Canfield ocean

From Wikipedia, the free encyclopedia
Jump to: navigation, search

The Canfield Ocean model refers to the Ocean composition theorized by geologist Donald Canfield. In a seminal paper in Nature in 1998, Canfield argued that the Ocean had become partially anoxic and sulfidic, causing mass extinction.[1][2]

Peter Ward studies the effects of ocean hypoxia(anoxic) and sulfidic oceans and climate change. He found warming of the ocean caused by a rise of carbon dioxide levels to about 1000 parts per million as a trigger for mass extinction.[3]

The term Strangelove ocean is a model name coined by a study published in 1985, which found a decrease in the δ13 C values of planktic skeletons following the Cretaceous–Paleogene extinction event, causing a homogenous ocean in decades or centuries, visible in the boundary sediment layer as a manifestation of the elimination in the surface-to-bottom carbon isotope gradient in ocean waters, the halt of ocean primary production. During a time when carbon fractionation by a photosynthesis-respiration mechanism became ineffective.[4] It was later shown that the burial rate of terrestrial organic carbon (biological pump) was likely unaffected.[5]

Definition[edit]

Euxinic Ocean conditions, a term describing restricted hydrologic circulation, leading to stagnant or anaerobic conditions, are the likely factor leading to sulfidic Oceans.[1] Euxinic describes anoxic conditions in the presence of H
2
S
hydrogen sulfide.[6]

See also[edit]

Further reading[edit]

Ward, Peter D. "Impact from the Deep". Scientific American 2006 (October): 64–71. 

External links[edit]

"Video: Peter Ward Our Future In a World Without Ice Caps" 2013 (April). 

References[edit]

  1. ^ a b Canfield, D.E. (1998). [Abstract PDF "A new model for Proterozoic ocean chemistry"]. Nature 396: 450–453. doi:10.1038/24839. 
  2. ^ Buick, R. (2007). "Did the Proterozoic 'Canfield Ocean'cause a laughing gas greenhouse?". Geobiology 5.2: 97–100. doi:10.1111/j.1472-4669.2007.00110.x. 
  3. ^ Raymond B. Huey, Peter D. Ward (2005). "Hypoxia, Global Warming, and Terrestrial Late Permian Extinctions". Science (AAAS) 308 (5720): 398–401. doi:10.1126/science.1108019. 
  4. ^ K. J. Hsü and J. A. McKenzie (1985). "A "Strangelove" ocean in the earliest Tertiary, in The Carbon Cycle and Atmospheric CO2: Natural Variations Archean to Present". Geophysical Monograph Series (American Geophysical Union) 32: 487–492. doi:10.1029/GM032p0487. Retrieved 2013-09-16. 
  5. ^ LR Kump (1991). "Interpreting carbon-isotope excursions: Strangelove oceans". Geology (Department of Earth System Science Center) 19: 299–302. doi:10.1130/0091-7613(1991)019<0299:ICIESO>2.3.CO;2. 
  6. ^ Timothy W. Lyons, Ariel D. Anbar, Silke Severmann, Clint Scott, and Benjamin C. Gill (January 19, 2009). "Tracking Euxinia in the Ancient Ocean: A Multiproxy Perspective and Proterozoic Case Study". Annual Review of Earth and Planetary Sciences 37: 507–53. doi:10.1146/annurev.earth.36.031207.124233. Retrieved April 11, 2014.