Bioremediation of Polluted Waters by Macroalgae
Suarez-Alvarez, S., Gomez-Pinchetti, J.L. and Garcia-Reina, G. 2012. Effects of increased CO2 levels on growth, photosynthesis, ammonium uptake and cell composition in the macroalga Hypnea spinella (Gigartinales, Rhodophyta). Journal of Applied Phycology 24: 815-823.
In a further assessment these possibilities and how they might be impacted by atmospheric CO2 enrichment (750 and 1600 ppm compared to an ambient value of 360 ppm), Suarez-Alvarez et al. cultivated 8-gram fragments of the macroalga Hypnea spinella in 1-L flasks containing filtered seawater enriched with 140 µM NH4Cl and 14 µM KH2PO4 for 7 days of acclimation, after which they were culled to their initial density and grown for 9 more days, during which period the three researchers measured various plant physiological properties and processes.
In the case of light-saturated net photosynthesis, the authors report that rates in the 750-ppm and 1600-ppm CO2 treatments were 41.5% and 50.5% greater, respectively, than what was measured in the 360-ppm treatment, while relative growth enhancements were 85.6% and 63.2% greater, respectively, and maximum ammonium uptake rates were enhanced by 24.2% and 19.9%, respectively, in the 750- and 1600-ppm CO2 treatments. "From a practical point of view," in the words of Suarez-Alvarez et al., "these results suggest that intensive culture of H. spinella operated in biofilters might be enhanced by CO2 supply to generate higher biomass productivities and better nitrogen biofiltration efficiencies," and they say that "the use of flue gases for this purpose would also improve the ability of bioremediation of these biofilters, as has already been tested for Gracilaria cornea," citing Israel et al. (2005). And thus it is that what climate alarmists call an air pollutant (CO2) may ironically soon play the role of a cleanser of water pollutants.
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