The assimilation of detritus‐bound metals by the marine copepod Acartia spinicauda
The assimilation of detritus‐bound metals by the marine copepod Acartia spinicauda
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海洋桡足类 Acartia spinicauda 对碎屑结合金属的同化
DOI：
10.4319/lo.2002.47.2.0604
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Wen
中科院分区：
文献类型：
--
作者：
Yan Xu;Wen
在实验室条件下，用放射性示踪法研究了不同生物来源的碎屑中Cd、Se和Zn对海洋桡足类刺尾纺锤水蚤的生物有效性。三种类型的碎屑，从macrophora石莼，细胞碎片的硅藻海链藻weissflocum和海链藻圆后，自然分解或提取，和桡足类粪便颗粒，进行了检查。从摄入的天然浮游植物组合的金属同化也实验量化。在以不同类型的碎屑喂养的桡足类中，金属的同化效率（AE）为Cd的47 - 83%，Se的30 - 59%，Zn的41 - 75%。这些值与以前测量的以活藻类细胞为食的桡足类的AE相当，表明与生物颗粒相关的金属可直接供海洋桡足类使用。标记时间对摄食来自美国的碎屑的桡足类的金属AE没有影响。莴苣金属AE是较高的桡足类喂养的新鲜制备的硅藻碎片比自然分解的碎片。锌与粪便颗粒同化的效率相当的那些与大型藻类和微藻碎片，但镉和硒的同化效率较低时，与粪便颗粒。在所有实验中，以天然浮游植物群落为食的桡足类中镉的AE（84 - 94%）最高。天然浮游植物群落细胞溶质中金属的分布对金属AE没有明显的影响。计算的金属的消除率是独立的碎屑类型，并与以前的研究相似。我们的研究表明，碎屑是一个潜在的食物来源的海洋桡足类和金属与碎屑可以有效地利用相对较高的AE。因此，碎屑可能在海洋中金属的总体地球化学循环中发挥重要作用。
The bioavailability of Cd, Se, and Zn associated with detritus of different biological origins to the marine copepod Acartia spinicauda was examined under laboratory conditions using the radiotracer approach. Three types of detritus, from the macroalga Ulva lactuca, cell debris of the diatoms Thalassiosira weissflogii and Thalassiosira rotula derived after natural decomposition or extraction, and copepod fecal pellets, were examined. The assimilation of metals from the ingested natural phytoplankton assemblage was also experimentally quantified. The assimilation efficiencies (AEs) of metals in copepods fed with different types of detritus were 47‐83% for Cd, 30‐59% for Se, and 41‐75% for Zn. These values were comparable to the AEs measured previously for copepods fed on living algal cells, indicating that metals associated with biogenic particles were directly available to marine copepods. Labeling time had no effect on the metal AEs in copepods fed on detritus derived from U. lactuca. The metal AEs were higher in copepods fed on the freshly prepared diatom debris than on naturally decomposing debris. Zn associated with fecal pellets was assimilated at comparable efficiencies to those associated with macroalgal and microalgal debris, but Cd and Se were assimilated at a lower efficiency when associated with fecal pellets. The AEs of Cd (84‐94%) in copepods fed on the natural phytoplankton assemblage were the highest among all the experiments. There was no obvious effect of the metal distribution in the cytosol of the natural phytoplankton assemblage on the metal AE. The calculated elimination rates of the metals were independent of detritus type and were similar to previous studies. Our study indicated that detritus is a potential food source for marine copepods and the metals associated with the detritus can be efficiently used with a relatively high AE. Detritus may thus play an important role in the overall biogeochemical cycling of metals in the ocean.