Studied diatomite rocks are light in weight and rich in soft materials as well as in amorphous silica, which is mainly present in the form of diatom
frustules.
One colony (a), solitary polyps and
frustules were maintained alive in a Petri dish and kept in the refrigerator (8 [degrees]C) for further observation, while the other colony (b) was immediately preserved with 70% ethanol.
Sedimentary diatom remains (their silica shells, called
frustules) are routinely used as paleoenvironmental proxies in remote northern regions where long-term instrumental data are rare or lacking (e.g., Pienitz et al., 2004).
It has been shown that major reservoirs built on boreal rivers can hold 30% to 70% of their annual water discharge (Dynesius and Nilsson, 1994), which can significantly decrease dissolved Si concentrations in rivers by providing preconditions for enhanced diatom growth and sedimentation of diatom
frustules, and subsequent burial in sediments behind dams (Conley et al., 2000).
Additionally, the polyp is able to asexually produce vermiform buds or "
frustules" which give rise to new polyps, consequently increasing the number of polyps over time (Edwards, 1976; Bakker, 1980).
de Stefano, "Nanostructures in diatom
frustules: functional morphology of valvocopulae in cocconeidacean monoraphid taxa," Journal of Nanoscience and Nanotechnology, vol.
Also silver bioaccumulations in epipelic diatom
frustules of Yoncali Village (after discharge of mine) were significantly higher than uncontaminated stations (an average of 7 times).
Diatoms are unicellular golden-brown algae (Bacillariophyta) characterized by silica shells (
frustules) that are well preserved in lake sediments.
Planktonic diatoms contribute
frustules to the sediment in deep open-water areas, while periphytic diatoms are primarily associated with shallower littoral habitats closer to shores (Wolin & Duthie 1999).