Phospholipid in Plankton Samples from Tokyo Bay and Sagami Bay

To evaluate the role of phospholipid in the phosphorus cycle of marine ecosystems, diatom and zooplankton samples from Tokyo Bay and Sagami Bay were used to determine phospholipid-phosphorus (phospholipid-P) and their classification. The concentration of phospholipid-P in plankton population ranged from 28.0 to 67.6μmol P/g for dry samples, corresponding 10.4 to 22.2% for the total phosphorus: Tokyo Bay samples had a higher concentration than those from Sagami Bay. In the Tokyo Bay samples, the phospholipid-P concentraions had a good correlation with the percentage of copepoda, while no correlation was found in the Sagami Bay samples. Phosphatidyicholine, phosphatidylinositol and other unknown components were isolated and identified for classification of phspholipids using silica gel chromatography, 1HNMR and gas chromatography. These phosphorus compounds were concluded to play an important role in the downward conveying systems of phosphorus in marine ecosystems.