The relationship between cupric ion activity and the toxicity of copper to phytoplankton

Culture experiments with the estuarine diatom Thalassiosira pseudonana (clone 3H) in highly chelated seawater media demonstrate that growth rate inhibition and copper content of cells are related to cupric ion activity, and not to total copper concentration. Cupric ion activity was altered independently of total copper concentration by varying the chelator concentration, and the pH...

Diatoms as tools for assay of total B12 activity and cyanocobalamin activity in sea water

The total cobamide concentration (vitamin B12 plus B12 analogs active for some organisms) can be determined in sea water by bioassay utilizing growth of the centric diatom Bellerochea polymorpha clone 675-d. Vitamin B12 activity can be determined by bioassay utilizing Thalassiosira pseudonana clone 3H; hence the activity of vitamin B12 analogs can be determined by difference...

Cupric ion activity and the growth of phytoplankton clones isolated from different marine environments

The responses to {Cu++} (free cupric ion activity) of 24 clones of 11 species of marine phytoplankton in 4 algal classes were studied in a Cu-Tris buffered medium with a fluorometric method of measuring acclimated growth rates…

Reduction of marine phytoplankton reproduction rates by copper and cadmium

The reproduction rates of 38 clones of marine phytoplankton were measured in media in which free cupric ion activity was controlled at different levels using a NTA-cupric ion buffer system. The major trend among species in their resistance to copper toxicity was a phylogenetic one, with cyanobacteria being the most sensitive, diatoms the least sensitive, and coccolithophores and dinoflagellates intermediate in sensitivity. The reproduction rates of most of the cyanobacteria were reduced at cupric ion activities above 10 −12 M, while most eukaryotic algae still had maximum reproduction rates at 10 −11 M. Four species, Emiliana huxleyi (Lohm.) Hay & Mohler, Skeletonema costatum (Grev.) Cleve, Thalassiosira pseudonana (Hustedt) Hasle & Heimdal and Thalassiosira oceanica (Hustedt) Hasle were particularly resistant to copper, being able to reproduce well at the highest cupric ion activities tested, 10 −9.5 M and 10 −9.2 M. There was no major difference, however, between neritic and oceanic species in their sensitivity to copper. The sensitivity of 20 species of marine phytoplankton to free cadmium ion activity was measured in a similar manner using an NTA-cadmium ion buffer system. As observed with copper, the prokaryotic cyanobacteria were the most sensitive to cadmium toxicity, diatoms were the least sensitive, and coccolithophores and dinoflagellates were intermediate. All cyanobacteria tested were dead at a cadmium ion activity of 10 −9.3 M whereas the reproduction rates of most of the eukaryotic algae were not reduced significantly until 10 −8.3 M. Comparison of these data with natural concentrations in sea water implies that cadmium is not an important ecological factor in unpolluted waters but natural copper concentrations may inhibit the reproduction of some phytoplankton species, especially cyanobacteria, in upwelled sea water. Copper may influence the seasonal succession of species

A method for the rapid and precise determination of acclimated phytoplankton reproduction rates

A rapid method for measuring, simultaneously, the asexual reproduction rates of hundreds of phytoplankton cultures is described. This method is based on the dairy measurement of in vivo chlorophyll fluorescence read directly in the culture tubes. Hundreds of these culture tubes, containing specially prepared culture medium, can be maintained in identical environments in specially designed constant environment devices. The method is capable of measuring the acclimated reproduction rates of phytoplankton cultures with an error of 3–4% (coefficient of variation). Complete acclimation, crucial to the detection of small genetic differences between clones, takes one to three weeks, thus necessitating long-term experiments. Studies using the methods described indicate that, in a constant environment, coccolithophores and dinoflagellates reproduce at constant rates, but diatoms do not