4 ms·

Out of curiosity, what happens when you dump wood in the deep ocean? Does the wood breakdown and does the carbon come back up as CO2 in the atmosphere?

EngManagerIsMe 3y ago
Wood in the ocean will float for a long time, eventually sinking and storing that carbon. It will be broken down over a very long span, and the CO2 will enter the hydrocycle and eventually be released as a gas. Probably on the order of millennia. That said, it's not clear what impact smothering the ocean floor would have in the habitats there, nor how we would get the wood to sink reasonably rapidly and stay sunk -- we don't want massive logs floating back up and hitting ships. I (personally) believe we are better served by heating the wood in an oxygen free environment (pyrolysis). This produces a charcoal like substance and energy, we can bury the biochar or use it as a soil amendment to achieve the same result (hundreds to thousands of years of sequestration) and get energy out of the process.
ccooffee 3y ago
Wood takes a very long time to saturate enough to properly sink. A partially-floating log in the ocean is sometimes called a "deadhead" log (supposedly named because the bobbing motion of the lighter end of the log resembles a human head, but this feels apocryphal). I cannot find reliable sources for how long it takes for a log to fully saturate with seawater before sinking below the surface. Some sailors have reported seeing the "same" deadhead for over a decade. (While the deadhead is still at- or close-to-the-surface, it is a major hazard for boats. Deadheads have been known to punch through boat keels and destroy propellers and other equipment.) After the logs become fully submerged and settle, I do not believe that they decompose rapidly, but (again) cannot find reliable sources. The state of Florida has a licensed program for "Deadhead Logging"[0], but much of the content I've found about that program is specific to river ecosystems, not oceans. A 2020 article entitled "First evidence of microbial wood degradation in the coastal waters of the Antarctic"[1] offers a few nice quotes: > Wood submerged in saline and oxygenated marine waters worldwide is efficiently degraded by crustaceans and molluscs. > Our results establish that there is ongoing wood degradation also in the Antarctic, albeit at a vastly reduced rate compared to warmer environments. Historical shipwrecks resting on the seafloor are most likely still in good condition, although surface details such as wood carvings, tool marks, and paint slowly disintegrate due to microbial decay. [0] https://floridadep.gov/water/submerged-lands-environmental-resources-coordination/content/deadhead-logging https://floridadep.gov/water/submerged-lands-environmental-r... [1] https://www.nature.com/articles/s41598-020-68613-y https://www.nature.com/articles/s41598-020-68613-y

EngManagerIsMe 3y ago

Wood in the ocean will float for a long time, eventually sinking and storing that carbon. It will be broken down over a very long span, and the CO2 will enter the hydrocycle and eventually be released as a gas. Probably on the order of millennia. That said, it's not clear what impact smothering the ocean floor would have in the habitats there, nor how we would get the wood to sink reasonably rapidly and stay sunk -- we don't want massive logs floating back up and hitting ships. I (personally) believe we are better served by heating the wood in an oxygen free environment (pyrolysis). This produces a charcoal like substance and energy, we can bury the biochar or use it as a soil amendment to achieve the same result (hundreds to thousands of years of sequestration) and get energy out of the process.

ccooffee 3y ago

Wood takes a very long time to saturate enough to properly sink. A partially-floating log in the ocean is sometimes called a "deadhead" log (supposedly named because the bobbing motion of the lighter end of the log resembles a human head, but this feels apocryphal). I cannot find reliable sources for how long it takes for a log to fully saturate with seawater before sinking below the surface. Some sailors have reported seeing the "same" deadhead for over a decade. (While the deadhead is still at- or close-to-the-surface, it is a major hazard for boats. Deadheads have been known to punch through boat keels and destroy propellers and other equipment.) After the logs become fully submerged and settle, I do not believe that they decompose rapidly, but (again) cannot find reliable sources. The state of Florida has a licensed program for "Deadhead Logging"[0], but much of the content I've found about that program is specific to river ecosystems, not oceans. A 2020 article entitled "First evidence of microbial wood degradation in the coastal waters of the Antarctic"[1] offers a few nice quotes: > Wood submerged in saline and oxygenated marine waters worldwide is efficiently degraded by crustaceans and molluscs. > Our results establish that there is ongoing wood degradation also in the Antarctic, albeit at a vastly reduced rate compared to warmer environments. Historical shipwrecks resting on the seafloor are most likely still in good condition, although surface details such as wood carvings, tool marks, and paint slowly disintegrate due to microbial decay. [0] https://floridadep.gov/water/submerged-lands-environmental-resources-coordination/content/deadhead-logging https://floridadep.gov/water/submerged-lands-environmental-r... [1] https://www.nature.com/articles/s41598-020-68613-y https://www.nature.com/articles/s41598-020-68613-y