Field of Science

Gaia

"Surface conditions on Earth, have been for most of geological time regulated by life…[]…This new link between Geology and Biology originated in the Gaia hypothesis''
NASA geologist Paul Lowman (2002)

The concept of a living planet is a rare but intriguing vision of pop-art and science-fiction. In the Italian movie "Planet on the Prowl" (1966) the gravitational pull of a planet is causing havoc on earth. A team is send into space to destroy the planet, but here they discover that the celestial body is a living (!) cybernetic organism (however artificial in origin) that will not simply surrender without fight. A very similar plot was already used by director Antonio Margheriti in "Battle of the Worlds" (1961), where the mainframe of an alien spaceship is mimicking a planet.
A classic approach to a planet as life form is found in comics in the shape of the evil characters of Ego the living planet ("Thor" Sept. 1966) and Mogo the living planet ("Green Lantern" May 1985). Both planets are self-concious and selfish entities that feed on other worlds.

In 1965 the independent scientist James Lovelock, inspired by research on the possible habitability  of planet Mars, proposed in a Nature-article to see the various spheres of earth (lithosphere, hydrosphere, biosphere and atmosphere) as an interconnected and self-regulating system. He followed the suggestions by novelist William Golding and called this idea the Gaia-hypothesis, after the ancient mythological titan Gaia - personification of earth (this unintentionally, but supposed religious connection caused most concern in the scientific community). However the general notion that the Gaia-hypothesis states that "earth as a living planet" or a "life form" in the sense of entity or even individual is incorrect.

 
Fig.1. "SimEarth" is a simulator for life-supporting planets, 1990-1992 by Maxis.

Lovelock argued that both biotic and abiotic processes limit the possible amplitude of changes in the salinity of the oceans, the surface temperature of earth and the atmospheric chemistry - therefore forcing earth into a life-supporting disequilibrium between two stable extremes like the frozen wasteland of Mars or a hellish world as Venus.


In 1971 microbiologist Lynn Margulis (1938-2011) joined Lovelock (here an interview with both scientists in 2011), emphasizing the significance of microbial life and activity for the Gaia-theory and arguing how natural selection, acting on single individuals, could account for the development of (apparently) stable systems. Egoistic organism do not manipulate deliberately the system so it can support them; however if an organisms harms his environment (and the life-supporting properties) it will be naturally selected and be removed from the system. Environments are also not static systems that will not react to biotic changes, but can oscillate around "set points" without loosing their life-supporting properties.

"Some 30 million types of extant organisms have descended with modification from common ancestors; that is, all have evolved. All of them-ultimately bacteria or products of symbioses of bacteria - produce reactive gases to and remove them from the atmosphere, the soil, and the fresh and saline waters. All directly or indirectly interact with each other and with the chemical constituents of their environment, including organic compounds, metal ions, salts, gases, and water. Taken together, the flora, fauna, and the microbiota (microbial biomass), confined to the lower troposphere and the upper lithosphere, is called the biota. The metabolism, growth, and multiple interactions of the biota modulate the temperature, acidity-alkalinity, and, with respect to chemically reactive gases, atmospheric composition at the Earth's surface."

Margulis also emphasized the link between geology and biology - for example:
Plate tectonics is like life (as we at the moment know) a unique feature of the planet Earth. Apart of the size, density and petrological composition, plate tectonics seems to depend from the existence of liquid water on a planet. Without an atmosphere, earth would be to cold to maintain water in liquid form; however the chemistry of the atmosphere is influenced both by the lithosphere (by volcanic eruptions) and controlled by the carbon-circle of the biosphere. Finally plate tectonics modified (and modifies) the surface of earth and the environments, forcing life forms to adapt and evolve - probably even with no plate tectonics life would be still possible on earth, but it surely would be much more monotonous.
So every subsystem is connected to the others and influence them, being at the same moment influenced by all other subsystems.

Today´s legacy of Lovelock and Margulis is the consideration to see geology as part of the Earth System Sciences and appropriately to understand the Earth as a system.

Bibliography:

MARGULIS, L. (2004): Gaia by Any Other Name. In (ed.) Schneider S.H. "Scientists Debate Gaia - The Next Century": 7 - 12

It Came From the Ice!

I am forced into speech because men of science have refused to follow my advice without knowing why. It is altogether against my will that I tell my reasons for opposing this contemplated invasion of the antarctic - with its vast fossil hunt and its wholesale boring and melting of the ancient ice caps. And I am the more reluctant because my warning may be in vain.
"At the Mountains of Madness" (1931/1936) by H. P. Lovecraft (1890-1937)


One of the most classic monster of movies is without doubt the "mummy", mostly of Egyptian origin and with human shape (despite the fact that thousands of Egyptian mummies of various animals are known). Still today we are fascinated by the effort put into the preservation of a body, the ultimate victory above decay, corruption and finally death himself.
But there are not only artificial mummies, nature offers various methods to create "natural mummies". Corpses can be preserved in bog deposits - to acid for decomposing organism -  or tar pits - to poorly oxygenated - or permafrost - to cold for an effective decomposition of organic matter.

Natural mummies discovered in permafrost of ice age mammals offers a broad spectrum for research: taxonomic relations and dispersal history can be studied trough the ancient DNA, the structure of soft tissue can be observed in detail, paleo diet can be inferred by the gut contents and faeces, on some carcasses the circumstances of death can be observed - some animals show injuries, pathological deformations or tissue changes and parasites.
In the Siberian permafrost the best preserved specimens are those of mammoths, especially young and small individuals like the 40.000 years old mammoth calfs "Dima" (discovered in 1977) and "Lyuba" (2007); one of the oldest specimens is the 50.000 years old male "Khroma" (2009). 

The carcass of Khroma, partially eaten by modern scavengers, was discovered in July 2009 by a local hunter on the banks of the river Khroma. A preliminary study showed that in the carcass fossil germs were preserved, most probably anthracis, which can cause anthrax and black lung disease.  To prevent any possible contamination of involved researchers it was decided to sterilize the specimen. The still frozen carcass was therefore bombarded with a massive dose of Gamma-rays in a laboratory in Grenoble. 
Bacteria can theoretically survive long periods when frozen. In 2007 an international research team announced the discovery of 500.000 years old bacteria with intact and active DNA-sequence in samples of permafrost.



The scenario of a still living pathogen or parasite inside a frozen and preserved body of an ice age mammal is also the main storyline of a TV-horror-production of 2009, named appropriately "The Thaw" (strangely the title for the German release is the exact opposite - "Frozen"). In a remote region of the Canadian tundra a carcass of mammoth (Mammuthus primigenius?) is discovered in a melting glacier. 
(P.S. prehistoric monsters entrapped in ice have a long tradition - see for example "The Beast from 20,000 Fathoms" in 1953, "Godzilla" in 1954 and "Dinosaurus!" in 1960)



This is a common misconception, the natural mummies discovered until now were preserved all in permafrost soil, which contains local ice lenses of secondary genesis. This ice maybe plays an important role in the desiccation and preservation of the carcass, as moisture migrates from the body to the ice.
Anyway - the warming of the Canadian Arctic due anthropogenic climate change not only releases dead mammoths from the melting underground, but also a deadly and living pathogen - a parasite in from of an arthropod (a - bug - as noobs call it) that needs body heat. To survive inside its host the parasite weakens the immune system (as some real parasites do) - this behaviour would finally cause the death of the host, if the flesh-eating bugs (arthropods) didn't also multiply so fast that they eat their victim from inside.

The movie uses a environmental cause (the disease is released due the warming of the planet caused by our actions) as premise, most of it is however clearly inspired (or copied) from the movie "The Thing" (1982), even if there the parasite - first hiding and then exactly copying its host-  is an alien lifeform.




The Thaw doesn't really explain the origin of the parasite, but it seems almost certain that it is of terrestrial origin and also so deadly that it caused the extinction of the entire Pleistocene megafauna. The idea of an unidentified hyperdisease killing animals was proposed in 1997 after the first epidemics of Ebola in 1976-1979 and 1994-1996. Main vector of the presumed pathogen was Homo sapiens, infecting mammoths and other large mammals during his travels around Siberia and North America. In 2006 a research on the pathological malformations of bones from American Mastodon (Mammut americanum) and bison bones suggested that the animals suffered from an infection of tuberculosis. A relatively large number of geographically and temporal separated individuals showed those malformations.
A recent example how dangerous pathogens can be for an isolated population was observed on the Christmas Islands in the Indian Ocean. In 1899 human colonization and introduced black rats (Rattus rattus) brought a unicellular parasitic protist (Trypanosoma) onto the islands. The endemic rat species (Rattus macleari) was not immune against the introduced parasite and the population suffered a rapid decline - in 1904 the species was considered extinct. However this is an example on a very confined space, involving a single species - it remains unclear how a single pathogen could wipe out so many species in such a short time on almost the entire planet.

Last but not least: a strange movie combines somehow The Thing with mammoths. In the TV-horror "Mammoth" (2006) an alien lifeform assimilates a partially frozen woolly mammoth exposed in a museum. The mammoth-alien-zombie goes on a rampage - killing people by adsorbing their life energy... until stopped by the Men in Black...



Bibliography:

JOHNSON, S.S. et al. (2007): Ancient bacteria show evidence of DNA repair. PNAS Vol. 104 (36): 14401-14405
ROTHSCHILD, B.M. & LAUB, R. (2006): Hyperdisease in the late Pleistocene: validation of an early 20th century hypothesis. Naturwissenschaften 93:557-564
WYATT, K.B.; CAMPOS, P.F.; GILBERT, M.T.P.; KOLOKOTRONIS, S.-O.; HYNES, W.H., et al. (2008): Historical Mammal Extinction on Christmas Island (Indian Ocean) Correlates with Introduced Infectious Disease. PLoS ONE 3(11): 1-9

November 17, 1918: The Ghost of Slumber Mountain

"The Ghost of Slumber Mountain" is an 11 minutes long movie written and directed by special effects pioneer Willis O´Brien and released November 17, 1918. It features the - at the time - pioneering technology of "stop motion animation" with five models of dinosaurs and prehistoric beasts. The main scene of this movie is also one of the most classic images of monster movies - a fierce battle between Triceratops and Tyrannosaurus. Unfortunately the producer Herbert M. Dawley, decided to re-cut the original movie from 30 minutes to less than 11 minutes, most of this material is today lost (however there exists a restored version with 19 minutes). Parts of the footage were reused in the movies "Along the Moonbeam Trail" (1920, a movie were dinosaurs live on the moon) and the documentary "Mystery of Life" (1931).

Invasion of the European Dinosaurs!! Part I: ca. 1800-1900

Fig.1. Archaeopteryx  


The fossil gallery at the recent Munich Show 2011 was dedicated to the "European Dinosaurs" - a good overview of some of the historic fossils (with the classics from Victorian Britain and Germany), but also special apparitions of the newest discoveries from the Mesozoic of the European continent.

Dinosaurs have a long tradition in Europe - the first (as such) recognized "terrible lizards" came from England: it was in 1824 that there Reverend William Buckland described the lower jaw of Megalosaurus

Fig.2. The jaw of Megalosaurus as published in Buckland´s "Notice on the Megalosaurus or great Fossil Lizard of Stonesfield" (1824).

Fig.3. Isolated tooth, Megalosaurus bucklandi, from the Jurassic Stonesfield-Formation (Oxfordshire), found previously of 1882.

But already in 1677 the English historian Robert Plot (1640-1696) describes in his "The natural history of Oxfordshire" a gigantic bone (today lost), found presumably in a quarry at Chipping Norton (also Oxfordshire), as the bone of an elephant of Roman age.
It seems plausible that in the next centuries ulterior bones were discovered, however only with the advent of comparative anatomy (promoted by the French naturalist Georges Cuvier) it became clear what these bones could be - the remains of large reptiles, however quite different to all living animals. After the description of Megalosaurus soon followed Iguanodon (1825), Hyaeosaurus (1833), Thecodontosaurus (1836) and Cetiosaurus (1836).
The first non-british dinosaur came from the Triassic sediments of Southern Germany, described by the German palaeontologist Hermann von Meyer as Plateosaurus in 1837. 

 Fig.5. Plateosaurus.

Streptospondylus and Poekilopleuron were described in 1832 and respectively in 1838 from Jurassic sediments in France. Archaeopteryx was first described (again by von Meyer) in 1861 based on a single feather, only later an almost complete specimen started an intense debate about the evolutionary connection between dinosaurs and birds. In the same year a distant cousin of Archaeopteryx was described by Andreas Wagner as a sort of very strange lizard: Compsognathus longipes.

Fig.6. The first fossil of Compsognathus, discovered in 1858 by physicist and fossil collector Joseph Oberndorfer.

The British anatomist Thomas Henry Huxley recognized it as example of one of the first complete dinosaurs and based his very cautionary and speculative hypothesis of a possible "relationship" between reptiles and birds on this species. Huxley described in 1868 another small dinosaur species, but this time a herbivore: Hypsilophodon.
In February 1878 miners discovered a bone bed of Iguanodon, the almost complete skeletons enabled palaeontologist Louis Dollo (1857-1931) to reconstruct a large, biped and herbivorous animal

Fig.7. Hypsilophodon foxii, Wealden (Lower Cretaceous), collected previously 1882.

Bibliography:

RAUHUT, O.W.M. (2011): Kontinent der Dinosaurier - Europa. Mineralientage München - Messekatalog: 132-146

Collapse !

"Anyone who thinks that exponential growth can go on forever in a finite world is either a madman or an economist."
Kenneth E. Boulding (1910-1993), American economist

The plot of the movie "Rapa Nui" (1994) is based loosely on native legends and the hypothetical collapse of environment and society on the remote island of Easter Island. This scenario is based primarily on the discovery during an archaeology expedition prior to 1961 of unknown palm-like pollen in sediments of swamps and lakes of the island - which today lacks completely native shrubs and trees.
The movie does compress more than 1.000 years of history in just one and a half hour, presenting a fast and sudden collapse of a highly developed society.