三重県伊勢・松坂地域における干潟のアマモ場のバイオマスとしての物質循環の地球化学的検討

Multi-element analysis of Zostera marina (submerged plant) was examined on the three plant tissues (leaf, stem and root) and also in relation to their seasonal growth in 2012 and 2013, at the tidal flat of Ise and Matsusaka areas, central Japan. Also Z. japonica was used for this study from Ise area. CaO concentrations of leaf were higher than those of stem and root and show systematic increase from March to July, 2013 which is related to absorption and increased amount of attached organisms of the leaf. Contents of MnO also show similar behavior with CaO which might be caused by higher Mn concentrations in reductive sea water in summer season. Contents of MnO of leaf of Z. japonica are significantly higher than those of Z. marina indicating characteristic absorption of Mn in plant tissue. P_2O_5 concentrations did not show regular change in season, and was concentrated in stem relative to those of leaf and root. Fe_2O_3 and As concentrations show higher level in root of most specimen of Z. marina, suggesting absorption of dissolved these elements in pore water of sediments under reducing conditions. Zinc concentrations show higher in leaf of most specimen of both Z. marina and Z. japonica, but did not show seasonal change. Cu behaves similarly to that of Zn, but its variation in plant tissue and seasonal change were not regular than those of Zn. TS (total sulfur), Br and Cl were high in all plant tissue and show relatively steady concentrations, which did not show seasonal change. Comparing multi-elements concentrations of two areas, most elements had similar values, excluding Fe_2O_3, P_2O_5 and Zn. These three elements of Z. marina in Matsusaka area show higher level than those of Ise area, suggesting relatively much inflow of domestic water from the town. The lower concentrations in CaO and MnO of Z. marina from Matsusaka area in 2012 might be related to less growth of the plant tissue compared to those of 2013. This feature was caused by higher rain precipitation in 2012 than that of 2013. The absence of biomass of Z. marina from Ise area in 2012 might be caused by flooding in the Miyagawa river estuary in this area.