USGS Scientific Investigations Report 2012-5069  - Spatial and Temporal Dynamics of Cyanotoxins and Their Relation to Other Water Quality Variables in Upper Klamath Lake, Oregon, 2007

Table 5. Spearman rank order correlations (r) between microcystin concentrations and other environmental variables, Upper Klamath Lake, Oregon, 2009. 

[Correlations were determined between microcystin concentration and wind speed recorded at site MDL. Water column stability was determined by calculating the relative thermal resistance to mixing (RTRM; see text for explanation) at site MDN on cyanotoxin sample dates. Boldface type indicates significant correlation at p < 0.05; *, indicates p < 0.1. Abbreviations: TN:TP, the ratio of total nitrogen to total phosphorus; DIN, dissolved inorganic nitrogen; DIP, dissolved inorganic phosphorus; DIN:DIP, the ratio of dissolved inorganic nitrogen to dissolved inorganic phosphorus; TPN, total particulate nitrogen; TPP, total particulate phosphorus; TPC, total particulate carbon; TPN:TPP, the ratio of total particulate nitrogen to total particulate phosphorus; <, less than] 

Environmental variable	Dissolved microcystins			Large particulate (cell associated) microcystins			Total microcystins
Environmental variable	Number of samples	Spearman rank order correlation coefficient (r)	p-value  (p)	Number of samples	Spearman rank order correlation coefficient (r)	p-value  (p)	Number of samples	Spearman rank order correlation coefficient (r)	p-value  (p)
Chlorophyll a	14	0.12	0.68	14	0.05	0.84	14	0.05	0.84
Total nitrogen	14	0.30	0.29	14	0.19	0.51	14	0.16	0.56
Total phosphorus	14	0.69	0.01	14	0.63	0.01	14	0.61	0.02
TN:TP	14	–0.73	< 0.01	14	–0.69	0.01	14	–0.69	0.01
DIN	14	0.18	0.53	14	0.13	0.64	14	0.13	0.64
DIP	14	0.53	0.05	14	0.41	0.13	14	0.41	0.14
DIN:DIP	14	–0.55	0.04	14	–0.71	< 0.01	14	–0.70	< 0.01
TPN	12	0.17	0.59	12	0.14	0.65	12	0.11	0.72
TPP	12	0.33	0.28	12	0.46	0.12	12	0.44	0.14
TPC	12	0.14	0.65	12	0.13	0.68	12	0.09	0.77
TPN:TPP	12	–0.46	0.12	12	–0.60	0.04	12	–0.64	0.02
Water temperature	14	–0.08	0.77	14	0.01	0.98	14	0.01	0.95
pH	14	0.33	0.24	14	0.38	0.17	14	0.32	0.26
Dissolved oxygen	14	0.15	0.59	14	0.23	0.42	14	0.23	0.42
Wind speed	14	–0.34	0.23	14	–0.44	0.11	14	–0.48	0.08*
Water column stability at site MDN	14	0.61	0.02	14	0.46	0.09*	14	0.51	0.05

Spatial and Temporal Dynamics of Cyanotoxins and Their Relation to Other Water Quality Variables in Upper Klamath Lake, Oregon, 2007–09

Spatial and Temporal Dynamics of Cyanotoxins and Their Relation to Other Water Quality Variables in Upper Klamath Lake, Oregon, 2007–09 