Bioturbation Of Benthic Animals On The Exchange And Coupling Of Sediment-water Interface In Paddy Field Ecosystem

In this paper, using benthic fish loach as an experimental subject, the bioturbation effects of benthic animals on the exchange and coupling of sediment-water interface in paddy field were studied by field sampling in paddy field in Xujia Village, Sheling Town, Shuangyang District, Changchun City, Jilin Province and simulation experiments in laboratory. The author takes the key ecological processes(vertical distribution of particles, resuspension, the cycling of biogenic elements) in sediment-water interface as core contents, explores deeply the coupling mechanism, biological mechanism, variation and influencing factors in sediment-water interface, and seeks a breakthrough in ecological fundamental theories and research methods to offer the basic parameters and the scientific evidence for control of non-point agricultural pollution and ecological modeling. The major research results include:(1) The vertical surface mobility that the loaches do on deep sediment particles is 1.385×10-3 g-1?cm-2?d-1,the maximum migration depth is 8cm;the vertical upward mobility that loaches do on the particles of deep sediment is 1.774×10-3 g-1?cm-2?d-1,the upward maximum migration depth is 4cm; the vertical downward mobility is 5.586 × 10-4 g-1?cm-2?d-1,the downward maximum migration depth is 5 cm.(2) The bioturbation effect of loaches plays a positive role in migration of sediment particles in paddy fields; paddy deposits are nutrient source foundation for rice root growth; particle migration is bound to cause the migration of sediment organic matter in sediments of various molecules, which is good to rice root absorption of nutrient elements.(3) The bioturbation effect of loaches causes the suspended solid content in overlying water of paddy fields to reach as high as 62.99mg/L, the suspended solid content increases by 50.48mg/L; the maximum depth of paddy surface erosion sediment caused by loach bioturbation is 2.3mm.(4) Loach plays a positive role in the balance of N-element of upward suspended water. Besides the changes of ammonia nitrogen, nitrite and nitrate made by the bioturbation effect of loaches, it is also related to the nitrobacteria growth in water.(5) Bioturbation effect of loach has a positive influence on the balance of P-element in overlying water, heightens the content of nutrients and does good to rice growth in terms of nutrient supply.