Colloidal andDissolved Organic Matter Excreted byaMixotrophic Flagellate during Bacterivory andAutotrophy
Colloidal andDissolved Organic Matter Excreted byaMixotrophic Flagellate during Bacterivory andAutotrophy
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混合营养鞭毛虫在食菌和自养过程中排出的胶体和溶解有机物
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发表时间：
1994
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影响因子：
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通讯作者：
L. Tranvik
中科院分区：
文献类型：
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作者：
L. Tranvik
本文研究了一种兼养型鞭毛虫--马拉汉Poterioochromonas malhamensis对溶解态和胶体态有机碳的排泄。将鞭毛体与14 C标记的细菌或无机14 C孵育，以比较来自初级生产的有机分泌物与来自巢细菌的分泌物。与初级生产的分泌物相比，> 0.02pum的胶体在巢菌分泌物中所占比例较大。比较了鞭毛藻对细菌特异性标记的不同细胞组分的摄食情况。细胞壁组分比其他组分产生的胶体有机碳少。为了研究鞭毛虫分泌物的降解性，将它们加入到清水中，并监测其对~（14）Co_2的矿化。细菌分泌物比光合作用分泌物更难降解。这些结果支持了细菌利用不稳定有机物，然后鞭毛噬菌和分泌物，导致不稳定有机物转化为更好的柠檬酸形式的假设。远洋环境中的有机质大多以溶解态存在。因此，溶解有机物（DOM;操作上定义为通过孔径通常为0.2 - 0.7-μ m的孔隙过滤器的有机物[1]）的动力学过程对我们来说是至关重要的。
Excretion ofdissolved andcolloidal organic carbon byamixotrophic flagellate, thechrysophyte Poterioochromonas malhamensis, wasstudied. Flagellates wereincubated either with14C-labeled bacteria orwith inorganic 14C, inordertocompare organic exudates originating fromprimary production withexudates originating fromingested bacteria. Colloids of>0.02pumconstituted a larger fraction oftheexudates originating fromingested bacteria, compared withexudates derived fromprimary production. Flagellate feeding onbacteria specifically labeled indifferent cell components wascompared. Cellwallcomponents gave risetolesscolloidal organic carbon thandidothercell constituents. Toinvestigate thedegradability of flagellate '4C-exudates, they wereaddedtolakewaterandmineralization to'4Co2wasmonitored. Bacterially derived exudates weremorerecalcitrant thanexudates originating fromphotosynthesis. Theresults support thehypothesis thatbacterial utilization oflabile organic compounds, followed byflagellate bacterivory and exudation, results inatransformation oflabile organic matter intomorerecalcitrant forms. Mostoftheorganic matter inpelagic environments generally exists inthedissolved form. Thus, processes involved inthe dynamics ofdissolved organic matter(DOM;operationally defined asorganic matterthatpasses theporesoffilters, usually of0.2-to0.7-,um poresize[1]) arecrucial toour