202
THE BIOLOGY OF EUPHAUSIIDS
tin, 3-5 ; barium, 30-50. An approximate conversion of these results
t o mg/100 g dry weight can be made by dividing them by a factor of
10 and comparing them then to the data in Table X suggests that
Vinogradova’s results for sodium may be low while her result for
strontium, as she remarks, is high.
Some interest is attached to a closely related field of investigation,
that is of the levels of radioisotopes occurring in euphausiids in the
oceans of the world, because, as we shall discuss later, the animals
occupy a most important position in the marine food chains. Radioisotopes of elements such as potassium and rubidium and those of the
thorium, uranium, and radium decay series occur naturally in the
marine environment. Others, however, have been and are being
introduced into the oceans by man either in the form of radioactive
effluents from industries or as fallout material from weapons’ testing
(Mauchline and Templeton, 1964). The fission products Zrg5-Nbg5,
Io3Ru, 137Cs, and 141Ce have been detected in Euphausia pacifica off
the coast of Oregon (Osterberg, 1962 ; Osterberg et al., 1964b). These
elements are not important in the metabolism of marine animals and
so their accumulation is incidental. Zinc-65, an element with metabolic
significance, however, also occurs in E . pacifica off the coast of Oregon
(Osterberg et al., 1964a). The 65Zn originates from the nuclear reactor
operations a t Hanford, Washington, the effluent liquors being discharged down the Columbia River and so into the Pacific Ocean. The
above authors were able to determine the path of dispersion of this
effluent in the sea area off the Oregon coast by comparing the levels of
65Zn in E . pacifica from different sea areas. Further interpretation of
these results is difficult because of the lack of knowledge of the distribution of stable zinc in euphausiids. Radioactive strontium,
originating from fallout from weapons’ testing has been detected in
E . pacifica in the western Pacific by Fukai et al. (1962). Strontium
behaves chemically like calcium but usually the biochemical system of
the organism discriminates against it in favour of calcium. Mauchline
and Templeton (1966) have investigated the levels of strontium and
calcium in organisms from the Irish Sea and shown that the Sr/Ca
atom ratio x 1000 is 5.6 in Leander serratus (=Palaernon serratus
(Pennant)) and 5-7 in Crangon vulgaris (C. crangon (L.)). These are
the only two crustaceans, comparable to euphausiids, which were
analysed. The ratios derived from the results in Table X are 5.5 for
Meganyctiphanes norvegica and 2.3 for Euphausia pacifica. The
comparable ratio in sea water is about 9 and this means that euphausiids, like other crustaceans, discriminate against strontium in favour
of calcium.
THE BIOLOGY OF EUPHAUSIIDS
tin, 3-5 ; barium, 30-50. An approximate conversion of these results
t o mg/100 g dry weight can be made by dividing them by a factor of
10 and comparing them then to the data in Table X suggests that
Vinogradova’s results for sodium may be low while her result for
strontium, as she remarks, is high.
Some interest is attached to a closely related field of investigation,
that is of the levels of radioisotopes occurring in euphausiids in the
oceans of the world, because, as we shall discuss later, the animals
occupy a most important position in the marine food chains. Radioisotopes of elements such as potassium and rubidium and those of the
thorium, uranium, and radium decay series occur naturally in the
marine environment. Others, however, have been and are being
introduced into the oceans by man either in the form of radioactive
effluents from industries or as fallout material from weapons’ testing
(Mauchline and Templeton, 1964). The fission products Zrg5-Nbg5,
Io3Ru, 137Cs, and 141Ce have been detected in Euphausia pacifica off
the coast of Oregon (Osterberg, 1962 ; Osterberg et al., 1964b). These
elements are not important in the metabolism of marine animals and
so their accumulation is incidental. Zinc-65, an element with metabolic
significance, however, also occurs in E . pacifica off the coast of Oregon
(Osterberg et al., 1964a). The 65Zn originates from the nuclear reactor
operations a t Hanford, Washington, the effluent liquors being discharged down the Columbia River and so into the Pacific Ocean. The
above authors were able to determine the path of dispersion of this
effluent in the sea area off the Oregon coast by comparing the levels of
65Zn in E . pacifica from different sea areas. Further interpretation of
these results is difficult because of the lack of knowledge of the distribution of stable zinc in euphausiids. Radioactive strontium,
originating from fallout from weapons’ testing has been detected in
E . pacifica in the western Pacific by Fukai et al. (1962). Strontium
behaves chemically like calcium but usually the biochemical system of
the organism discriminates against it in favour of calcium. Mauchline
and Templeton (1966) have investigated the levels of strontium and
calcium in organisms from the Irish Sea and shown that the Sr/Ca
atom ratio x 1000 is 5.6 in Leander serratus (=Palaernon serratus
(Pennant)) and 5-7 in Crangon vulgaris (C. crangon (L.)). These are
the only two crustaceans, comparable to euphausiids, which were
analysed. The ratios derived from the results in Table X are 5.5 for
Meganyctiphanes norvegica and 2.3 for Euphausia pacifica. The
comparable ratio in sea water is about 9 and this means that euphausiids, like other crustaceans, discriminate against strontium in favour
of calcium.