Iron in the Greenland ice core relative to Asian loess records over the past 110,000 years


Share post:

To testify the “iron hypothesis” in the North Greenland Eemian Ice Drilling (NEEM) ice core, Cunde Xiao and his colleagues firstly reconstructed the bioavailable Fe data in this deep ice core from the northern Hemisphere over the past 110 kyr B.P., which suggested that the dissolved Fe (DFe) records in NEEM ice core were significantly anti-correlated with the carbon oxide (CO2) concentrations during the cold periods. The pattern of Fe concentration was extremely similar to that of the number of dust particles. The results also emphasized that the changes of Fe fertilization effect could not be explained by a simple linear relationship with the glacial-interglacial changes in the CO2 concentration in the atmosphere.

Iron in the Greenland ice core relative to Asian loess records over the past 110,000 years
The δ18O (A), CO2 concentration (B), dust particle (C) and DFe (D) concentrations over the past 110 kyr B.P..
The red stars represent the ice samples for this study. The data of δ18O, dust particle and DFe
from NEEM ice core, CO2 data from Antarctic EDC ice core [Credit: Science China Press]

This study focused on the linkages between NEEM ice core and Chinese loess record over the past 110 kyr B.P. The changes of Fe fluxes in the NEEM ice core were in phase with that archived in Chinese loess, where the mineral dust distribution was controlled by the vast Asian deserts and large-scale wind pattern. They suggest that the dust input on a hemispheric scale were most likely driven by the changes in solar radiation during the last glacial-interglacial cycle, as a response to Earth’s orbital changes.

In the last glacial-interglacial cycle, the ratios between dissolved Fe and total dissolved Fe (DFe/TDFe) were higher during the warm periods (i.e., post-Industrial Revolution, the Holocene and the Last Interglacial period) than during the main cold period (i.e. the Last Glacial Maximum), indicating that the Fe fertilization effect was more complex during the Holocene, due to the presence of different composition of dust associated, with various grain sizes and other factors.

Although the burning of biomass has released large amounts of Fe-contained aerosols since the Industrial era, no significant responses were observed in Fe variations during the same time period.

The study is published in National Science Review.

Source: Science China Press [July 03, 2020]



Related articles

Accurate estimation of biodiversity is now possible on a global scale

We know remarkably little about the diversity of life on Earth, which makes it hard to know with...

Rewilding landscapes can help to solve more than one problem

Urbanisation, biodiversity loss, climate change: just some of the worldwide problems 'rewilding' - i.e. restoring food chains by...

Fueling a deep-sea ecosystem

Miles beneath the ocean's surface in the dark abyss, vast communities of subseafloor microbes at deep-sea hot springs...

Study links Arctic sea-ice dynamics to mercury and ozone depletion events

This week a new study published in Nature and co-authored by Drs. Chris Moore and Daniel Obrist of...

Hidden river once flowed beneath Antarctic ice

Antarctic researchers from Rice University have discovered one of nature's supreme ironies: On Earth's driest, coldest continent, where...

In the ocean’s twilight zone, tiny organisms may have giant effect on Earth’s carbon cycle

Deep in the ocean's twilight zone, swarms of ravenous single-celled organisms may be altering Earth's carbon cycle in...

Salt seeds clouds in the Amazon Rainforest

It’s morning, deep in the Amazon jungle. In the still air innumerable leaves glisten with moisture, and fog...

Study provides more solid measure of shrinking in polar ice sheets

The planet's two largest ice sheets have been losing ice faster during the past decade, causing widespread confusion...