Table of contents


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Editorial

The Law of the Sea p153

doi:10.1038/ngeo464

In 2008 ocean iron fertilization was regulated under two sets of international legislation. However, unclear definitions have led to the suspension of legitimate research.


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Correspondence

Near-real-time aftershock hazard maps pp154 - 155

John McCloskey & Suleyman S. Nalbant

doi:10.1038/ngeo449


Open access? p155

Peter Suber

doi:10.1038/ngeo450


Open access? p155

Global Earthquake Model founders

doi:10.1038/ngeo466


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Feature

Kick-starting ancient warming pp156 - 159

E. G. Nisbet, S. M. Jones, J. Maclennan, G. Eagles, J. Moed, N. Warwick, S. Bekki, P. Braesicke, J. A. Pyle & C. M. R. Fowler

doi:10.1038/ngeo454

Rapid global warming marked the boundary between the Palaeocene and Eocene periods 55.6 million years ago, but how the temperature rise was initiated remains elusive. A catastrophic release of greenhouse gases from the Kilda basin could have served as a trigger.


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Books and Arts

A marine voyage of discovery p160

Leslie R. Sautter reviews Chasing Science at Sea by Ellen Prager

doi:10.1038/ngeo453


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Research Highlights


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News and Views

Climate science: Patchy peat pp163 - 164

Torben R. Christensen

doi:10.1038/ngeo455

Nutrient-rich tropical and agricultural soils release vast quantities of the highly potent greenhouse gas nitrous oxide. New measurements show that vegetation-free patches of tundra in subarctic Europe can also emit large quantities of this gas.

Subject Category: Climate science

See also: Letter by Repo et al.


Carbon capture: Made to measure p164

Anna Armstrong

doi:10.1038/ngeo461


Hydrology: Forming valleys from below pp165 - 166

Alan D. Howard

doi:10.1038/ngeo447

Surface water is known to shape the formation and growth of valleys and channels. However, in some geologic settings, groundwater seeping upwards is important for the development of channel networks.

Subject Category: Hydrology, hydrogeology and limnology

See also: Letter by Abrams et al.


Geomorphology: Crater or not? p166

Ninad Bondre

doi:10.1038/ngeo452


Atmospheric science: Smoke above clouds pp167 - 168

Lorraine A. Remer

doi:10.1038/ngeo456

Aerosols in the atmosphere alter the radiative balance of the Earth by reflecting or absorbing solar radiation. Space-borne measurements of clouds and aerosols advected over the southeastern Atlantic Ocean indicate that the greater the cloud cover below the aerosols, the more likely the aerosols are to heat the planet.

Subject Category: Atmospheric science

See also: Letter by Chand et al.


Mantle mineralogy: Deep heat p168

Ninad Bondre

doi:10.1038/ngeo451


Planetary science: Ancient equatorial ice on Mars? pp169 - 170

Brian Hynek

doi:10.1038/ngeo448

NASA's Opportunity rover found enigmatic sulphate deposits at Meridiani Planum on Mars. A proposal that the deposits are sublimation leftovers of large ice-fields, similar in scale to those at the present-day polar caps, adds to the existing hypotheses.

Subject Category: Planetary science

See also: Article by Niles & Michalski


Palaeoclimate: Atmospheric carbon footprints? pp170 - 172

Edward J. Brook

doi:10.1038/ngeo446

According to one controversial idea, increases in atmospheric greenhouse-gas concentrations due to human activities can be detected as early as several thousand years ago. Eight years after the publication of this hypothesis, controversy continues.

Subject Category: Palaeoclimate and palaeoceanography


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Progress Article

A heat-induced molecular signature in marine dissolved organic matter pp175 - 179

Thorsten Dittmar & Jiyoung Paeng

doi:10.1038/ngeo440

Marine dissolved organic matter contains roughly as much organic carbon as all living biota on land and in the oceans combined. New techniques in analytical chemistry show that a significant portion of this material has undergone thermal alteration, either on land or in sediments deep below the sea floor.

Subject Categories: Biogeochemistry | Oceanography


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Letters

Satellite-derived direct radiative effect of aerosols dependent on cloud cover pp181 - 184

D. Chand, R. Wood, T. L. Anderson, S. K. Satheesh & R. J. Charlson

doi:10.1038/ngeo437

Aerosols from biomass burning can alter the radiative energy balance of the Earth by reflecting or absorbing solar radiation. Satellite measurements indicate that the amount of energy absorbed by aerosols at the top of the atmosphere increases with underlying cloud coverage.

Subject Categories: Atmospheric science | Climate science

See also: News and Views by Remer


Human amplification of drought-induced biomass burning in Indonesia since 1960 pp185 - 188

Robert D. Field, Guido R. van der Werf & Samuel S. P. Shen

doi:10.1038/ngeo443

Under drought conditions, biomass burning in Indonesia is a disproportionate contributor to the global carbon dioxide emissions from such events. An analysis of Indonesian records of large fires shows that their occurrence is linked to land use and population dynamics, and that the Indian Ocean climate and El Niño both have an equally important influence.

Subject Categories: Climate science | Ecology | Hydrology, hydrogeology and limnology

See also: related Backstory


Large N2O emissions from cryoturbated peat soil in tundra pp189 - 192

Maija E. Repo, Sanna Susiluoto, Saara E. Lind, Simo Jokinen, Vladimir Elsakov, Christina Biasi, Tarmo Virtanen & Pertti J. Martikainen

doi:10.1038/ngeo434

Nitrous oxide is a potent greenhouse gas whose concentration is increasing in the atmosphere; the highest emissions have been observed from agricultural and tropical soils. Now, measurements in subarctic East European tundra show that bare surfaces on permafrost peatlands, known as peat circles, release large quantities of nitrous oxide.

Subject Categories: Biogeochemistry | Climate science

See also: News and Views by Christensen


Growth laws for channel networks incised by groundwater flow pp193 - 196

Daniel M. Abrams, Alexander E. Lobkovsky, Alexander P. Petroff, Kyle M. Straub, Brandon McElroy, David C. Mohrig, Arshad Kudrolli & Daniel H. Rothman

doi:10.1038/ngeo432

Groundwater seepage is expected to affect channel features, but its role remains controversial. Two linear response relationships that describe channel evolution from groundwater flux are sufficient to characterize seepage-driven channel networks, linking the dynamics of channel growth to channel morphology.

Subject Category: Hydrology, hydrogeology and limnology

See also: related Backstory | News and Views by Howard


Preservation of iron(II) by carbon-rich matrices in a hydrothermal plume pp197 - 201

Brandy M. Toner, Sirine C. Fakra, Steven J. Manganini, Cara M. Santelli, Matthew A. Marcus, James W. Moffett, Olivier Rouxel, Christopher R. German & Katrina J. Edwards

doi:10.1038/ngeo433

Hydrothermal vents release significant quantities of dissolved iron into the oceans. Spectromicroscopic examination of a hydrothermal plume suggests that carbon-rich matrices protect this iron from oxidation and precipitation.

Subject Category: Biogeochemistry


Rapid oceanic and atmospheric changes during the Younger Dryas cold period pp202 - 205

Jostein Bakke, Øyvind Lie, Einar Heegaard, Trond Dokken, Gerald H. Haug, Hilary H. Birks, Peter Dulski & Trygve Nilsen

doi:10.1038/ngeo439

The Younger Dryas event was a brief return to cold conditions before the onset of interglacial warmth. An analysis of sediment records from Lake Kråkenes in Norway and the Nordic Seas shows that during the late Younger Dryas, Northern Europe underwent rapidly oscillating climate conditions, possibly related to the break-up of Nordic sea-ice.

Subject Category: Palaeoclimate and palaeoceanography


Glacial terminations as southern warmings without northern control pp206 - 209

E. W. Wolff, H. Fischer & R. Röthlisberger

doi:10.1038/ngeo442

The timing and mechanisms of the transition from a glacial to an interglacial state are controversial. An analysis of Antarctic ice-core records indicates that glacial terminations may begin as millennial-scale warmings in the southern hemisphere that, unlike previous events, are not reversed by abrupt warming in the northern hemisphere.

Subject Category: Palaeoclimate and palaeoceanography


Orbitally driven east–west antiphasing of South American precipitation pp210 - 214

Francisco W. Cruz, Mathias Vuille, Stephen J. Burns, Xianfeng Wang, Hai Cheng, Martin Werner, R. Lawrence Edwards, Ivo Karmann, Augusto S. Auler & Hanh Nguyen

doi:10.1038/ngeo444

The variations of tropical precipitation are antiphased between the hemispheres on orbital timescales. A comparison between a speleothem record of precipitation in northeast Brazil and rainfall reconstructions from the rest of tropical South America shows that a similar antiphasing operated in the same hemisphere during the Holocene.

Subject Category: Palaeoclimate and palaeoceanography


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Articles

Meridiani Planum sediments on Mars formed through weathering in massive ice deposits pp215 - 220

Paul B. Niles & Joseph Michalski

doi:10.1038/ngeo438

Although a number of hypotheses have been put forward to explain the sulphate deposits discovered by the Opportunity rover at Meridiani Planum, Mars, the sedimentary layers remain enigmatic. A re-analysis of the chemistry, sedimentology and geology of the deposits suggests they formed through a reworking of the sublimation residue from a large-scale deposit of ice and dust.

Subject Category: Planetary science

See also: related Backstory | News and Views by Hynek


Microbial dissolution of clay minerals as a source of iron and silica in marine sediments

John S. Vorhies & Robert R. Gaines

doi:10.1038/ngeo441

Interactions between microbes and minerals are evident in modern global elemental cycles. Relationships between minerals in Cambrian mudstones indicate that such interactions may have released otherwise unavailable, mineral-bound iron and silica into the ancient oceans.


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Erratum

Mercury methylation made easy p172

Richard Sparling

doi:10.1038/ngeo445


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Backstory

Seeing through the smoke p228

doi:10.1038/ngeo459

Robert Field and colleagues turned their attention to the newspapers and used the simplest of weather observations to better understand the climatological and human causes of Indonesia's fire problem.

See also: Letter by Field et al.


Mission Mars pE3

doi:10.1038/ngeo457

Robin Fergason and colleagues sent a rover to Meridiani Planum to better understand the history of the red planet.

See also: Article by Niles & Michalski


Unearthing the flow pE4

doi:10.1038/ngeo458

Daniel Rothman and colleagues imaged underground water and made friends with a hatchet-wielding prisoner during their attempt to understand the mechanics of stream development.

See also: Letter by Abrams et al.


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