溶解態及膠體態有機磷在西菲律賓海有光層中的分佈與變化

Distribution and Variation of Dissolved and Colloidal Organic Phosphorus in Euphotic Zone of the Western Philippine Sea

鄭佳瑜(Chia-Yu Cheng)

指導教授 ： 溫良碩

國立臺灣大學/理學院/海洋研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.00481

摘要

膠體態有機磷(Colloidal Organic Phosphorus, COP1 kDa ~ 0.45 μm)在海洋磷循環中扮演極其重要角色，但研究資料卻屈指可數。本研究以西菲律賓海，北緯21.69度，東經121.35至123.97度的橫斷面 (transect)為研究海域，探討此貧營養鹽海域有光層中溶解態有機磷及膠體態有機磷的分佈，除此之外，也探討溶解態有機磷及膠體態有機磷在有光層是否會受生物作用或光化學作用而有日夜變化。
本研究利用孔徑為0.45 μm的濾球(capsule filter)及濾膜分子量為1 kDa的交流超微過濾(Cross Flow Ultrafiltration, CFUF)分離樣水，將水體中磷物種分為總溶解態(total dissolved type, ≤0.45 μm)、真溶解態(truly dissolved type, ≤1 kDa) 及膠體態(colloidal type, 1kDa ~ 0.45 μm)，其後利用高溫化學氧化法消化分離出的樣水，再以磷鉬藍分光光度法(UV/VIS spectrometer)進行分析，最後可得到不同分子量 (≤0.45 μm、≤1 kDa、1kDa~0.45μm)的有機態和無機態磷。
由研究結果發現，在西菲律賓海，溶解態有機磷(Dissolved Organic Phosphorus, DOP)濃度範圍是0.03 ~ 0.24 μΜ，COP濃度範圍是0.01 ~ 0.15 μΜ，COP在DOP中佔了約61±16%。有光層中COP在葉綠素最大值深度80 ~ 120 m左右，也就是浮游植物生長旺盛處之深度，濃度達到最高，可見有光層中COP分佈主要受生物作用影響，除此之外，也發現DOP和COP確實有日夜變化，以上的現象皆凸顯了COP在海中磷循環的重要性。

關鍵字

膠體態有機磷 ； 交流超微過濾

並列摘要

Colloidal organic phosphorus (COP) plays an important role in marine P cycle; however, studies on COP are still scarce. This study focused on the distribution and variation of dissolved and colloidal organic phosphorus in euphotic zone of the Western Philippine Sea.
Seawater samples were separated into total dissolved (≤0.45 μm), truly dissolved (≤1 kDa), and colloidal (1 kDa ~ 0.45 μm) fractions by in-line filtration of 0.45 μm-size capsule filter and then Cross-Flow Ultrafiltration (1kDa). After separation, each fraction were digested by a high temperature oxidation method and analyzed by phosphomolybdate-blue spectrophotometry. Therefore, different fractions of both inorganic and organic phosphorus were determined.
Results shown that the DOP concentration ranged 0.06 ~ 0.24 μM, and the COP concentration ranged 0.03 ~ 0.15 μΜ in the euphotic zone. The COP accounted for a significant amount of 61±16% in the DOP. Also, it was found that the depths of COP maximum concentration coincided with the depths of chlorophyll A maximum. In addition, it is also found that COP varies between day time and night hours. All these evidences highlight the strong biological effect on production and assimilation of COP and its vital importance in marine P cycle.

並列關鍵字

colloidal organic phosphorus ； cross flow ultrafiltration

參考文獻

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