Sandford Floyd
Coe College, Cedar Rapids, Iowa 52402, USA.
Microsc Res Tech. 2003 Nov 1;62(4):336-55. doi: 10.1002/jemt.10400.
The siliceous skeletons of six hexactinellids and demosponges were compared using a series of physical and chemical tests. The sponges were two hermit-crab sponges (Class Demospongiae, family Suberitidae), one from Scotland, Suberites domuncula, and the other, Pseudospongosorites suberitoides, from the Gulf of Mexico, and four hexactinellids, Hyalonema sp., Euplectella aspergillum, Rhabdocalyptus dawsoni, and Aphrocallistes vastus. The operating hypothesis was that differences in the amorphous hydrated silica skeletons in Demosponges and Hexactinellids might prove taxonomically useful. Physical properties studied included SEM, glass density, glass transition temperature (Tg), TG/DTA to determine water content, and FTIR spectra. Chemical determinations were made using energy dispersive X-ray fluorescence (EDXRF). Spicular skeletal material is deposited in concentric layers around the axial canal. With the exception of differences at several bands in the IR spectra, the siliceous skeletons in demosponges and hexactinellids are largely indistinguishable. Density was similar in all sponges (range 2.03-2.13 g/cc) and similar to the density of opal (SiO2 x 1.5H2O) (mean = 2.09 g/cc). IR spectra were similar, with prominent absorption bands at 460-470, 800, and 1,090-1,100 cm(-1) (due to different vibrational modes of Si-O-Si linkages) and at 1,650 and 3,450-3,560 cm(-1) (due to water). The skeletons of all six showed similar spectra to that of silica gel both before and after heating to 1,200 degrees C. Water comprised 10-14% of the skeleton by weight, slightly higher in the demosponges. Average spicule chemical composition was 85.2% SiO2, 12.3% water, and 2.5% other elements (mainly S, Al, K, Ca, and Na). The percent amounts of Si did not differ significantly between the demosponges and the hexactinellids.
使用一系列物理和化学测试对六种六放海绵纲动物和寻常海绵纲动物的硅质骨骼进行了比较。这些海绵包括两种寄居蟹海绵（寻常海绵纲，Suberitidae科），一种来自苏格兰的Suberites domuncula，另一种是来自墨西哥湾的Pseudospongosorites suberitoides，以及四种六放海绵纲动物，分别是Hyalonema sp.、拂子介（Euplectella aspergillum）、道氏盘海绵（Rhabdocalyptus dawsoni）和巨穴海绵（Aphrocallistes vastus）。操作假设是，寻常海绵纲动物和六放海绵纲动物中无定形水合二氧化硅骨骼的差异可能在分类学上具有用途。所研究的物理性质包括扫描电子显微镜（SEM）、玻璃密度、玻璃化转变温度（Tg）、用于测定含水量的热重/差热分析（TG/DTA）以及傅里叶变换红外光谱（FTIR）。化学测定使用能量色散X射线荧光光谱法（EDXRF）。针状骨骼物质围绕轴向管道以同心层形式沉积。除了红外光谱中几个波段存在差异外，寻常海绵纲动物和六放海绵纲动物的硅质骨骼在很大程度上难以区分。所有海绵的密度相似（范围为2.03 - 2.13克/立方厘米），且与蛋白石（SiO₂·1.5H₂O）的密度相似（平均值 = 2.09克/立方厘米）。红外光谱相似，在460 - 470、800以及1090 - 1100厘米⁻¹处有明显吸收带（归因于Si - O - Si键的不同振动模式），在1650以及3450 - 3560厘米⁻¹处有吸收带（归因于水）。所有六种海绵的骨骼在加热至1200摄氏度前后的光谱都与硅胶的光谱相似。水占骨骼重量的10 - 14%，在寻常海绵纲动物中略高。平均针状体化学成分是85.2%的SiO₂、12.3%的水和2.5%的其他元素（主要是S、Al、K、Ca和Na）。寻常海绵纲动物和六放海绵纲动物中Si的百分比含量没有显著差异。
