"Resurrecting a Forest"

Critics have focused on the threats posed by novel life forms released into the environment, but little attention is paid to potential opportunities–to reconstruct extinct species or create customized ecological communities designed to produce ecosystem services. They may change the public perception of what is “natural” and certainly challenge the notion of evolution as a process beyond human construction.

-- from a framing statement for a meeting titled How Will Synthetic Biology and Conservation Shape the Future of Nature?, quoted by Carl Zimmer.

Deep Carbon

Less than 10% of the Earth's carbon is in its atmosphere, seawater and top crusts. The rest is locked away or in motion deep underground - a "hidden dimension of the planet as poorly understood as it is profoundly important to life on the surface."  

Carbon in Earth, a new publication by scientists collaborating on the Deep Carbon Observatory, notes that:

Among the gaps in our knowledge of deep carbon relate to the deep biosphere. Remarkable discoveries of subsurface microbial life and associated viruses hint at a surprising hidden diversity, primarily within the microbial domains of archaea and bacteria. [But] surprising discoveries of a rich subsurface community of eukayotes promises an even richer deep taxonomy. These findings, coupled with advances in single-cell genomics, predict a coming decade of extraordinary discovery.

Trophic cascade

Wiping out top predators like lions, wolves and sharks is tragic, bad for ecosystems – and can make climate change worse. Mass extinctions of the big beasts of the jungles, grasslands and oceans could already be adding to greenhouse gases in the atmosphere.

-- report, original paper.

It looks as if, across a range of terrestrial and marine ecosystems, climates and predators, carbon dioxide emissions typically increased more than tenfold after the predators are removed.

(Photo by Brian Skerry: Gray reef shark at Kingman Reef, where predator populations remain large)

Life in "the world’s largest wetland"

Scientists say they have found bacteria living in the cold and dark deep under half a mile of Antarctic ice, a discovery that might advance knowledge of how life could survive on other planets or moons and that offers the first glimpse of a vast ecosystem of microscopic life in underground lakes in Antarctica.

-- New York Times report

P.S. 8 March Russian scientist claim to have found new kind of bacterial life in Lake Vostok.

The invisible life of the upper troposphere

In a recent article for New Humanist (also here) I mentioned that researchers have suggested that bacteria not only survive in the harsh, beautiful environment of clouds but thrive and reproduce there. My sources were more than four years old. Recent work appears to have amply corroborated the hypothesis, as Ed Yong writes in an excellent piece:

The sky has a microbiome too, and one that may have a critical role in the creation of weather. When water changes from vapour to liquid, it condenses around microscopic particles in the air. When it freezes into ice, the same thing happens. Without these centres, completely pure water would condense and freeze at much lower temperatures than you’d expect. Dust, soot and sea salt can all act as nuclei for water’s transformations, but so can bacteria. For example, some plant-infecting species have proteins on their surfaces that ice can crystallise upon. Just by floating in the air, species like these could kick-start the births of clouds, raindrops and snow.

'The power of plankton'

The more we learn, the more questions we have. Some of the questions are in the realm of basic biology. What evolutionary processes maintained such an extraordinary diversity of microbial species? Have microorganisms that play key biogeochemical roles gone undiscovered?...

...Then there are the practical questions. As humanity pumps nitrogen into the oceans and carbon into the atmosphere, causing dead zones and disrupting the climate, how long can phytoplankton keep cleaning up our mess? Can we enlist phytoplankton genes to make hydrocarbons so we no longer have to drill for oil?...

...Ultimately, the microorganisms in the ocean will survive, as they have for billions of years, and they will help restore Earth to a biogeochemical steady state. If we can understand them better, perhaps we can help them help humanity survive as well.

 --  from an overview by Paul Falkowski of discoveries as to the nature and role of phytoplankton in Earth system.

Falkowski thinks that event in the best case it will take a long time — probably about 1,000 years — for the current damage being caused by humans to be reversed:

The phytoplankton will survive, but humans are going to pay the price. I find it very discouraging that a large segment of US society is not accepting conclusions that are based on objective science. It's distressing because everybody seems to be their own climate expert. I don't think humans realize that we're a vulnerable species.

'The only exuberant thing in this part of the cosmos'

Earth has not always looked like this. Suppose you can rewind time, slowly at first—you see the field of lights on the night side of Earth extinguished, these having been lit by industrially inclined humans only in the last few decades. Rewind at a million years a minute, and you can watch ice sheets regularly advancing and retreating across the Northern Hemisphere, every six seconds or so, roughly at the rate that you breathe. Accelerate the rewind to a hundred million years a minute, and you can review the whole history of the planet in three quarters of an hour.

The first thing you’ll notice at this speed is the continents skating over the surface. South America and Australia are moving south and join with Antarctica after twenty seconds, and suddenly Antarctica loses its ice sheet and turns green. North America sails back towards Europe, South America towards Africa, and the Atlantic closes up in less than a minute. The continents assemble into the supercontinent Pangaea after two minutes. As you continue into the past, you’d see the white flash of an occasional ice cap, but it’s the exception. Usually there is no ice on the planet at all. That is, until something strange happens about six minutes into the rewind. In the blink of an eye, the entire sphere is suddenly encased in white ice, and stays that way for a full ten seconds. It clears to blue again, then another ten seconds or so later repeats the cycle. You’ve just witnessed two episodes of ‘Snowball Earth’ and fast rewound through one of the revolutions on which we want to focus...

-- from the introduction to Revolutions that Made the Earth by Tim Lenton and Andrew Watson.

(The title of this post is a quote from Lewis Thomas)

Gaia's body

A newish detail from the deep:

huge currents hundreds of kilometres wide... picks up material from the vents and transports it long distances. In this way, large swaths of the ocean that would otherwise be bereft of life-giving nutrients - like those emanating from this black-smoker chimney - get fertilised.

-- report, paper

Deep history of life, and its future

Yesterday I listened to talks at the Geological Society by Lynn Margulis and Martin Brasier under the joint title Deep History of Life on Earth. Among take-home points, Margulis outlined what she described as five extensions of Gaia theory as of 2009:

1. Redistribution of elements

2. Salt: redistribution and retardation of its dissolution

3. Augmentation of solid, liquid and gas interfaces

4. Water retention and distribution on a planetary scale

5. Production of granite (a mineral found nowhere else in the solar system, comprising 0.4% of the Earth lithosphere) [1]

I asked Prof. Margulis if she had anything to say about Peter Ward's Medea hypothesis. She did not. Crispin Tickell, chairing, said it did not, in fact, contradict Gaia. [2]

Martin Brasier outlined key points from his book Darwin's Lost World, including the idea that the development of an anus (a through-gut and the capacity to digest in new ways) was a fundamental (my bad pun, not his) innovation enabling the Cambrian explosion.

He said his hunch was that the perturbations in the Earth system consequent upon human activities were so great that 'we could be on the cusp of a Cambrian-like transformation' of life on Earth (bigger than, say, the K-T) though whether it would be a 'new Cambrian explosion' or a 'return pre-Cambrian conditions' he was not, when I asked him, inclined to speculate.

Where the dust blows through these heights there once shone a silent sea. [3]

Footnotes

[1] Margulis spells out these questions and others more fully in a contribution to Scientists on Gaia (2004). See comment attached at the foot of this post.

[2] It seems to me, though, that there may be something to be said for Tyler Volk's view that 'Gaia is life in a wasteworld of byproducts' (dubbed 'Garbage Can Gaia' by Ward), and Prof. Basier hinted as much.

[3] The image is Suilven, an inselberg of Torridonian sandstone on top of Lewisian gneiss. The quote is from Cold Mountain. Brasier imagines Charles Lyell sketching three riddles after a walking on Quinag:

1. A mountain that stood on its head.
2. An ocean that disappeared.
3. A rock that swallowed time.

P.S. 8 July: The continents 'were green' in the Neoproterozoic, according to a Letter to Nature from L. Paul Knauth & Martin J. Kennedy. See also Dawn of the animals: Solving Darwin's dilemma.

The longer now

Over the next hundreds of millions of years the sun will continue to get brighter until eventually Earth becomes too hot to inhabit. Previous calculations had pegged that time at about a billion years from now, but the new paper argues that earlier models had neglected the role of atmospheric pressure in regulating the temperature of the planet on astronomical time scales.

Atmospheric pressure is a key variable in the overall greenhouse-gas effect because it determines how much infrared radiation greenhouse gases absorb. Higher pressures mean more absorption and consequently, more heat. Lower pressures have the opposite effect.

Life itself would be the mechanism for these temperature changes. By “fixing” nitrogen, pulling it out of the air and eventually into the Earth’s deep ocean, microbes could be making the atmosphere lighter one atom at a time.

-- Earth 'Gets Billion-Year Life Extension'.

It sounds as if the modeling is inconclusive at this stage. [1]

The claim is that, other things being equal, life-on-Earth will extinguish no more than two billion years from now. [2] Earth-without-life may not, however, vaporise until about 7.6 billion years from now.


Footnote

[1] (added 17 June) see Heavy Weather by Oliver Morton

[2] There are other scenarios. For an overview see How will the Biosphere End? in Big Questions Questions in Ecology and Evolution by Thomas Sherratt and David Wilkinson. There is said to be a 50% chance of a collision with the asteroid Eros in the next 100 million years. This would not produce enough energy to vaporise the oceans but it would release an order of magnitude more energy than the impact thought to have ended the Cretaceous. Not necessarily an end to all life, but perhaps an end to the multicellular kind.

Images: Home, Yann Arthus-Bertrand

Is it alive?

Nick Carr comments on a proposal for "whole brain emulation" that imagines a software model "so faithful to the original that, when run on appropriate hardware, it will behave in essentially the same way as the original brain." (Hat tip AS)

Carr is sceptical that the modeling could ever truly mirror humanity in part because it does not take account of "free will". I don't want to comment on that here, but the debate puts me in mind of another, possibly related issue: the (alleged) failure of global earth system modeling to adequately reflect the role played by complex adaptive living systems.

P.S. On brain simulations, it is claimed that at least one has already been done -- for half a mouse in 2007 (Towards Real-Time, Mouse-Scale Cortical Simulations by James Frye, Rajagopal Ananthanarayanan, and Dharmendra S Modha)

P.S. 21 Nov: IBM to build brain-like computers