago, while the mammoths of St. Paul Island in Alaska disappeared 5,600 years ago. The Wrangel Island was a part of Beringia, an ancient landmass, that included the land bridge between Siberia and Alaska. Global sea level transgression at the end of the Pleistocene isolated Wrangel Island from the mainland and broke up Beringia. Palynological and isotopic evidence suggest that present climatic conditions and floral composition were established right after the Pleistocene-Holocene transition.

A mammoth tooth on the riverbank on Wrangel Island. Image credit; Juha Karhu/University of Helsinki

Tooth specimens are about 90% of all the mammoth material for Wrangel Island. The multi-isotopic evidence (carbon, nitrogen and sulfur in collagen) measured on Wrangel Island mammoths supports the idea that this relict population mantained a typical mammoth ecology despite climate change and decreasing genetic diversity. It has been suggested that the extinction of the Wrangel Island mammoths was possibly caused by a short-term crisis, possibly linked to climatic anomalies, however the anthropogenic influence should not be dismissed despite lack of tangible evidence of hunting.



Laura Arppe, Juha A. Karhu, Sergey Vartanyan, Dorothée G. Drucker, Heli Etu-Sihvola, Hervé Bocherens. Thriving or surviving? The isotopic record of the Wrangel Island woolly mammoth population. Quaternary Science Reviews, 2019; 222: 105884 DOI: 10.1016/j.quascirev.2019.105884

Meet Ferrodraco lentoni, the Iron Dragon

Ferrodraco lentoni gen. et sp. nov. holotype. Scale bar = 50 mm. From Pentland et al., Scientific Reports.

Pterosaurs were the first flying vertebrates. From the Late Triassic to the end of the Cretaceous, the evolution of pterosaurs resulted in a variety of eco-morphological adaptations, as evidenced by differences in skull shape, dentition, neck length, tail length and wing span. Their reign extended to every continent, but due to the fragile nature of their skeletons the fossil record of pterosaurs is rather patchy, with most occurrences limited to fragmentary remains. The newly described Ferrodraco lentoni, from the Winton Formation (Cenomanian–lower Turonian), is the most complete pterosaur specimen ever found in Australia. Previously, and only based on fossil skull fragments, two other species of pterosaurs were described from Australia: Mythunga camara and Aussiedraco molnari.

Discovered in 2017, the holotype specimen AODF 876 (Australian Age of Dinosaurs Fossil) includes a partial skull, five partial neck vertebrae, and bones from both the left and right wings. The wingspan of Ferrodraco was approximately 4 m, with a skull probably reaching 60 cm in length. The generic name comes from the Latin language: ferrum (iron), in reference to the ironstone preservation of the holotype specimen, and draco (dragon). The species name, lentoni, honours former Winton Shire mayor Graham Thomas ‘Butch’ Lenton.

Ferrodraco lentoni gen. et sp. nov. holotype rostral sections AODF 876. Cross-section. Scale bar = 20 mm. From Pentland et al., Scientific Reports.

Based on several cranial synapomorphies, including the presence of a mandibular groove, smooth and blade-like premaxillary and mandibular crests, and spike-shaped teeth, Ferrodraco falls within the clade Anhangueria. This group has also been recorded in the Early Cretaceous of Brazil, China and England. It has been suggested that anhanguerians went extinct at the end of the Cenomanian. This interval was characterised by an increase in atmospheric and oceanic surface temperatures, a global oceanic anoxic event, and marine transgression. Given that Ferrodraco was recovered from a locality northeast of Winton, which is considered as early Turonian in age, the new specimen potentially represents a late-surviving member of the anhanguerians.



Adele H. Pentland et al., Ferrodraco lentoni gen. et sp. nov., a new ornithocheirid pterosaur from the Winton formation (cenomanian-lower turonian) of Queensland, Australia, DOI: 10.1038/s41598-019-49789-4