Redfieldforholdet (engelsk: Redfield ratio ) beskriver forholdet mellom grunnstoffene karbon, nitrogen, fosfor og oksygen i havvann. Begrepet har navn etter den amerikanske oseanografen Alfred C. Han postulerte at dette forholdet avspeiler hvordan stoffene . Redfield ratio or Redfield stoichiometry is the atomic ratio of carbon, nitrogen and phosphorus found in phytoplankton and throughout the deep oceans. Estimated threshold ratios for total nutrients (TN:TP) were substantially higher than the Redfield ratio , reflecting the relatively high amounts of biologically less available dissolved organic N in the study area.
This term is named after the . The best overall performing indicator, DIN:TP, had chlorophyll-response based threshold ratios far below Redfiel . The solution for this problem seems to be the so called Redfield ratio. Based on the proportion (ratio) between the quantity of nitrate and phosphate in your aquarium, you can calculate the chance of getting blue or green algae. Then change your water for a certain percentage or add fertilizer.
The Redfield ratio , which now has meanwhile not heard of the Dutch aquarium? The current state of affairs And it shows that there are still some snags .
He found that globally the elemental composition of marine organic matter (dead and living) was . So there is no surprise in that it does not hold universally. The various bacteria have differnt ratios of CNP. These reactions will be different . Redfield N:P reflects a physiological or biochemical constraint on the elemental composition of primary production. Ecological stoichiometry: – Ecological stoichiometry . One of the fundamental tenets of ocean biogeochemistry is the Redfield ratio. Redfield identified a similarity between the N:P ratio of plankton living in the surface ocean and that of dissolved nitrate and phosphate in the deep ocean.
He hypothesized that the deep ocean nutrient concentrations were . Nitrogen fixation tends to maintain nitrate close to Redfield ratio with phosphate, while denitrification tends to keep nitrate as the proximate limiting nutrient and tie it in Redfield ratio to dissolved oxygen. Under increases in phosphorus input to the ocean, the relative responsiveness of nitrogen fixation and denitrification . Exact ratios aside, all organisms have high C, less N and much less P that composes the organic molecules of their tissues. So in some sense, these are the ratios that photosynthetic organisms will be taking up out of the . I talk about what steps I took to finally beat my GHA issue. Below are a few links that I visited when researching.
If any quantity could be called the Holy Grail of biogeochemical oceanography, it is probably the relative proportions of the elements carbon, nitrogen, and phosphorus (known as the Redfield ratio ) that marine organisms use to make soft tissue.
According to the Droop Cell-Quota model it is possible for algae to exhibit this chemical composition whilst growing slowly because of light limitation. Redfield ratios in oceans provide another example of possible regulation by organisms of their environment at global scales. Although local limiting conditions and phytoplankton growth strategies can induce local variations in . However , the ratio of C:P in marine detritus has been suggested by Peng and Broecker .