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Assessing Interactions of Microalgae in Synthesizing Nanoparticles
Published in Pradipta Ranjan Rauta, Yugal Kishore Mohanta, Debasis Nayak, Nanotechnology in Biology and Medicine, 2019
Manoj Kumar Enamala, Azzuliani Binti Supangat, Chandrashekar Kuppam, Sudhakar Reddy Pamanji, Murthy Chavali, Maria P. Nikolova
A large number of species like Umbilicosphaera sibogae, Emiliania huxleyi, M. elegans, Scyphosphaera porosa, Pleris japonica, etc., have been used in the field of nanotechnology. In the recent past, many researchers have sequenced the genomes of these coccoliths, which prompted them to explore more about the structures of coccoliths and also helped them understand the pathways and mechanism of their synthesis process. Until then it was hard to imagine the structures of these coccoliths. Currently, this branch of study is also gaining prominence by modifying the structures and understanding the mechanisms of these species. The Umbilicosphaera sibogae eyelets of 1–2-µm in diameter were used in the filtration, whereas Calcidiscus leptoporous was used for studying the optical properties of the light by the light-scattering technique. These coccoliths were also used in the development of nanoactuators, which help in the movement of objects at nanoscales. Many coccoliths like Discosphaera tubifera and Rhabdosphaera clavigera are used in the applications of nanoactuators because of their hollow funnel and tubular shape and also because they have nanopores or slits which are helpful in designing these devices. Since these coccoliths have a wide variety of applications in the field of nanotechnology, there are quite a lot of challenges being faced with the growth of these coccoliths: for instance, there must be proper cultivation systems, the cultivation systems should be improved for many species, and genetic manipulations of coccolithophores should be developed and studied on a large-scale basis so that the calcium formation pathways can be exploited further for the efficient development of products (Boeckel and Baumann, 2008).
Responses of Calcifying Algae to Ocean Acidification
Published in Donat-P. Häder, Kunshan Gao, Aquatic Ecosystems in a Changing Climate, 2018
From a chemical point of view, obviously, ocean acidification will decrease the saturation of biologically important CaCO3 skeletons of calcifying algae. That is the major reason that most calcifying algae tested so far show a decrease in calcification in response to OA (Riebesell and Tortell 2011, Koch et al. 2013) . To date, only a few studies found positive effects of OA on calcification. Two studies on thecoccolithophore E. huxleyi appear to suggest that the calcification is stimulated by OA (Iglesias–Rodriguez et al. 2008, Shi et al. 2009). Beaufort et al. (2011) analyzed the relationship between coccolith mass and carbonate chemistry in the modern ocean and over the past 40,000 years, and found that the overall trend is that ocean acidification decreases calcification. However, these authors also reported that a heavily calcified E. huxleyi morphotype was found in modern high CO2/low pH oceans. Smith et al. (2012) investigated the E. huxleyi population dynamics from summer to winter. The predominance of less calcified cells was shifted from lightly– to heavily–calcified cells along with the lowered pH and CaCO3 saturation in the Bay of Biscay. Ries et al. (2009) also found that net calcification of coralline red algae and calcareous green algae increased under high levels of CO2. Recently, Peach et al. (2017) reported that the calcification of six green Halimeda species was not significantly influenced by OA. Previous studies suggested that different effects of elevated CO2 on calcification may attribute to different species or strains (Langer et al. 2006, Langer et al. 2009). Further studies are needed to explain the tolerance mechanisms of these calcifying algae to OA.
Latest Miocene (Kapitean/Messinian) glauconite and the central Chatham Rise greensand: an enigmatic, highly condensed, relict/palimpsest deposit on the modern seafloor
Published in New Zealand Journal of Geology and Geophysics, 2022
Campbell S. Nelson, Anna S. Lawless, Scott D. Nodder, Horst Zwingmann
In 15 of the 26 cores from central CR sufficiently deep penetration shows that the surficial interval unconformably overlies a relatively consolidated and often bored foram-nanno chalk deposit whose foraminiferal species indicate a mainly Early Oligocene (rarely Late Eocene or Early Miocene) age (Figure 6) (e.g. Kudrass and Cullen 1982; Falconer et al. 1984; Cullen 1987; Wood et al. 1989). XRD scans of five of these chalk samples (Lawless 2012) show they are completely dominated by low-Mg calcite (mainly from planktic foraminifera and nannofossils) with rare siliciclastic material (quartz, plagioclase feldspar and phyllosilicate or clay minerals). Acid digestion confirms their high CaCO3 content (75%–95%). Scanning electron microscopy images reveal a preponderance of whole and broken coccolith plates and scattered foraminiferal and siliceous microfossil debris, and possibly some phyllosilicate minerals, along with variable amounts of adhering micritic cement crystals (Lawless 2012, her Figures 3.36–3.38). These Oligocene carbonates are classical chalk deposits having a texture and composition very similar to those of the Cenozoic foram-nanno oozes and chalks at the nearby DSDP and ODP drill sites shown in Figure 1 (e.g. Nelson 1986; Hayward et al. 2004).
Recent progress at the interface between nanomaterial chirality and liquid crystals
Published in Liquid Crystals Reviews, 2021
Diana P. N. Gonçalves, Marianne E. Prévôt, Şenay Üstünel, Timothy Ogolla, Ahlam Nemati, Sasan Shadpour, Torsten Hegmann
With increasing zeta potential, ζ, achieved by the addition of surfactant cations, i.e. cetyltrimethylammonium (CTA+), these Au nanoplates tended to assemble edge-to-edge rather than face-to-face forming the afore-mentioned twisted nanoribbon, which closely resemble the twisted smectic layers of B4-phase HNFs. These nanoribbons ultimately assemble as spikes radially around an axis according to their ligand configuration (D- or L-cysteine), giving rise to micron-scale coccolith-like supraparticles with distinctive CD spectra. However, flat kayak-shaped supraparticles with a layered architecture were observed when the nanoplates were capped with racemic DL-cysteine at the Au nanoplate surface [178], in analogy to the FNRs formed by some of the afore-listed bent-core molecules with diminished chirality such as compound VI [160] in Figure 21d.