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John J. Cullen

@johncullenocean.bsky.social

4.1K followers 57 following 24 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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John J. Cullen @johncullenocean.bsky.social · 30/05/2025

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? 🌊

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?

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John J. Cullen @johncullenocean.bsky.social · 28/12/2024

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.

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John J. Cullen @johncullenocean.bsky.social · 12/01/2024

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.)

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