秋季东海溶解态和颗粒态氨基酸的组成与分布

COMPOSITION AND DISTRIBUTION OF DISSOLVED AND PARTICULATE AMINO ACIDS IN SEAWATER OF EAST CHINA SEA IN AUTUMN

本文对2012年秋季中国东海31个站位的海水样品中溶解态氨基酸(THAA)和颗粒态氨基酸(PAA)的组成与分布进行了研究。结果表明:表层海水中溶解游离氨基酸(DFAA)的平均浓度为(0.12±0.04)μmol/L(0.06—0.19μmol/L),溶解结合氨基酸(DCAA)的平均浓度为(0.61±0.51)μmol/L(0.15—1.79μmol/L),PAA的平均浓度为(0.11±0.06)μmol/L(0.02—0.27μmol/L)。THAA的水平分布特点大致为近岸高、远岸低;PAA的水平分布特点是近岸海域向远海海域分布呈现逐渐减小的趋势。THAA的垂直分布特点是由表层向底层逐渐降低。DCAA、PAA与chl a有很好的相关性,而DFAA与chl a的相关性不明显。东海表层海水中THAA的主要组分是天门冬氨酸、谷氨酸、丝氨酸、甘氨酸、苏氨酸及丙氨酸,PAA的主要组分是天门冬氨酸、谷氨酸、丝氨酸、甘氨酸、丙氨酸及亮氨酸。在表层海水中氨基酸是作为一个整体而对海洋生物地球化学过程产生影响的。

We investigated the distribution and composition of total hydrolyzed amino acid(THAA) and particulate amino acid(PAA) in seawater samples collected at 31 stations located in the East China Sea in October 2012. DFAA(dissolved free amino acid), THAA, DCAA(dissolved combined amino acid) and PAA concentrations were determined using HPLC in OPA-MPA pre-column derivatization. Chl a was extracted with 90%(V/V) aqueous acetone solution in the dark from cryopreserved membrane and centrifuged at a low speed; the supernatant was measured using a Hitachi F-4500 fluorescence spectroscopy photometer. Dissolved organic carbon(DOC) and dissolved inorganic nitrogen(DIN) were determined with Shimadzu TOC analyzer. The results show that the average concentration of DFAA ranged 0.06μmol/L to 0.19μmol/L in average of(0.12±0.04)μmol/L, while the average DCAA and PAA were(0.61±0.51)μmol/L(from 0.15μmol/L to 1.79μmol/L), and(0.11±0.06)μmol/L(from 0.02μmol/L to 0.27μmol/L), respectively. The concentrations of THAA and PAA displayed a decreasing trend inshore to offshore. The concentration of THAA showed a decreasing trend from the surface layer to the bottom layer. Both DCAA and PAA concentrations were significantly correlated with chlorophyll a concentration, but no significant correlation between the DFAA and the chlorophyll a concentrations. In the study area, the major constituents of THAA were aspartic, glycine, serine, glutamic, threonine acid, and alanine acid, while the major constituents of PAA were aspartic, glycine, serine, glutamic, alanine acid, and leucine acid. Therefore, various amino acid species co-play as a whole and affect the marine biogeochemical processes in the surface water.