Abstract
Iron is essential for phytosynthetic and respiratory electron transport, and is directly involved in nitrite and nitrate reduction, N2 fixation, chlorophyll synthesis, and a number of other biosynthetic or degradation reactions. Humic substances such as fulvic and humic acids that form complexes with many metals, retain metals such as iron in soluble form. The percentage of oogonium formation of Laminaria religiosa with fulvic acid-Fe (FA-Fe) was 3 times higher than that with amorphous iron (am-Fe) and the growth rate of young sporophytes of L. religiosa with FA-Fe was also 3 times higher than that with am-Fe. On the other hand, mangrove forests are effective areas for trapping inorganic nitrogen from anthropogenic nitrogen inputs. In the case of the mangrove crab food web, Sesarma mederi feeds on mangrove leaves and detritus, and Scylla serrata feeds on crabs and worms. In conclusion, the forests on land and in coastal seas are essential for increasing organisms in the sea.
