## 2 Results and Discussion
### Sources and Influencing Factors of T/O Compounds in Freshwater Bodies of the World
#### 2.5.1 Biotic Factors
In certain studies, positive correlations have been established with phycocyanin in specific regions (seven important reservoirs in eastern China [21]), while no correlation was found with _Dolichospermum_ (Dianchi Lake [46] and Lake Yangcheng in China [47]), or a negative correlation was reported (DECL (this study)). MIB exhibited no correlation with _Merismopedia_ in certain contexts (Lake Yangcheng in China [47]). However, positive correlations have been reported with _Phormidium_ in various water bodies (Huangpu River [58], Lake Yangcheng in China [47], raw water from drinking water treatment plants [78], and Lake Kasumigaura [9] and Lake Kasumigaura in Japan [17]), and a positive correlation has been observed with _Lyngbya_ in a specific study (California Aqueduct in the US [24]). In comparison, there has been relatively less extensive research on CYC and ION. Studies such as Taihu Lake [23; 64] and Dianchi Lake in China [46] have shown a positive correlation between Chl-\(a\) and both CYC and ION. Additionally, in Liangxi River [51] and 13 eutrophic lakes in China [48], there was a positive association between Chl-\(a\) and CYC. However, in certain locations, including DECL (this study) and nine sampling sites along the main canal of the Middle Route of South-to-North Water Diversion Project in China [71], CYC did not exhibit a correlation with Chl-\(a\). Similarly, in DECL (this study), Chaohu Lake [22], Songhua Lake [22], Taihu Lake [22], and nine sampling sites along the main canal of the Middle Route of South-to-North Water Diversion Project in China [71], and Lake Skinner in the US [93], and Lake Y in Japan [80]), it exhibited a positive correlation with _Pseudoanabena_. However, it is crucial to note that some studies report scenarios in which no correlation was observed. Furthermore, positive correlations between GSM and other factors, such as _Merismopedia_ (Namhan River in South Korea [18]), _Phormidium_ (Lake Kasumigaura in Japan [9]), _Plankton trix_ (Eagle Creek Reservoir in the US [28]), _Cylindospermopsis rachiorskii_ (Eagle Creek Reservoir in the US [49]), and _Coelosphaerium_ (Lake Shinji in Japan [77]), have been reported in certain studies. For MIB, its relationship with various factors mirrors that of GSM, displaying positive or non-correlative associations with Chl-\(a\), cyanobacteria, _Microystis_, _Pseudoanabena_, _Oscillatoria_, _Plankton trix_, and diatoms. In certain studies, positive correlations have been established with phycocyanin in specific regions (seven important reservoirs in eastern China [21]), while no correlation was found with _Dolichospermum_ (Dianchi Lake [46] and Lake Yangcheng in China [47]), or a negative correlation was reported (DECL (this study)). MIB exhibited no correlation with _Merismopedia_ in certain contexts (Lake Yangcheng in China [47]). However, positive correlations have been reported with _Phormidium_ in various water bodies (Huangpu River [58], Lake Yangcheng in China [47], raw water from drinking water treatment plants [78], and Lake Kasumigaura [9] and Lake Kasumigaura in Japan [17]), and a positive correlation has been observed with _Lyngbya_ in a specific study (California Aqueduct in the US [24]). In comparison, there has been relatively less extensive research on CYC and ION. Studies such as Taihu Lake [23; 64] and Dianchi Lake in China [46] have shown a positive correlation between Chl-\(a\) and both CYC and ION. Additionally, in Liangxi River [51] and 13 eutrophic lakes in China [48], there was a positive association between Chl-\(a\) and CYC. However, in certain locations, including DECL (this study) and nine sampling sites along the main canal of the Middle Route of South-to-North Water Diversion Project in China [71], CYC did not exhibit a correlation with Chl-\(a\).