Effects of calculation procedure and sampling site on trap method estimates of sediment resuspension in a shallow lake
Article first published online: 30 JUN 2005
Volume 52, Issue 4, pages 903–913, August 2005
How to Cite
HORPPILA, J. and NURMINEN, L. (2005), Effects of calculation procedure and sampling site on trap method estimates of sediment resuspension in a shallow lake. Sedimentology, 52: 903–913. doi: 10.1111/j.1365-3091.2005.00726.x
- Issue published online: 11 JUL 2005
- Article first published online: 30 JUN 2005
- Manuscript received 10 June 2004; revision accepted 14 April 2005.
- Sediment resuspension;
- shallow lake;
- sources of error;
- trap methods
Resuspension estimates given by two different trap methods in a shallow lake were compared. The sensitivity of the methods to errors in estimates of gross sedimentation and organic fraction of trapped material was explored. The methods were label method, in which resuspension is estimated by determining the organic fraction of surface sediment, suspended seston and trapped material, and SPIM/SPM method, where the relationship between settling particulate inorganic matter (SPIM) and total settling particulate matter (SPM) is used. During the whole 111 day study period, according to the label method, at a sheltered station 1949 g m−2 dry weight of sediment was resuspended, whereas SPIM/SPM gave an estimate of 1815 g m−2. The difference in the estimates was probably due to mineralization loss of organic material in the traps during the two week exposure periods. Sensitivity analysis showed that of the two methods, the label method was more sensitive to variations in the organic content of trapped material. At a wind-exposed station, the total amounts of resuspended matter given by the label method and by the SPIM/SPM method were 4966 g m−2 and 4971 g m−2, respectively. Due to wind effects, escape of trapped material took place, which caused underestimation of gross sedimentation and compensated the effects of mineralization loss to diminish the difference between the methods. Of the two methods, the SPIM/SPM method seems thus more suitable for lakes, where bacterial activity is high. If cyanobacterial blooms take place, the label method is probably more reliable, providing that the exposure time of sediment traps is kept adequately short.