USGS Scientific Investigations Report 2012–5017  - Geomorphic Setting, Aquatic Habitat, and Water-Quality Conditions of the Molalla River, Oregon, 2009

Table 12. Autecological preferences and indicator qualities of algal taxa identified in the Molalla River, Oregon, July and August 2010. 

[Taxa listed in descending order according to the total biovolume for each taxa considering all samples. Autecology from Porter, 2008. Bahls’ pollution tolerance from Bahls (1993). Abbreviations: sp., species; NF, nitrogen fixer; E, eutrophic; M, mesotrophic; ME, meso-eutrophic; O, oligotrophic; AH, always high (~100 percent saturation); FH, fairly high (>75 percent saturation); MOD, moderate (>50 percent saturation); L, LOW (>30 percent saturation); ALK‑P, alkaliphilic (pH >7); ALK-B, alkalibiontic (pH >7); INDIFF, indifferent; CIR, circumneutral (pH ~7); INDIFF, indifferent to pH; FB, fresh-brackish; F, freshwater; BF, brackish-fresh; S, sensitive; LT, less tolerant; VT, very tolerant; –, unknown; ~, approximate; >, greater than] 

Algal taxa	Algal division	Number of samples	Autelogical preference or indicator quality
Algal taxa	Algal division	Number of samples	Nitrogen fixer	Trophic (nutrient indicator)	Dissolved oxygen	pH	Salinity	Bahls’ pollution tolerance
Cymbella affinis	Diatom	9	No	E	AH	ALK-P	FB	S
Synedra ulna	Diatom	8	No	–	MOD	ALK-P	FB	LT
Achnanthes linearis	Diatom	10	No	–	–	CIR	–	S
Achnanthes minutissima	Diatom	10	No	–	AH	INDIFF	FB	S
Gomphonema subclavatum	Diatom	10	No	OM	AH	CIR	FB	LT
Gomphonema angustatum	Diatom	10	No	O	AH	ALK-P	FB	LT
Gomphoneis herculeana	Diatom	2	No	–	–	–	–	S
Cymbella minuta	Diatom	10	No	–	–	CIR	FB	LT
Cymbella cistula	Diatom	3	No	E	FH	ALK-P	FB	S
Cocconeis placentula	Diatom	8	No	E	MOD	ALK-P	FB	S
Fragilaria vaucheriae	Diatom	7	No	E	MOD	ALK-P	FB	LT
Cymbella tumida	Diatom	2	No	ME	AH	ALK-P	FB	S
Gomphonema ventricosum	Diatom	4	No	O	AH	–	F	–
Aphanizomenon flos-aquae	Blue-green	2	Yes	E	–	ALK-B	–	–
Synedra rumpens	Diatom	6	No	–	–	INDIFF	–	LT
Scenedesmus quadricauda	Green	3	No	E	–	ALK-P	–	–
Gomphonema tenellum	Diatom	5	No	–	–	–	–	S
Cymbella sp.	Diatom	3	No	–	–	–	–	–
Nitzschia frustulum	Diatom	4	No	E	MOD	ALK-P	BF	LT
Cymbella sinuata	Diatom	4	No	M	AH	CIR	FB	S
Gomphonema clevei	Diatom	4	No	–	–	–	–	S
Synedra tenera	Diatom	1	No	OM	AH	ALK-P	F	–
Navicula cryptocephala veneta	Diatom	5	No	E	L	ALK-P	BF	LT
Navicula graciloides	Diatom	1	No	E	AH	ALK-B	FB	–
Nitzschia dissipata	Diatom	1	No	ME	FH	ALK-P	FB	S
Nitzschia palea	Diatom	1	No	E	L	CIR	FB	VT
Rhoicosphenia curvata	Diatom	2	No	E	FH	ALK-P	FB	S
Gomphonema olivaceum	Diatom	1	No	E	FH	ALK-B	FB	S
Nitzschia microcephala	Diatom	1	No	E	MOD	ALK-P	FB	VT
Achnanthes hauckiana	Diatom	1	No	–	–	–	–	LT
Ankistrodesmus falcatus	Green	1	No	E	–	ALK-P	–	–
Navicula cryptocephala	Diatom	1	No	–	MOD	ALK-P	FB	S
Navicula decussis	Diatom	1	No	ME	–	ALK-P	FB	S

Geomorphic Setting, Aquatic Habitat, and Water-Quality Conditions of the Molalla River, Oregon, 2009–10

Geomorphic Setting, Aquatic Habitat, and Water-Quality Conditions of the Molalla River, Oregon, 2009–10 