THE NATURE OF SKELETAL DENSITY BANDING IN SCLERACTINIAN CORALS - FINE BANDING AND SEASONAL PATTERNS
THE NATURE OF SKELETAL DENSITY BANDING IN SCLERACTINIAN CORALS - FINE BANDING AND SEASONAL PATTERNS
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DOI：
10.1016/0022-0981(89)90084-1
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发表时间：
1989-01-01
影响因子：
2
通讯作者：
LOUGH, JM
中科院分区：
文献类型：
--
作者：
BARNES, DJ;LOUGH, JM
X射线照片由从两个直径为0.4-0.5 μ m的裂叶滨珊瑚菌落的生长轴上切下的切片和从一个大的实心滨珊瑚菌落的生长轴上钻取的720 mm长的芯上切下的切片制成。用不同角度倾斜的切片制作了实生青霉核切片的X射线照片。两个裂叶侧耳菌落的年密度带型显示，一个菌落生长异常迅速（约1000）。19毫米yr-1），而另一个比通常生长得更慢（8 mm. cntdot. yr-1）。快速生长的菌落保持光滑的外表面，而生长较慢的菌落在其大部分生长过程中显示出更常见的凹凸不平的外表面。光滑表面的快速生长的裂叶侧耳菌落的X射线照片显示一系列交替的致密带。1 mm宽，密度较低的条带可达3 mm宽。类似的细带以前曾被报道为月球带，在熟悉的大型珊瑚的年度密度带模式中，一个密度带和一个密度较低的带。一年一次的模式似乎是目前作为分组的罚款密集带。由于殖民地生长得异常迅速，而且蚁民地的外表面相对光滑，因此这些细小的条带清晰可见。结果，精细的条带通过骨骼切片的厚度与显示它们的X射线束对齐。在凹凸不平的菌落的X射线照片中，精细的条带并不那么明显，因为它们很少与X射线束对齐。滨珊瑚和许多（如果不是全部的话）大型珊瑚的年度带状图案似乎是由这种精细的条带组成的。精细的波段可能不一定代表月球的周期。从菌落中取出的用于X射线照相的切片的厚度，以及切片内细带的对齐和弯曲，倾向于合并或重叠单个细带的X射线图像，因此，强调其宽度、频率和密度的季节性模式。从不同角度拍摄的实生青霉核切片的X射线照片证实了这种精细带型的基本性质。在某些角度上，在其他角度上，只有熟悉的年度密度模式才能看到的区域中显示出精细的条带。细带出现在菌落的外生长表面，可能代表对环境因素的直接和立即反应。
X-radiographs were made of slices cut from the growth axes of two 0.4-0.5 m diameter colonies of Porites lobata, and of a slice cut from a 720 mm long core drilled from the growth axis of a large colony of P. solida. X-radiographs of the core-slice of P. solida were made with the slice tilted lengthways at several different angles. The annual density banding patterns for the two colonies of P. lobata revealed that one grew exceptionally quickly (.apprxeq. 19 mm .cntdot. yr-1) while the other grew more slowly than is usual (.apprxeq. 8 mm .cntdot. yr-1). The fast-growing colony maintained a smooth outer surface while the slower-growing colony displayed the more usual bumpy outer surface throughout most of its growth. X-radiographs of the smooth-surfaced fast-growing colony of P. lobata showed a series of alternating dense bands .apprxeq. 1 mm wide and less dense bands up to 3 mm wide. Similar fine bands have been previously reported as lunar banding within the familiar annual density banding pattern in massive corals of one dense band and one less dense band. An annual pattern appeared to be present as groupings of the fine dense bands. The fine bands were clearly displayed because the colony grew unusually quickly, and because it maintained a relatively smooth outer surface. As a result, the fine bands were aligned, through the thickness of the skeletal slice, with the X-ray beam that displayed them. Fine bands were not so apparent in X-radiographs of the bumpy-surfaced colony because they were seldom aligned with the X-ray beam. The annual banding pattern in Porites, and in many, if not all, massive corals, appears to be composed of such fine bands. The fine bands may not necessarily represent lunar periodicity. The thickness of slices removed from colonies for X-radiography, together with the alignment and curvature of fine bands within the slices, tends to merge or overlap the X-ray image of individual fine bands and, as a result, emphasizes seasonal patterns in their width, frequency and, perhaps, density. The fundamental nature of the fine banding pattern was demonstrated by X-radiographs of the core-slice of P. solida taken at different angles. At certain angles, the fine bands were displayed in regions where, at other angles, only the familiar annual density pattern had been seen. Fine bands appear to be generated at the outer growth surface of colonies and may represent a direct and immediate response to environmental factors.