Stable isotopic composition of deep-sea gorgonian corals Primnoa spp.: a new archive of surface processes
Stable isotopic composition of deep-sea gorgonian corals Primnoa spp.: a new archive of surface processes
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深海柳珊瑚 Primnoa spp. 的稳定同位素组成：表面过程的新档案
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
R. McKinney
中科院分区：
文献类型：
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作者：
O. Sherwood;J. Heikoop;D. Scott;M. Risk;T. Guilderson;R. McKinney
深海柳珊瑚Primnoa spp生活在65至3200米深的大西洋和太平洋，树状生长，骨骼轴由方解石和柳珊瑚制成的年轮组成。寿命可能会超过几百年。有人建议，骨骼的柳珊瑚素组分的同位素剖面可以用来重建地表生产力的长期、年度尺度变化。我们在一组现代和化石标本中测试了关于营养水平、菌落内和菌落间同位素重复性以及同位素标志保存的假设。通过对δ15N的测定表明，该菌具有较高的生物活性。主要摄食浮游动物和/或沉降性颗粒有机物(POM汇)，而不是悬浮POM(POMsusp)或溶解有机碳(DOC)。东北太平洋陆架水、西北大西洋斜坡水、日本海和南太平洋(南大洋区)海山样品中的δ13C和δ15N与表层表观氧利用密切相关，显示了表层水中骨骼同位素比和生物物理过程之间的耦合。同一菌落不同切片和同一区域不同菌落的时间序列同位素谱对δ13C的同源性较高，而δ15N谱的重复性较差。现代标本和化石标本在C：N、δ13C和δ15N方面的相似性表明，同位素特征在千年时间尺度上得到了保存。这些结果支持对报春花的利用。作为地表水过程的历史记录者，如生物生产力和来源养分的同位素组成。
The deep-sea gorgonian coral Primnoa spp. live in the Atlantic and Pacific Oceans at depths of 65 to 3200 m. They have an arborescent growth form with a skeletal axis composed of annual rings made from calcite and gorgonin. Lifespans may exceed several hundreds of years. It has been suggested that isotope profiles from the gorgonin fraction of the skeleton could be used to reconstruct long-term, annual-scale variations in surface productivity. We tested assumptions about the trophic level, intra- and inter-colony isotopic reproducibility, and preservation of isotopic signa- tures in a suite of modern and fossil specimens. Measurements of gorgonin δ 15 N indicate that Prim- noa spp. feed mainly on zooplankton and/or sinking particulate organic matter (POMsink), and not on suspended POM (POMsusp) or dissolved organic carbon (DOC). Gorgonin δ 13 C and δ 15 N in specimens from NE Pacific shelf waters, NW Atlantic slope waters, the Sea of Japan, and a South Pacific (South- ern Ocean sector) seamount were strongly correlated with surface apparent oxygen utilization (AOU; the best available measure of surface productivity), demonstrating coupling between skeletal iso- topic ratios and biophysical processes in surface water. Time-series isotopic profiles from different sections along the same colony, and different colonies inhabiting the same area were identical for δ 13 C, while δ 15 N profiles were less reproducible. Similarity in C:N, δ 13 C and δ 15 N between modern and fossil specimens suggest that isotopic signatures are preserved over millennial timescales. These results support the use of Primnoa spp. as historical recorders of surface water processes such as bio- logical productivity and the isotopic composition of source nutrients.