Permalink : http://hdl.handle.net/2115/56737

KEYWORDS : Microbial loop;Seagrass bed;Zostera marina;Bacteria;Heterotrophic nanoflagellates;Autotrophic nanoflagellates;Ciliates

Temporal fluctuations of bacteria, heterotrophic nanoflagellates (HNF), autotrophic nanoflagellates (ANF) and ciliates were investigated from spring to early summer at the stations in Akkeshi-ko Estuary with large scale seagrass bed of Zostera marina and Akkeshi Bay, Eastern Hokkaodo, Japan.　The ranges of bacterial density were 5.4×105-3.0×106 cells mL-1 in Akkeshi-ko Estuary (Stn. 1) and 2.3×105-1.9×106 cells mL-1 in Akkeshi Bay (Stns. 2, 3).　The ranges of HNF were 3.1×102-3.3×103 cells mL-1 in the estuary and 2.2×101-1.1×103 cells mL-1 in the bay.　The densities of ANF were 1.8×102-5.0×104 cells mL-1 (Stn. 1) and 2.2×101-3.6×104 cells mL-1 (Stns. 2, 3).　The densities of microorganisms were higher in the coastal area than offshore. 　In contrast, ciliate densities were <80-9.8×103 inds. L-1 in the estuary and <80-1.1×104 inds. L-1 in the bay.　Significant correlations were found between HNF and ANF, temperature and them, suggesting that major parts of ANF were mixotrophs of bacterial grazers like HNF.