Baun, Anders

Hartmann, Nanna Isabella Bloch

Hjorth, Rune

Olsson, Mikael Emil

Sørensen, Sara Nørgaard

Online Research Database In Technology

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Downloaded from orbit.dtu.dk on: Dec 20, 2017A certain shade of green: New insights into shading effects of nanoparticles on algalgrowthHjorth, Rune; Sørensen, Sara Nørgaard; Olsson, Mikael Emil; Baun, Anders; Hartmann, Nanna IsabellaBlochPublication date:2015Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Hjorth, R., Sørensen, S. N., Olsson, M. E., Baun, A., & Hartmann, N. I. B. (2015). A certain shade of green: Newinsights into shading effects of nanoparticles on algal growth. Poster session presented at SETAC Europe 25thAnnual Meeting, Barcelona, Spain.Cuttriss, A.J., Chubb, A.C., Alawady, A., Grimm, B. & Pogson, B.J. (2007). Regulation of lutein biosynthesis and prolamellar body  formation in Arabidopsis. Functional Plant Biology. 34. p.pp. 663–672. Hartmann, N. B., Engelbrekt, C., Zhang, J., Ulstrup, J., Kusk, K. O., & Baun, A. (2012). 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A certain shade of green: New insights into shading effects of nanoparticles on algal growth  Rune Hjorth, Sara Nørgaard Sørensen, Mikael Emil Olsson, Anders Baun and Nanna Bloch Hartmann  Technical University of Denmark, Department of Environmental Engineering, DK-2800 Kgs. Lyngby, Denmark Corresponding author: ruhj@env.dtu.dk Inhibitory effects of nanoparticles on algal growth have been the subject of many scientific studies. Physical effects – such as shading on a cellular level – is considered a potential effect mechanism (e.g. Hartmann et al., 2012; Schwab et al., 2011; Aruoja et al., 2009). A change in pigment composition upon nanoparticle exposure has been hypothesized to indicate shading on a cellular level (Wei et al., 2010). Pigment composition is known to be affected by changes in light conditions as a result of photo-acclimation. Here we investigate the pigment composition of green algae and how the composition change as a result of shading. Nanoparticles and shading in ecotoxicology Method Corrected growth rate Conclusion Carotenoid biosynthetic pathway Changes in pigment composition due to shading • It was confirmed that pigment ratios in green algae P. subcapitata are correlated to light intensity and thereby affected by shading. • Using this method we will test suspensions of nanoparticles suspected to affect algae growth through shading. • This method will assist to elucidate the effect mechanisms of nanoparticles and other turbid solutions towards algae.  The green microalgae Pseudokirchneriella subcapitata was incubated as described in OECD TG 201 using a mini-scale algal test (Arensberg et al., 1995) with different natural density filters on the outside of the vials which only allow for respectively 71, 25, 13 and 6 % light transmission through the glass. The algae pigments were  extracted with acetone and  analysed with HPLC-DAD.   Normal growth rate calculations are often based on chlorophyll concentrations (e.g. fluorescence measurements). However, a relative increase in chlorophyll can be caused by shading. A corrected growth rate can be estimated if the change in pigment composition due to shading is known. (Cuttriss et al., 2007) Green algae increase their content of xanthophylls at high light intensities and decease them at  lower levels. In our extractions, the xanthophylls  lutein, violaxanthin and neoxanthin as well as chlorophyll a and b were found in high enough concentrations to quantify.    

A certain shade of green: New insights into shading effects of nanoparticles on algal growth

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A certain shade of green: New insights into shading effects of nanoparticles on algal growth

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