Impending good news!

In a short time I will announce the creation of a new blog of exchange for young diatomists. Stay tuned for blog address (and googlegroups).

Potential for terrestrial diatom communities and diatom indices

A new and interesting development of diatom science is based on other uses of these organisms. In the article of Antonelli et al (2017). the focus lay on soil diatoms. 

The knowledge of soil diatoms comes of old. The first descriptions of such species were from Ehrenberg in his Mikrogeologie. The knowledge stems from 1847 (see Berger, 1927). 

Diatoms are usually used in the obtention of water quality values. Even though correlations between aerophytic diatoms and land uses are known, they were not followed. Thus, the present study portrays a hereto unknown aspect of bioindication.  Using aquatic indices of diatoms (IPS). Other than missing data from aerophyle species, the results appeared to adhere to predictions. 

This article reiterates the importance of diatom taxonomy. Since some species are not aquatic, they will need to be characterized before using them. It thus has to be an alternative or addition to metagenomics. Diatoms are organisms that colonize most of the surfaces. Though wet surfaces are the preferred milieu, aerophytic diatoms exist. They are useful to use in describing the surrounding land use status, as their aquatic counterparts.

All in all an interesting take and new ideas on new substrata.

Sources: Antonelli, M.; C. E. Wetzel, L. Ector, A. J. Teuling & L. Pfister. 2017. On the potential for terrestrial diatom communities and diatom indices to identify anthropic disturbance in soils. Ecological Indicators 75, pp. 73-81.

Ehrenberg, C. G. (1854). Mikrogeologie: Das Erden und Felsen schaffende Wirken des unsichtbar kleinen selbstständigen Lebens auf der Erde (Vol. 2). L. Voss.

Beger, H. (1927). Beiträge zur Ökologie und Soziologie der luftlebigen (atmophytischen) Kieselalgen. Berichte der Deutschen Botanischen Gesellschaft.

Digital holographic microscopy and diatoms

This first entry will provide a little overview on a new technique of imagery applied to diatoms. Since it is a potential boon to diatom physiology and ecology, I think this article is a worthy beginning to this blog of article commentaries.

1. Zetsche, E. M., El Mallahi, A., and Meysman, F. J. R. 2016. Digital holographic microscopy: a novel tool to study the morphology, physiology and ecology of diatoms. Diatom research, vol. 31 (1), pp. 1-16.

This interesting article provides us with two methods of Digital holography (explanation below). Using different equipment ('oLine D3HM', a stand-alone microscope and 'QMod', an additive to any microscope) a series of six experiments testing diatom imagery has been conducted. It is a fairly technical paper with many potential prospects, even though, given that it was published in a diatom-based magazine, a previous glossary could have been helpful. A very interesting side to this research is the comparison of imaging of dead and living organisms, that shows that this particular tool can provide this determination without the need of staining.

Eventually, this tool can be used as an addition to light microscopy, and will be very useful for ecological and physiological studies, since it can take images of movement. Also, the comparison of both types of holography, showing that, although the stand-alone model is defter for imaging, both types are equally helpful for this task. It makes it therefore possible to use the laboratory equipment of the diatom lab with only an add-on, providing the possibility of making a dual approach to diatom observation.

• Digital holographic microscopy is based on holographic microscopy (Gabor, 1948), a lesser known method added to light microscopy. Through a more or less complicated laser structure, based on two separate light beams (object and reference), a holograph is projected onto the screen.

Gabor, D. 1948. A new microscopic principle. Nature, 161(4098), 777-778.