Role of aluminum and growth rate on changes in cell size and silica content of silica-limited populations of Asterionella ralfsii var. Americana (bacillariophyceae)
- Univ. of Michigan, Ann Arbor (USA)
Changes in cell size and silica content were examined in response to aluminum additions in cultures of the acidophilic diatom Asterionella ralfsii var. americana Koern at pH 6.0. The effects of Al were examined over a range of steady-state growth rates using silica-limited semicontinuous cultures (Si:P = 8.0). Additions of {ge}2.8 {mu}mol{center dot}L{sup {minus}1} total Al decreased mean cell length, total surface area, and biovolume up to 40-50%. The effects of Al were dependent on growth rate with the magnitude of size reduction increasing at higher growth rates. The proportion of small (approximately 15-20 {mu}m) cell length classes increased relative to large (approximately 50 {mu}m length) cell length classes when total Al exceeded 2.8 {mu}mol{center dot}L{sup {minus}1}, particularly at higher growth rates. The relationship between cell quota and steady-state growth rate fit a Droop relationship at 0 and 2.8 {mu}mol{center dot}L{sup {minus}1} total Al, but this fit was highly variable in the presence of Al. Cell quotas in the 6.22 {mu}mol{center dot}L{sup {minus}1} total Al treatment were highest at low growth rates; therefore, a Droop relationship was an inappropriate descriptor of growth rate. Cells also became 30-40% more heavily silicified per unit surface area in the presence of Al and at growth rates {ge}0.22 day{sup {minus}1}. Although the mechanisms responsible for size reductions in response to Al additions are unclear, the relationship between metal concentration and frustule morphology may be useful as an indicator of Al loading to acidified lakes.
- OSTI ID:
- 6066618
- Journal Information:
- Journal of Phycology; (USA), Vol. 26:2; ISSN 0022-3646
- Country of Publication:
- United States
- Language:
- English
Similar Records
Net carbon dioxide exchange rates and predicted growth patterns in Alstroemeria Jacqueline' at varying irradiances, carbon dioxide concentrations, and air temperatures
Expression of an L-alanine dehydrogenase gene in Zymomonas mobilis and excretion of L-alanine
Related Subjects
ALUMINIUM
TOXICITY
DIATOMS
SENSITIVITY
ACIDIFICATION
BIOLOGICAL INDICATORS
GROWTH
LAKES
MORPHOLOGICAL CHANGES
ALGAE
CHROMOPHYCOTA
ELEMENTS
METALS
PLANTS
SURFACE WATERS
560300* - Chemicals Metabolism & Toxicology