Algal growth response to particle‐bound orthophosphate and zinc

Abstract

Dissolved nutrient concentrations in natural waters may at times be controlled by interactions between particulate and solution phases. Effects of Zn [O-l PM total Zn(II)] and orthophosphate (8-12 PM total P) additions on growth indices for the chlorophyte Selenastrum capricornutum Printz were examined in a synthetic growth medium containing 50 mg liter-l colloidal titania. Over the Zn(H) concentration range used, detrimental growth and yield effects were observed. Addition of P to a synthetic growth medium (S-3) increased stationary phase cell density, but had minimal effect on growth rate and duration of lag phase. Presence of TiO, particles in culture media significantly reduced Zn and P dissolved fractions. Although adsorbed Zn and P were less available to Selenastrum, desorption of both solutes increased their availability. Rapid desorption of Zn(I1) from TiO, particles served in effect to buffer Zn2+ free ion concentration, until Zn became partitioned primarily with the algal fraction as cell concentration approached stationary phase density. Although phosphate desorption from TiO, in nonbiological systems was negligible, Sefenastrum was able to scavenge some P initially adsorbed onto TiO,. Accurate primary productivity predictions in nature may therefore require an understanding of equilibrium and reaction rates involved in the partitioning of nutrients and toxic substances between dissolved and particulate phases.

Synergistic Effects of Nano-Sized Titanium Dioxide and Zinc on the Photosynthetic Capacity and Survival of Anabaena sp.

“…Large aggregates of TiO 2 nanoparticles entrapped algal cells (Figure 1b), which reduced the light available to the algal cells and inhibited their growth [32,33]. Moreover, nutrients adsorbed by nano-TiO 2 in culture medium would contribute to the toxicity [34]. …”

Toxicity of oxide nanoparticles to the green algae Chlorella sp.

“…2B and F), which may reduce the light available to the entrapped algal cells and thus inhibit their growth [1]. Besides the above-mentioned mechanisms of toxicity, nutrients like Zn and P in the algal growth medium may be adsorbed by nanoTiO 2 , which would then limit the availability of these nutrients to the algae and contribute to the toxicity [36]. 6.…”

Benthic algal populations respond to aluminum, acid, and aluminum-acid mixtures in artificial streams

“…Algal densities may decline if acidic waters impair nutrient (N or P) uptake and/or metabolism (Soeder & Stengel, 1974;Kuwabara, 1985;Kuwabara et al, 1986;Rybak et al, 1989). High nitrate levels in the Acid + Al treatment on day 28 may have been due to inhibited nitrate uptake.…”