Epilithic algae from an urban river preferentially use ammonium over nitrate

International Aquatic Research

مقاله 3، دوره 12، شماره 1، خرداد 2020، صفحه 30-39   

نوع مقاله: Original research

شناسه دیجیتال (DOI): 10.22034/iar(20).2020.671068

نویسندگان

Eduardo Cejudo^{* 1}؛ William Taylor²؛ Sherry Schiff²

¹Water Sciences Unit – Yucatan Center for Scientific Research. Calle 8 No. 39, Mz. 29, SM 64; Cancun, Quintana Roo, México. 77500

²Department of Earth Sciences, University of Waterloo. 200 University Ave. West. Waterloo, ON, Canada. N2L3G1

چکیده

Epilithon is a taxonomically diverse assemblage of aquatic organisms which grow on rocks; this biological compartment is involved in several reactions that contribute to the dynamics of dissolved organic nitrogen in water. Using ceramic tiles colonized in an urban river, this experimental study assessed the relative importance of ammonium uptake by inhibiting nitrification blocking ammonium oxidation with acetylene, as well it tested the hypothesis that epilithon preferentially assimilated ammonium over nitrate. In our experiments, ammonium uptake by epilithon accounted for 46% – 100 % of the ammonium decrease in the water column, whereas nitrate uptake accounted for 0% – 11% of the nitrate decrease. Ammonium uptake rates ranged from 197 to 519 μmol m-2 h-1, while nitrate uptake rates were from 47 to 85 μmol N-NO3- m-2 h-1. The rate of preferential assimilation (RPI) was between 1.15 and 1.26, indicating preference for ammonium over nitrate. The results of this research provide valuable information regarding the relative contribution of algal uptake relative to nitrification in epilithon from an urban river.

کلیدواژه‌ها

Epilithon؛ uptake؛ ammonium؛ nitrate