Dust inputs affect ocean CDR
Tom Goreau
- Review Article
- Published: 11 November 2025
Global dust impacts on biogeochemical cycles and climate
- Jinbo Zan,
- Barbara A. Maher,
- Xiaomin Fang,
- Thomas Stevens,
- Wenxiao Ning,
- Fuli Wu,
- Yibo Yang,
- Jian Kang &
- Zhe Hu
Nature Reviews Earth & Environment volume 6, pages789–807 (2025)
Abstract
Windblown mineral dust is a nutrient source to the ocean, influencing global ocean productivity, ocean carbon uptake and climate. In this Review, we examine how dust emission fluxes, sources and compositions have changed over the past 7 Myr and consider the implications for ocean productivity. Since the Late Cenozoic, global cooling and orogenic uplift have enhanced dust emissions from major source regions and fluxes to downwind ocean basins, with the associated nutrient supply varying with dust origin. Glacially derived Asian dust contains higher concentrations of ferrous iron (typically exceeding 30% of the total iron) and phosphorus than the aged, highly oxidized mineral dust from North Africa, which has negligible ferrous iron content. Indeed, Asian dust has a notable influence on Pacific Ocean productivity and, potentially, climate. For example, Middle Pleistocene increases in the content of Asian dust Fe2+ (~45%) and P (~55%) coincided with a threefold to fivefold rise in glacial productivity in the South China Sea and a concurrent shift in phytoplankton ecology in the lower-latitude North Pacific. Therefore, decreasing glaciogenic dust–nutrient supply under continued global warming could notably impact ocean productivity, especially in the Pacific Ocean. Future research should focus on constraining the composition and bioavailability of dust-derived nutrients across a wide range of globally important dust sources so that dust composition and related feedbacks can be better parameterized in Earth system models.
Tom Goreau
The abstract says that most Sahara dust iron is highly oxidized and low in P.
Actually Sahara dust is an extremely important source of trans-Atlantic phosphorus delivery, whose ecological impact stimulating tree growth has been measured in Brazil and Panama.
However almost all the P comes from a single source, a dry lake bed in Northern Chad being eroded by winds.
I spent some time in the northern Senegal Sahel with cattle herders, bathing in Sahara dust. The soil is full of iron concretions. To my surprise, the soil was extremely fertile and the natural, crop, and ornamental plants showed NO obvious plant nutrient deficiencies, as long as they had enough water (which seemed the major growth limiting factor, not soil fertility itself)!
The women complained that in the rainy season the children constantly were sick with malaria. Unfortunately I did not then have your Chinese Artemisia seeds to give them!
From:
Michael Pilarski <friendso...@yahoo.com>
Date: Tuesday, December 9, 2025 at 00:09
To: Carbon Dioxide Removal <carbondiox...@googlegroups.com>, Tom Goreau <gor...@globalcoral.org>
Cc: 'Michael MacCracken' via Healthy Planet Action Coalition (HPAC) <healthy-planet-...@googlegroups.com>, EcoRestoration Alliance <ecorestorat...@googlegroups.com>
Subject: Re: [ERA] Dust inputs affect ocean CDR
When I think of dust fertillzing oceans I think of the red dust clouds coming off of North Africa and blowing over the Atlantic to the Caribbean and Amazon
I find it very interesting that the authors cite "the aged, highly oxidized mineral dust from North Africa, which has negligible ferrous iron content." While the Asian glacially derived mineral dust has relatively high iron and phosphorus
John Hamacker always emphacized that glacial periods ground up huge amounts or rock and subsequently the dust was blown around the planet to fertilizer/remineralize the whole planet.
Hence we now have the movements to remineralize our soils with rock dusts and the oceans with iron rich dust.
These will be topics at the Global Earth Repair Convergence.
Michael "Skeeter" Pilarski
Earth Repair - Permaculture - Agroforestry - Wildcrafting - Medicinal Herbs
PO Box 1133
Port Hadlock, WA 98339
# (360)-643-9178
I acknowledge that I live on the stolen lands of the Chemacum, S'Klallam and Klallam Peoples.
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Bhaskar M V
Tom Goreau
The dry lake bed I’m referring to is in the Bodele depression in the northern desert areas of Chad.
Lake Chad is on the wetter southern border of Chad, and has been drying out for thousands of years, but many other lakes in the Sahara and Sahel have dried up completely, leaving nutrient rich salt flat muds that are easily wind eroded.
It’s so rich in phosphorus as to be a measurable trans-Atlsntic wind-blown dust nutrient source.
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Bhaskar M V
Tom Goreau
They may once have been connected but the Bodele depression is a lot lower than Lake Chad, but dried out first after they were separated.
Bhaskar M V
| Age | Few thousand years |
|---|---|
| Formed by | Drying up of Lake Chad |
As the Sahara dried out over the last few thousand years, Mega-Lake Chad receded to the current position of Lake Chad in the south-west corner of Chad. As the waters receded, the silts and sediments resting on the lakebed, which included fossilized diatoms, were left to dry in the scorching sun, forming a layer of fine dust. These small grains of sediment are swept up by the strong wind gusts that occasionally blow over the region. Once heaved aloft, the Bodélé dust can be carried for hundreds or even thousands of kilometers.[5] In winter, the depression produces an average of 700,000 tonnes of dust each day (Todd et al., 2007).[7]
Tom Goreau
These dust blown fossil diatoms will be important to provide silica for diatoms in the Atlantic Equatorial Upwelling zone, stimulating organic carbon sedimentation.