Dsitribution Of Particulate Amino Acid In Changjiang Estuary And Its Adjacent Area

Amino acid is the important reservoir of particulate nitrogen in water and ocean. It is great significant to make aware of the distribution, transportation and transformation of particulate nitrogen in the river and ocean. We established the HPLC method of amino acids analysis in our lab and measured the samples from Xuliujing, the Changjiang Estuary and the East China Sea. The main purpose of the current study is to elucidate the distribution and source of particulate amino acids.The particulate samples were collected monthly in Xuliujing Changjiang Estuary during 2006. Particulate Amino Acids (PAA), Particulate Organic Carbon (POC), Particulate Nitrogen (PN), and chlorophyll (Chl-a) analyses were carried out to study the change characteristics every month and the source of particulate amino acids in Xuliujing Changjiang Estuary. There is positive correlation (r=0.781, p<0.005) between TPAA and TSM. TPAA concentration reached to the top value (3.14μmol/L) in January, while it reduced to the minimum (1.11μmol/L) in October. The contrast between POC/Chl-α, TPAA/PN and Degradation Index (DI) indicate that the source of particulate amino acids is dominated by highly degraded terrestrial transport and fresh phytoplankton in Xuliujing Changjiang Estuary, and that they were affected by the factor, such as water reservoired in The Three Gorges and drought. weather in the year 2006 with exceptionally low water discharge.Particulate amino acid samples collected in East China Sea from the cruise in May 2007 were analyzed. The concentration of PAA in surface, S1 and S6 transect water are 0.46-5.53μmol/L, 0.44-4.24μmol/L and 0.09-1.94μmol/L individually. The distribution of high TPAA value points in surface water is along the isobath of 50 m, while the high value of TPAA concentration in surface water decreases around in S1 and S6 transect vertically. According to Degradation Index (DI), we conclude that particulate amino acids are mainly from the new production of phytoplankton in the offshore district of Zhejiang and Fujian Province. Moreover, the highly degraded material from river and sediment did more contribution to the PAA in the bottom of the ocean and sea area outside Changjiang Estuary.For the individual amino acids, Aspartic Acid (Asp), Glycine (Gly), Alanine (Ala), Glutamine (Glu), Threonine (Thr), Valine (Val), Serine (Ser) and Leucine (Leu) are the dominated amino acids. D-Arg, D-Asp, D-Glu, D-leu and D-Ala are the main D-amino acids, which is mostly derived from bacterial source.