TABLE 2.

Data from cross-inoculation of ammonia oxidizers enriched in either high- or low-ammonium medium into the other medium

Time of collection and type of sample	Low-NH4+ medium to high-NH4+ medium			High-NH4+ medium to low-NH4+ medium
	Nitrificationa	Hybridization signalb in:		Nitrification	Hybridization signal in:
		Original	Subculture		Original	Subculture
July
Lake water	−	Nm+	−	ND	ND	ND
Littoral sediment	−	ND	ND	+	Ns++	Ns+
				−	Nm+++	Nm+
Profundal sediment	−	Ns+	−	−	Ns+	ND
					Nm++
November
Lake water	−	Nm+	−	+	Ns+++	Ns+
Littoral sediment	−	Ns+	−	+	Ns+	Nm++
		Nm+			Nm++
Profundal sediment	−	Nm+	−	+	Ns+	Nm+
					Nm++

^aNitrification is indicated to have ceased (−) or continued (+) after inoculation into the contrasting medium. 

^bOrganisms continuing to nitrify in culture were identified by genus-specific oligonucleotide probing. Hybridization signal: +, weak; ++, moderate; +++, strong; Ns, Nitrosospira; Nm, Nitrosomonas.