Benthic microbial and whole‐community responses to different amounts of 13C‐enriched algae: In situ experiments in the deep Cretan Sea (Eastern Mediterranean)
Benthic microbial and whole‐community responses to different amounts of 13C‐enriched algae: In situ experiments in the deep Cretan Sea (Eastern Mediterranean)
复制标题
底栖微生物和整个群落对不同数量的富含 13C 的藻类的反应：克里特岛深海（东地中海）的原位实验
DOI：
10.4319/lo.2006.51.1.0157
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发表时间：
2006
影响因子：
4.5
通讯作者：
U. Witte
中科院分区：
文献类型：
--
作者：
S. Bühring;N. Lampadariou;L. Moodley;A. Tselepides;U. Witte
地中海东部深海是世界海洋中营养最贫乏的地区之一，因此非常适合研究资源有限的深海底栖群落对食物豆类的反应。此外，底栖生物对有机物 (OM) 沉积的响应可能会根据进入沉积物的 OM 量而有所不同。在这里，我们报告了使用 13C 标记的硅藻作为不稳定 OM 示踪剂的 36 小时脉冲追踪实验。两批 OM，相当于 25 mg C m−2（低碳 [L] 实验）和 250 mg C m−2（高碳 [H] 实验），被注入底栖着陆器的舱室中。添加的碳的命运遵循总群落呼吸和细菌同化（通过细菌特异性脂肪酸中的 13C 富集）。在这两个实验中，底栖反应都很明显，但随着 OM 添加量的增加，碳周转率也更高。然而，虽然H实验中细菌同化了较多的碳，但与L实验相比，细菌同化占总碳处理的比例相对较低。这一结果可能表明细菌反应发生了变化，或者其他生物成分在高负荷实验中发挥了更大的作用，或者两者兼而有之。这项研究表明，贫困的深海底栖群落对新鲜有机物质的输入能迅速做出反应。此外，碳流动路径可能会根据进入沉积物的 OM 量而有所不同。因此，只有在使用类似数量和质量的 OM 的情况下，才能对不同系统的底栖反应进行比较。
The deep eastern Mediterranean Sea is one of the most oligotrophic regions of the world’s oceans and is therefore highly suitable for investigating the response of a resource‐limited deep‐sea benthic community to food pulses. Additionally, the benthic response to organic matter (OM) deposition can differ according to the amount of OM entering the sediment. Here, we report on 36‐h pulse‐chase experiments with 13C‐labeled diatoms as a tracer of labile OM. Two loads of OM, equivalent to 25 mg C m−2 (low‐carbon [L] experiment) and 250 mg C m−2 (highcarbon [H] experiment), were injected into chambers of a benthic lander. The fate of the added carbon was followed in total community respiration and bacterial assimilation (through 13C enrichment in bacteria‐specific fatty acids). A benthic response was clearly evident in both experiments, but carbon turnover rates were higher with a higher OM addition. However, although a larger amount of carbon was assimilated by bacteria in the H experiment, bacterial assimilation accounted for a relatively lower proportion of total carbon processing compared with the L experiment. This result could indicate a modified bacterial response, a larger role of other biotic components in the high‐load experiment, or both. This study demonstrates that an impoverished deep‐sea benthic community rapidly responds to an input of fresh OM. Furthermore, the carbon flow pathways can differ according to the amount of OM entering the sediment. Consequently, comparison of benthic responses across systems can only be made in cases in which similar quantities and qualities of OM have been used.