Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6304344 | Journal of Experimental Marine Biology and Ecology | 2013 | 9 Pages |
Abstract
Biomass yields from some species of macroalgae exceed the yields in traditional terrestrial production systems. This renewable carbon source possesses a potential for energy purposes and thus reduction in fossil fuel carbon dioxide (CO2) emissions. Previous experiments have indicated that nitrous oxide (N2O) may be produced by green algae. We investigated the N2O emissions in the green alga Ulva lactuca. Significant N2O emissions, along with CO2 uptake, were demonstrated from vital U. lactuca material from different natural populations incubated in the laboratory with nitrite (NO2â) and nitrate (NO3â) and at a light intensity of 225 μmol photons mâ 2 sâ 1. No emission of N2O was observed in darkness. The N2O emission increased in a Michaelis-Menten characteristic manner with increasing concentrations of both NO3â and NO2â. The light dependency indicated that the N2O emission was related to algal photosynthesis, and not bacterial activity. As algal NO3â reductase (NR) converts NO3â to NO2â in light, and N2O emission was observed from both NO3â and NO2â, it is proposed that NO2â reductase (NiR) activity may have generated the observed N2O, however the mechanism needs further investigation. This apparent N2O production by algae emphasizes the need for experiments under natural conditions in order to evaluate potential greenhouse gas balances associated with large-scale productions for energy purposes.
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Authors
Kristian Rost Albert, Annette Bruhn, Per Ambus,