Comparison of material fluxes based on observations in different types of estuaries including mangrove area

Abstract

To quantify the natural river's self-purification mechanism, we conducted the field observations in 3 different estuaries-one urban river and two mangrove rivers-at the same period. From comparison of their water qualities, turbidity in urban area (Arakawa river) increased about 10 times immediately after rain. On the other hand, turbidity in mangrove estuaries (Fukido river and Miyara river) didn't change soon and the rate of increase was remarkably smaller than in urban river. TN (Total Nitrogen) and TP (Total Phosphorus) also had same tendencies. It showed that mangrove natural rivers moderate excess outflow of solids and nutrients to coastal area. Adding to it, we compared 2 types of mangrove estuaries with river form and land use and revealed the differences of their moderation effects.