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 4. Spearman rank order correlations (r) between microcystin concentrations and other environmental variables, Upper Klamath Lake, Oregon, 2007–09. 

[Data from only sites MDN and WMR were used in the analysis. Correlations with total and dissolved microcystin concentrations include only 2008 and 2009 data. Dissolved microcystin concentrations were not measured in 2007. Chlorophyll a data collected in 2007 were of poor quality and not reported. Boldface type indicates significant correlation at p < 0.05; * indicates p < 0.1. Abbreviations: TN:TP, the ratio of total nitrogen to total phosphorus; DIP, dissolved inorganic phosphorus; DIN, dissolved inorganic nitrogen; DIN:DIP, the ratio of dissolved inorganic nitrogen to dissolved inorganic 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	24	0.19	0.36	24	0.09	0.66	24	0.17	0.42
Total nitrogen	24	0.19	0.35	32	0.11	0.56	24	0.03	0.90
Total phosphorus	24	0.18	0.38	32	0.30	0.09*	24	0.13	0.53
TN:TP	24	–0.19	0.37	32	–0.52	0.01	24	–0.31	0.14
DIP	24	0.16	0.45	32	0.43	0.01	24	0.18	0.39
DIN	24	0.04	0.86	32	–0.14	0.45	24	–0.15	0.49
DIN:DIP	24	–0.23	0.28	32	–0.61	<0.01	24	–0.43	0.04
Water temperature	24	–0.27	0.19	32	–0.05	0.77	24	–0.38	0.07*
pH	24	0.27	0.19	32	0.40	0.02	24	0.33	0.12
Dissolved oxygen concentration	24	0.16	0.45	32	0.30	0.09*	24	0.33	0.12
Wind speed	24	–0.18	0.40	32	–0.08	0.64	24	–0.22	0.30
Water column stability at site MDN	24	0.53	0.01	32	0.38	0.03	24	0.39	0.06*

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 