Authors
Ryuji Kondo, Misaki Momoki, Makina Yamamoto, Atsushi Kaneda
A 2-year study was designed to investigate the spatiotemporal distribution of sulphide in the water column of a saline lake, Lake Hiruga in Fukui, Japan. Water samples were collected in Lake Hiruga periodically between April 2014 and March 2016 at appropriate depths with simultaneous in situ measurements of physicochemical parameters such as temperature, salinity and dissolved oxygen (DO) concentration. Sulphide started accumulating in the hypolimnion in September 2014, whilst that did in June 2015. The sulphide concentrations increased toward the end of December in both 2014 and 2015. Then the sulphide disappeared from the hypolimnion in April 2015 and February 2016. The difference in starting season of the sulphide accumulation was closely connected with DO concentrations in the hypolimnion in circulation periods of winter season. The DO concentrations were regulated by water column stability before thermal stratification periods. Our analysis of the sulphide distribution for the 2 years of the study suggested that accumulation of sulphide in the hypolimnion during stratified periods appears to be associated with strength of water column stability in the winter-spring seasons before stagnant periods in Lake Hiruga.
Freshwater Ecology 