Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.5194/bg-10-5555-2013 |
| Title (Primary) | Linkage between the temporal and spatial variability of dissolved organic matter and whole-stream metabolism |
| Author | Halbedel, S.; Büttner, O.; Weitere, M. |
| Journal | Biogeosciences |
| Year | 2013 |
| Department | ASAM; SEEFO; FLOEK |
| Volume | 10 |
| Issue | 8 |
| Page From | 5555 |
| Page To | 5569 |
| Language | englisch |
| UFZ wide themes | RU2; |
| Abstract | Dissolved organic matter (DOM) is an important resource for microbes, thus
affecting whole-stream metabolism. However, the factors influencing its chemical
composition and thereby also its bio-availability are complex and not thoroughly
understood. It was hypothesized that whole-stream metabolism is linked to DOM
composition and that the coupling of both is influenced by seasonality and
different land-use types. We tested this hypothesis in a comparative study on
two pristine forestry streams and two non-forestry streams. The investigated
streams were located in the Harz Mountains (central Europe, Germany). The
metabolic rate was measured with a classical two-station oxygen change technique
and the variability of DOM with fluorescence spectroscopy. All streams were
clearly net heterotrophic, whereby non-forestry streams showed a higher primary
production, which was correlated to irradiance and phosphorus concentration. We
detected three CDOM components (C1, C2, C3) using parallel factor (PARAFAC)
analysis. We compared the excitation and emission maxima of these components
with the literature and correlated the PARAFAC components with each other and
with fluorescence indices. The correlations suggest that two PARAFAC components
are derived from allochthonous sources (C1, C3) and one is derived
autochthonously (C2). The chromophoric DOM matrix was dominated by signals of
humic-like substances with a highly complex structure, followed by humic-like,
fulfic acids, low-molecular-weight substances, and with minor amounts of amino
acids and proteins. The ratios of these PARAFAC components (C1 : C2, C1 : C3, C3
: C2) differed with respect to stream types (forestry versus non-forestry). We
demonstrated a significant correlation between gross primary production (GPP)
and signals of autochthonously derived, low-molecular-weight humic-like
substances. A positive correlation between P / R (i.e. GPP/daily
community respiration) and the fluorescence index FI suggests that the amount of
autochthonously produced DOM increased overall with increasing GPP. In
accordance with the coupling between DOM and the metabolism, our data also
indicate that the composition of DOM is subject to seasonal fluctuations.
We concluded that temporal and spatial differences in DOM composition are driven by whole-stream metabolism, in addition to pronounced effects coming from allochthonous sources. |
| Persistent UFZ Identifier | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=13947 |
| Halbedel, S., Büttner, O., Weitere, M. (2013): Linkage between the temporal and spatial variability of dissolved organic matter and whole-stream metabolism Biogeosciences 10 (8), 5555 - 5569 |
|