Effect of salinity and inorganic nitrogen concentrations on nitrification and denitrification rates in intertidal sediments and rocky biofilms of the Douro River estuary, Portugal

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Magalhaes, CM (Author) Other; Joye, SB (Author) Other; Moreira, RM (Author) Other; Wiebe, WJ (Author) Other; Adriano Bordalo (Author) ICBAS

Journal

Title: Water Research

Vol. 39 No. 15

Pages: 1783-1794

ISSN: 0043-1354

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 158 Citations

Scopus - 184 Citations

Other information

Authenticus ID: P-000-3RB

DOI: 10.1016/j.watres.2005.03.008

Abstract (EN): The regulatory effects of salinity and inorganic nitrogen compounds on nitrification and denitrification were studied in intertidal sandy sediments and rocky biofilms in the Douro River estuary, Portugal, over a 12-month period. Nitrification and denitrification rates were measured in slurries of field samples and enrichment experiments using the difluoromethane and the acetylene inhibition techniques, respectively. Salinity did not regulate denitrification in either environment, suggesting that halotolerant bacteria dominated the denitrifier communities. However, nitrification rates were stimulated when salinity increased from 0 to 15 practical salinity units. NO(3)(-) addition experiments revealed that NO(3)(-) availability stimulates denitrification rates in sandy sediments, but not in rocky biofilms; however, in rocky biofilms a positive and linear relationship was observed between denitrification rates and water column NO(3)(-) concentrations (r = 0.92) during the monthly surveys. The N(2)O:N(2) ratios increased rapidly when NO(3)(-) increased from 63 to 363 mu M; however, results from monthly surveys showed that environmental parameters other than NO(3)(-) availability may be important in controlling the variation in N(2)O production via denitrification. Ammonium additions to sandy sediments stimulated nitrification rates by 35% for the 20 mu M NH(4)(+) addition, but NH(4)(+) appeared to inhibit nitrification at high concentration addition (200 mu M NH(4)(+)). In contrast, rocky biofilm nitrification was stimulated by 65% when 200 M NH(4)(+) was added.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12