The investigation of kinetic growth of Chlorella vulgaris cells by the method of integral and dynamic light scattering

Abstract

Laboratory measurements of light scattering on axenic cultures of the unicellular alga Chlorella vulgaris confirm multilevel light scattering by the cell (i.e. both by the outer cell membrane and the internal structure of the cell, as well as by its molecular structure). The technique of dynamic light scattering and analysis by the regulation method suggest that the light scattering phenomena is affected by particles of sizes corresponding either to the overall dimensions of the cell or to the dimensions of its internal structure. A correlation was found between the suggested sizes and the stage of physiological evolution of the culture. Three well‐known stages (adaptation, logarithmic and stationary growth) can be recognized easily in changes observed in the size distribution of the scattering centers as measured by the dynamic light scattering technique and in the shape changes of elements of the scattering matrix. The occurrence of cells containing large internal structure elements, such as autospores, affect elements of the scattering matrix, suggesting that cell structure should be taken into account as a scattering system producing rotatory polarization of the scattered light.

Light and photosynthetic microalgae: A review of cellular- and molecular-scale optical processes

“…Compared to the volume scattering function, Müller matrix of microalgae suspension contains more detailed information on the inner structure, size and shape of the cells (Quinby-Hunt et al 1989;Witkowski et al 1998;Witkowski et al 1993;Volten et al 1998). It has been shown that the elements M34, and M11 are sensitive to the size of the algae (Quinby-Hunt et al 1989), the difference M22-M11 to the shape (Quinby-Hunt et al 1989), and the elements M11, M12, M34 to the inner cellular structure (Quinby-Hunt et al 1989;Witkowski et al 1993;Volten et al 1998). In addition, Witkowski et al (Witkowski et al 1998) measured all elements of the Müller matrix and observed optical activity (or rotation of linearly polarized light) indicated by non-zero readings for M13, M14 and M24.…”

Simulating the optical properties of phytoplankton cells using a two-layered spherical geometry

“…The chloroplast of an autotrophic eukaryotic cell is the membrane bound organelle containing the highly absorbing pigment-protein complexes responsible for light harvesting and photosynthesis, and it will exert a profound optical effect. Algal related studies investigating the effects of cellular internal structure on scattering (Witkowski et al, 1993(Witkowski et al, , 1998 and absorption packaging (Geider and Osborne, 1987) indicate the importance of chloroplasts in modifying both the absorbing and scattering properties of algal cells. Imposing a simple two-layered geometry upon a hypothetical algal cell thus requires some knowledge of the variability of chloroplast size, or more appropriately, the relative chloroplast volume.…”

Measurements of the Volume Scattering Function and the Degree of Linear Polarization of Light Scattered by Contrasting Natural Assemblages of Marine Particles

“…The angular pattern of light scattering can also contain useful information about the composition of particulate assemblages, including the bulk refractive index of particles [15][16][17][18][19]. In addition, measurements of the scattering matrix that provide information about polarization effects of light scattering [15,[20][21][22][23] have the potential for identifying and discriminating different types of particles, such as phytoplankton species or minerals, which are present in complex natural assemblages [24][25][26][27][28][29][30][31][32][33][34]. Despite the potential usefulness of information provided by light scattering measurements, the complexity and variability in composition of natural particulate assemblages impose significant challenges in achieving an understanding of bulk light-scattering properties of seawater in terms of detailed compositional characteristics of particulate matter [35].…”