Measurement of ectoenzyme activities as an indication of inorganic nutrient imbalance in microbial communities

Abstract

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 23:301-311 (2001) - doi:10.3354/ame023301 Measurement of ectoenzyme activities as an indication of inorganic nutrient imbalance in microbial communities M. M. Sala1,*, M. Karner2, L. Arin1, C. Marrasé1 1Institut de Ciències del Mar (CSIC), P. Joan de Borbó s/n, 08039 Barcelona, Spain 2University of Hawaii, Department of Oceanography, 1000 Pope Road, Honolulu, Hawaii 96822, USA *E-mail: [e-mail] ABSTRACT: Assessment of nutrient limitation in microbial populations in marine environments is an important topic. Existing methodologies generally demand long incubations in an experimental assay manipulating nutrients. We suggest a novel approach using the ratio between 2 ectoenzymatic activities, alkaline phosphatase (APA) and aminopeptidase (AMA), to evaluate nutrient limitation of microbial communities in situ. APA is used as an indication of P limitation and AMA of N limitation. The ratio bypasses the use of biomass estimations to calculate specific activities, which are error-prone and time-consuming. Our results from enrichment experiments have shown that the ratio APA:AMA increases in P-deficient treatments, and decreases after inorganic P addition. After P deficient nutrient addition (n treatments) the ratio APA:AMA increased to 90-230%, whereas following N+P balanced additions the ratio decreased to 30-70% of the initial value. These results demonstrate that this approach is easy, quick and gives a general insight into the nitrogen versus phosphorus nutrient balance of the communities without the need for biomass estimations or measurement of actual nutrient concentrations. KEY WORDS: Alkaline phosphate · Aminopeptidase · N:P ratio · Microbial community Full text in pdf format PreviousExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 23, No. 3. Online publication date: February 28, 2001 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2001 Inter-Research.