Record details

    Delta15N as an indicator of N2-fixation by cyanobacterial mats in tropical marshes
Statement of responsibility
    Eliška Rejmánková, Jaroslava Komárková, Marcel Rejmánek
    Komárková, Jaroslava
    Rejmánek, Marcel
    Rejmánková, Eliška
Source title - serial
    Vol. 67, no. 3
    p. 353-368
    4 obr.
    Bibliografie na s. 366-368
    Zkr. název ser.: Biogeochemistry
Classfication no.
Conspectus category
Subject group
    izotopy N
    izotopy stabilní
    prostředí tropické
    sezónní změny
    vazba iontová
Geographical name
    Belize (Mexiko-Yucatán)
Abstract (in english)
   yanobacterial mats (CBM) are important components of wetland ecosystems in limestonebased regions of the Caribbean. During two sampling periods (July 1999 and January 2000) we measured N2-fixation in samples from 23 different marshes simultaneously with measurements of relevant environmental factors. Samples were evaluated for abundance of five groups of cyanobacteria: (1) Leptolyngbya, (2) Oscillatoria, (3) Chroococcales, (4) Nostoc-and Stigonematales, and (5) dead sheaths. Differences in nitrogen fixation, expressed as nitrogenase activity in nmol C2H4 cm-2 h-1, were best explained by the proportion of heterocyst-forming cyanobacteria. The samples were analyzed for the natura! abundance of delta15N. Delta15N values ranged from -1.99 to 11.44 per mille and were strongly negatively correlated with N2-fixation. With all data included, delta15N was also strongly correlated with nitrates in water.
   With the samples from Little Belize (high nitrate content marshes) excluded, the effect of nitrate became insignificant. N2-fixation predicted from delta15N measured on an independent data set from September 2000 was moderately accurate (r2 = 0.68, 0.52 and 0.54 for predictions based on July 1999, January 2000 and combined data sets, respectively). When individual sample sets were divided into two groups with delta15N < 2 and delta15N 2, the two groups were always highly significantly different in terms of their N2-fixation. The presented evidence suggests that delta15N can be used as a reliable indicator of N2-fixation by CBM
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    21. 3. 2008
Import date
    8. 8. 2012