A regularity in trace element contents of marine zooplankton species

Four zooplankton species, three Arthropoda and one Chaetognata, from the Sea of Japan were analyzed in 1984 for eight major and fifteen trace elements, mainly by instrumental neutron activation analysis. Major and trace element contents on a dry weight basis varied little within a factor of 3.7, except for Ca (a factor of 5.7) among the four species. A log-log linearity with a slope of almost-1 was observed between mean oceanic residence time calculated from the mean dissolved river-water input _R and the concentration factor with respect to mean seawater concentration (CF _SW )for each species. The products of _R and CF _SW were nearly constant within a factor of 10, except for Br and Sb over seven orders of variation of CF _SW for each zooplankton species. It demonstrates a new regularity in trace element contents of marine zooplankton species. This relationship leads to the conclusion that the concentration factors of elements for these zooplankton species with respect to elements for these zooplankton species with respect to mean dissolved river-water concentration (CF _RW )are nearly constant within a factor of 10 with average values of 2.98 to 3.43 in logarithm.