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Example Bjerrum plot: Change in carbonate system of seawater from ocean acidification.. A Bjerrum plot (named after Niels Bjerrum), sometimes also known as a Sillén diagram (after Lars Gunnar Sillén), or a Hägg diagram (after Gunnar Hägg) [1] is a graph of the concentrations of the different species of a polyprotic acid in a solution, as a function of pH, [2] when the solution is at ...
Water is the medium of the oceans, the medium which carries all the substances and elements involved in the marine biogeochemical cycles. Water as found in nature almost always includes dissolved substances, so water has been described as the "universal solvent" for its ability to dissolve so many substances.
In some cases their internal organs are replicated in phosphate. The phosphate mainly comes from the tissue itself, and may later be replaced by calcium carbonate. [2] A low pH makes CaCO 3 less likely to precipitate, clearing the way for phosphate to be laid down. [2] This is facilitated by the absence of oxygen in the decaying tissue.
Relationship of phosphate to nitrate uptake for photosynthesis in various regions of the ocean. Note that nitrate is more often limiting than phosphate. The Redfield ratio or Redfield stoichiometry is the consistent atomic ratio of carbon, nitrogen and phosphorus found in marine phytoplankton and throughout the deep oceans.
The balance of these carbonate species (which ultimately affects the solubility of carbon dioxide), is dependent on factors such as pH, as shown in a Bjerrum plot.In seawater this is regulated by the charge balance of a number of positive (e.g. Na +, K +, Mg 2+, Ca 2+) and negative (e.g. CO 3 2− itself, Cl −, SO 4 2−, Br −) ions.
The phosphorus cycle is the biogeochemical cycle that involves the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.Unlike many other biogeochemical cycles, the atmosphere does not play a significant role in the movement of phosphorus, because phosphorus and phosphorus-based materials do not enter the gaseous phase readily, [1] as the main source of gaseous phosphorus ...
The decreasing saturation of seawater with respect to calcium carbonate, associated with ocean acidification, a result of increased carbon dioxide (CO 2) absorption by the oceans, poses a significant threat to marine calcifiers. As CO 2 concentrations in seawater rise, a decrease in pH and a reduction in carbonate ion concentrations in seawater ...
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). [27] Ocean deoxygenation is the reduction of the oxygen content in different parts of the ocean due to human activities. [28] [29] There are two areas where this ...