Abstract
Almost all material cycles perform by fluid media as water and air on the earth. The carbon cycle, including ecosystems, is associated with the activation of material cycles. Recently, the link between basin and sea has gained recognition, and we have an increased need for construction on integrated governance of “SATO YAMA and SATO UMI”, “upstream and downstream”, etc. So this study aims to ascertain the roles of estuary tidelands located in boundary zones between basin and sea using estimation of material transport and natural water-soluble fulvic acid.
This paper dissertated in more detail field survey about（a）net primary production（NPP）in the soil from reed vegetation and soil respiration,（b）the vertical contour maps of organic matter content, humic carbon content, Fe2O3 content and weathering index in soil, and（c）input and output vector contour map of iron-fulvate complexes in characteristic creek with tidal fluctuation at Banzu tideland as follow-through from our previous research. The annual NPP in 48 ha of tideland was 98 t-C y－1 which is comparable to a carbon fixing amount in 25,000 artificial cedars. The contents of organic carbon and humic carbon in surface soil till 0.20 m correlated positively with the annual NPP. The generated humic substances in tideland re-leached most of the deposited iron from surface soil to deep underground, and the double amount of iron as iron-fulvate complexes flowed out to sea through the Obitsu river with tidal fluctuations.
