2010 Fiscal Year Final Research Report

Productivity in shallow subtidal zone mediated by seasonal changes in ecosystem function of tidal flats

Research Project

Project/Area Number	21780179
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	General fisheries
Research Institution	Saga University
Principal Investigator	YOSHINO Kenji Saga University, 低平地沿岸海域研究センター, 特別研究員 (40380290)
Project Period (FY)	2009 – 2010
Keywords	安定同位体 / 底性微細藻類 / 干潟 / 生態系機能
Research Abstract	We investigated mudflat ecosystem function using stable isotope analyses in Ariake Bay to test whether ecosystem function of mudflat seasonally changes from water purification to the fueling of neighboring subtidal production by sourcing of benthic microalgae. Isotope analyses showed that the energy contribution of mudflat benthic microalgae to subtidal benthic production increased from 44% in summer to 60% even in offshore area in winter, when the activity of mudflat grazer decreased. However, such fueling function was relatively high. Isotope signatures of demersal fish also showed benthic algae-oriented signatures, about 70% contribution of benthic algae. Hence, mudflat in Ariake Bay fundamentally functions as source of organic materials and partly supports higher production of higher trophic organism of this area.