Abstract
Bacterial population on laminariaceous brown alga Eisenia bicyclis was examined by scanning electron microscopy and on a young, smooth blade sample surface, homogeneous coccoid were seen scattering along algal cell borders. A bacterial population collected from such a young sample did not grow in natural sea water containing 0.05% pepton and 0.005% yeast extract but grew well in a medium supplemented with algal excreted organic matter (EOM) or algal materials. Growth was seldom detected by the MPN method with pepton-yeast extract mediums, although with the medium supplemented by EOM, about 103 bacteria/cm2 of sample surface area was detected. These results indicate that the bacterial population on the young blade's surface requires the algal excreted organic matter for its growth.
