@article{oai:soar-ir.repo.nii.ac.jp:00016346, author = {AIKINS, Samuel and KIKUCHI, Eisuke}, journal = {信州大学山地水環境教育研究センター研究報告}, month = {Feb}, note = {Grazing pressure effects exerted by four species of amphipods on epiphytic microalgae were determined in Nakakita river estuary (Gamo lagoon) Japan, considering microalgal strength of adhesion to surfaces with regard to their susceptibility to grazing. Grazing effects were examined for three groups of diatoms, including naturally storongly-attached cells, moderately-attached cells and fairly-attached cells. Diatom species with filamentous forms or low adhesive strength were susceptible to grazing, while those with tighter adhesion were less affected by grazing pressure. Seasonal trends of both amphipods and microalgae found on the macroalgae Gracilaria vermiculophylla showed high densities of amphipods and low densities of microgae during warmer months (June to September) and vice versa in colder months (December to March). This immerse relationship between densities of amphipods and diatoms suggests a casual relationship and shows that effects grazing pressure by amhpipods on epiphytic diatom communities seem to be strong in Gamo lagoon. A manipulated experiment (feeding pressure experiment) revealed that Melosira sp. and Nitzchia sp. were mostly selected by tube-dwelling species (Corophium uenoi and Grandidierella japonica), whilst Gyrosigma sp. and Melosira sp. selected by free-living species (Eogammarus passjeticus and Melita setiflagella)., Article, 信州大学山地水環境教育研究センター研究報告 2: 17-20(2004)}, pages = {17--20}, title = {Grazing pressure by amphipods on microalgae in Nanakita river estuary (Gamo lagoon), Japan}, volume = {2}, year = {2004} }