Preferred use of bacteria over phytoplankton by deep-sea nematodes in polar regions
Preferred use of bacteria over phytoplankton by deep-sea nematodes in polar regions
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DOI：
10.3354/meps08535
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发表时间：
2010-01-01
影响因子：
2.5
通讯作者：
Vanreusel, Ann
中科院分区：
文献类型：
--
作者：
Ingels, Jeroen;Van den Driessche, Pieter;Vanreusel, Ann
本研究在实验装置中探讨了南极和北极深海线虫的选择性摄食特性。人们认为线虫在极地深海食物网的碳通量中起着重要作用，但对它们的自然饮食的了解有限。研究人员首次将来自两极地区的深海多核沉积物样本与c -13标记的细菌或硅藻一起在研究船上孵卵，以确定线虫群落是否更喜欢新鲜沉降的植物碎屑而不是细菌食物来源。在2112至2400米水深处收集岩芯，在北极（Hausgarten）船上孵育1、3和6天，在南极（Kapp Norvegia）船上孵育1、7和14天。线虫的天然碳同位素信号与有机沉积碳表现出明显的平均偏移（+3.2 ppm）。细菌对线虫饮食的贡献解释了这种碳-13偏移，并观察到自然的碳-13同位素特征。线虫对两区表层沉积物中富含C-13细菌的脉冲具有明显、较快的选择性响应（最大响应时间为6 ~ 7 d）。这表明细菌比新鲜的浮游植物更适合作为北极和南极深海线虫群落的碳源。结果还表明，细菌可能提供了一条途径，通过微生物对有机物的改造，未使用的碎屑可能进入传统的后生动物食物网。同时，线虫群落的吸收率很小，这表明在极地深海中，线虫对新沉积有机物的底栖矿化的贡献可能有限。
The present study explored the selective feeding properties of Antarctic and Arctic deep-sea nematodes within an experimental setup. Nematodes are assumed to play an important role in the carbon flux within the polar bathyal food webs, but knowledge about their natural diets is limited. For the first time, deep-sea multicore sediment samples from both polar regions were incubated aboard research vessels with either C-13-labelled bacteria or diatoms to determine whether the nematode community prefers freshly settled phytodetritus to a bacterial food source. The cores were collected at 2112 to 2400 m water depth and incubated onboard for 1, 3 and 6 d in the Arctic (Hausgarten) and for 1, 7 and 14 d in Antarctica (Kapp Norvegia). Natural carbon isotope signals of nematodes and organic sedimentary carbon showed a clear average offset (+3.2 parts per thousand). The contribution of bacteria to the diet of nematodes explained this C-13 offset and observed natural C-13 isotopic signatures. The nematodes showed a clear, relatively rapid (maximum at 6 to 7 d) and significant selective response to the pulse of C-13 enriched bacteria in surface sediments of both regions. This indicated that bacteria were preferred over fresh phytoplankton as a carbon source for both Arctic and Antarctic deep-sea nematode communities. The results also suggest that bacteria may provide a path through which unused detritus may enter the traditional metazoan food web by microbial reworking of organic matter. At the same time, uptake rates of nematode communities were minimal, which suggests the contribution of nematodes to benthic mineralisation of freshly deposited organic matter may be limited in deep polar seas.