TY - JOUR
T1 - The response of nitrifying microbial assemblages to ammonium (NH4+) enrichment from salmon farm activities in a northern Chilean Fjord
AU - Elizondo-Patrone, Claudia
AU - Hernández, Klaudia
AU - Yannicelli, Beatriz
AU - Olsen, Lasse Mork
AU - Molina, Verónica
N1 - Funding Information:
This research was supported by funds from the Comisión Nacional de Investigación Científica y Tecnológica (CONICYT, Chile) , FONDECYT grants No. 1110190 and 1110824 , Andrés Bello University Introduction to Research grant No. DI-409-13/I and the WAFOW project at NTNU , financed by the Norwegian Research Council (project no: 193661 ). LMO acknowledge CINTERA, Norwegian Research Council project NTNU (project no: 10345301 ). We are grateful to D. Poo-Muñoz, S. Rojas and L.E. Escobar for technical support. This study was carried out in the Huinay Research Station, and we could not have achieved this without the help and positive attitudes of all the staff there. We acknowledge the support given by Dr. R. Melendez (Laboratorio de Biología Marina, UNAB) and Dr. R. Paredes (Laboratorio de Salud Ecosistémica, UNAB) for their laboratory facilities and technical staff assistance. C. Elizondo was supported by UNAB Conservation Medicine PhD grant at the Faculty of Ecology and Natural Resources, UNAB. This is publication no 126, of the Huinay Scientific Station.
PY - 2015/12/5
Y1 - 2015/12/5
N2 - The consequences of aquaculture include alterations in nitrogen cycling in aquatic environments that may lead to ecosystem degradation. Herein salmon aquaculture release of ammonium (NH4+) to the water column and its effects on natural archaea and bacteria ammonia-oxidizers (AOA and AOB) and nitrite-oxidizing bacteria (NOB) community structure were studied in the Comau fjord using molecular approaches, such as: cloning (AOA and AOB richness), qPCR for C. Nitrosopumilus maritimus (AOA) and Nitrospina sp. (NOB) abundance (DNA) and RT-qPCR only for Nitrospina sp activity (RNA). Sampling was carried out in brackish (0.7-25 salinity, <5 m depth) and marine (>30 salinity, 25 m depth) waters during contrasting salmon production periods: rest (winter 2012), growth and harvest (summer and winter 2013). During the rest period, the highest NH4+ concentration was observed at Vodudahue River, whereas during productive periods NH4+ accumulated in the brackish layer inside salmon cages and in the vicinty (up to 700 m distance from the cages). The nitrifier community from the fjord reference station (Stn-C) was characterized by C. N. maritimus (AOA) and Nitrosomonas sp. (AOB) sequences affiliated with cosmopolitan ecotypes (e.g., marine, freshwater, hydrothermal), maxima abundances of C. N. maritimus (AOA) and Nitrospina sp. and extreme ranges of Nitrospina sp. activity occurred in the brackish layer. During productive periods, abundances of C. N. maritimus were co-varied with NH4+ concentrations inside salmon cages (summer) and the adjacent areas (winter). Productive periods were characterized by lower abundances but more homogeneity between brackish and marine areas than for the Stn-C nitrifiers. The physiological state of Nitrospina sp. estimated from cDNA:DNA ratios indicated higher growth during winter 2013 associated with NH4+ enrichment derived from production and river input. Our results suggest that in Comau Fjord, NH4+ enrichment events occur during salmon production and also naturally by river inputs, supporting an abundant and active nitrifying community potentially processing only part of the extra NH4+ that occurs, predominantly outside the salmon cages. Our work highlights the abundance and activities of nitrifying communities and identifies these communities as being sensitive to increased loads of NH4+.
AB - The consequences of aquaculture include alterations in nitrogen cycling in aquatic environments that may lead to ecosystem degradation. Herein salmon aquaculture release of ammonium (NH4+) to the water column and its effects on natural archaea and bacteria ammonia-oxidizers (AOA and AOB) and nitrite-oxidizing bacteria (NOB) community structure were studied in the Comau fjord using molecular approaches, such as: cloning (AOA and AOB richness), qPCR for C. Nitrosopumilus maritimus (AOA) and Nitrospina sp. (NOB) abundance (DNA) and RT-qPCR only for Nitrospina sp activity (RNA). Sampling was carried out in brackish (0.7-25 salinity, <5 m depth) and marine (>30 salinity, 25 m depth) waters during contrasting salmon production periods: rest (winter 2012), growth and harvest (summer and winter 2013). During the rest period, the highest NH4+ concentration was observed at Vodudahue River, whereas during productive periods NH4+ accumulated in the brackish layer inside salmon cages and in the vicinty (up to 700 m distance from the cages). The nitrifier community from the fjord reference station (Stn-C) was characterized by C. N. maritimus (AOA) and Nitrosomonas sp. (AOB) sequences affiliated with cosmopolitan ecotypes (e.g., marine, freshwater, hydrothermal), maxima abundances of C. N. maritimus (AOA) and Nitrospina sp. and extreme ranges of Nitrospina sp. activity occurred in the brackish layer. During productive periods, abundances of C. N. maritimus were co-varied with NH4+ concentrations inside salmon cages (summer) and the adjacent areas (winter). Productive periods were characterized by lower abundances but more homogeneity between brackish and marine areas than for the Stn-C nitrifiers. The physiological state of Nitrospina sp. estimated from cDNA:DNA ratios indicated higher growth during winter 2013 associated with NH4+ enrichment derived from production and river input. Our results suggest that in Comau Fjord, NH4+ enrichment events occur during salmon production and also naturally by river inputs, supporting an abundant and active nitrifying community potentially processing only part of the extra NH4+ that occurs, predominantly outside the salmon cages. Our work highlights the abundance and activities of nitrifying communities and identifies these communities as being sensitive to increased loads of NH4+.
KW - Ammonium (NH) enrichment
KW - Nitrifying communities
KW - Nitrospina sp.
KW - Patagonian fjords
KW - Salmon farming
UR - http://www.scopus.com/inward/record.url?scp=84949320807&partnerID=8YFLogxK
U2 - 10.1016/j.ecss.2015.03.021
DO - 10.1016/j.ecss.2015.03.021
M3 - Article
AN - SCOPUS:84949320807
VL - 166
SP - 131
EP - 142
JO - Estuarine, Coastal and Shelf Science
JF - Estuarine, Coastal and Shelf Science
SN - 0272-7714
ER -