Characteristic of variations of C:N:P:Chl ratios of seston in eutrophic shallow Lake Kasumigaura

Abstract

The ratios of C/P, N/P and Chl/P abruptly fluctuated at each station throughout the years. The ranges of these ratios were 13-129 in C/P, 1.9-18.9 in N/P, and 0.2-2.4 in Chl/P. Average ratios increased from the inner part of bays to the central part of the lake. High Chl/P ratios were observed in the range of high N/P ratio and in the range from 40-150μg l-1 of chlorophyll a concentration. Average C/P, N/P and C/N ratio were 39-69, 6.5-10.2 and 6.1-6.9 at each station, respectively. Only the C/P ratio indicated a moderate P deficiency as an average through the years, especially in the central part of the lake. The C/N ratio was frequently ↔7.7 in spring and summer, indicating a moderate N deficiency in these seasons in this lake. -from Authors