Dissolved Sugar in the South China Sea： A Preliminary Study
Date Issued
2004
Date
2004
Author(s)
CHIANG, I-TING
DOI
zh-TW
Abstract
測醣方法修改自1997年由Myklestad等人所共同提出的TPTZ分光光度法，而修改後的方法已足夠測得海水樣品的含醣量及濃度變化，並能得到總醣和單醣的垂直濃度分佈。測醣方法的偵測下限，單醣為10μgC/L以下，總醣約為20~35 μgC/L。目前所測得的海水總醣濃度範圍是35~120 μgC/L，單醣則為10~73μgC/L，總醣濃度約為單醣濃度的2~3倍。
由ORI-705的結果知道南海中部有光層(200 公尺以淺區域)總醣含量為22~54μgC/L，單醣濃度則為11~33μgC/L；由葉綠素、TEP、單醣、總醣良好的相關性，推測浮游植物是本區有機物的主要來源。ORI-710測得南海北部的總醣含量為35~117 μgC/L，而單醣含量為49~73μgC/L。
Carbohydrates are important components of marine organisms. They are contained in cell walls of plants, bacteria, and fungi, providing structural support. They are also involved in energy reserve, such as D-glucose is stored in the form of polysaccharides, starch in plants and glycogen in animals. Carbohydrates usually comprise 20 to 40％ of dry biomass of phytoplankton（Persons et al., 1961）. Recent studies had indicated that the concentration of carbohydrates in seawater could vary daily and seasonally. In general, total dissolved carbohydrate（monosaccharides and polysaccharides）is about 1 to 10 times greater in concentration than monosaccharides found in seawaters（Thurman, 1985）.
In this study, as the world first, concentration of dissolved monosaccharides and polysaccharides in the surface euphotic zone were measured in South China Sea at 21oN 30’ along 119oE 59’. A modified highly sensitive spectrophotometric method based on the alkaline ferricyanide reaction was adapted and employed, which uses 2,4,6-tripyridyl-s-triazine（TPTZ）as reagent instead, together with reduced iron giving a strongly colored complex. This method together with acid hydrolysis procedure was used to determine dissolved mono- and polysaccharides in seawater. In spring of 2004 (Cruise : ORI 710), concentration of total dissolved carbohydrates in the water column decreased as increasing depth during day time, and strong diurnal variation were observed, with a maximal value of 270μg/L between 60 and 70m depth at midnight. The concentration of total dissolved carbohydrates ranged from 180 to 380 μg/L while the concentration of monosaccharides ranged from 0 to 50 μg/L. In sum, total dissolved carbohydrate is about 8 times greater in concentration than monosaccharides found in South China Sea. These changes corresponded to that of Chlorophyll-a, bacterial production and transparent exopolymer particles（TEP） in the water column. The strong correlation found between total dissolved carbohydrates and bacterial production suggested that bacterial metabolism is fueled by availability of carbohydrates in seawater.
Subjects
海水單醣測定
南海
醣類
South China Sea
sugar
carbohydrates
SDGs
Type
thesis
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