| Title |
Suggestion for Trophic State Classification of Korean Lakes |
| Authors |
공동수 ( Dongsoo Kong ) ; 김범철 ( Bomchul Kim ) |
| DOI |
https://doi.org/10.15681/KSWE.2019.35.3.248 |
| Keywords |
Eutrophication; Phosphorus; Secchi depth; Trophic state classification; Water quality |
| Abstract |
Most of the lakes in Korea are artificial, and their limnological characteristics are significantly different from those of natural lakes in other countries. In this study, the relationship between trophic state parameters was investigated, based on summer average data of the upper layer, in 81 lakes in Korea , 2013-2017. Compared with trends of foreign natural lakes, chlorophyll α (Chl.α) concentration was slightly lower at the same total phosphorus (TP) concentration, and transparency (Secchi depth, SD) was noticeably lower at the same Chl.α concentration. This is because of excessive allochthonous loading of non-algal material during the monsoon period, and the reduction in phosphorus availability to algal growth, by light limitation and short hydraulic residence time. Considering these characteristics, we suggested site-specific thresholds of trophic state classification for Chl.α, TP and SD, based on annual average data at the upper layer of lakes (3-10 μg L-1 of Chl.α measured by UNESCO method; 13-33 μg L-1 of TP; 1.6-3.2 m of SD for mesotrophic state class, respectively). The threshold value of TP for each trophic state class, corresponded to the upper value of previously reported range, and that of SD was out of the range. We suggested applying only TP and Chl.α in assessment of trophic state of lakes in Korea, excluding SD. |