CHAPTER 9
Phytoplankton
9.1
Sampling
Collier and Edmonds [624] warn that, when algae samples are taken from seawater
and the samples are shipped to the laboratory in containers in contact with seawater,
appreciable transfer of the elements occurs from the solid to the liquid phase. Subsequent analysis of the solid could, in these cirmumstances, lead to low analysis in the
solid phase.
One of the first results observed in leaching experiments was the high concentration of many of the elements in the seawater. Elements initially associated with the
algae were released to the seawater during the 2 h it took to bring the samples from
the tow site into the ship's laboratory for processing. This data can be expressed as the
percentage of the estimated total particulate element which had been released to the
seawater by the time of separation of the cadmium, manganese, and nickel. There was
always an initial pulse of copper released, but its concentration then decreased by
some secondary process. The release of zinc, barium, iron, and aluminium was always
low with respect to their total concentrations.
Suspension of the samples in distilled water accelerated the release of nickel,
cadmium, manganese, and phosphorus up to the level of their maximum release into
seawater after 72 h. The implication of this rapid remineralization process must be
considered during the sampling and handling of algal matter by towing, filtration, and
trapping. The rapid release of elements requires careful containment of the sample,
and complete mass balancing from the time of collection, if any systematics of their
chemistry is to be understood. Variations in sampling techniques will result in large
variations in the collected concentrations of nickel, cadmium, and manganese, and
perhaps other trace components. Washing the samples with distilled water causes an
even more extensive release. This rapid solubilization, coupled with sample contamination, may account for much of the variability in concentrations seen over the long
history of reported plankton elemental analyses.
Phytoplankton
9.1
Sampling
Collier and Edmonds [624] warn that, when algae samples are taken from seawater
and the samples are shipped to the laboratory in containers in contact with seawater,
appreciable transfer of the elements occurs from the solid to the liquid phase. Subsequent analysis of the solid could, in these cirmumstances, lead to low analysis in the
solid phase.
One of the first results observed in leaching experiments was the high concentration of many of the elements in the seawater. Elements initially associated with the
algae were released to the seawater during the 2 h it took to bring the samples from
the tow site into the ship's laboratory for processing. This data can be expressed as the
percentage of the estimated total particulate element which had been released to the
seawater by the time of separation of the cadmium, manganese, and nickel. There was
always an initial pulse of copper released, but its concentration then decreased by
some secondary process. The release of zinc, barium, iron, and aluminium was always
low with respect to their total concentrations.
Suspension of the samples in distilled water accelerated the release of nickel,
cadmium, manganese, and phosphorus up to the level of their maximum release into
seawater after 72 h. The implication of this rapid remineralization process must be
considered during the sampling and handling of algal matter by towing, filtration, and
trapping. The rapid release of elements requires careful containment of the sample,
and complete mass balancing from the time of collection, if any systematics of their
chemistry is to be understood. Variations in sampling techniques will result in large
variations in the collected concentrations of nickel, cadmium, and manganese, and
perhaps other trace components. Washing the samples with distilled water causes an
even more extensive release. This rapid solubilization, coupled with sample contamination, may account for much of the variability in concentrations seen over the long
history of reported plankton elemental analyses.