ISSN:
1573-515X
Keywords:
lacustrine sediment
;
organic matter
;
sedimentation rates
;
recycling
;
burial
;
carbon
;
nitrogen
;
silicon
;
phosphorus
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
Notes:
Abstract The areal distribution of organic C contents, δ13C values, total N and P and biogenic Si contents in surficial sediments were used to study the distribution, origin and diagenetic transformations of sedimented biogenic debris in the eutrophic subalpine Lake Bled (Slovenia), which for most of the yearhas an anoxic hypolimnion. The influence of an allochthonous input, restricted to the western basin, was clearly traced by higher organic C and total N and P contents, higher δ13C values, and higher sedimentation rate in comparison to the eastern basin. The low δ13C values of sedimentary organic matter in the major part of the lake, lower than the δ13C values of different types of organic matter, suggest that this sedimentary organic matter is most probably the product of a microbial community and not a residue of primary production. The temporal variation of benthic diffusive fluxes of NH4, Si and PO4, derived from modelling the pore water profiles, was related to sedimentation of phytoplanktonic blooms, while the PO4 fluxes were also dependent on changing redox conditions at the sediment-water interface in the period of the winter-spring overtum. The removal of PO4 in pore waters is probably due to the adsorption of phosphate and precipitation of apatite and vivianite. The budget of C, N and P at the sediment-water interface revealed a high recycling efficiency (〉70%), also confirmed by the rather uniform (or only slightly decreasing) vertical profiles of organic C, total N and P in sediment cores and C/N and C/P ratios. The percentage of biogenic Si recycling is low (〈10%), suggesting its removal in sediments.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00000353
Permalink
