BIOLOQY OF SEAWEEDS OF ECONOMIC IMPORTANUE
221
2. Toxic chemicals
Whilst marine algae are known to accumulate trace elements to a
considerable degree there is, nevertheless, some evidence that
harmful elements may be assimilated. For example, the arsenic content
of dried Popphyra was found to be at a higher level in culture fields
where there was contamination from industrial effluents (Kawmhiro
et al., 1961). Certain aspects of the metabolism of Porphyra tenera
were adversely influenced by low concentrations of industrial waste,
e.g. " black liquor " from pulp mills, waste from distilleries, resinous
wastes (Tsuruga, 1963b) ; these effects were more noticeable in shallow
inshore waters. The possibility that certain herbicides may prove
harmful on draining into the sea must a€so be borne in mind (Boney,
1963), although experiments with low concentrations of pentachlorophenate, a herbicide used in paddy fields, when measured in terms of
appearance showed the enzyme activity and phosphorus metabolism
of the Conchmelie-phase of Popphyra to be less sensitive than those of
certain inshore fish (Tomiyama et al., 1962).
3. Radioactive elements in sea water
The fact that there may be an increase in the quantity of radioactive material in the sea due to disposal of waste, and as a, result of
fall-out from atomic explosions, is clearly a problem affecting seaweed
industries concerned with edible products. .Studies on the uptake of
radioactive elements by seaweeds can be considered from two aspects:
those concerned with the uptake of material in natural habitats, and
studies which are linked with the metabolic utilization of labelled
compounds. The latter have also rendered information of value for
work on seaweeds of economic importance. Palumbo (1969) reported
the gross beta radioactivity of the marine algae at Eniwetok Atoll
(during 1964-66), and showed that the highest levels of radioaotivity
were recorded in plants collected from shores of islands closest to the site
of the test detonation and in the downwind path of the fallout. Both
the algae and the bottom sand retained more radioactivity than the
surface waters, and the algae tended to absorb isotopes with the longer
half-lives. Akamsin et al. (1960) observed that Cystoseira barbata
accumulated appreciable quantities of nakural radioactivity from the
surrounding medium, and suggested its use as an indicator of the
quantities of artificial radioactivity in sea water. Subsequently
Polikarpov (1961) measured the uptake of strontium-90, caesium-137
and cerium-144 by Cystoseira barbata and the rate of loss of these isotopes
when the thalli disintegrated in the sea. Work on various aspects of
this problem has also been carried out in Japan. Thus Tsuruga and
221
2. Toxic chemicals
Whilst marine algae are known to accumulate trace elements to a
considerable degree there is, nevertheless, some evidence that
harmful elements may be assimilated. For example, the arsenic content
of dried Popphyra was found to be at a higher level in culture fields
where there was contamination from industrial effluents (Kawmhiro
et al., 1961). Certain aspects of the metabolism of Porphyra tenera
were adversely influenced by low concentrations of industrial waste,
e.g. " black liquor " from pulp mills, waste from distilleries, resinous
wastes (Tsuruga, 1963b) ; these effects were more noticeable in shallow
inshore waters. The possibility that certain herbicides may prove
harmful on draining into the sea must a€so be borne in mind (Boney,
1963), although experiments with low concentrations of pentachlorophenate, a herbicide used in paddy fields, when measured in terms of
appearance showed the enzyme activity and phosphorus metabolism
of the Conchmelie-phase of Popphyra to be less sensitive than those of
certain inshore fish (Tomiyama et al., 1962).
3. Radioactive elements in sea water
The fact that there may be an increase in the quantity of radioactive material in the sea due to disposal of waste, and as a, result of
fall-out from atomic explosions, is clearly a problem affecting seaweed
industries concerned with edible products. .Studies on the uptake of
radioactive elements by seaweeds can be considered from two aspects:
those concerned with the uptake of material in natural habitats, and
studies which are linked with the metabolic utilization of labelled
compounds. The latter have also rendered information of value for
work on seaweeds of economic importance. Palumbo (1969) reported
the gross beta radioactivity of the marine algae at Eniwetok Atoll
(during 1964-66), and showed that the highest levels of radioaotivity
were recorded in plants collected from shores of islands closest to the site
of the test detonation and in the downwind path of the fallout. Both
the algae and the bottom sand retained more radioactivity than the
surface waters, and the algae tended to absorb isotopes with the longer
half-lives. Akamsin et al. (1960) observed that Cystoseira barbata
accumulated appreciable quantities of nakural radioactivity from the
surrounding medium, and suggested its use as an indicator of the
quantities of artificial radioactivity in sea water. Subsequently
Polikarpov (1961) measured the uptake of strontium-90, caesium-137
and cerium-144 by Cystoseira barbata and the rate of loss of these isotopes
when the thalli disintegrated in the sea. Work on various aspects of
this problem has also been carried out in Japan. Thus Tsuruga and