After a restorative run and morning squash game with Mark, I spent the morning preparing a second set of SEM stubs of the diatoms I had sonicated and cleaned yesterday afternoon (the batch I’d made yesterday seemed a little too dense, having left behind a thick chalky white dot where the water dried up). I booked the next available SEM slot, which\u2014miraculously\u2014was at 1pm today, raced to get the stubs sputter coated, and checked them out.<\/p>\n
The results are not far off what I expected to see\u2014a lot of flimsy, warped diatoms\u2014and also indicated that even the little sonicating I did yesterday (one blast of about 30 seconds or so, then three more short blasts of <5 seconds) was too much for these weakly silicified things, turning most of the material into rubble.<\/p>\n
Here a selection of what I saw.<\/p>\n
Each sample had a sharp edge where the water droplet was\u2014with a lot of indiscriminate goop (organic matter?)\/fine-grained debris over most of the surface, except at the edge, where some coarser material was visible:<\/p>\n
There were some moderately intact valves amidst the debris:<\/p>\n Many of those looked like they were so flimsy they were essentially warping or folding; some had very large-pored\/flimsy “skirts”:<\/p>\n The second set of samples I made were a little less crowded, but still far too dense:<\/p>\n Even the best-preserved specimens didn’t look like much:<\/p>\n![\"\"](\"http:\/\/blogs.law.harvard.edu\/kotrc\/files\/2010\/09\/B100.jpg\")
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