Use of environmental scanning electron microscopy to image the spore adhesive of the marine alga Enteromorpha in its natural hydrated state

The environmental scanning electron microscope (ESEM) has been used to image the adhesive secreted by zoospores of the marine alga Enteromorpha as they settle on a surface, under natural, hydrated conditions. Results reveal a featureless, swollen gel-like adhesive pad, in contrast to the fibrillar character of the adhesive when imaged by standard SEM. At high spore densities the adhesive is confluent. Dynamic hydration/dehydration events were followed by changing the water vapour pressure in the sample chamber. Rapid hydration and swelling were observed indicating a very hygroscopic material. Adhesive footprints were detected when surfaces from which spores had been removed by water jetting were examined. (C) 2002 Elsevier Science B.V. All rights reserved.