John J. Cullen
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johncullenocean.bsky.social
John J. Cullen
@johncullenocean.bsky.social
4K followers 48 following 20 posts
Professor Emeritus in Oceanography, Dalhousie University. 🇨🇦🧪🌊 I've spent a long time trying to understand and explain how the ocean works.
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johncullenocean.bsky.social
The arguments about uncertain global effects and limited efficacy have been supported by others for years.

One more thing: if harmful blooms or hypoxic fish kills happen anywhere that is influenced by OIF, legal fingers will point, deservedly or not.

Who will underwrite liability insurance?
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Slide illustrating a fish kill off Oregon in 2002. It had nothing to do with OIF. Sinking carbon from ocean fertilization decomposes at depth, reducing concentrations of oxygen. (Picture of fish kill) If a hypoxic event like this happens again, who or what is to blame? Can it be proved?
May 30, 2025 at 5:00 PM
johncullenocean.bsky.social
Mary Somerville was born on 26 December 1780. Among her many accomplishments, she described foundational principles of ocean optics – including the influence of phytoplankton on ocean color. The 20th century pioneers of ocean-color remote sensing were unaware. She was far ahead of her time. 🌊🧪
Portrait of Mary Somerville with list of some accomplishments and picture of 10-pound note Quotes from her 1848 "Physical Geography" on the colour of sea water.
December 28, 2024 at 4:19 PM
johncullenocean.bsky.social
Frenger et al. (doi/10.1111/gcb.17124) remind us that export flux of organic C by the biological pump cannot be equated to the flux of atmospheric CO2 to the ocean. We must account for upward transport of DIC, including DIC:N:P in vertically transported nutrients. Read quote from classic 1979 paper.
From Eppley and Peterson, 1979 (Nature 282: 677-680): "To what extent does the sinking flux of particulate organic carbon constitutes a 'sink' for atmospheric CO 2 from fossil fuel burning? Since dissolved inorganic carbon moves upward along with the vertically transported nitrate, in approximately the Redfield ratio of 106 C atoms: 16 N atoms, only the sinking flux due to new production associated with nitrogen fixation and nutrient inputs from terrestrial and atmospheric sources can be identified as a biologically-mediated transport of atmospheric carbon dioxide to the deep ocean." (Read the whole paper for context.)
January 12, 2024 at 7:43 PM