ISSN:
1432-184X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The contribution of bacteria to phosphorus (P) and nitrogen (N ) release from, or retention in, sediment was studied in a flow-through system. “Live” and formaldehyde-“killed” sediment communities were incubated in 25-liter bottles with a continuous flow of P- or P + N-enriched water. Sediment bacteria in the killed communities were inhibited by adding formaldehyde (final concentration 0.04% v/v) to the sediment before the start of the experiment. Bacterial activity in the live sediments measured with [3H]thymidine and [14C]leucine incorporation techniques did not change essentially during the experiment period (7–8 days). Chemical mechanisms were found to be of principal importance in PO4-P retention in the sediment. In the live samples, the net retention of PO4-P was lower than in the killed samples, which was likely due to the reduced O2 conditions in the sediment as a consequence of bacterial mineralization. In total P exchange, however, bacteria increased the retention rate by recycling dissolved organic P in the sediment. In the live communities the retention of N was very efficient, and all the introduced NH4 -N and NO3-N was immobilized by sediment bacteria. Nitrogen enrichment, however, did not alter the P exchange rates. The gradual emergence of bacterial activity (and grazing) in the killed communities, subsequent to the dilution of formaldehyde concentration, enhanced the release of PO4-P and NH4-N from sediment.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00167160
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