Laghi di Monticchio (Southern Italy, Region Basilicata): genesis of sediments—a geochemical study
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Citations
Biogeochemical processes involving dissolved CO 2 and CH 4 at Albano, Averno, and Monticchio meromictic volcanic lakes (Central-Southern Italy)
Multidisciplinary characterisation of sedimentary processes in a recent maar lake (Lake Pavin, French Massif Central) and implication for natural hazards
Modern seasonality in Lake Challa (Kenya/Tanzania) and its sedimentary documentation in recent lake sediments
Stable oxygen isotopes in chironomid and cladoceran remains as indicators for lake-water δ18O
Geochemical insight into differences in the physical structures and dynamics of two adjacent maar lakes at Mt. Vulture volcano (southern Italy)
References
Weichselian palynostratigraphy, palaeovegetation and palaeoenvironment; the record from Lago Grande di Monticchio, southern Italy
Capture of molybdenum in pyrite-forming sediments: role of ligand-induced reduction by polysulfides
Vegetation history and palaeoclimate of the last glacial period at Lago Grande di Monticchio, Southern Italy
A compilation of data on lead 210 concentration in surface air and fluxes at the air‐surface and water‐sediment interfaces
Vegetation history and climate of the last 15,000 years at Laghi di Monticchio, southern Italy
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Frequently Asked Questions (21)
Q2. What can be used to assess microbial activity within sediments?
Pore water profiles can be used to assess microbial activity within sediments and the diffusive exchange between sediments and the overlying water.
Q3. What is the sulphur content of the sediments from different depths?
The diffusive penetration of oxygen into surface sediments, which depends on the oxygen concentration of the overlying water and the oxygen consumption rate in the sediment (mainly aerobic mineralization of organic matter and oxidation of reduced sulphur), determines the sediment depth where sulphate reduction can principally proceed from a thermodynamic viewpoint.
Q4. What is the effect of sulphate on the DSC of the lake water?
Besides groundwater inflow, post-depositional ion release from this debris, in particular release of mono- and divalent cations and silica may significantly contribute to the DSC of the lake water.
Q5. What is the main reason for the higher Si consumption in the lake water of LGM?
Presuming that LGM and LPM are fed by groundwater inflow of similar composition, an inhibited P-cycle in LPM due to meromixis should be the major reason for the overall higher Si consumption in the lake water of LGM.
Q6. What is the role of sulphate in the bio-degradation of organic matter?
Sulphate is utilized as an electron acceptor for the bio-degradation of organic matter in the absence of other preferentially used electron acceptors (O2, NO3, reactive Fe(III), e.g. Furrer and Wehrli 1996) and is consumed by anaerobic methane oxidation (e.g. Iversen and Jørgensen 1985).
Q7. What mechanism can transfer dissolved oxy-anions of U(VI) and Mo(?
Co-precipitation with FeOOH is an important mechanism that can transfer dissolved oxy-anions of U(VI) and Mo(VI) from the water column into the sediments (e.g. Bruno et al. 1995; Gustafsson 2003).
Q8. What is the significance of the sulphate reduction in the lake?
In the nearly non-calcareous sediments from deeper parts of the lake basin, seasonal production of alkalinity associated with sulphate reduction is important.
Q9. What is the role of elemental sulphur in the formation of pyrite?
Elemental sulphur seems to play a key role in the formation of pyrite, which is less sensitive to oxidation (unpublished personal experimental results).
Q10. What is the Ca/Sr signature of the autochthonous calcite?
Assuming a substantial post-depositional dissolution of autochthonous calcite, pore water in the surface sediments should reflect the Ca/Sr signature of the autochthonous calcite.
Q11. What are the main factors that influence the diffusive nutrient exchange across the lake interface?
Diffusive nutrient exchange across the sediment/water interface is further influenced by a complex of interacting parameters including, e.g. temperature, oxygen availability, vertical and temporal variations in H2S production by SO4 reduction, abundance of bio-degradable organic matter, PO4 retention or release associated with authigenic mineral formation.
Q12. What was the method used for the determination of phosphorus and sulphur?
After a HNO3/HClO4/HF/HCl-decomposition of 0.25 g solid sample, the determination of major and minor elements, including phosphorus and sulphur, was carried out by sequential ICP-AES (ARL 35000) and external calibration.
Q13. What is the effect of the hypolimnion of LGM on the lake bottom?
Increase of Ca and DIC in the hypolimnion of LGM towards the lake bottom reflects post-depositional dissolution of autochthonous carbonate.
Q14. What is the way to obtain an integral picture of pore water chemistry?
During the exposure of the dialysis cell, changes in interstitial water chemistry can occur, which is why in situ dialysis pore water profiles detected in this manner give an integral picture over the exposure time of the dialysis cells.
Q15. What is the effect of the inflow of groundwater on the P-cycle of LGM?
Hydrogen sulphide produced by SO4 reduction releases PO4 from its precipitates with Fe. Inflow of SO4-bearing groundwater may therefore indirectly influence the P-cycle of LGM.
Q16. How does the SRP pore water profile at 12 m show the phosphate release?
Lowering of the pH seems to be sufficient to prevent precipitation of Ca and Mn, which show elevated concentrations in the pore water at the 12 m site.
Q17. What is the trend of 210Pb in the lower section of the 4 m profile?
In the lower core section (31.5–55.5 cm) of the 4 m profile, however, unsupported 210Pb values vary between 38 and 69 mBq/g without showing a declining trend versus depth.
Q18. How much biogenic opal is in the sediments from the 23 m site?
If the authors consider TOC and N contents, biogenic opal accounts for approximately 50 wt% in the nearly non-calcareous sediments from the 23 m site.
Q19. What mechanism may explain the lower Feexc of the profundal LGM sediments?
Three mechanisms may explain the lower Feexc of the profundalLGM sediments: (i) The dissolved Fe influx into the deep water and possible focussing of the settling FeOOH flux towards the centre of the lake basin does not counterbalance the Feexc loss by deposition of FeOOH particles in the shallow water area during overturn.
Q20. Why do LPM sediments have a higher OI than LGM?
Because of the permanent absence of oxygen in the LPM deep water, it appears astonishing that OI values of LPM sediments exceed the average OI of LGM sediments by a factor of ~1.5.
Q21. What is the underlying geochemical signature of the LGM sediments?
The geochemical signatures of deeper sediments at the 8 m depth, showing distinctly lower Al contents (Fig. 5g), could reflect the presence of minerogenic debris with a geochemical composition that completely differs from those of the other LGM cores.