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The color-change that occurs in the blue bottle experiment has features of a clock reaction, in which a visible change in the concentration of one or more reagents suddenly occurs upon the exhaustion of a limiting reagent. For example, the limiting reactant, oxygen, is consumed by another reactant, benzoin, with the help of safranin as a ...
At high temperatures the carbon will bond with and remove the oxygen in the metal oxides used as colorants in the glazes. This loss of oxygen results in a change in the color of the glazes because it allows the metals in the glaze to be seen in an unoxidized form. A reduction atmosphere can also affect the color of the clay body.
Global map of low and declining oxygen levels in the open ocean and coastal waters, 2009. [1] The map indicates coastal sites where anthropogenic nutrients have exacerbated or caused oxygen declines to <2 mg/L (<63 μmol/L) (red dots), as well as ocean oxygen minimum zones at 300 m (blue shaded regions).
The Great Oxidation Event (GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, or Oxygen Crisis, was a time interval during the Earth's Paleoproterozoic era when the Earth's atmosphere and shallow seas first experienced a rise in the concentration of free oxygen. [2]
The UN Environment Programme reported 146 dead zones in 2004 in the world's oceans where marine life could not be supported due to depleted oxygen levels. Some of these were as small as a square kilometer (0.4 mi 2), but the largest dead zone covered 70,000 square kilometers (27,000 mi 2). A 2008 study counted 405 dead zones worldwide.
Global map of low and declining oxygen levels in coastal waters (mainly due to eutrophication) and in the open ocean (due to climate change).The map indicates coastal sites where oxygen levels have declined to less than 2 mg/L (red dots), as well as expanding ocean oxygen minimum zones at 300 metres (blue shaded regions).
Cyanobacteria (blue-green algae) bloom on Lake Erie (United States) in 2009. These kinds of algae can cause harmful algal bloom. A harmful algal bloom (HAB), or excessive algae growth, is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, water deoxygenation, mechanical damage to other organisms, or by other means.
Oxygen condenses at 90.20 K (−182.95 °C, −297.31 °F) and freezes at 54.36 K (−218.79 °C, −361.82 °F). [52] Both liquid and solid O 2 are clear substances with a light sky-blue color caused by absorption in the red (in contrast with the blue color of the sky, which is due to Rayleigh scattering of blue light).