**6. Conclusions**

The temperature profiles, which result primarily from the molecular diffusion of heat through the sediment, resemble those typical of field soils and their form is similarly dependent on the thermal properties of the mud and the ambient meteorological conditions. The diurnal temperature variation is more visible near the surface (0.10 m and 0.20 m). The temperature increase gradually from morning, peak at noon and gradually decrease at afternoon. However, at 1.0 m and 2.0 m depth, the variation of temperature was not so prominent. This is due to the volumetric heat capacity and the thermal conductivity of the tidal mud. From the seasonal variation of temperature, it is seen that during late summer,

The volumetric heat capacity of the tidal mud refers to the value which indicates the ability to store heat. If the volumetric heat capacity of a soil is high then the soil is more stable in terms of temperature change or the thermal environment. Figure 10 illustrates the variation of volumetric heat capacity with depth of the various samples. Sample 2 shows a great variation in volumetric heat capacity. The peak shows at 0.35 m depth and value is about 6.3 MJ/m3 °C. Clay soil generally has higher volumetric heat capacity than sandy soil for the same water content and soil density (Hamed, 2003). Volumetric heat capacity is very important for the acid infected tidal mud. Sulphate reducing bacteria (SRB) plays an important role in the geo-environmental condition of the Ariake Sea. These Bacteria like the layer where the volumetric heat capacity is higher (Moqsud et al.2006). Because in that layer

0 5 10 15 20 25 30 35 40 45 50

m)

 S 1 S 2 S 3 S 4 S 5

Depth ( x 10-2

The temperature of underground soil is affected mainly by the soil thermal properties (Nassar et al., 2006) and these properties play a significant role in the geo-environmental condition in the global environment. The thermal properties of the mud are also induced by the mineralogical matter presence in the mud. The effects of this mineral matter on the

The temperature profiles, which result primarily from the molecular diffusion of heat through the sediment, resemble those typical of field soils and their form is similarly dependent on the thermal properties of the mud and the ambient meteorological conditions. The diurnal temperature variation is more visible near the surface (0.10 m and 0.20 m). The temperature increase gradually from morning, peak at noon and gradually decrease at afternoon. However, at 1.0 m and 2.0 m depth, the variation of temperature was not so prominent. This is due to the volumetric heat capacity and the thermal conductivity of the tidal mud. From the seasonal variation of temperature, it is seen that during late summer,

**5.3 Volumetric heat capacity variation with depth** 

it shows the more stable condition which is liked by the bacteria.

5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 6.6

Fig. 10. Variation of volumetric heat capacity with depth

thermal properties of the Ariake sea mud needs further study.

Volumetric heat capacity (MJ/m3

**6. Conclusions** 

 0C) the surface and subsurface temperature is always higher than the deeper depth of the mud while in the winter the opposite phenomenon occurs. The thermal properties of mud collected from tidal flat showed a different trend from the mud collected inside the sea due to the exposure to the sunlight and the tidal wave turbulation in the tidal flat areas. In this study an innovative idea has been adopted to explain the deterioration and the natural remediation of the tidal flat mud in the Ariake Sea. The proposed mechanisms for understanding the transient seepage of pore water liquid of the tidal mud which contributes to the transport of sea laver treatment acid in the tidal mud and also natural remediation of contaminated tidal mud of the Ariake Sea was described clearly. The seasonal variation of temperature and the volumetric heat capacity of the mud have played a significant role for the maintaining the deterioration and natural remediation in the Ariake sea mud.

## **7. References**

