220
A. B. kONXY
B. Effects of various contaminants on seaweeds
1. Sewage and oil pollution
It is well known that coastal waters are richer in plant nutrients
than the open sea due to land drainage and disposal of sewage from
large population centres. The rank growth of UZva plants, with thicker
fronds and high nitrogen content, in the vicinity of sewage outfalls in
the Belfast Lough was described many years ago by Cotton (1910), but
there are indications from work in recent years that sewage and industrial waste can prove harmful to marine algae. Thus Katayama and
Fujiyama (1957) reported that Porphyra plants in laver fields in the
sea off Fukuyama developed a tumour-like growth (or crown gall) in
heavily polluted waters during December and January. I n clearer
waters onset of the disease was delayed by one or two months. Analysis
showed that severity of tumour growth could be correlated with
increase in the DNA content of the thallus. Whilst no specific cause was
mentioned, the effect was attributed to toxic effluents. A similar report
from Tokyo Bay described a cancer disease of the Porphyra fronds with
abnormally swollen cells and gall-like growths. This, together with a
chytrid infection, appreciably lowered the " nori " yield in the subsequent harvest (Arasaki et al., 1960). Polluted harbour water appears
to have a harmful effect on Chondrus crispus (Grenager, 1957), although
Porphyra perforata (Kylin) appears to favour polluted waters during
winter and spring (Denmark, Holland, German Baltic, Nice; Den
Hartog, 1964). Qigartina forms richer growths where sewers enter the
sea on Great Cumbrae, Scotland (Marshall et al., 1949). Fuel oil
contamination has a distinctly harmful effect, and harvestable crops of
Gigartina and Chondrus were reported to be ruined on shores in the
sheltered waters of Plymouth Sound, and in certain localities on the
west coast of Scotland both oil and tar pollution of Bigartim beds was
reported (Marshall et al., 1949).
Marked reduction in the Hacrocystis population near sewage
outfalls has been reported from California (North, 1964). This was
attributed either to toxic effluents, or to the greater turbidity of the
water cutting down submarine illumination to the extent that growth
of the giant kelp could not keep pace with the browsing action of
associated animals. By enclosing young Macrocystis plants in wire
cages (l-cm mesh), and removing the " browsing " pressure the plants
were able to grow successfully in the vicinity of the sewage outfall.
Clearly not all sewage effluents are harmful, but with edible products
there will be obvious concern for both the hygienic condition and
appearance of the product.
A. B. kONXY
B. Effects of various contaminants on seaweeds
1. Sewage and oil pollution
It is well known that coastal waters are richer in plant nutrients
than the open sea due to land drainage and disposal of sewage from
large population centres. The rank growth of UZva plants, with thicker
fronds and high nitrogen content, in the vicinity of sewage outfalls in
the Belfast Lough was described many years ago by Cotton (1910), but
there are indications from work in recent years that sewage and industrial waste can prove harmful to marine algae. Thus Katayama and
Fujiyama (1957) reported that Porphyra plants in laver fields in the
sea off Fukuyama developed a tumour-like growth (or crown gall) in
heavily polluted waters during December and January. I n clearer
waters onset of the disease was delayed by one or two months. Analysis
showed that severity of tumour growth could be correlated with
increase in the DNA content of the thallus. Whilst no specific cause was
mentioned, the effect was attributed to toxic effluents. A similar report
from Tokyo Bay described a cancer disease of the Porphyra fronds with
abnormally swollen cells and gall-like growths. This, together with a
chytrid infection, appreciably lowered the " nori " yield in the subsequent harvest (Arasaki et al., 1960). Polluted harbour water appears
to have a harmful effect on Chondrus crispus (Grenager, 1957), although
Porphyra perforata (Kylin) appears to favour polluted waters during
winter and spring (Denmark, Holland, German Baltic, Nice; Den
Hartog, 1964). Qigartina forms richer growths where sewers enter the
sea on Great Cumbrae, Scotland (Marshall et al., 1949). Fuel oil
contamination has a distinctly harmful effect, and harvestable crops of
Gigartina and Chondrus were reported to be ruined on shores in the
sheltered waters of Plymouth Sound, and in certain localities on the
west coast of Scotland both oil and tar pollution of Bigartim beds was
reported (Marshall et al., 1949).
Marked reduction in the Hacrocystis population near sewage
outfalls has been reported from California (North, 1964). This was
attributed either to toxic effluents, or to the greater turbidity of the
water cutting down submarine illumination to the extent that growth
of the giant kelp could not keep pace with the browsing action of
associated animals. By enclosing young Macrocystis plants in wire
cages (l-cm mesh), and removing the " browsing " pressure the plants
were able to grow successfully in the vicinity of the sewage outfall.
Clearly not all sewage effluents are harmful, but with edible products
there will be obvious concern for both the hygienic condition and
appearance of the product.