2013/08/20 New Papers (AGU)

♣Global Biogeochemical Cycles♣

1. Localized refractory dissolved organic carbon sinks in the deep ocean

Dennis A. Hansell and Craig A. Carlson

Article first published online: 12 AUG 2013 | DOI: 10.1002/gbc.20067

Key Points

•    Refractory DOC conserved over great distances in the deep Pacific Ocean

•    Nonconservative behavior when mixed into localized deep ocean systems

Deep DOC gradients due to mixing between the conserved and nonconserved systems

2. A joint atmosphere-ocean inversion for the estimation of seasonal carbon sources and sinks

K. Steinkamp and N. Gruber

Article first published online: 18 AUG 2013 | DOI: 10.1002/gbc.20064

Key Points

•    Each data constraint has a significant influence on the inverse flux estimates

•    Conclusions drawn from different constraints disagree in some regions

The Amazonian biosphere is estimated to release 0.6 PgC each year

3.Regional variation in the particulate organic carbon to nitrogen ratio in the surface ocean

A. C. Martiny, Jasper A. Vrugt, Francois W. Primeau and Michael W. Lomas

Article first published online: 18 AUG 2013 | DOI: 10.1002/gbc.20061Environmental

Key Points

•    The median upper ocean particulate C:N ratio is broadly constrained at 6.5.

•    The C:N ratio is 7.1 in low compared to 6.2 in high nutrient regions

The C:N ratios in picophytoplankton are greater than global mean

4. Estimation of atmospheric nutrient inputs to the Atlantic Ocean from 50°N to 50°S based on large-scale field sampling: Iron and other dust-associated elements

A. R. Baker, C. Adams, T. G. Bell, T. D. Jickells and L. Ganzeveld

Article first published online: 18 AUG 2013 | DOI: 10.1002/gbc.20062

Key Points

•    3-monthly total Fe inputs for the Atlantic are in general agreement with models

•    Broad-scale Fe solubility appears to be higher than those derived from models

Input from wet deposition varies significantly according to rainfall rate

5. A modeling assessment of the role of reversible scavenging in controlling oceanic dissolved Cu and Zn distributions

S. H. Little, D. Vance, M. Siddall and E. Gasson

Article first published online: 18 AUG 2013 | DOI: 10.1002/gbc.20073

Key Points

•    A 1-D reversible scavenging model is applied to oceanic [Cu] and [Zn]

•    Dissolved Cu is well described by the process of reversible scavenging

•    Dissolved Zn is not, reflecting its behaviour as a true nutrient-type element

6. Evidence of active dinitrogen fixation in surface waters of the eastern tropical South Pacific during El Niño and La Niña events and evaluation of its potential nutrient controls

J. Dekaezemacker, S. Bonnet, O. Grosso, T. Moutin, M. Bressac and D.G. Capone

Article first published online: 18 AUG 2013 | DOI: 10.1002/gbc.20063

Key Points

•    High N2 fixation was measured in the OMZ and below the euphotic zone

•    High N2 fixation was measured in water masses with high nitrate concentrations

Fe, DOC, and DIN additions through (in)direct mechanism stimulated N2 fixation

♣Geophysical Research Letters♣

7. Anthropogenic impacts on mass change in North China

Qiuhong Tang, Xuejun Zhang and Yin Tang

Article first published online: 12 AUG 2013 | DOI: 10.1002/grl.50790

Key Points

•    Mass variations in North China were largely affected by human activities

•    Anthropogenic mass redistribution could be comparable to groundwater depletion

GRACE is capable to assess the exploitation of natural resources in North China

8. Advective timescales and pathways of Agulhas leakage

Siren Rühs, Jonathan V. Durgadoo, Erik Behrens and Arne Biastoch

Article first published online: 12 AUG 2013 | DOI: 10.1002/grl.50782

Key Points

•    More than half of Agulhas leakage reaches the Gulf Stream regime

•    Advective timescale of Agulhas leakage into the North Atlantic is one to two decades

Detailed pathways through the tropics require sufficient resolution

9. An evaluation of the potential radiative forcing and climatic impact of marine organic aerosols as heterogeneous ice nuclei

Yuxing Yun and Joyce E. Penner

Article first published online: 12 AUG 2013 | DOI: 10.1002/grl.50794

Key Points

•    Effect of marine organic aerosol (MOA) as ice nuclei evaluated on a global scale

•    MOA could be an important missing ice nuclei source for the SH

MOA has a significant impact on the ice water path and anthropogenic forcing

10. Spatial variations in the composition of turbidites due to hydrodynamic fractionation

David R. Pyles, Kyle M. Straub and Jane G. Stammer

Article first published online: 12 AUG 2013 | DOI: 10.1002/grl.50767

Key Points

•    Turbidity currents fractionate sediment grains by their density and shape

•    This process results in large-scale spatial variations in turbidite composition

Results from this study have implications to practical geophysical problems

♣Paleoceanography♣

11. What caused the long duration of the Paleocene-Eocene Thermal Maximum?

Richard E. Zeebe

Article first published online: 14 AUG 2013 | DOI: 10.1002/palo.20039

Key Points

•    PETM duration of more than 50 kyr is a mystery

•    I present first-principle calculations pointing to slow methane release

Long PETM duration due to hydrate release and temperature-enhanced metabolism

♣Geochemistry, Geophysics, Geosystems♣

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♣Climate of the Past♣

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♣Geological society of America bulletin♣

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