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Limitations on Limitation
Author(s) -
Laakso Thomas A.,
Schrag Daniel P.
Publication year - 2018
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/2017gb005832
Subject(s) - proterozoic , nutrient , phosphorus , limiting , biosphere , environmental science , primary productivity , anoxic waters , biogeochemistry , ecology , chemistry , environmental chemistry , geology , biology , paleontology , mechanical engineering , tectonics , organic chemistry , engineering
Abstract Phosphorus is believed to be the globally limiting nutrient in the modern ocean, but a number of nutrients have been invoked as limiting the Proterozoic biosphere. Mass balance calculations suggest that Proterozoic net primary productivity must have been 1 to 2 orders of magnitude less than today in order to maintain low oxygen levels despite increased burial efficiency in anoxic environments. The resulting demand for nutrients is so low that nitrogen, molybdenum, and iron could not have limited the rate of primary production following the evolution of extant nitrogenases. Phosphorus demand was approximately equal to the modern riverine flux, making phosphorus the most likely candidate for the limiting nutrient throughout the Proterozoic.