Morphology and microstructure of marine silk fibers

Reports of textiles recovered from marine sites are uncommon and research is needed regarding the physico-chemical structure of water-degraded archaeological textiles and how the marine environment has altered them (1,2). Recovery of trunks full of clothing from the ocean floor site of the shipwrecked S.S. Central America (3) provided a unique opportunity for the study of materials exposed to a marine environment. Recognizing that these textiles could be used to understand both their cultural use in the Gold Rush era and the processes of textile degradation in the deep ocean, research has been conducted on the functions and the structures of the textiles and clothing (4,5), as well on the physical and chemical characteristics of the fibers from which the textiles were made (6-12). Silk textiles appeared to be in fairly good condition apart from some staining and surface deposits. Morphological features revealed through optical and scanning electron microscopy were compared to those of modern silk and silk obtained from historic textiles of comparable age. Elemental composition of the fibers and surface deposits was determined using energy dispersive spectroscopy. Chemical composition and alterations in secondary structure were studied through infrared microspectroscopy. The implications of the stability of silk in this marine site are discussed.