TABLE 2.

Concentration of bacteria by tangential flow filtration^a

Sample	Seawater		Bacteria			% of bacteria recovered in:
	Initial vol (liters)	Concn factor	Initial no. (105 ml−1)	No. in retentate (107 ml−1)	Concn factor	Retentateb	Permeatec	Retentate + permeated	Ultraconcentrated samplee
Oceanic
Southern (south)	95	103	2.7	0.39	14	14	32	46	11
Southern (north)	300	268	5.7	13	225	84	12	96	16
Subtropical Pacific (south)	448	446	5.3	1.3	24	5.3	7.3	13	4
Subtropical Pacific (north)	550	546	5.8	1.8	31	5.6	68	74	1
Equatorial Pacific	634	649	7.6	9.6	126	19	51	70	9
Transitional north Pacific	320	307	5.0	0.69	14	4.5	NDf	ND	3
Coastal
Tokyo Bayg	50	95	49	11	21	22	31	53	18
Otsuchi Bay
2 June 1995	140	157	14	19	131	83	0.02	83	26
5 June 1995	190	110	14	12	88	43	0.03	43	23
17 May 1996	95	88	12	0.84	6.9	7.8	1.5	9.3	2
20 May 1996	100	98	7.0	0.89	13	14	1.8	16	2

^aBacterial cell abundances in prefiltered seawater (initial), the concentrated fraction (retentate), and the filtrate fraction (permeate) are compared. 

^b(Total number of cells in retentate/total number of cells in prefiltered seawater) × 100. 

^c(Total number of cells in permeate/total number of cells in prefiltered seawater) × 100. 

^d[(Total number of cells in retentate + total number of cells in permeate)/total number of cells in prefiltered seawater] × 100. 

^e(Total number of cells in the concentrate used for measuring carbon and nitrogen/total number of cells in raw seawater) × 100. 

^fND, not determined. 

^gA hollow-fiber cartridge filtration system was used to concentrate bacteria.