Tag: iron fertilization

Nature – Taqieddin et al. (2024): Electrochemical ocean iron fertilization and alkalinity enhancement approach toward CO2 sequestration

Amir Taqieddin, Stephanie Sarrouf, Muhammad Fahad Ehsan, Ken Buesseler, Akram N. Alshawabkeh IN: npj Ocean Sustainability, https://doi.org/10.1038/s44183-024-00064-8

Herein, a novel self-operating electrochemical technology is presented that not only combines ocean iron fertilization (OIF) and ocean alkalinity enhancement (OAE), but also recovers hydrogen gas (H2) from seawater, hence offering a promising solution for achieving quantifiable and transparent large-scale mCDR. Experimental results show that the electrochemical OIF (EOIF) can not only increase the concentration of ferrous iron (Fe+2) by 0–0.5 mg/L, but also significantly increases the seawater pH by 8% (i.e., a 25% decrease in the hydrogen ions concentration). The release of iron (Fe+2/Fe+3) can be regulated by adjusting the magnitude of the electric current and its form (e.g., pulsed current and polarity reversal), as well as by optimizing the electrode material and geometry.


Bach et al. (2023): Identifying the most (cost-)efficient regions for CO2 removal with iron fertilization in the Southern Ocean

Lennart T. Bach, Veronica Tamsitt, Kimberlee Baldry, Jeffrey McGee, Emmanuel C. Laurenceau-Cornec, Robert F. Strzepek, Yinghuan Xie, Philip W. Boyd IN: Global Biogeochemical Cycles, https://doi.org/10.1029/2023GB007754

Ocean iron fertilization (OIF) aims to remove carbon dioxide (CO2) from the atmosphere by stimulating phytoplankton carbon-fixation and subsequent deep ocean carbon sequestration in iron-limited oceanic regions. Here, the authors utilize five requirements that strongly influence whether OIF can lead to atmospheric CO2 removal (CDR): The requirement (a) to use preformed nutrients from the lower overturning circulation cell; (b) for prevailing iron-limitation; (c) for sufficient underwater light for photosynthesis; (d) for efficient carbon sequestration; (e) for sufficient air-sea CO2 transfer.


Is ocean iron fertilization back from the dead as a CO₂ removal tool?

by Jeremy Hance, Conversation News, November 14, 2023

“In 2009, a controversial scientific experiment dumped 6 metric tons of dissolved iron into the Southern Ocean to see if it would trigger a massive bloom of phytoplankton in iron-deficient waters. In one way, the experiment succeeded: The scientists produced a phytoplankton bloom. However, they didn’t get what they were really after: Proof that such a scheme could lead to large-scale carbon dioxide sequestration. You see, when phytoplankton die, they sometimes sink to the bottom of the sea — a phenomenon known as marine snow — carrying the carbon dioxide they absorbed during photosynthesis with them to be sequestered in the seabed for decades to millennia. In 2009, the vast majority of the experimental bloom was consumed by zooplankton near the surface and failed to reach the ocean floor. Since then, except for an even more controversial attempt by a for-profit company in 2012 in Canadian waters, there have been no large-scale experiments of ocean iron fertilization as a potential tool to counteract climate change.”


Tagliabue et al. (2023): Ocean iron fertilization may amplify climate change pressures on marine animal biomass for limited climate benefit

Alessandro Tagliabue, Benjamin S. Twining, Nicolas Barrier, Olivier Maury, Manon Berger, Laurent Bopp IN: Global Change Biology, https://doi.org/10.1111/gcb.16854

Previous OIF (ocean iron fertilization) modelling has found that while carbon export increases, nutrient transport to lower latitude ecosystems declines, resulting in a modest impact on atmospheric CO2. Here, the authors combine global ocean biogeochemistry and ecosystem models to show that, while stimulating carbon sequestration, OIF (may amplify climate-induced declines in tropical ocean productivity and ecosystem biomass under a high-emission scenario, with very limited potential atmospheric CO2 drawdown.


Rohling (2023): Marine methods for carbon dioxide removal: fundamentals and myth-busting for the wider community

Eelco J Rohling IN: Oxford Open Climate Change, kgad004, https://doi.org/10.1093/oxfclm/kgad004

This review outlines the basic operation of the marine carbon cycle in straightforward terms, with some simplifications, to help advance the debate among the wider community. Break-out boxes provide additional detail where desired, and references (and the sources cited therein) provide avenues for further study. The review then discusses two potential marine methods for atmospheric carbon removal that are thought to offer the greatest potential in terms of carbon removal mass: ocean iron fertilization and ocean alkalinity enhancement.


Financial times – Ocean fertilisation revived as climate change alarm grows

Clive Cookson on ft.com

“…This renewed interest has also given a new lease of life to ocean-based methods of carbon dioxide removal (CDR). While fertilisation to stimulate the growth of green phytoplankton (microscopic algae), which absorb CO₂ in nutrient-poor waters, will be used in the Alaska and New England projects, there are other methods. One is to counter the growing acidity of seawater as it absorbs CO₂ by adding alkaline minerals, enhancing its absorptive capacity.”


Yuan, Peng; Liu, Dong (2021): Proposing a potential strategy concerning Mineral-enhanced Biological Pump (MeBP) for improving Ocean Iron Fertilization (OIF)

Yuan, Peng; Liu, Dong (2021): Proposing a potential strategy concerning Mineral-enhanced Biological Pump (MeBP) for improving Ocean Iron Fertilization (OIF). In Applied Clay Science 207, p. 106096. DOI: 10.1016/j.clay.2021.106096.

“To address the low efficiency of the vertical C export of OIF, a potential strategy for enhancing oceanic biological pump using clay minerals, so-called mineral-enhanced biological pump (MeBP), is proposed herein.”


Ming, Tingzhen; et al. (2021): A nature-based negative emissions technology able to remove atmospheric methane and other greenhouse gases

Ming, Tingzhen; Richter, Renaud de; Dietrich Oeste, Franz; Tulip, Robert; Caillol, Sylvain (2021): A nature-based negative emissions technology able to remove atmospheric methane and other greenhouse gases. In Atmospheric Pollution Research. DOI: 10.1016/j.apr.2021.02.017.

“As some anthropogenic emissions cannot be zero, to compensate them it will be necessary to remove GHGs from the atmosphere. Among possible methods, the Iron Salt Aerosol (ISA) offers new possibilities, including removal of methane and several other GHGs, as well as carbon dioxide.”